scholarly journals Effects of thermocline deepening on lake plankton communities

2011 ◽  
Vol 68 (2) ◽  
pp. 260-276 ◽  
Author(s):  
Ariane Cantin ◽  
Beatrix E. Beisner ◽  
John M. Gunn ◽  
Yves T. Prairie ◽  
Jennifer G. Winter
Keyword(s):  
Taxonomic Composition ◽  
Zooplankton Biomass ◽  
Phytoplankton Production ◽  
Thermocline Depth ◽  
Turbulent Environments ◽  
Planktonic Food ◽  
Basin Scale ◽  
Zooplankton Communities ◽  
The Vertical Distribution ◽  
Plankton Communities

Theory predicts, and some evidence demonstrates that in lakes, the depth of the thermocline can have a large structural influence on the spatial distribution, and strongly influences the composition of plankton communities. However, experimental assessments of responses of the planktonic food web to thermocline depth have not yet been done at the whole-basin scale. We conducted an experiment wherein we artificially lowered the thermocline in an isolated basin of a three-basin lake, maintaining another isolated basin as a control. The vertical distribution and taxonomic composition of both phytoplankton and zooplankton were monitored throughout the summer months. Greater phytoplankton production, especially in the epilimnion, attributable mainly to increases in the chlorophytes was observed with thermocline deepening, but at the deepest thermoclines, production was limited. Total zooplankton biomass was unaffected by thermocline depth, suggesting top-down control by predators. Zooplankton biomass peaks were less pronounced in the manipulated basin, but tended to follow the thermocline whether at its normal position or as it was deepened. Zooplankton composition was significantly altered by large increases in densities of predatory cyclopoid copepods and rotifers; taxa commonly found in turbulent environments. Overall, both phytoplankton and zooplankton communities demonstrated important shifts in structure and composition in response to thermocline deepening.

scholarly journals Short Communication: Zooplankton as indicator of trophic status of lakes in Ilmen State Reserve, Russia

2021 ◽  
Vol 22 (3) ◽  
Author(s):  
Irina V. Mashkova ◽  
Anastasiya Kostryukova ◽  
Elena Shchelkanova ◽  
Viktor Trofimenko
Keyword(s):  
Trophic Status ◽  
Short Communication ◽  
Ecological Status ◽  
Taxonomic Composition ◽  
Zooplankton Biomass ◽  
Taxonomic Structure ◽  
The Status ◽  
Ilmen State Reserve ◽  
Chelyabinsk Region ◽  
Zooplankton Communities

Abstract. Mashkova IV, Kostryukova AM, Shchelkanova EE, Trofimenko VV. 2021. Short Communication: Zooplankton as indicator of trophic status of lakes in Ilmen State Reserve, Russia. Biodiversitas 22: 1448-1455. Zooplankton is a potentially powerful tool for assessing the trophic state of aquatic ecosystems. The current paper studied taxonomic composition and biomass of zooplankton communities in ten lakes within Ilmen State Reserve, Chelyabinsk region, Russia and identified the influence of trophic status on its formation. Integrated samples were taken from epilimnion in the summer of 2016-2019. Several criteria were used to determine trophic status: the taxonomic structure and biomass of zooplankton; some hydroecological indicators some hydroecological indicators and the Carlson index. The trophic status of the studied lakes, determined based on the zooplankton biomass, revealed that most of the lakes were in the status of mesotrophic. The number of zooplankton species in the lakes was 44 with Pleuroxus laevis, Bosmina longirostris, Simocephalus vetulus were the most numerous species in mesotrophic lakes; while Chaetonotus ploenensis, Keratella quadrata frenzeli, Leptodora kindti are rare. Zooplankton communities of Bolshoye Miassovo and Maloye Miassovo Lakes were characterized by high species diversity and considered as one of the most significant among the foothill lakes of the eastern slope of South Ural. The study reveals that hydroecological assessment of the ecological status is not exactly precise, as values are not stable and can change not only under the anthropogenic influence but also due to many natural abiotic environmental factors. The research shows that species composition and biomass of zooplankton communities could provide a more accurate assessment of the trophic status of water-bodies.

