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Seawater samples were collected from the euphotic zone of the Sargasso Sea near Bermuda in August of 1989 and March–April of 1990. Microbial population abundances, chlorophyll concentration, particulate carbon and particulate nitrogen were measured. Calculations were performed to establish the relative and absolute importance of the various microbial assemblages. The choice of conversion factors (g C and N cell −1 , or g C and N μm −3 ) for the microbial populations dramatically affected the estimation of “living” and “detrital” particulate material in the samples, and the relative importance of the various microbial groups. Averaged over all samples on either of the two cruises, microbial biomass constituted a greater proportion of the total particulate carbon and nitrogen during March–April (55% and 63%, respectively), than during August (≈24% and 30%, respectively) using “constrained” conversion factors that were derived. Accordingly, detrital material constituted the bulk of the particulate material during August, but was similar to the amount of microbial biomass during March–April. The bacterial assemblage constituted the largest single pool of microbial carbon (35%) and nitrogen (45%) in the water, and a significant fraction of the total particulate carbon (≈10–20%) and nitrogen (≈15–30%). Phototrophic nanoplankton (microalgae 2–20 μm in size) were second in overall biomass, and often dominated the microbial biomass in the deep chlorophyll maxima that were present during both cruises. The results temper recent assertions concerning the overwhelming importance of bacterial biomass in the oligotrophic Sargasso Sea but still support a major role for these microorganisms in the open ocean as repositories for carbon and nutrients. | Phototrophic and heterotrophic nanoplankton (PNAN, HNAN; 2–20mm protists) and microplankton (PMIC, HMIC; 20–200mm protists and micrometazoa) are major taxa involved in partitioning carbon and energy within the pelagic food web. In the Ross Sea, Antarctica, plankton biomass appears to be controlled by the seasonal recession ofthe sea ice and the f ofthe Ross Sea polynya during the short austral spring-summer period. During four cruises in 1996–1997 within the southern Ross Sea as part of the US JGOFS program, we determined the abundances and biomasses ofphototrophic and heterotrophic nanoplankton and microplankton primarily along a transect at 76130 0 S. The colonial prymnesiophyte Phaeocystis antarctica (excluding mucus carbon) contributed significantly to community structure during both non-bloom and bloom periods (B25% and 90%, respectively, ofmicrobial biomass). However, shif ts occurred both seasonally and spatially between a diatom/heterotrophic dinoflagellate and a colonial P. antarctica-dominated assemblage. While nanoplankton biomass varied o50% during any particular cruise, PNAN and HNAN biomass ranged more than three orders ofmagnitude among the f our cruises (0.1–359 and 1.5–268 mmol C m � 2 , respectively). Cruise averages ofPMIC biomass ranged f rom 2.5 to 530 mmol C m � 2 , and a maximum biomass of1530 mmol C m � 2 was observed during the bloom ofcolonial P. antarctica in summer. Average heterotrophic biomass was o30% ofthe total microbial biomass (excluding bacteria) from early austral spring through summer. This value rose to E87% in autumn following the decline and disappearance of P. antarctica. The contribution oftotal nano- and microplankton biomass to POC in the upper 60 m over the three sampled seasons varied from 7% to 52.4% with an overall average of 21.8% for all four cruises which is comparable to contributions of these assemblages in other oceans even with the strong seasonal dominance of P. antarctica. r 2001 Elsevier Science Ltd. All rights reserved. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 18,900 |
SYNOPSIS. The foraminifer Rosalina floridana builds a chambered, calcareous test which is periodically enlarged by the addition of new chambers. R. floridana begins to form a chamber by constructing an algal growth cyst which covers the dorsal side of the animal and is cemented to the substrate. The pseudopods that build the cyst coalesce to form a cytoplasmic template or anlage on which the chamber walls will be secreted. Electron micrographs reveal the anlage cytoplasm to be a “froth” of nearly empty vesicles which contain mitochondria, fibrillar material, and electron dense granules. The organic lining of the new chamber is secreted on the anlage by pseudopods extending thru it. After the organic lining is completed, cytoplasm from within the test flows into the forming chamber and forces the anlage cytoplasm out thru the new aperture. This “frothy” anlage cytoplasm forms a sheath over the dorsal surface of the test; while it is in place, a layer of calcite is deposited on the walls of the new chamber and over the rest of the test. When calcification is completed, the sheath breaks up and is incorporated into newly formed pseudopods as the foraminifer gradually moves out of the growth cyst and begins normal feeding. ::: ::: ::: ::: The production of vesiculated cytoplasm in normal pseudopods and in the anlage is viewed as a method of greatly increasing cytoplasmic volume with a resultant very small loss in cytoplasmic mass. In the anlage during the production of the organic lining the vesiculated cytoplasm apparently acts only as a support for the membranes being secreted by the pseudopods and presumably does not take part in the secretory process. This same cytoplasm forms the sheath that is present during calcification. The view is advanced that, altho the sheath could be active during calcification with the mitochondria within the vesicles actively transporting calcium to sites of crystal growth, its more probable function is to form a partition between the parts to be calcified and the environment. The foraminifer could then secrete CaCO3 from pooled reserves in the cytoplasm into the area between the sheath and the chamber membranes. The basal membrane is considered the nucleating agent during calcification and is responsible for the ordering of the crystals so their C axes are perpendicular to the surface of the chamber. | Ocean acidification (OA) can have adverse effects on marine calcifiers. Yet, phototrophic marine calcifiers elevate their external oxygen and pH microenvironment in daylight, through the uptake of dissolved inorganic carbon (DIC) by photosynthesis. We studied to which extent pH elevation within their microenvironments in daylight can counteract ambient seawater pH reductions, i.e. OA conditions. We measured the O(2) and pH microenvironment of four photosymbiotic and two symbiont-free benthic tropical foraminiferal species at three different OA treatments (~432, 1141 and 2151 µatm pCO(2)). The O(2) concentration difference between the seawater and the test surface (ΔO(2)) was taken as a measure for the photosynthetic rate. Our results showed that O(2) and pH levels were significantly higher on photosymbiotic foraminiferal surfaces in light than in dark conditions, and than on surfaces of symbiont-free foraminifera. Rates of photosynthesis at saturated light conditions did not change significantly between OA treatments (except in individuals that exhibited symbiont loss, i.e. bleaching, at elevated pCO(2)). The pH at the cell surface decreased during incubations at elevated pCO(2), also during light incubations. Photosynthesis increased the surface pH but this increase was insufficient to compensate for ambient seawater pH decreases. We thus conclude that photosynthesis does only partly protect symbiont bearing foraminifera against OA. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 18,901 |
Plankton distributions are frequently patchy and phytoplankton patches have long been suggested as important resources in otherwise nutritionally dilute environments. The present study confirms this hypothesis empirically in a coastal fjord with naturally forming phytoplankton patches and examines the implications for plankton distributions, abundance and rates of patch formation, maintenance and decline. Phytoplankton patches were identified using a CTD mounted fluorometer and sampled with a horizontally mounted 2 l Niskin bottle in 3 separate field seasons in summer 2007 and 2008 and spring 2009. We quantified chl a and macronutrient concentrations as well as phyto- plankton growth and zooplankton (<200 µm) grazing rates. Average phytoplankton growth was equal inside and outside of patches (0.34 ± 0.07 d -1 ) and there was no indication of nutrient limitation to phytoplankton growth. Average grazing rate inside patches (0.25 ± 0.03 d -1 ) was significantly higher than outside of patches (0.09 ± 0.03 d -1 ). Grazing pressure was not simply a function of prey availability; there was no significant relationship between grazing rate and initial chl a concentration. Protistan grazing consumed on average 65% of primary production within and 26% outside of patches. Model predictions of population dynamics suggest that protistan grazing focused within patches and more rapid phytoplankton accumulation outside of patches eroded layer structures within hours to days. Formation of plankton patches due to phytoplankton growth was not supported by the data. Averaging rates, irrespective of phytoplankton distribution, greatly overestimated layer persistence and minimally underestimated primary production and its availability to higher trophic levels. These results emphasize empirically the importance of predator-prey interactions to the ubiq- uitous phenomenon of plankton patchiness and ultimately microbial food web dynamics. | Using multidisciplinary observations from regional- to small-scale, we examined the development of thin phytoplankton layers in water mass frontal zones of a coastal upwelling system. Two fronts developed successively in the same region of Monterey Bay, California, USA, during August and September 2003: (1) when warm, fresh offshore waters flowed into the bay following relaxation and reversal of upwelling favorable winds, and (2) when a cold upwelling filament flowed into the bay after upwelling favorable winds resumed. Thin phytoplankton layers were observed dur- ing the presence of both fronts. The layers exhibited peaks in chlorophyll fluorescence and optical backscattering, indicating biomass maxima in the layers. Maximum chlorophyll concentrations in the layers ranged from 11 to 37 µg l -1 and were 4 to 55 times greater than background levels. Layer ver- tical thickness ranged from 1 to 5 m, averaging 2.3 m. All thin layers were in the thermocline, near the 12.5°C isotherm, and the depth of the layers varied between 12 and 33 m, in parallel with varia- tions in thermocline depth. Synoptic mapping of the first frontal zone shortly before the thin layers developed showed strong phytoplankton patchiness. The role of vertical shear in thin layer formation from phytoplankton patches is supported by multiple results: (1) most thin layers (92%) were associ- ated with sharp changes in the direction of horizontal currents; (2) layer thickness was significantly (p < 0.03) negatively correlated with shear; (3) the median shear profile, computed from all thin layer velocity profiles, peaked sharply at the center of thin layers. | An electronically steerable parasitic array radiator antenna is presented. The antenna has only a single element connected to a receiver or a transmitter. This active element is surrounded by parasitic elements loaded with variable reactors (varactors). The loaded reactance and the length of the parasitic radiators are designed so that each of the parasitic elements plays its role of director or reflector depending on its bias voltage on the loaded reactance. This design guarantees that the radiation pattern can be controlled by changing the bias voltages on the varactors. For omnipattern forming, a voltage vector is obtained such that the received power is maximised under the assumption that each component of the voltage vector is equal. An experiment yields an omnipattern with an average −0.83 dBi gain over the angles [0°, 360°). For sector pattern forming, a single-source power maximisation technique is proposed to optimise the voltage vector such that the received signal power is as large as possible in the direction of the source. Experiments yield twelve sector patterns at every 30°. The average gain is 5.5 dBi in the patterns' beam directions. The average 3 dB beamwidth is 72.4° for the sector patterns in the directions 0°, 60°, 120°, 180°, 240°, and 300°, while the average value is 90.1° for the remaining patterns. | eng_Latn | 18,902 |
Mammillaria gaumeri, an endemic cactus from Yucatan, is threatened due to human-mediated habitat fragmentation but knowledge regarding factors that would inform management plans is limited, including information on optimal microhabitats and growth. We studied seasonal patterns of microclimate, net CO2 uptake and growth of adult individuals during the dry, rainy and northwind (late fall to winter) seasons in separate populations located in a coastal dune and in a dry forest. To provide an assay of primary productivity, we measured the production of new axillary buds (areoles) from the apex. We found that patterns of net CO2 uptake in the three seasons were consistent with obligate crassulacean acid metabolism. The reduction in soil water potential and the increase in water vapor pressure deficit led to a reduction in 24-h net CO2 uptake from 18.0 to 1.3 mmol C02/m2, after 30 d of drought. Dry-weight gain was maximal during the rainy season and there was no growth during the dry season, thus seasonal patterns of net CO2 uptake and growth for M. gaumeri reflected soil and atmospheric water contents. Annual dry-weight gain increased linearly with plant size and with total daily photosynthetic photon flux density (PPFD) up to 80 percent of ambient. Maximal growth was in exposed microhabitats receiving 60-80 percent of total ambient PPFD. We hypothesize that low-magnitude disturbances, resulting in more exposed microhabitats, might be beneficial for growth and conservation of adult individuals of this rare species. | Expression of crassulacean acid metabolism (CAM) is characterized by extreme variability within and between taxa and its sensitivity to environmental variation. In this study, we determined seasonal fluctuations in CAM photosynthesis with measurements of nocturnal tissue acidification and carbon isotopic composition (δ13C) of bulk tissue and extracted sugars in three plant communities along a precipitation gradient (500, 700, and 1,000 mm year−1) on the Yucatan Peninsula. We also related the degree of CAM to light habitat and relative abundance of species in the three sites. For all species, the greatest tissue acid accumulation occurred during the rainy season. In the 500 mm site, tissue acidification was greater for the species growing at 30% of daily total photon flux density (PFD) than species growing at 80% PFD. Whereas in the two wetter sites, the species growing at 80% total PFD had greater tissue acidification. All species had values of bulk tissue δ13C less negative than −20‰, indicating strong CAM activity. The bulk tissue δ13C values in plants from the 500 mm site were 2‰ less negative than in plants from the wetter sites, and the only species growing in the three communities, Acanthocereus tetragonus (Cactaceae), showed a significant negative relationship between both bulk tissue and sugar δ13C values and annual rainfall, consistent with greater CO2 assimilation through the CAM pathway with decreasing water availability. Overall, variation in the use of CAM photosynthesis was related to water and light availability and CAM appeared to be more ecologically important in the tropical dry forests than in the coastal dune. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 18,903 |
