Zooplankton In Lakes Research Articles

Composition and structure of under-ice zooplankton of diverse lakes in Kenozersky National Park (Arkhangelsk Region)

Composition and structure of under-ice zooplankton of diverse lakes in Kenozersky National Park (Arkhangelsk Region)

Population asynchrony within and between trophic levels have contrasting effects on consumer community stability in asubtropical lake.

Clarifying the effects of biodiversity on ecosystem stability in the context of global environmental change is crucial for maintaining ecosystem functions and services. Asynchronous changes between trophic levels over time (i.e. trophic community asynchrony) are expected to increase trophic mismatch and alter trophic interactions, which may consequently alter ecosystem stability. However, previous studies have often highlighted the stabilising mechanism of population asynchrony within a single trophic level, while rarely examining the mechanism of trophic community asynchrony between consumers and their food resources. In this study, we analysed the effects of population asynchrony within and between trophic levels on community stability under the disturbances of climate warming, fishery decline and de-eutrophication, based on an 18-year monthly monitoring dataset of 137 phytoplankton and 91 zooplankton in a subtropical lake. Our results showed that species diversity promoted community stability mainly by increasing population asynchrony both for phytoplankton and zooplankton. Trophic community asynchrony had a significant negative effect on zooplankton community stability rather than that of phytoplankton, which supports the match-mismatch hypothesis that trophic mismatch has negative effects on consumers. Furthermore, the results of the structural equation models showed that warming and top-down effects may simultaneously alter community stability through population dynamics processes within and between trophic levels, whereas nutrients act on community stability mainly through the processes within trophic levels. Moreover, we found that rising water temperature decreased trophic community asynchrony, which may challenge the prevailing idea that climate warming increases the trophic mismatch between primary producers and consumers. Overall, our study provides the first evidence that population and trophic community asynchrony have contrasting effects on consumer community stability, which offers a valuable insight for addressing global environmental change.

Virulence and transmission biology of the widespread, ecologically important pathogen of zooplankton, Spirobacillus cienkowskii.

Spirobacillus cienkowskii is a bacterial pathogen of zooplankton, first described in the 19th century and recently placed in a new family of bacteria, the Silvanigrellaceae. Spirobacillus causes large epidemics in lake zooplankton populations and increases the probability that zooplankton will be eaten by predators. However, little is known about how Spirobacillus transmits among hosts, to what extent it reduces host survival and reproduction (i.e., how virulent it is), and what role virulence plays in Spirobacillus' life cycle. Here, we experimentally quantified Spirobacillus' virulence and showed that Spirobacillus must kill its host to transmit horizontally. We also found evidence that Spirobacillus may transmit vertically via Daphnia's seed-like egg sacks. Our work will help scientists to (i) understand Spirobacillus epidemics, (ii) use Spirobacillus as a model pathogen for the study of host-parasite interactions, and (iii) better understand the unusual group of bacteria to which Spirobacillus belongs.

Deep lakes support higher zooplankton functional diversity than shallow lakes: A case study in lacustrine environments affected by mining tailings (lower Doce River basin, Brazil)

Abstract Tragic incidents involving mine tailings spills have impacted many aquatic ecosystems around the world. The massive mine tailings dam collapse of Fundão, which occurred in Brazil in 2015, affected several aquatic ecosystems, including shallow and deep lakes in the lower Doce River basin. Until now, the effects of mine tailings on the functional diversity of zooplankton remain poorly understood. We investigated the functional diversity of zooplankton (functional groups, functional richness [FRic] and functional evenness [FEve]) in shallow and deep lakes, exploring the influence of environmental variables and metals. In addition, trends in functional redundancy and functional vulnerability were also assessed to understand patterns of resilience in mining‐impacted ecosystems. Surveys were performed monthly on three deep and three shallow lakes affected by the dam failure, from October 2018 to September 2019. In the deep lakes, the zooplankton community was dominated by smaller filter‐feeders and omnivorous species, associated with cyanobacteria density and chlorophyll‐a. Medium‐sized filters were associated to iron, suspended particulate organic matter and total organic carbon in shallow lakes. The smaller filter‐feeders and omnivorous trophic groups had a higher contribution to increasing the functional diversity of zooplankton than medium‐sized filter‐feeders in both deep and shallow lakes. FRic and FEve were higher in deep lakes than in shallow lakes. Shallow lakes were highly vulnerable to species loss and functional diversity was modulated by environmental changes and metal pollution. Tropical shallow lakes impacted by mining tailings should receive particular attention in conservation plans, as a consequence of their high level of pollutant retention in comparison with deep lakes. In addition, we highlight the importance of using a functional approach to better understand the ecosystem changes resulting from the impacts of mine tailings on aquatic environments.

