Taxonomic Composition Of Zooplankton Research Articles

Zooplankton in brackish water bodies of the plain territory of the Altai territory in the vegetation season of 2022

The zooplankton of three small brackish lakes (Bulatovo, Korostelevskoye and Markovskoye) located in the plain territory of Altai Krai was studied in 2022. Data on the main characteristics of the zooplankton habitat are presented. An assessment of the ecological state of lakes is given based on qualitative and quantitative indicators of zooplankton. The taxonomic composition and main quantitative characteristics of zooplankton in the spring, summer and autumn periods are characterized. Seasonal dynamics of quantitative indicators and changes in the taxonomic composition of zooplankton were noted. The lowest quantitative indicators of zooplankton development were noted in the spring season (April). All identified representatives of zooplankton were cosmopolitans. Common to all lakes are 5 taxa of crustaceans and rotifers (Keratella quadrata, Filinia longiseta, Daphnia magna, Cyclopidae ind., Diaptomidae ind.). In the spring and autumn seasons, copepods dominated in abundance and biomass, reaching 99.9% of the zooplankton population. Differences in the composition of the dominant taxa in the summer season were noted between the lakes. In the lake Bulatovo was dominated in numbers by rotifers due to Brachionus quadridentatus, and in biomass by cladocerans due to Daphnia magna. In the lake Korostelevskoe, the dominant taxonomic group in terms of numbers was copepods, the basis of which were Diaptomidae ind., in terms of biomass — cladocerans due to Diaphanosoma brachiurum. Only in the lake In Markovskoe, copepods — Diaptomidae ind. — dominated in numbers and biomass. The zooplankton of the studied lakes was characterized by a poor species composition, but high summer numbers and biomass (from 342 thou. eq./m3 and 7.13 g/m3 in Lake Markovskoe to 1895 th. eq./m3 and 33.7 g/m3 in Lake Bulatovo). In the summer season, the zooplankton biomass of the lake. Markovskoye belonged to reservoirs of the α-eutrophic type, lakes Bulatovo and Korostelevskoye were of the polytrophic type. The majority of noted species (60%) were indicators of β-mesosaprobic conditions.

Tracking dietary fatty acids in triacylglycerols and phospholipids of zooplankton

Abstract Fatty acids (FA) in lake zooplankton are largely provided by dietary FA and affected by taxonomic composition of zooplankton, temperature, and other environmental conditions. However, the extent to which dietary FA are retained and/or bioconverted in zooplankton remains unclear. In this lake study, we examined how dietary FA (seston), temperature and physico‐chemical variables (i.e., concentrations of chlorophyll a, dissolved organic carbon, nitrate, ammonium, phosphate) explained the FA variation in membrane (phospholipids; PL) and storage (triacylglycerols; TAG) lipids of zooplankton. We tested the hypotheses that: (1) increasing dietary FA increases the FA content stored as TAG by zooplankton, whereas the FA content in PL remains unaffected by naturally occurring changes in dietary FA supply; and (2) FA in seston better predict the FA variations stored by zooplankton as TAG, whereas lake temperature better predicts the FA variations in zooplankton PL. Results show that an increase in dietary polyunsaturated FA increased polyunsaturated FA in TAG and PL of zooplankton, but not eicosapentaenoic acid or docosahexaenoic acid in PL. Moreover, the FA content of seston was more similar to that of zooplankton TAG than it was to the content of PL, indicating major taxon‐specific differences in membrane FA. Dietary FA are a major predictor of FA in TAG of zooplankton, while the taxonomic composition of zooplankton is a major predictor of FA in PL. Temperature and physico‐chemical variables explained little of the variations in zooplankton FA. This field study improves our understanding of how FA in PL and TAG of different zooplankton taxa respond to changes of dietary FA, temperature, concentrations of chlorophyll‐a, dissolved organic carbon, nitrate, ammonium, and phosphate to fulfil their physiological requirements.