The vertical and horizontal distribution of the cyanobacterium, Planktothrix rubescens, was studied in a deep alpine lake (Lac du Bourget) in a 2-year monitoring program with 11 sampling points, and a 24-h survey at one sampling station. This species is known to proliferate in the metalimnic layer of numerous deep mesotrophic lakes in temperate areas, and also to produce hepatotoxins. When looking at the distribution of P. rubescens at the scale of the entire lake, we found large variations (up to 10 m) in the depth of the biomass peak in the water column. These variations were closely correlated to isotherm displacements. We also found significant variations in the distribution of the cyanobacterial biomass in the northern and southern parts of the lake. We used a physical modeling approach to demonstrate that two internal wave modes can explain these variations. Internal waves are generated by wind events, but can still be detected several days after the end of these events. Finally, our 24-h survey at one sampling point demonstrated that the V1H1 sinusoidal motion could evolve into nonlinear fronts. All these findings show that internal waves have a major impact on the distribution of P. rubescens proliferating in the metalimnic layer of a deep lake, and that this process could influence the growth of this species by a direct impact on light availability. | (I) A study of the horizontal and vertical distribution of the phytoplankton in a small productive lake, Esthwaite Water in the Lake District, was made during thermal stratification. Distribution patterns of the phytoplankton were related to horizontal variations in specific conductance and pH and to the vertical distribution of temperature and oxygen. (2) A diel study of the changes in the vertical distribution of the dominant algal species, chlorophyll a, temperature and oxygen was also made at the time of maximum phytoplankton density. (3) Appreciable non-uniform horizontal distribution of the phytoplankton was observed only when buoyant blue-green algae or the dinoflagellate Ceratium hirundinella were present. (4) On most occasions horizontal variations of phytoplankton density showed clear systematic patterns related to wind-induced water movements. These patterns were particularly pronounced when individual species formed well-defined vertical aggregations in regions of upwelling or downwelling water. (5) Observations on the vertical distribution of Ceratium showed that this alga underwent diel vertical migrations, with a proportion of the population aggregating at the metalimnion at night. During calm weather large daytime sub-surface accumulations of the alga were found. Vertical perturbations of such small-scale, vertical aggregations may have produced the extreme small-scale horizontal variations of algal concentration noted on two occasions. (6) Daily mean wind speeds above 100 km day 1 were normally sufficient to break down patches of phytoplankton, whereas values below 50 km day-' allowed the formation of dense, small-scale, near-surface aggregations of Ceratium. (7) Lateral transport of algal cells at the metalimnion by water currents could assist in maintaining high nutrient gradients at the cell surface, and contribute to the sustained growth of the phytoplankton. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 18,904 |
The ecological environment of lake–river ecotone is complex and changeable, it is an important water purification area and pollution buffer zone, where the microorganisms play an important role in the mediation of material cycle, nutrition transfer, and element transformation. Microbial diversity is sensitive to environmental changes. In this study, 12 water samples from the lake–river ecotone of the Poyang Lake in China were collected to determine microbial gene sequences employing next-generation DNA sequencing techniques, and to evaluate total nitrogen (TN) and total phosphorus (TP) using UV spectrophotometric method. The results showed the major Poyang Lake has the largest microbial population, followed by Yao Lake, Ganjiang River and Raohe River. Based on the Shannon and Simpson Index, major Poyang Lake has the largest biodiversity of microbial communities, followed by Ganjiang River, Yao Lake, and Raohe River. Microbial characteristics vary with the TN and TP concentration, for instance, the nitrifying bacteria were relatively rich in Yao Lake and Ganjiang River ecotone, and the polyphosphate-accumulating organisms (PAO) in Raohe River were richer than those in Ganjiang River. The tag numbers of Euryarchaeota, Acidobacteria, Chlamydiae and Proteobacteria in Ganjiang River were more than in Raohe River, while significant differences were found between the major Poyang Lake and other lake–river ecotone, the operational taxonomic units (OTU) number (removing singletons) of major Poyang Lake have 3047, which was far more than the others. The study indicates that the Poyang Lake serves as a huge microbial gene pool, including a large number of DNA from ammonia oxidizing bacteria to ammonia oxidizing archaea. | Cyanobacterial harmful algal blooms are a major threat to freshwater eco-systems globally. To deal with this threat, researches into the cyanobacteria bloom in fresh water lakes and rivers have been carried out all over the world. This review presents an overlook of studies on cyanobacteria blooms. Conventional studies mainly focus on investigating the environmental factors influencing the blooms, with their limitation in lack of viewing the microbial community structures. Metagenomics study provides insight into the internal community structure of the cyanobacteria at the blooming, and there are researchers reported that sequence data was a better predictor than environmental factors. This further manifests the significance of the metagenomic study. However, large number of the latter appears to be confined only to present snapshoot of the microbial community diversity and structure. This type of investigation has been valuable and important, whilst an effort to integrate and coordinate the conventional approaches that largely focus on the environmental factors control, and the Metagenomics approaches that reveals the microbial community structure and diversity, implemented through machine learning techniques, for a holistic and more comprehensive insight into the cause and control of Cyanobacteria blooms, appear to be a trend and challenge of the study of this field. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 18,905 |
Microphytobenthos (MPB) are ubiquitous in coastal sediments, but the fate of their production (carbon biomass) is poorly defined. The processing and fate of MPB- derived carbon in subtropical intertidal sediments was inves- tigated through in situ labeling with 13 C-bicarbonate. Of the added 13 C, 100 % was fixed within 4 h, suggesting that MPB productivity was limited by inorganic carbon avail- ability. Although there was rapid transfer of 13 C to bacteria (within 12 h), a relatively small fraction of 13 C was trans- ferred to heterotrophs (up to 12.5 % of total fixed 13 C into bacteria and 0.01 % into foraminifera). MPB was the ma- jor reservoir for 13 C throughout the study, suggesting that production of extracellular polymeric substances was lim- ited and/or MPB recycled 13 C. This retention of 13 C was re- flected in remarkably slow estimated turnover times for the MPB community (66-100 d). Over 31 d, 70 % of the 13 C was lost from sediments. This was primarily via resuspen- sion ( 55 %), enhanced by elevated freshwater flow follow- ing rainfall. A further 13 % was lost via fluxes of dissolved inorganic carbon during inundation. However, 13 C losses via dissolved organic carbon fluxes from inundated sediments (0.5 %) and carbon dioxide fluxes from exposed sediments ( 30 d, despite high resuspension, demonstrates the potentially sub- stantial longer term retention of MPB-derived carbon in un- vegetated sediments and suggests that MPB may contribute to carbon burial ("blue carbon"). | Carbon and nitrogen flows within the food web of a subtidal sandy sediment were studied using stable isotope natural abundances and tracer addition. Natural abundances of 13 C and 15 N stable isotopes of the consumers and their potential ben- thic and pelagic resources were measured. δ 13 C data revealed that consumers did not feed on the bulk microphytobenthos (MPB) but rather were selective in their food uptake, preferring either benthic diatoms (-16‰), or benthic cyanobacteria (-20‰). MPB was labelled through a pulse-chase experi- ment with 13 C-bicarbonate and 15 N-nitrate. The fate of MPB was followed in the different heterotrophic compartments. Transfer of 13 C and 15 N to consumers was fast, although only a small fraction of total label was transferred to the heterotrophic compartments within the 4 d of the experiment. Heterotrophic bac- teria were responsible for most of the total hetero- trophic incorporation of 13 C. Within the metazoan community, the incorporation of 13 C by the meio- fauna was more than 2-fold that of the macrofauna, despite a significantly lower biomass. The dual labelling also revealed differential feeding or assim- ilation strategies in meio- and macrofauna. The low 13 C: 15 N ratios of the meiofauna (the smaller organ- isms) seemed to indicate that they preferentially assimilated N or specifically grazed on N-rich resources. However, the macrofauna (larger organ- isms) seemed to feed on bulk sediment, consistent with high 13 C: 15 N ratios. This dual approach, which combined natural abundance and a pulse-chase addition of stable isotopes, revealed crucial informa- tion on the key role of MPB in structuring benthic communities in sandy sediments. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 18,906 |
In order to study the setup of a Microcystis bloom and the evolution of its toxic potential, we studied the temporal and vertical variations in Microcystis aeruginosa abundance, microcystins (MC) concentrations (intracellular and extracellular), and the relative proportion of potentially microcystin-producing cells (MC-producing cells) in relation to physicochemical parameters in the recently setup Moroccan reservoir “Yaacoub Al Mansour.” The Microcystis bloom appeared relatively late in the season and was associated with a low proportion of MC-producing cells in the water surface layer, probably related to non-limiting nutrient concentrations. Interestingly, the setup of the bloom leads to a vertical gradient, showing a decrease in Microcystis cell abundance inversely coupled with an increase in the proportion of MC-producing cells. Thus, this can be the result of the growth where non-MC-producing cells remain in the lighted water layer easier than MC-producing ones. Nevertheless, parameters other than light intensity may influence the toxic potential of bloom as no vertical pattern was observed concerning microcystins cellular quotas. The high microcystins concentrations measured in the deep water layer have also proved the importance of considering the deep part of aquatic ecosystem in the management of health risks associated with cyanobacterial proliferations. | In temperate latitudes, toxic cyanobacteria blooms often occur in eutrophied ecosystems during warm months. Many common bloom-forming cyanobacteria have toxic and non-toxic strains which co-occur and are visually indistinguishable but can be quantified molecularly. Toxic Microcystis cells possess a suite of microcystin synthesis genes ( mcyA – mcyJ ), while non-toxic strains do not. For this study, we assessed the temporal dynamics of toxic and non-toxic strains of Microcystis by quantifying the microcystin synthetase gene ( mcyD ) and the small subunit ribosomal RNA gene, 16S (an indicator of total Microcystis ), from samples collected from four lakes across the Northeast US over a two-year period. Nutrient concentrations and water quality were measured and experiments were conducted which examined the effects of elevated levels of temperatures (+4 °C), nitrogen, and phosphorus on the growth rates of toxic and non-toxic strains of Microcystis . During the study, toxic Microcystis cells comprised between 12% and 100% of the total Microcystis population in Lake Ronkonkoma, NY, and between 0.01% and 6% in three other systems. In all lakes, molecular quantification of toxic ( mcyD -possessing) Microcystis was a better predictor of in situ microcystin levels than total cyanobacteria, total Microcystis, chlorophyll a , or other factors, being significantly correlated with the toxin in every lake studied. Experimentally enhanced temperatures yielded significantly increased growth rates of toxic Microcystis in 83% of experiments conducted, but did so for non-toxic Microcystis in only 33% of experiments, suggesting that elevated temperatures yield more toxic Microcystis cells and/or cells with more mcyD copies per cell, with either scenario potentially yielding more toxic blooms. Furthermore, concurrent increases in temperature and P concentrations yielded the highest growth rates of toxic Microcystis cells in most experiments suggesting that future eutrophication and climatic warming may additively promote the growth of toxic, rather than non-toxic, populations of Microcystis , leading to blooms with higher microcystin content. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 18,907 |
Nutrients brought to land by seabirds may provide important subsidies to terrestrial ecosystems. We measured the total Kjeldahl nitrogen (TKN) and carbon and nitrogen isotope ratios of soils from islands with and without seabirds in the Marlborough Sounds, New Zealand, to investigate one means by which seabirds may influence island ecosystem function. Isotope analysis revealed a seabird influence in island soils on the seabird- inhabited islands. However, significant differences in TKN were not related to seabird presence or absence. Pre- existing differences between the islands and high productivity even in the absence of seabirds were concluded to be the reasons for the lack of measurable seabird influence on nitrogen levels. | This study quantifies the flow of energy and biomass from a productive marine system to a relatively unproductive terrestrial system. Biomass from marine food webs (here, the Gulf of California) enters the terrestrial webs of islands and coastal areas through two conduits: (1) shore drift of algal wrack and carrion and (2) colonies of seabirds. Both conduits support dense assemblages of consumers: arthropods are 85-560 times more abundant in the supralittoral than inland and 2.2 times more abundant on islands with seabird colonies than those without. Marine input (MI), not terrestrial primary productivity (TP) by land plants, provides most energy and biomass for terrestrial communities on 16 of 19 study islands. The ratio of perimeter to area (P/A) significantly predicts arthropod abundance on islands and is the major determinant of the relative importance of allochthonous flow; we expect P/A ratio to be important wherever transport of nutrients, detritus, and organisms among habitats occurs. Similar tran... | MLL1 regulates circadian promoters by depositing H3K4 trimethyl marks, whose levels are also modulated by the NAD+-dependent deacetylase SIRT1. SIRT1 is now shown to promote circadian deacetylation of MLL1, thus affecting MLL1's methyltransferase activity. | eng_Latn | 18,908 |
The phylogenetic diversity of coral-associated microbes has been extensively examined, but some contention remains regarding whether coral-associated microbial communities are species-specific or site-specific. It is suggested that corals may associate with microbes in terms of function, although little is known about the differences in coral-associated microbial functional gene composition and metabolic potential among coral species. Here, 16S rRNA Illumina sequencing and functional gene array (GeoChip 5.0) were used to assess coral-associated microbial communities. Our results indicate that both host species and environmental variables significantly correlate with shifts in the microbial community structure and functional potential. Functional genes related to key biogeochemical cycles including carbon, nitrogen, sulfur and phosphorus cycling, metal homeostasis, organic remediation, antibiotic resistance and secondary metabolism were shown to significantly vary between and among the four study corals (Galaxea astreata, Porites lutea, Porites andrewsi and Pavona decussata). Genes specific for anammox were also detected for the first time in the coral holobiont and positively correlated with ammonium. This study reveals that variability in the functional potential of coral-associated microbial communities is largely driven by changes in environmental factors and further demonstrates the importance of linking environmental parameters with genomic data in complex environmental systems. | Deep-sea hydrothermal vents are one of the most unique and fascinating ecosystems on Earth. Although phylogenetic diversity of vent communities has been extensively examined, their physiological diversity is poorly understood. In this study, a GeoChip-based, high-throughput metagenomics technology revealed dramatic differences in microbial metabolic functions in a newly grown protochimney (inner section, Proto-I; outer section, Proto-O) and the outer section of a mature chimney (4143-1) at the Juan de Fuca Ridge. Very limited numbers of functional genes were detected in Proto-I (113 genes), whereas much higher numbers of genes were detected in Proto-O (504 genes) and 4143-1 (5,414 genes). Microbial functional genes/populations in Proto-O and Proto-I were substantially different (around 1% common genes), suggesting a rapid change in the microbial community composition during the growth of the chimney. Previously retrieved cbbL and cbbM genes involved in the Calvin Benson Bassham (CBB) cycle from deep-sea hydrothermal vents were predominant in Proto-O and 4143-1, whereas photosynthetic green-like cbbL genes were the major components in Proto-I. In addition, genes involved in methanogenesis, aerobic and anaerobic methane oxidation (e.g., ANME1 and ANME2), nitrification, denitrification, sulfate reduction, degradation of complex carbon substrates, and metal resistance were also detected. Clone libraries supported the GeoChip results but were less effective than the microarray in delineating microbial populations of low biomass. Overall, these results suggest that the hydrothermal microbial communities are metabolically and physiologically highly diverse, and the communities appear to be undergoing rapid dynamic succession and adaptation in response to the steep temperature and chemical gradients across the chimney. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 18,909 |