Peculiarities of the structure of zooplankton communities in floodplain water bodies of the Middle Ob

The zooplankton of the caught floodplain lakes of the Middle Ob, located at various distances from the main riverbeds, was studied. It is shown that the development of the summer complex of zooplankton in floodplain lakes begins simultaneously with the passage of the flood; a significant diversity of species and the largest biomass increase in them in the summer months. The more often the floodplain lakes is filled with hollow waters, the higher the species diversity and the calculated indicators of plankton are in it. The factors that register the signs of zooplankton development in the caught lakes are revealed: the frequency of flooding, water temperature, the content of consumption for a number of taxa — the gas regime. Studies have shown that that the zooplankton of the caught reservoirs is subject to increased impact of the communities of the special territory of rivers and lakes of the above-floodplain terrace of the distribution of faunal diversity, increased species richness and specific species structure.

Zooplankton condition in lakes of Belarus under climate change

The analysis of long-term data on zooplankton of mesotrophic lakes of Belarus was carried out in order to determine ways to assess the impact of climate change. The possibilities of using the parameters of zooplankton communities to register climate change are shown. It is indicated that changes in the density of cold-loving species can be used to register the effects of temperature increase.

Horizontal migration of zooplankton in lake–wetland interfaces. Can temperature-driven surface exchange flows modulate its patterns?

Lake ecology can be affected by exchange flows driven by horizontal temperature gradients in lake–wetland interfaces. In this work, we investigate the hypothesis that thermally driven flows modulate the horizontal migration patterns of freshwater zooplankters. A 48-h field campaign in a shallow lake (Lake Vela, Quiaios, Portugal) was carried out to test this hypothesis. Thermal differences between the littoral and limnetic areas were measured along two transects featuring a Schoenoplectus lacustris and a Myriophyllum aquaticum stand in the littoral. In parallel, the physiochemistry and chlorophyll a, as a proxy for food availability differences between the littoral and the limnetic zones, were monitored. Zooplankton samples were collected for assessing overall and group-specific number-density differences. The diel period (day or night) and the site (littoral or limnetic zone) did not interact significantly to modulate the variation patterns for the studied physiochemical variables, indicating that these parameters should not explain horizontal zooplankton distribution patterns. The expected patterns for zooplankton diel horizontal migration as driven by the presence of visual predators were occasionally confirmed by our limnetic versus littoral abundance records through time, depending on the transect. Group-specific abundance patterns indicate particular features: copepods always preferred the littoral over the limnetic zone regardless of the diel period; chydorids always preferred the littoral zone regardless of the macrophyte stand involved; bosminids tended to preferentially concentrate in the limnetic zone. No consistent relationship was identified between the expected flow direction due to temperature differences and zooplankton abundance changes, although it occasionally occurred through the dataset.

Biotic and thermal drivers alter zooplankton phenology in western Lake Erie

AbstractEnvironmental change, particularly warming and eutrophication, can alter phenology in aquatic systems. Understanding controls on zooplankton phenology is important due to their central role in food webs. While patterns in zooplankton phenology have been well documented, we lack an understanding of how abiotic and biotic drivers influence lake zooplankton phenology during the summer. We examined the phenology of four common zooplankton taxa (Daphnia retrocurva, Skistodiaptomus oregonensis, Mesocyclops spp., Dreissenid veligers) in western Lake Erie during 1995–2022, a period with increasing eutrophication and Bythotrephes longimanus biomass. Many phenology metrics varied by 3 weeks or more from 1995 to 2022. The dominant controls of phenology were temperature and biotic factors, especially grazer‐defended phytoplankton (cyanobacteria and other colonial or filamentous taxa) and the invasive predator B. longimanus, which frequently interacted. Our results show that aspects of environmental change interact to shape zooplankton phenology, which can influence phytoplankton biomass and energy flow to higher trophic levels.