Cladoceran- and copepod-dominated zooplankton communities graze at similar rates in low-productivity lakes

1998 ◽  
Vol 55 (2) ◽  
pp. 414-422 ◽  
Author(s):  
Hélène Cyr
Keyword(s):  
Zooplankton Community ◽  
Grazing Rate ◽  
Taxonomic Composition ◽  
Zooplankton Biomass ◽  
Phytoplankton Assemblage ◽  
Different Types ◽  
The Difference ◽  
Zooplankton Communities ◽  
Copepod Biomass

Many studies suggest that the taxonomic composition of a zooplankton community should determine its grazing rate and selectivity for different types of particles. It is generally believed that copepod-dominated communities should (i) have lower grazing rates and (ii) consume larger particles than communities dominated by large cladocerans. I tested these hypotheses in situ by comparing zooplankton grazing in 19 communities from low-productivity lakes where the zooplankton ranged from >99% copepod biomass to >90% large cladoceran biomass (Holopedium gibberum, Daphnia spp.). The zooplankton grazed 1-14% of total chlorophyll per day and 0-17% of the chlorophyll in algae <35 µm per day. Grazing rates increased with increasing zooplankton biomass (r2 = 0.34, P < 0.01), but once the effect of zooplankton biomass was accounted for, similar grazing rates were found in copepod- and in cladoceran-dominated communities. The difference in grazing rates on small algae and on the whole phytoplankton assemblage, on the other hand, varied systematically with zooplankton taxonomic composition. Holopedium-dominated communities were most efficient at grazing algae <35 µm, Bosmina-dominated communities had similar grazing rates on algae <35 µm and on the whole phytoplankton assemblage, and copepod-dominated communities had similar or slightly higher grazing rates on the whole phytoplankton assemblage. Qualitative differences in grazing selectivity of different zooplankton taxa are observed in complex natural communities.

scholarly journals FEATURES OF FORMATION OF THE WINTER PLANKTON COMMUNITIES IN THE NEFTEGAVAN (“OIL HARBOUR”) - MAKHACHKALA AREA OF THE MIDDLE COASTAL CASPIAN

2020 ◽  
pp. 12-19
Author(s):  
Magomed Magomedovich OSMANOV ◽  
Ayshat Abdulmajidovna ABDURAKHMANOVA
Keyword(s):  
Coastal Waters ◽  
Taxonomic Composition ◽  
Winter Period ◽  
Water Plants ◽  
Zooplankton Communities ◽  
High Degree ◽  
Degree Of Similarity ◽  
Plankton Communities ◽  
Pelagic Ecosystems

Made has been the analysis of the pelagic ecosystems state in the Western coastal waters of the Middle Caspian in winter period of 2020 in the Neftegavan area, Seaport of Makhachkala. The taxonomic composition of phytoplankton and zooplankton communities, and the density of hydrobionts inhabiting them have been determined. It is noted that in phytocenoses during mass blossom of Rhizosolenia calcar avis (Schultze,1843) the diatom water plants (Bacillariophyta) dominated, and in zooplankton communities the paddle-footed crustaceans, mainly acarcidis ( Acartai tonsa Dana,1843) dominated on abundance. All sampling stations were characterized by a high degree of similarity of phyto-zooplankton in taxonomic composition but they differed significantly in number and biomass.

Grazing by Zooplankton and Its Relationship to Community Structure

1992 ◽  
Vol 49 (7) ◽  
pp. 1455-1465 ◽  
Author(s):  
Hélène Cyr ◽  
Michael L. Pace
Keyword(s):  
Community Structure ◽  
Water Temperature ◽  
Size Distribution ◽  
Grazing Rate ◽  
Food Concentration ◽  
Taxonomic Composition ◽  
Zooplankton Biomass ◽  
Substantial Portion ◽  
Zooplankton Size ◽  
Zooplankton Communities

Zooplankton can consume a substantial portion of the phytoplankton, but grazing rates are notoriously variable seasonally and among sites. We developed models relating grazing rates to characteristics of Zooplankton communities, food concentration, and water temperature. Grazing rates were measured in 30 Zooplankton communities that differed in biomass, size distribution, and taxonomic composition. Crustaceans grazed per day 2–21% of the chlorophyll in algae <35 μm, which is within the range of most grazing rates measured in other studies. Grazing rates were positively related to Zooplankton biomass and negatively related to food concentration, although much variation among communities remains unexplained (R2 = 0.19–0.35). Surprisingly, we could not detect a general relationship between Zooplankton size distribution and grazing rate. Communities dominated by large Zooplankton (mostly Daphnia and Diaphanosoma) did not tend to have higher grazing rates than communities dominated by small Zooplankton. Zooplankton taxonomic composition was significantly related to grazing rates but explained little variation among communities. Grazing rates calculated from published allometric equations were biased, usually overestimating phytoplankton removal by Zooplankton.