Competition at different levels of phosphorus availability was observed in continuous cultures of freshwater phytoplankton communities. Although dilution rates ranged 10-fold in all, the outcome of competition was usually similar among cultures and resulted in dominance of the small diatom Synedra acus. Species growth rates decreased significantly with increasing cell, or colony, size among the 16 species examined. A variable internal stores model of algal growth, combined with functions relating its species-specific parameters to cell size, correctly predicted the observed inverse correlation between cell size and competitive ability. The model’s predictions, and the empirical correlation between size and growth, were poor at low dilution rates (<0.2–0.3 d−1), probably due to cell death. The results indicated that variation of phosphorus supply is unlikely to be a major selective influence on the size or species composition of uniformly phosphorus-limited communities. | Both in situ primary production and biomass (chlorophyll α) of fractionated phytoplankton (<64,µ, <25 µm and < 10 µm) were studied in 10 Canadian Shield lakes to elucidate the spatial and temporal variability of the contribution of size fractions to the biomass and primary production of the phytoplankton community. Mean summer biomass and production of each size fraction varied significantly between lakes. Within lakes, temporal variation was low for biomass but great for production. However, temporal variation can be considered of minor importance during the sampling period, as compared to the spatial variation between lakes. Algae from the < 10 µm size fraction were the most important in biomass (41–65 %) and production (23–69%). The temporal trends for both phytoplankton variables thus generally followed closely that of the < 10 µm size fraction. Among the physical, chemical and morphometric variables of the studied lakes, water transparency (Secchi disk), total phosphorus, lake volume, lake area, and mean depth gave the best correlations with phytoplankton variables. | In this work we develop the 2D model suggested in [32] in order to study the impact of fibrinogen concentration and the fibrin polymer production rate on clot growth in flow. The model is based on the method of Dissipative Particle Dynamics describing blood plasma flow and platelet suspension and on a system of partial differential equations describing blood coagulation regulatory network. We study the influence of parameters on clot development and on its final size. | eng_Latn | 18,910 |
[1] The bacterial community of the mineral spring Wettinquelle in the Vogtland/NW Bohemian region (German-Czech border) was characterized by sequence analysis of amplified small subunit ribosomal RNA genes. The acidulous spring water consists mostly of old groundwater from deep aquifers, which is mixed with 15–20% young water from upper groundwater horizons. The spring water contains high concentrations of iron, Ca2+ and SO42− ions. A remarkable attribute is the high radon activity of 27 kBq L−1 water. Free escaping spring gas consists mainly of CO2 originating from the mantle, N2 (1.2%) and traces of other gases, like methane and helium. Close relatives of Gallionella ferruginea, a micro-aerobic oxidizer of ferrous iron, contributed most to the clone library. Clones with sequences related to Thiobacillus aquaesulis, members of the Sulfuricurvum-cluster and members of several branches of the OP11 group were present in significantly lower numbers but still with some microdiversity. These bacterial groups, which contributed strongly to the clone library and have known physiology, obviously depend on the oxygen in the younger water and reduced compounds from the below. | Fuschna Spring in the Swiss Alps (Engadin region) is a bicarbonate iron(II)-rich, pH-neutral mineral water spring that is dominated visually by dark green microbial mats at the side of the flow channel and orange iron(III) (oxyhydr)oxides in the flow channel. Gradients of O2, dissolved iron(II), and bicarbonate establish in the water. Our goals were to identify the dominating biogeochemical processes and to determine to which extent changing geochemical conditions along the flow path and seasonal changes influence mineral identity, crystallinity, and microbial diversity. Geochemical analysis showed microoxic water at the spring outlet which became fully oxygenated within 2.3 m downstream. X-ray diffraction and Mossbauer spectroscopy revealed calcite (CaCO3) and ferrihydrite [Fe(OH)3] to be the dominant minerals which increased in crystallinity with increasing distance from the spring outlet. Denaturing gradient gel electrophoresis banding pattern cluster analysis revealed that the microbial community composition shifted mainly with seasons and to a lesser extent along the flow path. 16S rRNA gene sequence analysis showed that microbial communities differ between the flow channel and the flanking microbial mat. Microbial community analysis in combination with most-probable-number analyses and quantitative PCR (qPCR) showed that the mat was dominated by cyanobacteria and the channel was dominated by microaerophilic Fe(II) oxidizers (1.97 × 107 ± 4.36 × 106 16S rRNA gene copies g−1 using Gallionella-specific qPCR primers), while high numbers of Fe(III) reducers (109 cells/g) were identified in both the mat and the flow channel. Phototrophic and nitrate-reducing Fe(II) oxidizers were present as well, although in lower numbers (103 to 104 cells/g). In summary, our data suggest that mainly seasonal changes caused microbial community shifts, while geochemical gradients along the flow path influenced mineral crystallinity. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 18,911 |
Over the last two decades, many studies on functional morphology have suggested that material properties of seaweed tissues may influence their fitness. Because hydrodynamic forces are likely the largest source of mortality for seaweeds in high wave energy environments, tissues with material properties that behave favorably in these environments are likely to be selected for. However, it is very difficult to disentangle the effects of materials properties on seaweed performance because size, shape, and habitat also influence mechanical and hydrodynamic performance. In this study, anatomical and material properties of 16 species of foliose red macroalgae were determined, and their effects on hydrodynamic performance were measured in laboratory experiments holding size and shape constant. We determined that increased blade thickness (primarily caused by the addition of medullary tissue) results in higher flexural stiffness (EI), which inhibits the seaweed's ability to reconfigure in flowing water and thereby increases drag. However, this increase is concurrent with an increase in the force required to break tissue, possibly offsetting any risk of failure. Additionally, while increased nonpigmented medullary cells may pose a higher metabolic cost to the seaweed, decreased reconfiguration causes thicker tissues to expose more photosynthetic surface area incident to ambient light in flowing water, potentially ameliorating the metabolic cost of producing these cells. Material properties can result in differential performance of morphologically similar species. Future studies on ecomechanics of seaweeds in wave-swept coastal habitats should consider the interaction of multiple trade-offs. | Macroalgae use flexibility and reconfiguration, i.e. the alteration of shape, size and orientation as water velocity increases, to reduce the hydrodynamic forces imposed in the wave-swept rocky intertidal zone. Quantifying the effects of flexibility on hydrodynamic performance is difficult, however, because the mechanisms of reconfiguration vary with water velocity and the relationship between algal solid mechanics and hydrodynamic performance is poorly understood. In this study, the hydrodynamic performance, morphology and solid mechanics of 10 rocky shore macroalgal species were quantified to evaluate the influences of flexibility and morphology on reconfiguration. Hydrodynamic performance was measured in a flume by direct measurement of changes in size and shape during reconfiguration across a wide range of velocities, material stiffness was quantified with standard materials testing, and structural properties were calculated from material and morphological data. Hydrodynamic parameters varied significantly among species, indicating variation in the magnitude of reconfiguration and the velocities required for full reconfiguration. Structural properties also varied among species, and were correlated with hydrodynamic performance in some instances. The relationship between hydrodynamic and structural properties is velocity dependent, such that flexibility influences different aspects of reconfiguration at low and high velocities. Groups are identifiable among species based on hydrodynamic and structural properties, suggesting that these properties are useful for addressing functional-form hypotheses and the effects of hydrodynamic disturbance on macroalgal communities. | Upon ultrastructural examination it was found that prolonged mebendazole therapy of patients with hydatid disease often resulted in complete necrosis of the germinal layer ofEchinococcus granulosus cysts. The affected cysts showed only remnants of degenerated germinal layer tissue including heterogeneous vesicular membranes, electron-dense amorphous structures, myeloid bodies, lipid globules, crystal-like precipitates and remnants derived from muscular tissue. Examination of the hydatid cysts of treated mice revealed the same time-related deteriorative effect of the anthelmintic as described previously for other cestode species. The advanced stage of degeneration of the germinal layer tissue observed in the murine cysts after treatment resembled the morphologic features present in the necrotic human cysts and gave additional information about the degeneration phenomenon. | eng_Latn | 18,912 |
Karenia mikimotoi is one of the most common red-tide dinoflagellates proliferating in the eastern North Atlantic and around Japan. Kills of marine fauna are associated with its blooms. In mixed water columns it migrates vertically, while in stratified water columns, the population remains confined within pycnocline layers. Wind events, increasing mixing and agitation initiate declines in its populations. This paper is focused on the formulation of mortality rate relative to shear rate. Autotoxicity is demonstrated by the use of a synthetic toxin. Bioconvection observed in cultures allows the establishment of a trade-off between phototropism, which leads to the local accumulation of cells, and their autotoxicity, which would prevent cell concentration. The combination of these processes allows diffusion of the toxin into the underlying water, where it subsequently degrades. Confinement of the population in the pycnocline layer results also from another trade-off between growth conditions and shear-rate-modulated mortality. A simplified encounter kernel was introduced into the population dynamics equation to account for a mortality factor. Under realistic forcing conditions with a small number of parameters, this model reproduced the confinement of the population in the pycnocline layer, the proper timing and the duration of the recurrent K. mikimotoi bloom on the Ushant front (France). | Algal allelopathy is a manifold ecological/physiological phenomenon that is focused on chemical interactions and autotoxicity. We investigated the allelopathic interactions between Karenia mikimotoi and Dunaliella salina in laboratory cultures based on diff erent temperature (15°C, 20°C, and 25°C) and lighting (40, 80, and 160 μmol/(m2·s)) conditions. The growth of D. salina in bi-algae culture (1:1 size/density) was significantly restrained. The results of cell-free filtrate culture indicate that direct cell-tocell contact was not necessary in interspecific competition. Further experimental results demonstrated that allelochemicals released from K. mikimotoi were markedly influenced by both temperature (P =0.013) and irradiance (P =0.003), resulting in diff erent growth characteristics of D. salina in filtrate mediums. Compared with the plateau period, K. mikimotoi exudates in the exponential phase had a stronger short-term inhibition effect on D. salina in normal conditions. A clear concentration-dependent relationship was observed in the effect of allelochemicals released from K. mikimotoi with low-promoting and high-repressing effects on D. Salina in a short time-scale. In addition, allelopathic substances remain stable and effective under high temperature and pressure stress. Many flocculent sediments adhering with D. salina cells were observed in all filtrate mediums, while the quantity and color depended on the original culture conditions. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 18,913 |
A new crystalline clathrate class of syndiotactic poly(p-methylstyrene) has been found through thermal and WAXS analyses. In these clathrate forms, the polymer chains assume a T6G2T2G2 conformation with a repetition period of 11.7 ± 0.1 A and t2 symmetry. The new conformation, supported by molecular mechanics calculations, presents a cavity, favorable to the formation of clathrate structure, only on one side of the polymer chain. This cavity is bigger than those presented by this polymer with a helical s(2/1)2 chain conformation found for all the other clathrates. After annealing, the clathrates of this new class are transformed in form II. For this new class of clathrates the term γ is proposed. | © 2013 Furukawa and Nakaoki, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Absorption Kinetics of Phenol into Different Size Nanopores Present in Syndiotactic Polystyrene and Poly (p-methylstyrene) | Diel periodicity in the expression of key genes involved in carbon and nitrogen assimilation in marine Synechococcus spp. was investigated in a natural population growing in the surface waters of a cyclonic eddy in the northeast Atlantic Ocean. Synechococcus sp. cell concentrations within the upper mixed layer showed a net increase of three- to fourfold during the course of the experiment (13 to 22 July 1991), the population undergoing approximately one synchronous division per day. Consistent with the observed temporal pattern of phycoerythrin (CpeBA) biosynthesis, comparatively little variation was found in cpeBA mRNA abundance during either of the diel cycles investigated. In marked contrast, the relative abundance of transcripts originating from the genes encoding the large subunit of ribulose bisphosphate carboxylase/oxygenase (rbcL) and glutamine synthetase (glnA) showed considerable systematic temporal variation and oscillated during the course of each diel cycle in a reciprocal rhythm. Whereas activation of rbcL transcription was clearly not light dependent, expression of glnA appeared sensitive to endogenous changes in the physiological demands for nitrogen that arise as a natural consequence of temporal periodicity in photosynthetic carbon assimilation. The data presented support the hypothesis that a degree of temporal separation may exist between the most active periods of carbon and nitrogen assimilation in natural populations of marine Synecoccoccus spp. | eng_Latn | 18,914 |
Virus-like particles (VLP), collected from the permanently anoxic Cariaco Basin between 10 October 1996 and 2 November 1999, were enumerated in water column and sediment trap samples. Vertical distributions of VLP from 18 depths between 7 and 1310 m generally corresponded to those of bacterial abundance and bacterial net production (BNP), with primary maxima consistently found in surface waters and midwater maxima near the O 2 /H 2 S interface. Temporal variations in VLP concentrations (0.81 to 630 x 10 8 VLP 1 -1 ) were highly correlated with chlorophyll a (chl a), bacterial abundance and BNP in the upper 250 m. In the redox transition zone (RTZ = 250 to 450 m), VLP abundance covaried with bacterial growth rates, but not bacterial abundance nor chemoautotrophic production. In the anoxic layer (>450 m), temporal variations in VLP abundance were not significantly correlated with any measured variable. In the RTZ, the median VLP:bacteria ratio (VBR = 3) was significantly lower than in the oxic (VBR = 16) and anoxic (VBR = 31) layers for all observations, suggesting varying relationships between viruses, hosts and environment among these layers. Vertical fluxes of VLP associated with sedimenting debris varied between 0.39 and 520 × 10 9 VLP m -2 d -1 , a range similar to bacteria (0.88 to 330 x 10 9 bacteria m -2 d -1 ). VBRs in the sinking inventories were very low, varying from 0.01 to 1.2 and averaging 0.60, suggesting that VLP are not as numerically important in sinking particles as they are in suspended communities. Comparisons of sinking fluxes with suspended VLP inventories indicate that vertical transport is relatively unimportant in redistributing viruses in the water column. Estimated removal rates by sinking from the oxic, transition and anoxic layers averaged 0.11% mo -1 (n = 16) for apparent VLP. | Bundera Sinkhole in northwestern Australia is an anchialine ecosystem characterised by a highly stratified water column comprising a complex polymodal profile of several physico-chem- ical parameters. We studied the microscale and finescale dynamics of the resident microbial commu- nity within the sinkhole. Sub-millimetre scale distributions of phytoplankton abundance were measured in the top 8 m of the water column using a free-falling high resolution fluorometer. Depth profiles were characterised by a strong, 10 to 20 cm layer of elevated fluorescence, occurring at approximately 1 m depth, which despite changes in magnitude and width was found to persist dur- ing a 24 h sampling period. Near surface distributions of microbial populations were measured using a syringe sampling profiler, which allowed for collection of water samples at 5 cm resolution, and flow cytometric analysis. These samples revealed a complex microbial assemblage, with multiple sub- populations of viruses, bacteria and picophytoplankton present throughout the water column. Within 3 m profiles, the bacterial and virus populations showed marked shifts in relative abundance, with changes of over 35-fold observed across as little as 20 cm. Samples collected from the surface to a depth of 30 m by divers also revealed distinct peaks and layers in the relative abundance of the dif- ferent bacteria and virus sub-populations, which often corresponded to heterogeneities in chemical and nutrient parameters, and at some depths indicated the prevalence of chemolithotrophic popula- tions. The complex patterns described here represent the first comprehensive observations of micro- bial spatiotemporal dynamics throughout an anchialine ecosystem and reveal a highly structured microbial habitat consisting of discrete niches, each dominated by heterotrophic, phototrophic or chemoautotrophic microorganisms. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 18,915 |