Aggregating taxa and the influence of scale: Potential concerns for analysis of stability using functional measures

AbstractA functional group approach to analyzing ecological processes calls for aggregating species populations' data (e.g., biomass, abundance) into larger functional units. This method offers a more direct insight into the coarse community and ecosystem dynamics than a species level. Since aggregation changes the scale of analysis, it is reasonable to expect that the results and inferences will also change. To gauge the nature and size of this effect, we examined two sets of communities using the same methodology at taxonomic and functional levels. We asked how asynchrony among constituent populations stabilizes the regional biomass or abundance in two systems: zooplankton in North American temperate lakes and rock pool invertebrates in Jamaica. We aggregated species into pairs by organism size for the functional level analysis because it correlates well with life history traits. We hypothesized that taxonomical and functional level analyses would yield different pictures and inferences. We analyzed asynchrony among local populations, metapopulations, and populations of different species at different locations. We found that in lakes, different asynchrony classes contributed to the stabilization of the regional metric than in the rock pools. We further found that aggregation of taxa into functional units changed the pattern of differences between lakes and rock pools revealed by taxonomical analysis and that each set of communities responded differently to species lumping. While aggregating taxa leads to different results, the taxonomic and functional lenses add new insights to the biological interpretation of mechanisms stabilizing communities when interpreted jointly. Specifically, population asynchrony—a known stabilizing factor—can provide complementary stabilizing mechanisms when seen through taxonomic and functional lenses. Without exposing these modes, inferences about abundance/biomass/richness stabilizing contributions arising from asynchrony will remain tenuous. Exposing these modes offers a path for significant breakthroughs in linking local, spatial, and functional structures to multispecies system dynamics.

Interactive effects of climate-atmospheric cycling on aquatic communities and ecosystem shifts in mountain lakes of southeastern Tibetan Plateau

Recent climate warming and atmospheric reactive nitrogen (Nr) deposition are affecting a broad spectrum of physical, ecological and human systems that may be irreversible on a century time scale and have the potential to cause regime shifts in ecological systems. These changes may alter the limnological conditions with important but still unclear effects on lake ecosystems. We present changes in cladoceran with comparisons to diatom assemblages over the past ~200 years from high-resolution, well-dated sediment cores retrieved from six high mountain lakes in the southeastern (SE) margin of the Tibetan Plateau. Our findings suggest that warming and the exponential increase of atmospheric Nr deposition are the major drivers of ecological regime changes. Shifts in cladoceran and diatom communities in high alpine lakes began over a century ago and intensified since 1950 CE, indicating a regional-scale response to anthropogenic climate warming. Zooplankton in the forest lakes showed asynchronous trajectories, with increased Nr deposition as a significant explanatory factor. Forest lakes with higher dissolved organic carbon (DOC) concentrations partially buffered the impacts of Nr deposition with little structural change, while lakes with low DOC display symptoms of resilience loss related to Nr deposition. Biological community compositional turnover in subalpine lakes has shown marked shifts, equivalent to those of low-elevation lakes strongly affected by direct human impacts. This suggests that local effects override climatic forcing and that lake basin features modified by anthropogenic activity act as basin-specific filters of common forcing. Our results indicate that snow and glacial meltwaters along with nutrient enrichment related to climate warming and atmospheric Nr deposition, represent major threats for lake ecosystems, even in remote areas. We reveal that climate and atmospheric contaminants will further impact ecological conditions and alter aquatic food webs in higher altitude biomes if climate and anthropogenic forcing continue.