Changes in the planktonic food web of a new experimental reservoir

1997 ◽  
Vol 54 (5) ◽  
pp. 1088-1102 ◽  
Author(s):  
M J Paterson ◽  
D Findlay ◽  
K Beaty ◽  
W Findlay ◽  
E U Schindler ◽  
...  
Keyword(s):  
Organic Matter ◽  
Bacterial Biomass ◽  
Zooplankton Community ◽  
Zooplankton Biomass ◽  
Phytoplankton Production ◽  
First Year ◽  
Terrestrial Vegetation ◽  
Terrestrial Organic Matter ◽  
Planktonic Food ◽  
Before And After

Changes in plankton community structure were examined in an experimental reservoir (Lake 979) before and after impoundment. The role of allochthonous organic matter in planktonic food webs is unclear, and reservoir creation can be viewed as an extreme manipulation of terrestrial organic matter inputs. After impoundment of Lake 979, concentrations of phosphorus, nitrogen, and dissolved organic carbon increased as a result of decomposition of flooded terrestrial organic matter. In the first year of impoundment, mean bacterial biomass increased 10 times , and individual bacterial cell volumes increased 2 times over pre-flooding averages. Phytoplankton production and biomass decreased to approximately 25% of pre-flooding levels. Zooplankton biomass and production by Cladocera increased 10 times , and zooplankton community composition changed from dominance by small-sized Bosmina longirostris to dominance by large Daphnia rosea. In the first year of impoundment, production by Cladocera usually exceeded phytoplankton14C productivity, suggesting that the main pathway of carbon flow to secondary producers shifted from an autochthonous to an allochthonous base derived from flooded terrestrial vegetation. In the second year of flooding, bacterial biomass decreased and phytoplankton biomass was higher than in the two previous years of study.

scholarly journals A biodiversity survey on the planktonic protistan grazers of the Gulf of Naples (Italy)

2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Gabriele Del Gaizo ◽  
Luca Russo ◽  
Maria Abagnale ◽  
Angela Buondonno ◽  
Marta Furia ◽  
...  
Keyword(s):  
Light Availability ◽  
Taxonomic Composition ◽  
Primary Producers ◽  
Biodiversity Survey ◽  
Gulf Of Naples ◽  
Unicellular Eukaryotes ◽  
Planktonic Food ◽  
Multicellular Organisms ◽  
Plankton Communities ◽  
Made In

Plankton communities include both unicellular and multicellular organisms. An important unicellular component is represented by those protists (i.e., unicellular eukaryotes) that are non-strictly autotrophic organisms and consume bacteria and other protists. These organisms are an important link between primary producers and metazoans and are usually known as microzooplankton, protozooplankton, or mixoplankton, as many of them couple phagotrophic and photoautotrophic behaviours. Herein we report on the diversity of these organisms sampled at two sampling sites (coastal and offshore stations), at two depths (0 and 10 m), in the Gulf of Naples during the early autumn of 2020. Despite efforts to list plankton biodiversity of primary producers and metazoan grazers made in this area so far, protistan grazers are still poorly investigated and previous information date back to decades ago. Our survey identified dinoflagellates and oligotrich ciliates as the most abundant groups, while tintinnids were less quantitatively relevant. The taxonomic composition in samples investigated herein remarked that reported by previous studies, with the sole exception of the tintinnid Ascampbeliella armilla, which was never reported before. A coastal-offshore gradient in the taxonomical composition of protistan grazers was also observed, with some species more abundant within coastal waters and other better thriving in offshore ones. Surface and sub-surface communities also differed in terms of species composition, with the deeper communities in the two sites being more similar reciprocally than with communities at the surface. These differences were associated with distinct environmental conditions, such as light availability, as well with the standing feeding environment, arising potential implications in the functioning of the planktonic food web at the local scale.

scholarly journals Drivers of trophic amplification of ocean productivity trends in a changing climate