Temporal variation in prey selection by adult European sardine (Sardina pilchardus) in the NW Mediterranean Sea

In the North-Western Mediterranean Sea (NWMS), changes in size and taxonomic composition of zooplankton have been hypothesized to underlie observed changes in populations of Sardina pilchardus, one of the main small pelagic fish species. The present study was undertaken to better understand the link between the temporal variability of zooplankton and the diet of adult sardine in the Bay of Marseille over a period of 16 months by comparing the taxonomic and prey size composition of sardine stomach content with net-collected zooplankton samples from a fixed station. A greater similarity was found between sardine stomach content and 80-μm mesh size net samples than with the traditionally used 200-μm net samples. Sardine showed a high diet plasticity over the entire study period, covering a broad diversity of prey species and a wide prey size range (ranging from 400 to 1000 μm in measured total length), including a lot of small copepods (Microsetella/Macrosetella spp., Corycaeidae and Oncaeidae). The most consumed prey groups were not necessarily the most abundant in the zooplankton sampled with nets, suggesting potential prey selection. Sardine showed most often an opportunistic selective predation on larger individuals for most taxonomic prey groups. Results highlighted the diet flexibility of sardine between months and showed seasonal variation in prey size, suggesting a continuous filter-feeding mode on relatively small prey when prey densities were high and more frequent selective particulate-feeding on larger prey when prey densities were low. Sardines were able to feed on a wide diversity of prey and size range and thus to shift their diet between months. This ability probably allows them to adapt to high spatial and temporal variability of the zooplankton community in a context of both human-induced and climatic changes.

Geoenvironmental Implications and Biocenosis of Freshwater Lakes in the Arid Zone of East Kazakhstan

Steppe and semi-desert lakes of Central Asia represent unique and still poorly known aquatic ecosystems. The paper provides summaries of multi-proxy environmental and biological investigations of the previously unexplored ground of Sibe lakes in the naturally pristine zone of East Kazakhstan, and of their contributions to people. Data on the taxonomic composition of zooplankton and zoobenthos of these freshwater lacustrine basins are presented in terms of the species’ frequency of occurrence; the abundance of the aquatic biomass and the analyzed water geochemical variables insofar as they are dependent and correlative. The qualitative and quantitative records display variability in the biocenosis diversity due to the lakes’ geochemistry and hydrology differences—some lakes being oligotrophic and others being moderately trophic. In the latter case, the lakes characterized by an increased macrozoobenthos biomass are favourable for local ichthyofauna. Sapro-biological analysis reveals the predominance of β-saprobic species in the zooplankton composition pointing to slight or moderate pollution of surface waters due to natural biotic substances. This observation is in agreement with differences in the water quality of solitary lakes. The uneven distributions of benthic invertebrates (in terms of taxonomy and species populations) in the water bodies suggest specific hydro-ecological conditions that predetermine the structure of the lakes’ biocenosis. The littoral part of the lakes is characterized by the highest abundance of zooplankton and benthic fauna. The Sibe lakes are an example of an autonomous functioning of the lacustrine basins in the upland arid steppe zone, which is characterized by pronounced climate “continentality” and a high level of the sub-aquatic flora and fauna endemism. The present results are relevant to the understanding of the ecosystems’ dynamics and the modern anthropogenic impacts upon the pristine parkland-steppe landscapes of Central Asia, with implications for regional nature protection and sustainable eco-recreation.