Methylophilus: A New Genus of Methanol-Utilizing Bacteria | A new genus, Methylophilus, and species of restricted facultative methanol-utilizing bacteria are described. These bacteria are aerobic gram-negative rods that occur singly and in pairs. In addition to methanol and glucose, a limited range of other carbon compounds including fructose and methylamines may be used as the sole carbon and energy source. The fatty acid composition is primarily of the nonhydroxylated straight-chain saturated and monounsaturated types. The major isoprenoid quinone components are ubiquinones with eight isoprene units. The major polar lipid components are phosphatidylglycerol and phosphatidylethanolamine. The deoxyribonucleic acid base composition is 50 to 53 mol% guanine plus cytosine. The name of the genus proposed for these bacteria is Methylophilus gen. nov. The name of the type species is Methylophilus methylotrophus sp. nov. The type strain is AS1 (= NCIB 10515). | AbstractWe sequenced the complete mitogenome of Marenzelleria neglecta, a non-indigenous polychaete of the Baltic Sea originating from North America. This is the first complete mitogenome made avai... | eng_Latn | 18,916 |
Marine green alga Cladophora aokii Yamada and its epiphytes from Yinggehai, Hainan, China: morphological taxonomy, formation and analysis of its environmental adaption | Based on specimens collected in Yinggehai, Hainan, China from 2013 to 2016, a stable epiphytic taxon is found on the surface of the individual of marine green alga Cladophora aokii Yamada. According to the morphological characteristics, the taxonomy of Cl. aokii and its epiphytes is carried out. There are some epiphytes attached on Cl. aokii Yamada including Cl. fascicularis (Mertens ex C. Agardh) Kutzing, Chaetomorpha pachynema (Montagne) Kutzing, Ceramium camouii Dawson, Licmophora abbreviata Agardh, Lyngbya sp. and Chattonella sp.. The formation of the individual of Cl. aokii is dissected and explained, which can help to analyze the adaption in details among this species, its epiphytes and native marine environment. The results reveal the marine macroepiphytic taxonomy in Hainan, China, and preliminarily explain the adaptive relationship between macroalgae and environment. | The paper reviewed the 13 C_NMR features of natural taxane diterpenoids according to their carbon_skeleton types. In the 13 C_NMR it is easy to distinguish the 6/8/6 and 5/7/6 membered rings by observation of the 13 C_NMR data of C_1 and C_15. The remarkable differences of the resonance of C_13 and C_12 were found. In addition, based on various chemical environments many obscured chemical shifts of carbons can be distinguished, such as the oxygenated tertiary carbons of C_2, C_5, C_7, C_9 and C_13, and sometimes between C_9 and C_10, as well as between aliphatic quaternary carbons of C_8 and C_15, and secondary carbons of C_6 and C_14. All the above_mentioned characteristics are helpful for structural elucidation and assignments of the carbon signals of taxoids. | eng_Latn | 18,917 |
Adaptive hyperplasia of epidermal chloride-secreting cells in fry of mummichog, Fundulus heteroclitus L., incubated and reared in supranormal salinity | Cells, structurally identical with branchial chloride-secreting cells, were observed to be broadly distributed in buccal and pharyngeal epithelia and various regions of the trunk epidermis, in early fry of the mummichog, Fundulus heteroclitus L., that had been incubated in embryonal and alevin stages in sea water concentrated by additional salts to 60‰ salinity, at 20 °C. Although there was some proliferation of these cells in the buccal and pharyngeal epithelia, such apparently adaptive hyperplasia and hypertrophy of these cells did not occur in early fry that had previous incubation and rearing in seawater concentrations of 30, 20, and 10‰ salinity (S), and in fresh water (< 0.5‰ S) | Understanding the susceptibility of coastal ecosystems to nutrient loads from anthropogenic sources and the extent of eutrophication in subtropical and tropical estuaries is still a challenge. This study assessed eutrophication in Guaymas Bay, a subtropical lagoon that receives nutrient-rich urban wastewater discharges. Eutrophication was evaluated by means of the Assessment of Estuarine Trophic Status model. Our results showed that the trophic status of Guaymas Bay was “good.” It is important to consider that: (1) the dissolved oxygen and chlorophyll a levels observed are indicative of a healthy ecosystem, and (2) the key factors explaining this finding are the high susceptibility to eutrophication of the lagoon and the dominance of macroalgae species that respond to nutrient enrichment. This implies that the Overall Eutrophic Condition Index of the Assessment of Estuarine Trophic Status model is a valuable tool for use as an eutrophication indicator based on the abundance of primary producers (macroalga... | eng_Latn | 18,918 |
They contain symbiotic bacteria called Rhizobia within nodules in their root systems , producing nitrogen compounds that help the plant to grow and compete with other plants . | They have symbiotic bacteria called Rhizobia in nodules in their root systems , producing nitrogen compounds that help the plant to grow and compete with other plants . | The island was made a Site of Special Scientific Interest because of its maritime life . This includes internationally rare lichens ; bryophyte , plants , bird species ; and intertidal communities . | eng_Latn | 18,919 |
where do flagella live? | Flagella are not alive. That's like saying that my spaghetti sauce lives in my pantry. Flagella are bundles of proteins that extend out of single celled organisms and are used by those organisms for motion.\n\nCertain species of bacteria and protoza, as well as animal sperm cells, have one flagellum (or many flagella) | Right here!\n\nI can't really choose one favorite song, but Great Milenko is my favorite card. | eng_Latn | 18,920 |
The Luftsichel: an old sign in upper lobe collapse. | The Luftsichel is a paramediastinal translucency due to interposition of the apex of the lower lobe between the mediastinum and the shrunken upper lobe. It occurs more commonly on the left than the right. It is so common on the left that it should be regarded as the typical appearance. It is to be distinguished from mediastinal hernia. | ABSTRACT--- Lichens are symbiotic plant composed of two different types of organisms i.e. fungi and algae. Lichens sensitive to air pollutan of sulfur dioxide (SO 2 ). Sikidang creater are still active to emist off SO 2 and will be affected the availability of lichens as well as the their individual density along SO 2 gradient. Sampling of lichens taken with sistematic method. Point sampling four were taken along transect line and sample plot 5 m x 5 m in size was applied..The occurance of species and density was record in every sampling plot. The environment factor measured were air SO 2 , pH, moisturized and air temperature. There were three species of lichens in Sikidang Creater, those are Cladonia beaumontii, Dactylina artica abd Parmelia cumberlandia. The highets density of species lichens is Cladonia beaumontii. Keywords : density, Lichens. Sikidang Creater | eng_Latn | 18,921 |
Kerapatan Jenis Lichenes Di Sekitar Kawah Sikidang Pegunungan Dieng (Density of Lichens Arround Sikidang Creater of Dieng Plateau) | ABSTRACT--- Lichens are symbiotic plant composed of two different types of organisms i.e. fungi and algae. Lichens sensitive to air pollutan of sulfur dioxide (SO 2 ). Sikidang creater are still active to emist off SO 2 and will be affected the availability of lichens as well as the their individual density along SO 2 gradient. Sampling of lichens taken with sistematic method. Point sampling four were taken along transect line and sample plot 5 m x 5 m in size was applied..The occurance of species and density was record in every sampling plot. The environment factor measured were air SO 2 , pH, moisturized and air temperature. There were three species of lichens in Sikidang Creater, those are Cladonia beaumontii, Dactylina artica abd Parmelia cumberlandia. The highets density of species lichens is Cladonia beaumontii. Keywords : density, Lichens. Sikidang Creater | On the basis of regional geological characteristic,sea island were stated in distribution of Qingdao.Base on the rock feature,geological structure feature and main geological processes involved in formed sea island in Qing-dao area,the sea island in Qingdao area were divided into type tectonic processes(type Ⅰ),type magma processes(type Ⅱ),type metamorphic processes(type Ⅲ)and the geological environment of main sea island in Qingdao area were analysed. | ind_Latn | 18,922 |
Impact of hypolimnetic oxygenation on profundal macroinvertebrates in a eutrophic lake in central Alberta. I. Changes in macroinvertebrate abundance and diversity | Hypolimnetic oxygenation from 1988 to 1991 in the north basin of Amisk Lake increased mean summer (June-August) dissolved oxygen (DO) concentrations in the deep hypolimnion (25 m) from 2000 ·m-2 from 1988 to 1991 whereas Chaoborus spp., Tubificidae, and other taxa remained uncommon at similar depths. Shannon-Weaver indices of diversity decreased as oxygenation progressed, in contrast with previous studies. Similar patterns in densities and diversity were observed in the south basin of Amisk Lake, although the increase in DO concentrations was smaller relative to the north basin. The impact of increased water temperature on macroinvertebrates appeared minor relative to the effects of increased DO concentrations. No changes in mac... | The aim of the present study is to determine seasonal changes in the functional diversity of alder culturable rhizobacterial communities, studying the Eco-physiological index (EPI) and changes in morphological and physiological bacterial groups (MAP), and to investigate if these changes are related to the genetic diversity of main bacterial genera by PCR-RAPDs. To calculate the diversity parameters (EPI, MAP and genetic diversity), Shannon algorithm was used. Our results show that there is a succession that involves a sequence of changes in alder culturable rhizobacterial communities, both from a structural and functional point of view. In the colder months, EPI and MAP (functional diversity) were lower than in spring and summer. As regards genetic heterogeneity, results are in accordance with EPI and MAP which have higher diversity in summer and spring. The seasonal changes described above could be related to environmental conditions and plant physiology status. | eng_Latn | 18,923 |
The Sequencing, Assembly and Annotation of Sugar Producing Green Algae and the Design of a Low Cost Turbidostat | University of Minnesota M.S. thesis.October 2017. Major: Microbial Engineering. Advisor: Brett Barney. 1 computer file (PDF); vi, 56 pages. | *Corresponding author: Stephen J. Hawkins, Ocean and Earth Science, National Oceanography Centre Southampton, Waterfront Campus, University of Southampton, European Way, Southampton, SO14 3ZH, UK, Tel: (023) 8059 3596; E-mail: [email protected] January 24, 2013; Accepted January 25, 2013; Published January 28, 2013Citation: Hawkins SJ, Vale M, Firth LB, Burrows MT, Mieszkowska N, et al. (2013) Sustained Observation of Marine Biodiversity and Ecosystems. Oceanography 1: e101. doi:10.4172/ocn.1000e101Copyright: © 2013 Hawkins SJ, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. | eng_Latn | 18,924 |
A simple method for cryopreservation of Ginkgo biloba callus | Two-years-old Ginkgo biloba cell culture initiated from cotyledonary explants was cryopreserved by a simple desiccation method. Preliminary incubation of callus clumps on MS preculture medium supplemented with 100 g l−1 sucrose and 2 mg l−1 ABA for 7 and 14 days resulted in accumulation of endogenous soluble sugars and was essential for cell culture post-cryopreservation survival. The optimal time for the preculture on sucrose-and-ABA containing medium was found to be 14 days. The sufficient desiccation duration was determined as 150 min. FCM profiles of calli maintained for 2 years remained stable and were not affected by cryopreservation. | A taxonomic and nomenclatural history of Platydictya Berk. is outlined and the genus is considered to be a member of the Hypnaceae. Platydictya densissima (Card.) Robins., a species originally described from the Antarctic as Amblystegium densissimum Card. and considered to be endemic to this region, is briefly evaluated. It is shown that this species is identical to the holarctic P. jungermannioides (Brid.) Crum which is now established as a bipolar disjunct and is the only representative of the genus Platydictya in the Southern Hemisphere. Platydictya jungermannioides is very rare in Tierra del Fuego and on South Georgia, whereas in the maritime Antarctic it is locally frequent, extending from the South Orkney Islands to Alexander Island. The austral plants of P. jungermannioides are described and illustrated and the regional and global distributions of the species are mapped. The ecological requirements of the species in Antarctica are also described. | eng_Latn | 18,925 |
New Records for the Freshwater Algae of Turkey | Samples were collected from different habitats (plankton, epipelon, epiphyton, and epilithon) at 20 stations situated on rivers and dam systems in the Tigris Basin between December 2004 and November 2005. Twenty-five new records were identified for the Turkish freshwater algae. They belong to the following divisions: 3 to Cyanobacteria, 1 to Rhodophya, 1 to Euglenozoa, 2 to Myzozoa, 1 to Ochrophyta, 9 to Chlorophyta, and 8 to Charophyta. | Abstract Some Icelandic concreting materials undergo alkali-aggregate reaction when used with high alkali cement. Due to the low average temperatures in Iceland, the risk of alkali expansion is diminished. Sufficient quantity of Icelandic natural pozzolans can prevent damaging expansion in concretes with reactive aggregates. | eng_Latn | 18,926 |