2014 ◽  
Vol 11 (24) ◽  
pp. 7125-7135 ◽  
Author(s):  
C. A. Stock ◽  
J. P. Dunne ◽  
J. G. John
Keyword(s):  
Food Web ◽  
21St Century ◽  
Trophic Level ◽  
Net Primary Production ◽  
Trophic Levels ◽  
The Arctic ◽  
Phytoplankton Production ◽  
Planktonic Food ◽  
Projected Changes ◽  
Zooplankton Growth

Abstract. Pronounced projected 21st century trends in regional oceanic net primary production (NPP) raise the prospect of significant redistributions of marine resources. Recent results further suggest that NPP changes may be amplified at higher trophic levels. Here, we elucidate the role of planktonic food web dynamics in driving projected changes in mesozooplankton production (MESOZP) found to be, on average, twice as large as projected changes in NPP by the latter half of the 21st century under a high emissions scenario in the Geophysical Fluid Dynamics Laboratory's ESM2M–COBALT (Carbon, Ocean Biogeochemistry and Lower Trophics) earth system model. Globally, MESOZP was projected to decline by 7.9% but regional MESOZP changes sometimes exceeded 50%. Changes in three planktonic food web properties – zooplankton growth efficiency (ZGE), the trophic level of mesozooplankton (MESOTL), and the fraction of NPP consumed by zooplankton (zooplankton–phytoplankton coupling, ZPC), explain the projected amplification. Zooplankton growth efficiencies (ZGE) changed with NPP, amplifying both NPP increases and decreases. Negative amplification (i.e., exacerbation) of projected subtropical NPP declines via this mechanism was particularly strong since consumers in the subtropics have limited surplus energy above basal metabolic costs. Increased mesozooplankton trophic level (MESOTL) resulted from projected declines in large phytoplankton production. This further amplified negative subtropical NPP declines but was secondary to ZGE and, at higher latitudes, was often offset by increased ZPC. Marked ZPC increases were projected for high-latitude regions experiencing shoaling of deep winter mixing or decreased winter sea ice – both tending to increase winter zooplankton biomass and enhance grazer control of spring blooms. Increased ZPC amplified projected NPP increases in the Arctic and damped projected NPP declines in the northwestern Atlantic and Southern Ocean. Improved understanding of the physical and biological interactions governing ZGE, MESOTL and ZPC is needed to further refine estimates of climate-driven productivity changes across trophic levels.

scholarly journals Ice-on and ice-off dynamics of ciliates and metazooplankton in the Łuczański Canal (Poland)

2020 ◽  
Vol 54 (4) ◽  
pp. 1121-1134
Author(s):  
Krystyna Kalinowska ◽  
Maciej Karpowicz
Keyword(s):  
Field Experiments ◽  
Cold Water ◽  
Ice Cover ◽  
Zooplankton Biomass ◽  
Zooplankton Grazing ◽  
Top Down ◽  
Cover Time ◽  
Trophic Coupling ◽  
Cold Water Temperature ◽  
Zooplankton Communities

Abstract The ciliate–metazooplankton trophic coupling is well documented from both laboratory and field experiments. The knowledge about these relationships during winter ice-covered periods is very scarce. The abundance and composition of planktonic ciliates, rotifers and crustaceans were studied during the ice-covered and ice-free periods in the Łuczański Canal (Masurian Lakeland, Poland). We hypothesised that in winter, rotifers play a major role in the top-down control of ciliates and that ciliate–metazooplankton relationships differ not only between the ice-covered and ice-free periods, but also between ice-covered months. Our study showed that ciliates formed a significant part of zooplankton biomass during the winter ice-covered period when crustaceans occurred in very low abundances. Despite cold water temperature and the presence of ice cover, time was probably a cue that initiates zooplankton development. The ciliate, rotifer and crustacean numbers and biomass, as well as chlorophyll a concentrations, were lower in February than in ice-free periods. In the winter month with ice cover, bottom-up control by resources was more important than top-down control by zooplankton grazing in regulating ciliates. In the spring month with ice cover, crustaceans and rotifers may include ciliates as an important part of their diets. In April, the studied groups of organisms were not related to each other in contrast to the summer, when zooplankton communities were closely related to each other. In autumn, rotifers may play an important role in controlling ciliates. The abundance, composition and ciliate–metazoan relationships can vary considerably not only across seasons, but also across ice-covered months.