Taxonomic and size structures of zooplankton communities in the fjords along the Atlantic water passage to the Arctic

Abstract Current climate change is significantly modifying Arctic ecosystems and their components, but the reference and direction of these changes are still undefined. The aim of this study was to provide well-grounded data on the present composition and structure of zooplankton from boreal to Arctic latitudes. This comparative study was performed with a unified methodology in six fjords located along the west coasts of Norway and Svalbard. Comparisons between the fjords' environmental characteristics (temperature, salinity, chlorophyll, and particles) and the zooplankton community, described with several metrics (abundance and biovolume) and traits (taxonomy and size), were performed to recognise the potential of various ecological indicators for future monitoring. While hydrography and the taxonomic composition of zooplankton were specific to each fjord and changed along the latitudinal environmental gradient, the clustering of particle characteristics (size, concentration, and transparency) and zooplankton size structures alludes to their susceptibility to additional, local processes. The differences in the biotic and abiotic characteristics distinguished the semi-closed fjords from the fjords prone to Atlantic water advection. The fjords with a limited water mass exchange incorporated local or Arctic-type waters and were host to specific zooplankton communities and particles, with the marked presence of species adapted to high particle concentrations (Microsetella norvegica) or species of Arctic affiliation (Calanus glacialis). In the open fjords, zooplankton communities were characterised by the predomination of Oithona similis and Calanus finmarchicus, confirming influence of Atlantic water. The zooplankton community size structure, expressed as abundance, was mainly shaped by changes in the contributions of small copepods, whereas the size structure expressed as biovolume reflected the differences in the co-occurring sibling species of Calanus spp. and/or differences in their dominating life stages. The results of this integrative across-system study constitute a necessary baseline for the future monitoring of changes in the zooplankton communities, which are likely to occur in response to climate change at high latitudes.

The Effect of Glacier Recession on Benthic and Pelagic Communities: Case Study in Herve Cove, Antarctica

Changes in macrobenthic and pelagic communities in the postglacial, partially isolated, lagoon Herve Cove in Admiralty Bay, King George Island, were investigated 15 years after the first comprehensive studies had been conducted in this region. The bottom area of the cove has enlarged from approximately 12 ha to 19 ha after the retreat of the Dera Icefall. Based on a photographic survey of the benthos and taxonomic composition of zooplankton, ecological succession and the colonization of new species have been observed. Several new species occur such as gastropods, seastars, sea urchins and isopods, and their presence in different parts of the cove, as well as breeding aggregations suggests that they reproduce there. The influence of glacial streams is notable in bottom assemblages. We propose that Herve Cove is a good research area for studies on ecological succession in newly opened areas. The colonization of this lagoon has been recognized to be in its developing stage, and research should be continued.

Early Summer Zooplankton in the Sea of Azov during the Period of Its Salinization

Data on the taxonomic composition of zooplankton in the Sea of Azov and Taganrog Bay are presented for the period of 2005–2015. The main plankton communities have been identified and the changes in the taxonomic diversity of plankton animals and their community structure caused by sea salinization have been analyzed. The salinization of the sea observed these years affected the early summer zooplankton, and the species composition of its communities is shown to become much poorer; their taxonomic diversity decreased 1.4–1.5 times. The increase in salinity caused the replacement of freshwater and brackish water species by the euryhaline copepod Acartia tonsa that spread all over the sea.

Higher temperatures enhance the effects of invasive sportfish on mountain zooplankton communities

Summary1. Decades of introductions of exotic sportfish to mountain lakes around the world have impoverished them biologically, and this may be exacerbated by global warming. We assessed the current status of invasive salmonids and native zooplankton communities in 34 naturally fishless lakes along an elevational gradient, which served as an environmental proxy for the expected effects of climate change.2. Our main goal was to explore how climate‐related variables influence the effects of stocked salmonids on the total biomass, species richness and taxonomic composition of zooplankton. We predicted that warmer conditions would dampen the negative predatory effects of exotic brook trout (Salvelinus fontinalis) on zooplankton communities because more temperate lakes contain a greater diversity of potentially tolerant species.3. Instead, we discovered that the persistence of stocked brook trout in the warmer lakes significantly amplified total zooplankton biomass and species richness. In colder and deeper lakes, zooplankton were relatively unaffected by S. fontinalis, which however persisted better in alpine lakes than at lower elevations after stocking practices were halted over two decades ago. Warmer lake conditions and higher concentrations of dissolved organic carbon (DOC) were significant primary drivers of zooplankton species turnover, both favouring greater species diversity.4. Our findings of an ecological surprise involving potential synergistic positive effects of climate warming and exotic trout on native zooplankton communities presents a conundrum for managers of certain national mountain parks. Present mandates to eradicate non‐native trout and return the mountain lakes to their naturally fishless state may conflict with efforts to conserve biodiversity under a rapidly changing climate.