Which cells form the middle layer of plant leaves? | Leaf Structure, Function, and Adaptation About Watch and Favorite Watch Watching this resources will notify you when proposed changes or new versions are created so you can keep track of improvements that have been made. Favorite Favoriting this resource allows you to save it in the “My Resources” tab of your account. There, you can easily access this resource later when you’re ready to customize it or assign it to your students. Leaf Structure, Function, and Adaptation Leaves have many structures that prevent water loss, transport compounds, aid in gas exchange, and protect the plant as a whole. Learning Objective Describe the internal structure and function of a leaf Key Points The epidermis consists of the upper and lower epidermis; it aids in the regulation of gas exchange via stomata. The epidermis is one layer thick, but may have more layers to prevent transpiration . The cuticle is located outside the epidermis and protects against water loss; trichomes discourage predation. The mesophyll is found between the upper and lower epidermis; it aids in gas exchange and photosynthesis via chloroplasts . The xylem transports water and minerals to the leaves; the phloem transports the photosynthetic products to the other parts of the plant. Plants in cold climates have needle-like leaves that are reduced in size; plants in hot climates have succulent leaves that help to conserve water. Terms Full Text Leaf Structure and Function The outermost layer of the leaf is the epidermis. It consists of the upper and lower epidermis, which are present on either side of the leaf. Botanists call the upper side the adaxial surface (or adaxis) and the lower side the abaxial surface (or abaxis). The epidermis aids in the regulation of gas exchange. It contains stomata, which are openings through which the exchange of gases takes place. Two guard cells surround each stoma , regulating its opening and closing. Guard cells are the only epidermal cells to contain chloroplasts. The epidermis is usually one cell layer thick. However, in plants that grow in very hot or very cold conditions, the epidermis may be several layers thick to protect against excessive water loss from transpiration. A waxy layer known as the cuticle covers the leaves of all plant species . The cuticle reduces the rate of water loss from the leaf surface. Other leaves may have small hairs (trichomes) on the leaf surface. Trichomes help to avert herbivory by restricting insect movements or by storing toxic or bad-tasting compounds. They can also reduce the rate of transpiration by blocking air flow across the leaf surface . Trichomes give leaves a fuzzy appearance as in this (a) sundew (Drosera sp.). Leaf trichomes include (b) branched trichomes on the leaf of Arabidopsis lyrata and (c) multibranched trichomes on a mature Quercus marilandica leaf. Below the epidermis of dicot leaves are layers of cells known as the mesophyll, or "middle leaf." The mesophyll of most leaves typically contains two arrangements of parenchyma cells: the palisade parenchyma and spongy parenchyma . The palisade parenchyma (also called the palisade mesophyll) aids in photosynthesis and has column-shaped, tightly-packed cells. It may be present in one, two, or three layers. Below the palisade parenchyma are loosely-arranged cells of an irregular shape. These are the cells of the spongy parenchyma (or spongy mesophyll). The air space found between the spongy parenchyma cells allows gaseous exchange between the leaf and the outside atmosphere through the stomata. In aquatic plants, the intercellular spaces in the spongy parenchyma help the leaf float. Both layers of the mesophyll contain many chloroplasts. (a) (top) The central mesophyll is sandwiched between an upper and lower epidermis. The mesophyll has two layers: an upper palisade layer and a lower spongy layer. Stomata on the leaf underside allow gas exchange. A waxy cuticle covers all aerial surfaces of land plants to minimize water loss. (b) (bottom) These leaf layers are clearly visible in the scanning electron micrograph. The numerous small | Lesson: Molluscs: Snails, Bivalves and Octopus Lesson: Molluscs: General Lesson Plan BY: Avril Bourquin and Robynn Honeychurch First things first! Printout and use the lesson plan checklist to assist you in making the most out of your lesson plan Length of Lesson: Approximately 3 hours for the general lesson plan. This however, can be any length depending on the plan you choose to use or make up from the materials presented here. Their is more than enough information and additional resources presented here, that it can quite easily be split into many different lesson plans formats. *Please note that this is an extensive lesson plan containing a lot of information and ideas. You, as the teacher should take the time to read through the following pages and determine which format and which activities will work best for you and your students. TEACHERS:By no means try to present all the information in one lesson plan. Scan this lesson plan, then decide which lesson plan format and materials you wish to use for your class. Lesson Plans presented in this package Lesson Plan Format 2 hours plus Suggested lesson plans that can be created from the information found in this general lesson plan Snails, Bivalves and Octopus: decide which grade level and materials are most appropriate for you. A lot of information and activities have been placed here so that you may easily personalize a lesson plan best suited for you and your class and time available for this subject. Gastropods (Marine Gastropods lesson plan information is coded brown) Bivalves (Bivalve lesson plan information is Coded Green) Cephalopods (Cephalopod information is coded Navy Blue) Instructional Goal To provide students with an introduction to the invertebrate phylum, mollusca and to help them gain a basic understanding of molluscs in general. In most of these lesson plans, three main classes will be discussed in general. Those classes are; the gastropods, bivalves and cephalopods. The main emphasis in the K to 8 lesson plans will be on the terrestrial (land snail) gastropods mainly. The 8 - 12 lesson plan will also include a discussion on the other classes. Those of the Polyplacophora, Scaphopoda, Monoplacophora and Aplacophora. Discussions and materials presented will cover such things as anatomy of the mollusc, needs of the mollusc and procreation of the molluscs. Your students will also learn how and why molluscs are important to humans and the environment. They will also be presented with the habitat and environmental problems involved around and with molllusc. Performance Objective Students will create a report, including drawings and notes based on the information presented to them and the observations they make of their molluscs, shells, habitats and work sheets presented in this lesson plan. Students should be encouraged to participate in discussions about molluscs, their value to humans and the environment and a bit on "Molluscs: Friend or foes?". Students should also help out in making a molluscan habitat and other classroom projects (e.g. posters) based on molluscs. Rationale Molluscs are an integral part of our environment. In studying this life form, students will observe the way these animals are a very important member of our world today. The mollusc's reliance upon the environment in which they live, and the way in which we humans rely on them, exemplifies the interconnectedness of all the ecosystems of the earth. Lesson Content Students will be presented information, visual, and written plus worksheet projects on the main classes of molluscs: gastropods (ex.: snails), bivalves (ex.: oysters and clams), and cephalopods (ex.: octopuses). Senior levels will also include the the other four classes of molluscs. Students will: discuss what molluscs require to live and stay healthy hear (younger students) | eng_Latn | 18,927 |
Which area of the ocean has a lot of seaweed? | What dpes seaweed do in the ocean? | Is seaweeds an example of algae? | eng_Latn | 18,928 |
What are some competition in tundra? | What is an example of competition in the arctic? | What competition is there in the ocean? | eng_Latn | 18,929 |
What are some density dependant factors that might take place in a mangrove population that is becoming really dense? | What is an example of an density independant factor? | Why do deserts have low population density? | eng_Latn | 18,930 |
In any ecosystem what does the first trophic level belong to? | What is the first level of the trophic? | What are the parts of the ecosystem belongs to the ecosystem? | eng_Latn | 18,931 |
What type of plants live in the Coastal Ocean biome? | What are the plants that live on the mounatain biome? | Which biome has the most plants and animals? | eng_Latn | 18,932 |
Does the clouded leopard live in the desert? | Where does a normal leopard live? | What biome does the clouded lepord live in? | eng_Latn | 18,933 |
What plants can grow in marine water? | A type of plant which grows in water? | A type of plant which grows in water? | eng_Latn | 18,934 |
What are some underwater vegetation? | Are some volcanoes underwater? | What is eats underwater plants? | eng_Latn | 18,935 |
What type of creature are Krill? | Krill, Krill Pictures, Krill Facts - National Geographic Size relative to a paper clip Please add a "relative" entry to your dictionary. The lowly krill averages only about two inches (five centimeters) in length, but it represents a giant-sized link in the global food chain. These small, shrimp-like crustaceans are essentially the fuel that runs the engine of the Earth’s marine ecosystems. Krill feed on phytoplankton, microscopic, single-celled plants that drift near the ocean’s surface and live off carbon dioxide and the sun’s rays. They in turn are the main staple in the diets of literally hundreds of different animals, from fish, to birds, to baleen whales. Simply put, without krill, most of the life forms in the Antarctic would disappear. Alarmingly, there are recent studies that show Antarctic krill stocks may have dropped by 80 percent since the 1970s. Scientists attribute these declines in part to ice cover loss caused by global warming. This ice loss removes a primary source of food for krill: ice-algae. Pink and opaque, Antarctic krill are among the largest of the 85 known krill species. Their estimated numbers range from 125 million tons to 6 billion tons in the waters around Antarctica. During certain times of year, krill congregate in swarms so dense and widespread that they can be seen from space. Antarctic krill can live up to 10 years, an amazing longevity for such a heavily hunted creature. They spend their days avoiding predators in the cold depths of the Antarctic Ocean, some 320 feet (100 meters) below the surface. During the night, they drift up the water column toward the surface in search of phytoplankton. | What is the collective noun for a group of whales? | Reference.com What is the collective noun for a group of whales? A: Quick Answer The collective noun for a group of whales is a pod. Since many kinds of whales are social, they can often be found in pods made up of their relatives or even unrelated whales. Full Answer Whales that are most often seen in pods are toothed whales such as the killer whale. Killer whale pods are led by a matriarch who can live into her 80s or 90s. Their ways of hunting and interacting with each other are extremely sophisticated and complex. On the other hand, baleen whales such as blue whales are mostly solitary. The exception to this is a mother with her calf. | eng_Latn | 18,936 |
Where is the ‘benthic zone’? | Benthic Zone - MicrobeWiki Benthic Zone This student page has not been curated. Contents 6 References Introduction The benthic zone is the lowest level of a marine or freshwater system and includes the sediment surface, the water just above it, and some sub-surface layers. Benthic zones exist all over the world in every appreciable water system, be it an ocean, lake, pond, river, or stream. The benthic zone starts at the shore and extends down along the bottom of the lake or ocean. This means that it could be as shallow as a few inches at its start, but may reach depths of 6,000 meters as it coincides with the abyssal plain at the bottom of the ocean. Because of the depths it can reach, the benthic zone is often characterized by low sunlight and low temperatures (Alldredge 1988). This usually attributes to little life and biodiversity, so one would be inclined to assume that it is a vast waste. However, the presence of sediment layers at the benthic zone provides many nutrients and adds greatly to species richness. Because the benthic zone has such a range of depths, many kinds of organisms may live there. Crustaceans, sponges, bivalves, snails, sea stars, polychaetes, fish, and many others can inhabit the zone (Konhauser 2007). This page will focus more on deep oceanic benthic zones, but will touch on other zones as well. Benthic zone of the sea floor. Diagram showing the different zones of an ocean. Note the wide range of the benthic zone. Although specific for an ocean, this is how the benthic zone is characterized across all water systems. Physical environment Physical Characteristics Because the benthic zone can occur in such a wide range of environments, physical and chemical characteristics vary largely and are almost always context dependent. Nutrients are not available in the way they are in much higher depths in the water column, so organisms in the benthic zone are nutrient limited. Temperature Temperature in the benthic zone ranges from warmer temperatures at shallow depths because of close proximity to the water surface, but may drop to 2 °C to 3 °C at the most extreme depths of the abyssal zone. At such cold temperatures, abundance of life is quite low and organisms move at a very slow pace. Warmer waters at shallower depths provide much more energy and can host more complex systems (Alldredge 1988). Chemical Environment The nutrients at the sediment layer are usually the limiting source of energy for the organisms that inhabit the benthic zone at great depths. These nutrients actually originate from dead or decaying organic matter from higher up in the water column. This organic matter drifts down continuously from shallower depths and settles on the bottom, where it is consumed and is the main driver of the benthic zone food chain (Gooday et al. 1990). Most areas do not have sufficient heat or sunlight to sustain much life, so organic matter is very important to the chemical environment. Pressure Pressure ranges from very little in a few inches of water to tremendously great at the bottom of the ocean. For an extreme example, the deepest spot in the Mariana Trench (the deepest trench in the ocean) is around 36,000 feet below sea level and experiences pressures that are more than 1000 times greater than standard surface pressure ("Deepsea Challenge"). High pressure in zones of great depth make for a very homogenous environment that produces a number of peculiar traits among organisms. One such peculiarity is the enhanced size of certain organisms. At great depths in arctic and antarctic waters, dissolved oxygen content is quite high. This allows organisms to grow much larger when compared to close relatives in temperate zones (De Broyer and Danis 2005). Light Availability In water, light becomes very limited in its significance at depths below about 200 meters. Between 200 and 1000 meters, the intensity of light quickly dissipates. This zone is termed the dysphotic zone and photosynthesis is no longer possible. At 1000 meters, the aphotic zone starts and light availability becomes negligible (NOAA). Microb | Bix Beiderbecke - Music on Google Play Bix Beiderbecke About the artist Leon Bismark "Bix" Beiderbecke was an American jazz cornetist, jazz pianist, and composer. With Louis Armstrong and Muggsy Spanier, Beiderbecke was one of the most influential jazz soloists of the 1920s. His turns on "Singin' the Blues" and "I'm Coming, Virginia", in particular, demonstrated an unusual purity of tone and a gift for improvisation. With these two recordings, especially, he helped to invent the jazz ballad style and hinted at what, in the 1950s, would become cool jazz. "In a Mist", one of a handful of his piano compositions and one of only two he recorded, mixed classical influences with jazz syncopation. A native of Davenport, Iowa, Beiderbecke taught himself to play cornet largely by ear, leading him to adopt a non-standard fingering some critics have connected to his original sound. He first recorded with Midwestern jazz ensembles, The Wolverines and The Bucktown Five in 1924, after which he played briefly for the Detroit-based Jean Goldkette Orchestra before joining Frankie "Tram" Trumbauer for an extended gig at the Arcadia Ballroom in St. Louis. Beiderbecke and Trumbauer joined Goldkette in 1926. | eng_Latn | 18,937 |