Qualitative composition and species diversity of Saikul Lake zooplankton

The article presents the results of hydrobiological studies of zooplankton of Lake Saikul. The qualitative composition and species diversity of zooplankton were studied and the quantitative indicators of zooplankton of Lake Saikul were given. A total of 50 samples were collected and processed. A total of 39 taxa of aquatic animals were found in Saikul Lake, including 15 species of rotifers, 14 species of cladoceran and 10 species of paddle-legged crustaceans.

Dietary fatty acid transfer in pelagic food webs across trophic and climatic differences of Chinese lakes

In eutrophic lake ecosystems, cyanobacteria typically lead to unbalanced phytoplankton community structure and low dietary quality for consumers at higher trophic levels. However, it still remains poorly understood how zooplankton manage to respond to seasonal and spatial differences in lake trophic gradients and temperature factors to retain highly required dietary nutrients from phytoplankton. In this field study, we investigated seston and different size classes of zooplankton of temperate and subtropical large lakes of different trophic conditions in China. We used fatty acids (FA) as dietary nutrients from seston to zooplankton to investigate how eutrophication affects the FA composition of various zooplankton size classes. This study revealed a curvilinear relationship between total phosphorus (TP) and polyunsaturated fatty acids (PUFA) contents of edible phytoplankton (“seston”) across 3 seasons and 2 climatic areas. The PUFA content of seston increased until mesotrophic lake conditions (TP: 11–20 μg L−1), after which the dietary provision of PUFA for respective consumers declined. Seston FA, rather than trophic condition or water temperature, primarily predicted changes in zooplankton FA, while this predictive power decreased with zooplankton size. Despite increasing eutrophic lake conditions, LC-PUFA content of the zooplankton consistently increased per unit biomass. The results indicate that the nutritional value of phytoplankton was highest in mesotrophic lakes, and lake zooplankton selectively increased their LC-PUFA retention with body size and/or were able to convert dietary FA endogenously to meet their size-specific FA demands, independent of lake location or time (season) or the measured trophic condition of the lake (from oligo- to eutrophic).

Species Diversity of Zooplankton of Small Steppe Lakes of the Northern Part of Kazakhstan

The inland waters of Northern Kazakhstan are important components of the ecosystems of this region and have unique characteristics. Endorheic steppe lakes are important ecosystems with significant ecological value. They play an important role in maintaining biodiversity, they provide water resources for living organisms, they serve as breeding and migration sites for various animal species, and their zooplankton communities have a key role in the trophic web of these waters. Therefore, the purpose of this work is to study the diversity of zooplankton communities in some small steppe lakes in the northern part of Kazakhstan (Pavlodar, Kostanay, North Kazakhstan, and Akmola regions), which have different environmental conditions. Sampling to study the species diversity of zooplankton in the steppe water bodies of Northern Kazakhstan was carried out from 13 areas, 12 of which are plain lakes, and 1 of which is a reservoir, and sampling was performed in 2021 and 2022 during in the spring, summer, and autumn periods. Within the research period of 2021–2022, between 6 and 36 species of zooplankton were found in small steppe lakes. A total of 92 taxa were found. Rotifers (46 taxa) were found to have the richest number of species representatives. Cladocera were represented by 21 taxa, and Copepods by 25 taxa. All studied steppe lakes in the northern part of Kazakhstan are characterized by high specificity in terms of taxonomic composition, since the similarity indices did not exceed 0.632. According to cluster analysis, the studied samples of water bodies are divided into five clusters, in which lakes with a relatively similar taxonomic composition are combined. The halophile species (e.g., Arctodiaptomus salinarus) indicate water salinization. Our results confirm the applicability of the use of zooplankton in assessing water quality and the current ecological state of aquatic ecosystems.