Spatial and Temporal Variations in the Zooplankton Community of Phosphorescent Bay, Puerto Rico

Nocturnal variations of zooplankton abundance and hydrographic conditions were examined at three locations (centre, north shore and south shore) in Phosphorescent Bay, Puerto Rico, from May 1992 through April 1993. Seven taxa accounted for approximately 96% of the annual mean zooplankton abundance:Oithonaspp. (43·5%),Acartia tonsa(31·5%), copepod nauplii (8·8%),Paracalanusspp.(6·7%), gastropod veligers (2·5%), larvaceans (1·7%) andPseudo-diaptomus cokeri(1·6%). Copepods dominated numerically throughout the year and comprised 94·3% of total zooplankton. Higher abundance of zooplankton (mean±1SD=252259±176797 individualsm−3) was associated with cool water temperatures (24·9–27·4°C) and dry conditions (0·3–2·9cm precipitation/month) which prevailed between December and March relative to the period between April and November (warm/wet season) (mean±1SD=59773±26861 individualsm−3), when temperature and precipitation were higher (27·3–30·3°C, 3·1–20·6cmmonth−1). Fluctuations of zooplankton populations, particularly copepods, followed progressive increments in chlorophyllaconcentrations. This abundance pattern was consistent at the three sampling stations. Zooplankton abundance was higher on the north shore of the bay. The taxonomic composition of zooplankton was similar at the sampling stations studied.

Zooplankton of tikehau atoll (Tuamotu archipelago) and its relationship to particulate matter

The standing stock and taxonomic composition of zooplankton (>200 μm) were monitored in the lagoon of Tikehau atoll from April 1985 to April 1986. These data were supplemented by two 10 d studies on the variability, structure and functioning of the pelagic ecosystem. The biomass of animals >200 μm comprised 50% of the total biomass of all organisms from 35 to >2000 μm. The zooplankton populations were characterized by successive blooms of copepods, larvaceans, pteropods and salps, probably arising from the periodic input of detritus from the reef during windy periods. As a result, the ecosystem was not in a steady state and the data for the fluxes of organic matter are presented separately for April 1985 and April 1986. Using the C:N:P ratio method, net growth efficiencies, K2, were calculated for total mesozooplankton, mixed copepods, and two planktonic species, Undinula vulgaris and Thalia democratica. Combined with nitrogen and phosphorus excretion rates, these K2 values enabled the assessment of production rates. On a 24 h basis, P:B ratios (%) were close to 100 for the total zooplankton and 54, 34 and 800 for mixed copepods, U. vulgaris and T. democratica, respectively. These ratios are 5.7 times lower than that recorded for phytoplankton. High productivity may be ascribable to the high density of seston, the high temperature (29.5°C), and the kind of organisms present. Zooplankton production equalled 38 and 30% of 14C uptake during April 1985 and April 1986, respectively. Ingestion of animals >35μm was calculated by means of assimilation efficiencies and amounted to 17 and 7% of particulate organic carbon, 100 and 38% of living carbon, and 64 and 140% of primary production during the two periods, respectively. Finally, inorganic exduring was 32 and 18% of phytoplankton nitrogen and phosphorus requirements. A model based on the dimensional structure of the pelagic food-web, has been drawn to illustrate the biomass and carbon, nitrogen and phosphorus fluxes in the study area. The lagoon appears to export part of its planktonic biomass, which is 4.2 times lower one sea mile outside the main pass connecting the lagoon to the open ocean.