The Great Barrier Reef lies off the shores of what country? | Untitled The Great Barrier Reef Overview: Off of the coast of Queensland in Northeastern Australia, lies the Great Barrier Reef, one of the great natural wonders of the world. Stretching some 1250 miles from the northern tip to the southern tip, the Great Barrier Reef is home to nearly 500 different types of reef building corals. The Concise Oxford Dictionary defines a reef as a ridge of rock, shingle, or sand at or just above or below the surface of the water. This definition includes the two major features of coral reef, the first is that they are composed of rock in the form of limestone, and the second feature is that they never extend very far above sea level. The tops of coral reefs are exposed to air but only in very short intervals which occur during times of low tides ("Coral"). Coral reefs, as the name implies, have corals living on their surface, but these are not the only living organisms growing on coral reefs. The major part of a coral reef is nonliving limestone. The living plants and animals associated with coral reefs constitute only a thin layer on the surface. Coral reefs vary greatly in shape and size. Some stretch only a few meters across, in lagoon reefs, to over ten kilometers long in some wall or platform reefs. Coral reefs consist of consolidated limestone debris, and, once established, tend to grow both outwards and upwards when the plants and animals living on their surface are able to flourish. The life and death processes of these organisms result in a steady contribution of their skeletal remains to the structure of the reef This is especially significant in the tropic seas where plants and animals tend to grow rapidly (Buddemeier, 1976). Also, tropic seas contain large amounts of limestone which is used by reef-forming organisms to construct their shells and skeletons which upon death accumulate to form reefs. Corals constitute the major building blocks in reefs. It is the coral-zooxanthellae association which enables corals to produce limestone in a very efficient manner. However, it is important to realize that corals are not always necessarily going to be the dominant organism on reefs. Upon close investigation of reef rock, it is found that coral skeletons are not the only component. The corals, along with larger mollusks, provide the bulk of a structure that includes sand-sized fragments of calcareous plants, Foraminifera, and other organisms. Coral reefs may also possess large areas that are completely void of living coral, which is usually the result of unfavorable living conditions (Patton, 1976). Nevertheless, on most reefs of the Great Barrier Reef, the living corals are the most abundant animal, with the genus Acropora being the most dominant. Coral skeletons make up varying percentages of reef rock. These skeletons range from the fast growing Acropora whose branches average I centimeter to massive Porites, where a single colony may be several meters across. All Scleractinia and the limestone secreting species of hydrozoans contribute to the formation of reefs. The skeletons of dead corals are transported and accumulated by water movement to be cemented into the structure of the reef by calcareous plants. Algae are marine plants whose role in the formation and maintenance of coral reefs is almost as important as the corals themselves. In some places the role of plants may even be greater than that of the corals. There are many types of algae found on coral reefs, but the most important in reef formation are the calcareous algae. Calcareous secreting algae have the ability to produce limestone in the form of an encrustation over the reef, which acts as a cement, binding together loose fragments of debris to form a hard tough surface. This surface is especially characteristic of the windward areas of a reef where wave action is most violent; here the algae give the reef surface a smooth pavement-like texture of a pink, purple, or light brown color. If coral skeletons could be considered the bricks that make up a reef, the calcareous algae could be looked at a | Australia's southern skies light-up with Southern Lights or Aurora Australis | Daily Mail Online Next Forget the Northern Lights... here's the Southern Spectacular: Australia's skies are lit up with the fantastic colours of the Aurora Australis The Aurora Australis or 'Southern Lights' is best seen in parts of Tasmania on a clear and cold night's sky It is the Southern Hemisphere's version of the Aurora Borealis or 'Northern Lights' best seen in North America The phenomenon occurs when electrons emanating from the sun and gases in the upper atmosphere collide The result is this illuminating spectrum of green, purple, yellow and red lights streaking across the sky | eng_Latn | 18,938 |
Three examples of how humans use algae? | Is seaweeds an example of algae? | Give you at least 10 examples scientific? | eng_Latn | 18,939 |
A symbiotic relationship between a fungus and plant is what? | What is the symbiotic relationship between Fungus and Blue-Green algae? | What are the major symbiotic relationships? | eng_Latn | 18,940 |
What are the nonliving parts of taiga ecosystem? | What is the important nonliving ecosystem? | Who studies living and nonliving things in the ecosystem? | eng_Latn | 18,941 |
Orginisms living in intertidal zones have structural adaptations that protect them from? | Organisms living in intertidal zones have structures to protect them from what? | Organisms living in intertidal zones have structures to protect them from what? | eng_Latn | 18,942 |
Do solar-pool covers speed the growth of algae? | Will solar covers increase algae growth? | Will solar covers increase algae growth? | eng_Latn | 18,943 |
Wat eats plants in the ocean? | What is eats underwater plants? | Fish that eat plankton? | eng_Latn | 18,944 |
Where can you find plankton plants? | Is plankton part of the planet kingdom? | Where can you find a recycling bin? | eng_Latn | 18,945 |
How many tettestrial biome is on the earth? | What biome is earth or land based? | Why is there six kingdoms now and there were only two before? | eng_Latn | 18,946 |
What happenes when wo organism attempt to occupy the same niche? | What is two organisms attempt to occupy the same niche? | What is two organisms attempt to occupy the same niche? | eng_Latn | 18,947 |
An ecosystem with high will have a wide variety of types of organisms living in it? | An ecostsyem with high will have a wide variety of types of organisms living in it? | An ecostsyem with high will have a wide variety of types of organisms living in it? | eng_Latn | 18,948 |
Which plants can stay in cold places? | Can plants still live if the soil is cold? | What plants can you grow in a cold climate? | eng_Latn | 18,949 |
Where is the most common place plants like to grow? | What does a plant use to stay alive in dark places? | A type of plant which grows in water? | eng_Latn | 18,950 |
The island was designated a `` Site of Special Scientific Interest '' for its maritime communities ; internationally rare lichens ; bryophyte , vascular plant and bird species ; and intertidal communities . | The island was made a Site of Special Scientific Interest because of its maritime life . This includes internationally rare lichens ; bryophyte , plants , bird species ; and intertidal communities . | The biodiversity characteristic of each biome , especially the diversity of fauna and subdominant plant forms , is a function of abiotic factors and the biomass productivity of the dominant vegetation . | eng_Latn | 18,951 |
Its habitat lies in a transitional zone between three ecoregions : dry spiny bush , humid littoral forest , and humid forest . | Its habitat lies in a transitional zone between three ecoregions : dry spiny bush , humid littoral forest ( near and in water ) , and humid forest . | Limpets found on sheltered shores ( limpets that are less frequently in contact with wave action , and thus less frequently in contact with water ) have a greater risk of desiccation because of the effects of sunlight , water evaporation and the wind . | eng_Latn | 18,952 |
Diatoms are a major group of algae , and are among the most common types of phytoplankton . | They are one of the most common types of phytoplankton . | A diocese is an area of land under the charge of a bishop . | eng_Latn | 18,953 |
Major biogeographic realms , analogous to the eight terrestrial ecozones , represent large regions of the ocean basins : Arctic , Temperate Northern Atlantic , Temperate Northern Pacific , Tropical Atlantic , Western Indo-Pacific , Central Indo-Pacific , Eastern Indo-Pacific , Tropical Eastern Pacific , Temperate South America , Temperate Southern Africa , Temperate Australasia , Southern Ocean . | Major biogeographic realms , analogous to the seven terrestrial ecozones , represent large regions of the ocean basins : North Temperate Atlantic , Eastern Tropical Atlantic , Western Tropical Atlantic , South Temperate Atlantic , North Temperate Indo-Pacific , Central Indo-Pacific , Eastern Indo-Pacific , Western Indo-Pacific , South Temperate Indo-Pacific , Southern Ocean , Antarctic , Arctic , and Mediterranean . | The Río de la Plata is home for the Loggerhead Sea Turtle , Green Sea Turtle , Leatherback Sea Turtle , the rare La Plata Dolphin , and many species of fish . | eng_Latn | 18,954 |
The formation of cell types such as nerve cells occurs with a number of intermediary , less differentiated cell types . | The formation of cell types like nerve cells occurs with a number of intermediary , less differentiated cell types . | In southern Chile , south of the Biobío River lots of rain has made dense forests of laurels , magnolias , and various species of conifers and beeches , which become smaller and more stunted to the south . | eng_Latn | 18,955 |
Seaweed is a macroscopic , multicellular , benthic marine algae . | Seaweed is a term used for several forms of multicellular marine algae . | Erik Wiese , a member of the `` SpongeBob SquarePants '' crew , stated that `` Sailor Mouth '' was one of his favorite episodes because of its random and satirical nature , saying `` Sometimes SpongeBob just catches me off-guard . '' | eng_Latn | 18,956 |
Riverina soils are generally sandy along the river channels , with more saline grey and brown clays found on rarely flooded areas on the perimeter of the floodplain . | Riverina soils are generally sandy along the rivers , with more saline grey and brown clays found on rarely flooded areas on the edge of the floodplain . | The land area of Andros has hundreds of small islets and cays connected by mangrove estuaries and tidal swamp lands . There are three major islands -- North Andros , Mangrove Cay , and South Andros . | eng_Latn | 18,957 |
Seaweed is under consideration as a potential source of bioethanol . | Seaweed is currently under consideration as a potential source of bioethanol . | The grain can be seen as an example of where a Christian saint ( Walpurga ) took over from an older pagan concept , in this case of the Grain Mother . | eng_Latn | 18,958 |
The inner Gulf of Honduras is lined by the Belize Barrier Reef which forms the southern part of the 900 km long Mesoamerican Barrier Reef System , the second-largest coral reef system in the world . | The inner Gulf of Honduras is lined by the Belize Barrier Reef . It forms the southern part of the 900 km long Mesoamerican Barrier Reef System . | Cyanobacteria in coral reefs can fix twice the amount of nitrogen than on land -- around 1.8 kg of nitrogen is fixed per hectare per day . | eng_Latn | 18,959 |
Microscopic forms that live suspended in the water column ( phytoplankton ) provide the food base for most marine food chains . | Microscopic forms that live suspended in the water column are called phytoplankton . They provide the food base for most marine food chains . | Thus , the pseudanthium represents an evolutionary of the inflorescence to a reproductive unit that may function in pollination like a single flower , at least in plants that are animal pollinated . | eng_Latn | 18,960 |
Several cyanobacterial strains are also capable of diazotrophic growth , an ability that may have been present in their last common ancestor in the Archaean . | Several cyanobacterial strains are also capable of diazotrophic growth . | The Azerbaijani diaspora is a term used to describe the communities of ethnic Azerbaijanis living outside of places of their ethnic origin : Republic of Azerbaijan and Iranian Azerbaijan . | eng_Latn | 18,961 |
As bikonts , they all descend from a heterotrophic eukaryote ancestor with two flagella . | As bikonts , they all descend from a heterotrophic eukaryote with two flagella . | Its habitat lies in a transitional zone between three ecoregions : dry spiny bush , humid littoral forest ( near and in water ) , and humid forest . | eng_Latn | 18,962 |
Some are parasites of plants , insects , and small animals , while others form symbiotic relationships with plants . | Some are parasites of plants , insects , and small animals . Others form symbiotic relationships with plants , where the plant and the fungi need each other to grow . | The species can be found through most of Sub-Saharan Africa from the Western Cape , South Africa , to southern Morocco and southwestern Algeria . Outside Africait lives through Arabia , Iran and western Asia to Turkmenistan and the Indian subcontinent . | eng_Latn | 18,963 |
The species ' range is broad , but it is common nowhere . | The species ' range is broad . | A fundamental classification of biomes is into : Biomes are often given local names . | eng_Latn | 18,964 |
The entire shoreline of the Gulf is a rugged combination of forest , mountain , and a number of tidewater glaciers . | The entire shoreline of the Gulf is a combination of forest , mountain , and a number of tidewater glaciers . | Major biogeographic realms , analogous to the seven terrestrial ecozones , represent large regions of the ocean basins : North Temperate Atlantic , Eastern Tropical Atlantic , Western Tropical Atlantic , South Temperate Atlantic , North Temperate Indo-Pacific , Central Indo-Pacific , Eastern Indo-Pacific , Western Indo-Pacific , South Temperate Indo-Pacific , Southern Ocean , Antarctic , Arctic , and Mediterranean . | eng_Latn | 18,965 |
What are some examples of terrestrial biomes? | What are some examples of the 7 terrestrial biomes? | What are three types of thematic maps? How do they differ? | eng_Latn | 18,966 |
What algae is the ancestor of true plants? | The algae are a polyphyletic group and are placed in various divisions, some more closely related to plants than others. There are many differences between them in features such as cell wall composition, biochemistry, pigmentation, chloroplast structure and nutrient reserves. The algal division Charophyta, sister to the green algal division Chlorophyta, is considered to contain the ancestor of true plants. The Charophyte class Charophyceae and the land plant sub-kingdom Embryophyta together form the monophyletic group or clade Streptophytina. | Little is known about the bacteria that degrade cellulose. Symbiotic bacteria in Xylophaga may play a role in the degradation of sunken wood; while bacteria such as Alphaproteobacteria, Flavobacteria, Actinobacteria, Clostridia, and Bacteroidetes have been detected in wood submerged over a year. | eng_Latn | 18,967 |
An atoll is a circular one of these that has grown around a sunken volcanic island | Coral Reef: Formation - MarineBio.net 4.1.1 ... ocean water in the tropics enough so that it has a lower density than the subsurface water. ... These plants are called phytoplankton and photosynthesize to grow. ... Aerial view of the stages of coral reefs (fringing, barrier, atoll). ... in warm, clear ocean waters (such as would be common around a new oceanic island). | Free Flashcards about ANCIENT HISTORY - StudyStack SITE WHERE 1 OF THE 7 WONDERS OF THE ANCIENT WORLD "HUNG" AROUND, BABYLON. THIS PENINSULA NEAR ALEXANDRIA HAD A LIGHTHOUSE... | eng_Latn | 18,968 |
What do bacterial endosymbionts give necessary nutrition to? | Endosymbiosis is any symbiotic relationship in which one symbiont lives within the tissues of the other, either within the cells or extracellularly. Examples include diverse microbiomes, rhizobia, nitrogen-fixing bacteria that live in root nodules on legume roots; actinomycete nitrogen-fixing bacteria called Frankia, which live in alder tree root nodules; single-celled algae inside reef-building corals; and bacterial endosymbionts that provide essential nutrients to about 10%–15% of insects. | An example of mutual symbiosis is the relationship between the ocellaris clownfish that dwell among the tentacles of Ritteri sea anemones. The territorial fish protects the anemone from anemone-eating fish, and in turn the stinging tentacles of the anemone protect the clownfish from its predators. A special mucus on the clownfish protects it from the stinging tentacles. | eng_Latn | 18,969 |
How is it postulated that Mars life might have evolved? | About 1150 species of fungi have been recorded from Antarctica, of which about 750 are non-lichen-forming and 400 are lichen-forming. Some of these species are cryptoendoliths as a result of evolution under extreme conditions, and have significantly contributed to shaping the impressive rock formations of the McMurdo Dry Valleys and surrounding mountain ridges. The apparently simple morphology, scarcely differentiated structures, metabolic systems and enzymes still active at very low temperatures, and reduced life cycles shown by such fungi make them particularly suited to harsh environments such as the McMurdo Dry Valleys. In particular, their thick-walled and strongly melanized cells make them resistant to UV light. Those features can also be observed in algae and cyanobacteria, suggesting that these are adaptations to the conditions prevailing in Antarctica. This has led to speculation that, if life ever occurred on Mars, it might have looked similar to Antarctic fungi such as Cryomyces minteri. Some of these fungi are also apparently endemic to Antarctica. Endemic Antarctic fungi also include certain dung-inhabiting species which have had to evolve in response to the double challenge of extreme cold while growing on dung, and the need to survive passage through the gut of warm-blooded animals. | A large percentage of herbivores have mutualistic gut flora that help them digest plant matter, which is more difficult to digest than animal prey. This gut flora is made up of cellulose-digesting protozoans or bacteria living in the herbivores' intestines. Coral reefs are the result of mutualisms between coral organisms and various types of algae that live inside them. Most land plants and land ecosystems rely on mutualisms between the plants, which fix carbon from the air, and mycorrhyzal fungi, which help in extracting water and minerals from the ground. | eng_Latn | 18,970 |