Crustacean Plankton Communities in Forty-Five Lakes in the Experimental Lakes Area, Northwestern Ontario

1971 ◽  
Vol 28 (2) ◽  
pp. 231-244 ◽  
Author(s):  
Kazimierz Patalas
Keyword(s):  
Common Species ◽  
Medium Size ◽  
Experimental Lakes Area ◽  
Northwestern Ontario ◽  
Lake Morphology ◽  
Diaptomus Oregonensis ◽  
Crustacean Plankton ◽  
Limnocalanus Macrurus ◽  
Zooplankton Communities ◽  
Plankton Communities

Zooplankton communities were characterized on the basis of samples taken in summer as vertical net hauls in the central part of lakes. Twenty-eight species of crustaceans were found in the 45 lakes studied. The highest number of species as well as the highest numbers of individuals (per unit of area) usually occurred in the largest deepest lakes with most transparent water.The most common species were: Bosmina longirostris, Tropocyclops prasinus mexicanus, Mesocyclops edax, Diaptomus minutus, Holopedium gibberum, and Cyclops bicuspidatus thomasi. Daphnids were rather scarcely represented.Senecella calanoides, Limnocalanus macrurus, and Diaptomus sicilis were confined to rather deeper lakes, whereas Diaptomus oregonensis was found mostly in smaller shallower lakes and Diaptomus leptopus in very small, but relatively deep lakes. Diaptomus minutus and C. b. thomasi, though widely distributed, showed a preference for deeper lakes, whereas T. p. mexicanus tended towards smaller shallower lakes.In particular lakes, the number of dominants ranged between 1 and 5, but three dominants per lake was the most commonly encountered case. The simplest community was composed of one cyclopoid, though the most common consisted of one cyclopoid, one diaptomid, and one cladoceran.Four types of communities were distinguished, each of them characteristic for a group of lakes of specific size and depth: (I) in the largest and deepest lakes (389–1007 ha of area, 30–117 m maximum depth); (II) in lakes of medium size and depth (6.5–200 ha, 4.8–33 m); (III) in small and very shallow lakes (3.1–28 ha, 2.7–7.3 m); (IV) in very small lakes with medium depth (1.3–3.7 ha, 6.1–12.8 m).The high degree of similarity between the plankton communities of the Experimental Lakes Area (ELA) and southern Ontario, as well as of some Great Lakes, suggest that they all basically belong to the same zoogeographical area.The fact that most species were distributed evenly throughout ELA may indicate the relative uniformity of the area. In ELA, lake morphology is mainly responsible for defining the type of community.

Modelling the Initiation of Spring Phytoplankton Blooms: a Synthesis of Physical and Biological Interannual Variability off Southwest Nova Scotia, 1983–85

1989 ◽  
Vol 46 (S1) ◽  
pp. s183-s199 ◽  
Author(s):  
R. Ian Perry ◽  
Peter C. F. Hurley ◽  
Peter C. Smith ◽  
J. Anthony Koslow ◽  
Robert O. Fournier
Keyword(s):  
Nova Scotia ◽  
Mixed Layer ◽  
Phytoplankton Bloom ◽  
Mixed Layer Depth ◽  
Critical Value ◽  
Zooplankton Biomass ◽  
Phytoplankton Production ◽  
Spring Phytoplankton Bloom ◽  
Turbulent Dissipation ◽  
Differential Advection

Chlorophyll and nitrate data from monthly surveys off southwest Nova Scotia indicate the spring phytoplankton bloom began near the end of March of each year, occurring early (late) in 1984 (1983). The highest chlorophyll biomass(all months) was found in 1985. Using survey data, the Sverdrup hypothesis for the initiation of the bloom was tested by comparing the critical depth, Zcr, for net phytoplankton production to the observed mixed-layer depth, Zmix. Survey median Zcr/Zmix were consistently less than 1 until May, suggesting that observed blooms were initiated by events outside the specific survey periods. Results of a mixed-layer model incorporating surface heating, differential advection and turbulent dissipation by wind and tide showed reasonable agreement with observed mixed depths, and patterns of the mean (modelled) mixed-layer light intensity are significantly correlated with observed chlorophyll biomass. In 1983 and 1984, mean light intensities first exceeded the critical value for a bloom to occur in late March. In 1985, transient periods of stratification in mid-February and early March produced intensities greater than the critical value. These events, together with higher nitrate concentrations and lower Zooplankton biomass, appear to be responsible for the high chlorophyll biomass observed in 1985.

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