Are all species of algae similar? | The algae are a polyphyletic group and are placed in various divisions, some more closely related to plants than others. There are many differences between them in features such as cell wall composition, biochemistry, pigmentation, chloroplast structure and nutrient reserves. The algal division Charophyta, sister to the green algal division Chlorophyta, is considered to contain the ancestor of true plants. The Charophyte class Charophyceae and the land plant sub-kingdom Embryophyta together form the monophyletic group or clade Streptophytina. | Even more complex morphological changes are sometimes possible. For example, when starved of amino acids, Myxobacteria detect surrounding cells in a process known as quorum sensing, migrate toward each other, and aggregate to form fruiting bodies up to 500 micrometres long and containing approximately 100,000 bacterial cells. In these fruiting bodies, the bacteria perform separate tasks; this type of cooperation is a simple type of multicellular organisation. For example, about one in 10 cells migrate to the top of these fruiting bodies and differentiate into a specialised dormant state called myxospores, which are more resistant to drying and other adverse environmental conditions than are ordinary cells. | eng_Latn | 18,971 |
Cyanobacteria inhabit nearly all illuminated environments on Earth and play key roles in the carbon and nitrogen cycle of the biosphere . | They play key roles in the carbon and nitrogen cycle of the biosphere . | Adam thought Ciceri 's backdrop for Act 1 was `` not so good ... it is all weak and pale '' but he liked the set for Act 2 : '' [ Ciceri 's ] second act is a delight , a dark humid forest filled with bulrushes and wild flowers , and ending with a sunrise , seen at first through the trees at the end of the piece , and very magical in its effect . '' | eng_Latn | 18,972 |
The Phenomena of Self-Organization in Bacterial Cells and Populations | Bacteria are, as a rule, motile microorganisms, which permits them to make an active search for a better environment. Some examples of accompanied phenomena, characterized by interconnected processes at a molecular, cellular (unicellular organisms) will be considered and populational level will be given. | *Corresponding author: Stephen J. Hawkins, Ocean and Earth Science, National Oceanography Centre Southampton, Waterfront Campus, University of Southampton, European Way, Southampton, SO14 3ZH, UK, Tel: (023) 8059 3596; E-mail: [email protected] January 24, 2013; Accepted January 25, 2013; Published January 28, 2013Citation: Hawkins SJ, Vale M, Firth LB, Burrows MT, Mieszkowska N, et al. (2013) Sustained Observation of Marine Biodiversity and Ecosystems. Oceanography 1: e101. doi:10.4172/ocn.1000e101Copyright: © 2013 Hawkins SJ, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. | eng_Latn | 18,973 |
Current knowledge on biotechnological interesting seaweeds from the Magellan Region, Chile | This paper is a compilation of data from investigations made with marine benthic algae from the Magellan Region that have biotechnological utilization in human consumption or medicine or as a source of phycolloids or food supplements or animal feed. The most important Rhodophyta species are: Ahnfeltia plicata (Hudson) E.M. Fries for agarose production, Gigartina skottsbergii Setchell & N.L.Gardner for carrageenan production, and Callophyllis variegata (Bory de Saint-Vincent) Kutzing for human consumption. The most important Heterokontophyta species are: Macrocystis pyrifera (L.) C. Agardh, and Durvillaea antarctica (Chamisso) Hariot for human consumption, alginate production, and as biofertilizer for agricultural crops. M. pyrifera is also used as a food supplement for salmon, chickens, quails, sheep and bovines and for biofuel production. | Roman layers were studied in this experiment.They were divided into three treatments,and 0,5%,7% alfalfa( Medicago Sativa)leaf powderwere added into corn-soybean based diet respectively.The results which we analyzed by T-Test showed that:adding Medicago Sativa meal in diet had a remarkable effect on the colour of egg yolk,which not obvious on egg quality and eggshell quality.However,eggshell color became deeper when added 7% Medicago Sativa meal. | eng_Latn | 18,974 |
Proteins Synthesized During Induction of the CO 2 Concentrating Mechanism in Chlamydomonas reinhardtii | The unicellular green alga, Chlamydomonas reinhardtii, can grow photoautotrophically at very low CO2 concentrations. C. reinhardtii can grow under these co nditions because it has the capacity to concentrate inorganic carbon, (Ci), internally to levels much higher than could be obtained by diffusion (1). This ability to concentrate Ci has been seen in many microalgae, both eukaryotic and prokaryotic (2–6). The CO2 concentrating mechanism of algae is a major photosynthetic adaptation that is still poorly characterized. | The CYP305B1V1 gene from Bombyx mandarina M.was cloned and sequenced.The results showed that the length of ORF of CYP305B1V1 is(1 464) nt,which encodes 487 aa.Homologous analysis showed that the DNA homology of CYP305B1V1 of silkworm and wild silkworm reaches 99%,which is consistent with deduced amino acid sequences.We presume that CYP305B1V1 of wild silkworm contains at least 6 introns and they all obey the GT-AG rule by searching and aligning the silkworm genome database on NCBI. | eng_Latn | 18,975 |
Microbial Production of Hydrogen: An Overview | Production of hydrogen by anaerobes, facultative anaerobes, aerobes, methylotrophs, and photosynthetic bacteria is possible. Anaerobic Clostridia are potential producers and immobilized C. butyricum produces 2 mol H2/mol glucose at 50% efficiency. Spontaneous production of H2 from formate and glucose by immobilized Escherichia coli showed 100% and 60% efficiencies, respectively. Enterobactericiae produces H2 at similar efficiency from different mono-saccharides during growth. Among methylotrophs, methanogenes, rumen bacteria, and thermophilic archae, Ruminococcus albus, is promising (2.37 mol/mol glucose). Immobilized aerobic Bacillus licheniformis optimally produces 0.7 mol H2/mol glucose. Photosynthetic Rhodospirillum rubrum produces 4, 7, and 6 mol of H2 from acetate, succinate, and malate, respectively. Excellent productivity (6.2 mol H2/mol glucose) by co-cultures of Cellulomonas with a hydrogenase uptake (Hup) mutant of R. capsulata on cellulose was found. Cyanobacteria, viz., Anabaena, Synechococcu... | When the creation of a new safety reservoir for the drinking water supply of the Antwerp region was envisaged it was decided that a number of actions would be undertaken to create a favourable environment for bioregulation (biomanipulation). These were: the use of boulders for the side-walls instead of concrete or bitumen, first flooding with a shallow layer of water to leach out the minerals contained in the upper clay layer of the bottom floor, introduction of freshwater mussels and of a number of fish species (bitterlings, predators such as eels, pike-perch and pike) and of submerged, floating-leaved and emergent aquatic plant species. This paper is a report on the results of these bioregulation measures obtained so far. | eng_Latn | 18,976 |
Bacterial Diversity and Function in the Baltic Sea with an Emphasis on Cyanobacteria | Abstract In this article we summarize the current knowledge of Baltic Sea cyanobacteria, focusing on diversity, toxicity, and nitrogen fixation in the filamentous heterocystous taxa. We also review the recent results of our microbial diversity studies in planktonic and benthic habitats in the Baltic Sea. Based on molecular analyses, we have improved the understanding of cyanobacterial population structure by assessing genetic diversity within species that are morphologically inseparable. Moreover, we have studied microbial functions such as toxin production and nitrogen fixation in situ under different environmental conditions. Phosphorus limitation of bloom-forming, nitrogen-fixing cyanobacteria was clearly verified, emphasizing the importance of continuous efforts to reduce this element in the Baltic Sea. We have designed a rapid and reliable detection method for the toxic cyanobacterium Nodularia spumigena, which can be used to study bloom formation of this important toxin producer. | Aim To explore an innovative planning and design concept about new waterfront area during rapid urbanization.Methods Field investigation was used to determine the core issue,and the idea of bionics was used as the origin of thought and a space prototype.Results Planning on the whole has achieved a "multi-core,one axis,nine-area "space structure,a "five vertical and three horizontal" road frame and five styles of landscape partition based on different layout and construction style.Conclusion Biomimetic principle applied in the urban design of a new urban waterfront area is a new exploration.The new urban waterfront district plan derived from bionics will guide the regional economic and social scientific development and harmonious coexistence between human being and nature. | eng_Latn | 18,977 |
Bacterial Degradation ofLignified WoodCellWallsin Anaerobic Aquatic Habitats | Test blocks of beech (Fagus sylvatica) and Scots pine (Pinus sylvestris) were buried in fresh, brackish, and seawater anaerobic muds for periods ranging between 1 and 18 months. At appropriate time intervals the test blocks were recovered and examined for changes in weight and for bacterial attack of lignified wood cell walls. Only small weight losses occurred. Scanning electron microscopy studies revealed that there was extensive superficial bacterial erosion of beech wood cell walls. The decay patterns are illustrated by micrographs and discussed in relation to other types of bacterial attack. 33 references. | Laboratory determination of temperature stress levels and assessment of their ecological consequences was carried out for selected zooplankton species to develop data for ecological impact associated with industrial use of natural water for cooling. An included literature search revealed substantial fish and benthos data, but little on stress temperature effects on zooplankton. Information was gathered on two cladocerans, four copepods and an isopod. | eng_Latn | 18,978 |
A β-Hydroxychalcone from Leptospermum scoparium | A β-hydroxychalcone 1, so far not reported as a natural compound, was separated from the diethyl ether extract of Leptospermum scoparium (Myrtaceae). Furthermore, three known flavonoids 2-4 were isolated. The 13 C-NMR spectra of 2-4 are reported, since they have as yet not been reported in the literature | Net or large phytoplankton species composition and most phytoplankton abundance was measured at three OTEC sites. In the Gulf of Mexico and'Hawaii, diatoms dominated while the blue-green algae Trichodesmium was most common at Puerto Rico. The species ratio of diatoms to dinoflagellates was approximately 1:1. The species diversity varied from site to site, Hawaii > Puerto Rico > Gulf of Mexico. Chlorophyll a, which is a measure of the pigment of all algae size ranges, showed a subsurface peak of 0.14 to 0.4 g per liter at 75 to 125 m. Occasional surface peaks upto 0.4 ..mu..g per liter occurred. Further refinement of collection techniques is needed to delineate the subtle environmental effects expected by OTEC plant discharges. | eng_Latn | 18,979 |
Nitrogen fixation by cyanobacteria in coral reefs can fix twice the amount of nitrogen than on land -- around 1.8 kg of nitrogen is fixed per hectare per day . | Cyanobacteria in coral reefs can fix twice the amount of nitrogen than on land -- around 1.8 kg of nitrogen is fixed per hectare per day . | Sense of smell : Frisch discovered that bees can distinguish various blossoming plants by their scent , and that each bee is `` flower constant '' .45 -51 Polarization pattern : Light scattered in a blue sky forms a pattern of partially polarized ultraviolet light . | eng_Latn | 18,980 |
The Ordovician -- Silurian Extinction Events may have been caused by an ice age that occurred at the end of the Ordovician period , due to the expansion of the first terrestrial plants , as the end of the Late Ordovician was one of the coldest times in the last 600 million years of earth history . | The extinctions may have been caused by an ice age that occurred at the end of the Ordovician period : the end of the Ordovician was one of the coldest times in the last 600 million years of earth history . | and Ralstonia metallidurans Oligotroph An organism capable of growth in nutritionally limited environments Osmophile An organism capable of growth in environments with a high sugar concentration Piezophile An organism that lives optimally at high hydrostatic pressure ; common in the deep terrestrial subsurface , as well as in oceanic trenches Polyextremophile An organism that qualifies as an extremophile under more than one category Psychrophile\/Cryophile An organism that grows better at temperatures of 15 ° C or lower ; common in cold soils , permafrost , polar ice , cold ocean water , and in or under alpine snowpack Radioresistant Organisms resistant to high levels of ionizing radiation , most commonly ultraviolet radiation , but also including organisms capable of resisting nuclear radiation Thermophile An organism that can thrive at temperatures between 60-80 ° C Thermoacidophile Combination of thermophile and acidophile that prefer temperatures of 70-80 ° C and pH between 2 and 3 Xerophile An organism that can grow in extremely dry , desiccating conditions ; this type is exemplified by the soil microbes of the Atacama Desert | eng_Latn | 18,981 |
Most thinking in genetics has focused upon vertical transfer , but there is a growing awareness that horizontal gene transfer is a highly significant phenomenon and among single-celled organisms perhaps the dominant form of genetic transfer . | Most thinking in genetics has focused on vertical transfer , but there is a growing awareness that horizontal gene transfer is a significant phenomenon . | and Ralstonia metallidurans Oligotroph An organism capable of growth in nutritionally limited environments Osmophile An organism capable of growth in environments with a high sugar concentration Piezophile An organism that lives optimally at high hydrostatic pressure ; common in the deep terrestrial subsurface , as well as in oceanic trenches Polyextremophile An organism that qualifies as an extremophile under more than one category Psychrophile\/Cryophile An organism that grows better at temperatures of 15 ° C or lower ; common in cold soils , permafrost , polar ice , cold ocean water , and in or under alpine snowpack Radioresistant Organisms resistant to high levels of ionizing radiation , most commonly ultraviolet radiation , but also including organisms capable of resisting nuclear radiation Thermophile An organism that can thrive at temperatures between 60-80 ° C Thermoacidophile Combination of thermophile and acidophile that prefer temperatures of 70-80 ° C and pH between 2 and 3 Xerophile An organism that can grow in extremely dry , desiccating conditions ; this type is exemplified by the soil microbes of the Atacama Desert | eng_Latn | 18,982 |
Thus , while these two cities may each have the same average maximum temperature , the standard deviation of the daily maximum temperature for the coastal city will be less than that of the inland city as , on any particular day , the actual maximum temperature is more likely to be farther from the average maximum temperature for the inland city than for the coastal one . | However , the standard deviation of the daily high temperature for the coastal city will be less than that of the inland city . | and Ralstonia metallidurans Oligotroph An organism capable of growth in nutritionally limited environments Osmophile An organism capable of growth in environments with a high sugar concentration Piezophile An organism that lives optimally at high hydrostatic pressure ; common in the deep terrestrial subsurface , as well as in oceanic trenches Polyextremophile An organism that qualifies as an extremophile under more than one category Psychrophile\/Cryophile An organism that grows better at temperatures of 15 ° C or lower ; common in cold soils , permafrost , polar ice , cold ocean water , and in or under alpine snowpack Radioresistant Organisms resistant to high levels of ionizing radiation , most commonly ultraviolet radiation , but also including organisms capable of resisting nuclear radiation Thermophile An organism that can thrive at temperatures between 60-80 ° C Thermoacidophile Combination of thermophile and acidophile that prefer temperatures of 70-80 ° C and pH between 2 and 3 Xerophile An organism that can grow in extremely dry , desiccating conditions ; this type is exemplified by the soil microbes of the Atacama Desert | eng_Latn | 18,983 |
The Weather Prediction Center serves as a center for quantitative precipitation forecasting , medium range forecasting ( three to eight days ) and the interpretation of numerical weather prediction models . | The HPC serves as a center of excellence in Quantitative Precipitation Forecasting , Medium Range Forecasting ( three to seven days ) and the interpretation of numerical weather prediction models . | and Ralstonia metallidurans Oligotroph An organism capable of growth in nutritionally limited environments Osmophile An organism capable of growth in environments with a high sugar concentration Piezophile An organism that lives optimally at high hydrostatic pressure ; common in the deep terrestrial subsurface , as well as in oceanic trenches Polyextremophile An organism that qualifies as an extremophile under more than one category Psychrophile\/Cryophile An organism that grows better at temperatures of 15 ° C or lower ; common in cold soils , permafrost , polar ice , cold ocean water , and in or under alpine snowpack Radioresistant Organisms resistant to high levels of ionizing radiation , most commonly ultraviolet radiation , but also including organisms capable of resisting nuclear radiation Thermophile An organism that can thrive at temperatures between 60-80 ° C Thermoacidophile Combination of thermophile and acidophile that prefer temperatures of 70-80 ° C and pH between 2 and 3 Xerophile An organism that can grow in extremely dry , desiccating conditions ; this type is exemplified by the soil microbes of the Atacama Desert | eng_Latn | 18,984 |
What are some examples of obligate aerobes? | What are obligate aerobes? What are some examples? | Why does the Rhizobium bacteria appear only on leguminous plants and not on other plants? | eng_Latn | 18,985 |
What do anaerobic bacteria consume? | Certain bacteria form close spatial associations that are essential for their survival. One such mutualistic association, called interspecies hydrogen transfer, occurs between clusters of anaerobic bacteria that consume organic acids, such as butyric acid or propionic acid, and produce hydrogen, and methanogenic Archaea that consume hydrogen. The bacteria in this association are unable to consume the organic acids as this reaction produces hydrogen that accumulates in their surroundings. Only the intimate association with the hydrogen-consuming Archaea keeps the hydrogen concentration low enough to allow the bacteria to grow. | Another non-obligate symbiosis is known from encrusting bryozoans and hermit crabs that live in a close relationship. The bryozoan colony (Acanthodesia commensale) develops a cirumrotatory growth and offers the crab (Pseudopagurus granulimanus) a helicospiral-tubular extension of its living chamber that initially was situated within a gastropod shell. | eng_Latn | 18,986 |
what is the genus of halophiles | Share to: A halophile is a type of archeabacteria, this peticular species thrives in salty sollutions there for it is found in places such as the dead see and the great salt lake.he scientific name for methanogens is Methanospirillum Hungatii and the scientific name for halophiles is Haloferax Mediteranei. | Halobacterium salinarum is an extremely halophilic marine Gram-negative obligate aerobic archaeon. Despite its name, this microorganism is not a bacterium, but rather a member of the domain Archaea. [1] It is found in salted fish, hides, hypersaline lakes, and salterns. | eng_Latn | 18,987 |
what are the two most important nurients for stimulating eutrophication | Eutrophication Eutrophication is a process in which bodies of water (lakes, ponds, and rivers) receive excess nutrients that stimulate excessive growth of algae. The two most ⦠common nutrients that initiate eutrophication are nitrogen and phosphorous, two limiting nutrients in the growth of algae.These two nutrients are usually introduced to the body of water through fertilizer run-off.utrophication occurs when a body of water has too many phosphates. The most common source of phosphorus in lakes is from agricultural run off. The second major cause is n ⦠atural due to high amounts of organic materials falling to the surface of the water. | There are two types of eutrophication: natural eutrophication and anthropogenic eutrophication. Eutrophication is widespread in freshwater ecosystems, and it plays a major role in the normal aging process of many ponds and lakes. The main cause of anthropogenic eutrophication is human activity. Nutrients from fertilized fields, lawns, and farms are deposited in rivers, streams, lakes and oceans when it rains. | eng_Latn | 18,988 |
Net in situ growth rates of phytoplankton in an oligotrophic, tropical shelf ecosystem | In situ growth rates of phytoplankton in tropical shelf waters of the Great Barrier Reef were measured with diffusion chambers. A broad disparity was observed between the growth responses of diatom species or assemblages (p,,,. = 2-5 doublings d-l) and assemblages of microflagellatcs, nonmotile ultraplankton, or phototrophic picoplankton (p,,,, 0.5) at ambient concentrations of dissolved inorganic N ~0.2 pm01 liter-' and the time-averaged diurnal irradiances in situ >50 pEinst m-2 SK'. If relative constancy in phytoplankton standing crop and composition is to bc maintained, grazing rates must vary widely at the species level, but be broadly similar to growth rates over time scales of days. Although the full 40-80-m water column in the central Great Barrier Reef lies the euphotic zone, phytoplankton growth rates near the bottom seem to bc light limited. | Studied on the distribution pattern of Populus euphratica Oliv Populus Pruinosa Schrenk community,discussed on the location of the community changes of Populus euphratica Oliv Populus Pruinosa Schrenk,and deduced their spreading mechanism and the populus evolution.The results showed that their populus are mostly concentrated,which is closely to rivers,their trend is from south to north. | eng_Latn | 18,989 |
The Genetic Material of Prokaryote Algae (Cyanophyceae) | SUMMARYChromatinosome structure and distribution in blue-green algae cells with prokaryote structure was studied. Investigations were performed in three orders of Cyanophyta: Chroococcales, Nostocales and Oscillatoriales. A comparison is made between the structure of chromatinosome in the representatives of the three orders. A new mechanism of chromosome replication was evidenced in prokaryota, different from that of another prokaryota, namely bacteria. Certain phylogenetic references are being made. | The invasion of natural and anthropogenic habitats by alien plants is a global problem. To understand the factors that regulate the success of alien plant species we sampled alien plant biomass and species composition in 66 sites representing a wide variety of habitat types within Bruce Peninsula National Park, Ontario, Canada. We quantified the response of existing alien biomass to a suite of habitat variables including habitat productivity, standing biomass, species richness, soil nutrients and disturbance factors. Standing biomass in the sites varied from 0 to nearly 60 000 g/m2 and annual productivity ranged from 0 to nearly 800 g·m−2·yr−1. The response of both absolute and relative alien biomass (dominance) to the independent variables was assessed using univariate plots and multivariate canonical correspondence analysis. The results show that total standing alien biomass and site disturbance history can predict alien dominance, but other factors including primary productivity, nutrient levels, and s... | eng_Latn | 18,990 |
High-Alloy Materials for Offshore Applications | High-alloy materials possessing good corrosion resistance in hot, sour brines are being seriously considered for offshore applications. These alloys are available in a wide range of strength levels which can be attained by the methods of cold working or precipitation hardening. Results of testing INCONEL alloys 625 and 718 and INCOLOY alloys 825 and 925 for resistance to general corrosion, hydrogen embrittlement, and stress-corrosion cracking (SCC) are presented. This paper also contrasts the range of mechanical properties available in precipitation-hardened materials with properties of cold-worked alloys. | Net or large phytoplankton species composition and most phytoplankton abundance was measured at three OTEC sites. In the Gulf of Mexico and'Hawaii, diatoms dominated while the blue-green algae Trichodesmium was most common at Puerto Rico. The species ratio of diatoms to dinoflagellates was approximately 1:1. The species diversity varied from site to site, Hawaii > Puerto Rico > Gulf of Mexico. Chlorophyll a, which is a measure of the pigment of all algae size ranges, showed a subsurface peak of 0.14 to 0.4 g per liter at 75 to 125 m. Occasional surface peaks upto 0.4 ..mu..g per liter occurred. Further refinement of collection techniques is needed to delineate the subtle environmental effects expected by OTEC plant discharges. | eng_Latn | 18,991 |
Combination of the mutation process with the sensitization and repair processes leading to increased frequencies of mutations in algal populations | The possibility of using a combination of the mutation process with the induction of the repair processes has been studied to increase the mutation frequencies in algal populations after UV-treatment. From this study it follows that the repair process induced by visible light is much more effective than the dark repair processes in the chlorococcal algae used. In these algae, visible light perhaps does not induce only those repair processes which affect their DNA, but probably also some recovery ones which affect their damaged structures and physiological functions. A suitable combination of the sensitization of algal cells by a DNA-base analogue before UV-treatment and the induction of the light repair and recovery processes resulted in a rather high increase of viable mutations in chlorococcal algae. These findings may be useful in the breeding of chlorococcal algae, which have no possibility of hybridization (except somatic). | Understanding the susceptibility of coastal ecosystems to nutrient loads from anthropogenic sources and the extent of eutrophication in subtropical and tropical estuaries is still a challenge. This study assessed eutrophication in Guaymas Bay, a subtropical lagoon that receives nutrient-rich urban wastewater discharges. Eutrophication was evaluated by means of the Assessment of Estuarine Trophic Status model. Our results showed that the trophic status of Guaymas Bay was “good.” It is important to consider that: (1) the dissolved oxygen and chlorophyll a levels observed are indicative of a healthy ecosystem, and (2) the key factors explaining this finding are the high susceptibility to eutrophication of the lagoon and the dominance of macroalgae species that respond to nutrient enrichment. This implies that the Overall Eutrophic Condition Index of the Assessment of Estuarine Trophic Status model is a valuable tool for use as an eutrophication indicator based on the abundance of primary producers (macroalga... | eng_Latn | 18,992 |
PHYTOPLANKTON AND BIOMASS DISTRIBUTION AT POTENTIAL OTEC SITES | Net or large phytoplankton species composition and most phytoplankton abundance was measured at three OTEC sites. In the Gulf of Mexico and'Hawaii, diatoms dominated while the blue-green algae Trichodesmium was most common at Puerto Rico. The species ratio of diatoms to dinoflagellates was approximately 1:1. The species diversity varied from site to site, Hawaii > Puerto Rico > Gulf of Mexico. Chlorophyll a, which is a measure of the pigment of all algae size ranges, showed a subsurface peak of 0.14 to 0.4 g per liter at 75 to 125 m. Occasional surface peaks upto 0.4 ..mu..g per liter occurred. Further refinement of collection techniques is needed to delineate the subtle environmental effects expected by OTEC plant discharges. | AbstractObjective: The objective of this study was to enhance the solubility and bioavailability of Lupeol.Methods: Utilizing a thin-film dispersion method, we prepared Lupeol-loaded PEGylated lipo... | yue_Hant | 18,993 |
which biome is also called mediterranean | This biome actually goes by several names. It is found surrounding large parts of the Mediterranean Sea and is thus sometimes called the Mediterranean Biome, others call it a Woodland Biome, while others call it a Shrub or Chaparral Biome.Chaparral Community near Malibu, California.arge animals simply can't stand the heat of day in many of these locations, and it's hard for a large animal to burrow. Mediterranean Gecko-Hemidactylus turcicus. Left: The Mediterranean Gecko is a nocturnal insectivore of the Mediterranean Biome. | The Mediterranean Biome This biome actually goes by several names. It is found surrounding large parts of the Mediterranean Sea and is thus sometimes called the Mediterranean Biome, others call it a Woodland Biome, while others call it a Shrub or Chaparral Biome. | eng_Latn | 18,994 |
what are tundra | Definition of tundra for English Language Learners. : a large area of flat land in northern parts of the world where there are no trees and the ground is always frozen. | Tundra. The tundra is a treeless polar desert found in the high latitudes in the polar regions, primarily in Alaska, Canada, Russia, Greenland, Iceland, and Scandinavia, as well as sub-Antarctic islands. The region's long, dry winters feature months of total darkness and extremely frigid temperatures.undra. The tundra is a treeless polar desert found in the high latitudes in the polar regions, primarily in Alaska, Canada, Russia, Greenland, Iceland, and Scandinavia, as well as sub-Antarctic islands. The region's long, dry winters feature months of total darkness and extremely frigid temperatures. | eng_Latn | 18,995 |
what is the taiga known as | The Taiga is a biome which is also known as a boreal forest. Consisting of mostly coniferous forests. It is the worlds biggest biome. Winter in the Taiga lasts around 5 - 7 mo ⦠nths, with average temperatures below freezing. Temperatures vary throughout the year from â54 °C to 30 °C (-65 °F to 86 °F). | What is taiga? what is the taiga? what landforms are in a taiga? what is a taiga? what can you do at the taiga? products from the taiga? more. The taiga shield ecozone is located on both sides of hudson bay, with the eastern the landforms have been largely shaped by glaciation during the last ice age.ther Sites. ------------------------------------. Site About. ----------------------------------. Taiga landforms Taiga is the russian word for forest and is the largest biome in the world contents: ecosystem overview, landforms and climate, plants, wildlife, and human activities. | eng_Latn | 18,996 |
what habitats are found in a tundra | Tundra Biome Flora. There are also quite a few types of plants found in the tundra biome. They include Arctic Willow, Arctic Moss, Caribou Moss, and Tufted Saxifrage. In this particular biome, the bitter cold makes it hard for most types of plants to survive.undra Biome Flora. There are also quite a few types of plants found in the tundra biome. They include Arctic Willow, Arctic Moss, Caribou Moss, and Tufted Saxifrage. In this particular biome, the bitter cold makes it hard for most types of plants to survive. | One of the most common plants in the Tundra are lichen. Lichen is a decomposer made of plants and fungus working together. Lichen can live in the Tundra because they can be close to the ground and can have short roots.rmines, arctic foxes, wolverine,lemmings, arctic wolves, tundra wolves, snowy owls, Caribou, arctic hares, musk oxen and of course, the polar bear,are all included in the Tundra biome. | eng_Latn | 18,997 |
what is a biome ks2 | A depositional feature along a shoreline of a river, lake or the sea. Biome KS2 A biome is a large area on the Earth's surface that is defined by the types of animals and plants living there (www.geographyforkids.com) An area of the world whose flora and fauna is determined by climatic conditions.Characteristics KS2 A distinguishing quality, attribution or trait.limate KS2 The long term prevalent weather conditions of an area, determined by latitude, altitude etc. Average weather conditions of a place, including rainfall and temperature. Coast KS1 The line or zone where the land meets the sea. The boundary between land and sea. | All photos © of K2C Biosphere Region | [email protected] |. Website designed by Bushveld Connections. In Southern Africa seven biomes are found, namely Fynbos, Savannah, Grassland, Nama-Karoo, Succulent Karoo, Desert and Forest.Each of these biomes is classified according to rainfall, dominant life forms and other structural characteristics.ll photos © of K2C Biosphere Region | [email protected] |. Website designed by Bushveld Connections. In Southern Africa seven biomes are found, namely Fynbos, Savannah, Grassland, Nama-Karoo, Succulent Karoo, Desert and Forest. | eng_Latn | 18,998 |
five unique characteristics of the coniferous biome | Taiga Biome Facts. The taiga biome is the largest terrestrial biome and extends across Europe, North America, and Asia. It is located right below the tundra biome. The taiga biome is also known as coniferous forest or boreal forest.This biome typically has short, wet summers and long, cold winters. Precipitation is moderate in the taiga. It gets plenty of snow during the winter and plenty of rainfall during the summer.aiga Biome Facts. The taiga biome is the largest terrestrial biome and extends across Europe, North America, and Asia. It is located right below the tundra biome. The taiga biome is also known as coniferous forest or boreal forest. | LOCATION: Taiga, also known as coniferous or boreal forest, is the largest terrestrial biome on earth. It extends in a broad band across North America, Europe, and Asia to the southern border of the arctic tundra.recipitation is relatively high in the taiga and falls as snow during the winter and rain during the summer. The total yearly precipitation in the taiga biome is 10 - 30 inches (25 - 75 cm). PLANTS: Compared to other biomes, the taiga has less diversity in plant life. | eng_Latn | 18,999 |
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