Studying the Metazoan Zooplankton Community Characteristics and Evaluating the Water Quality Based on the Ecological and Functional Zones in Gaoyou Lake

To study the metazoan zooplankton community structure and water quality, we investigated the amount of metazoan zooplankton and the water quality in Gaoyou Lake from January to December 2022. Furthermore, we also evaluated the multi-index and nutritional status of Gaoyou Lake using the comprehensive nutritional status index of water quality, dominant population composition of the metazoan zooplankton, B/T index, and Shannon–Weaver diversity index based on the situation of each ecological and functional zone. The results indicated that the metazoan zooplankton of Gaoyou Lake included 21 families, 31 genera, and 63 species. The rotifers had 8 families, 16 genera, and 34 species, accounting for 53.9% of all species. The cladocerans had 6 families, 7 genera, and 16 species, which accounted for 25.4% of all species. The copepods had 7 families, 8 genera, and 13 species, that accounted for 20.7% of all species. The density and species of small metazoan zooplankton (rotifers) had a higher proportion than large metazoan zooplankton (crustaceans). The average annual metazoan zooplankton density was 1595.7 ind./L, the average annual biomass was 4.31 mg/L, the average annual total nitrogen (TN) was 1.101 mg/L, and the average annual total phosphorus (TP) was 0.082 mg/L. The TN and TP of the Gaoyou Lake were over the standard. The comprehensive nutritional status indices of the water quality in the entire lake and the ecological and functional areas were consistent with the metazoan zooplankton evaluation results, which determined that Gaoyou Lake showed mild eutrophication.

Upward migration of calanoid copepods is driven by high food quality in surface waters in an alpine lake

Abstract The diel vertical migration of zooplankton includes downward migration to deep water during the day and upward migration to surface water at night. Diurnal downward migration has been well explained; zooplankton migration to surface water at night remains unclear. This study aimed to explore the reason of the nocturnal upward migration of the calanoid copepod Arctodiaptomus sp. In Lake Heihai, an alpine lake (elevation 4,090 m above sea level) without predators. Herein, we present the vertical profiles of the lake, including water temperature, chlorophyll a (Chl‐a), fatty acids, and astaxanthin synthesis precursors (ASPs) of seston in the water column. The distributions and concentrations of fatty acids and astaxanthin in Arctodiaptomus sp. were characterised through field investigations during the day and at night. Meanwhile, the effect of ultraviolet radiation (UVR) on ASPs in seston was explored through indoor experiments. Lake Heihai had the characteristics of low temperature, low food availability, high transparency, and high UVR intensity. Arctodiaptomus sp. was distributed in water layers below 6 m during the day and throughout the water column at night. Arctodiaptomus sp. accumulated large amounts of fatty acids, especially polyunsaturated fatty acids (PUFAs), and inhibitors of fatty acid oxidation–astaxanthin in the cold alpine lake. The concentrations of lutein, a kind of ASP, and PUFAs in seston were highest in surface waters. The indoor experiment verified that UVR can enhance the synthesis of ASP. The calanoids migrated to surface waters at night to obtain ASPs and PUFAs in seston, which were at high concentrations in surface waters. PUFAs and ASP may be of high food quality for zooplankton in alpine lakes. The findings indicated that the upward migration of Arctodiaptomus sp. at night was driven by the high quality of food sources (PUFAs and ASP) in surface waters. Arctodiaptomus sp. adapts behaviour and physiology to the environment of the alpine lake. We explored why zooplankton migrated to surface waters at night from the perspective of their physiological characteristics and adaptability to the environment. Our findings provide a new way to investigate the diel vertical migration of zooplankton, especially in alpine lakes.

Assessment of the Zooplankton Community and Water Quality in an Artificial Freshwater Lake from a Semi-Arid Area (Irbid, Jordan)

Zooplankton play a crucial role in aquatic food chains and contain many species, which could be bioindicators of water quality and ecosystem health. The ecological impacts of eutrophication on zooplankton composition in freshwater lakes have recently gained wide interest. Geographic location and water-body size influence zooplankton diversity in freshwaters; meanwhile, less is known about the composition and dynamic of the zooplankton community and their relationship with the trophic status in artificial water in semi-arid areas. The present study aimed to assess the physical–chemical parameters and to document the seasonal distribution of zooplankton species and their relationship with environmental factors and trophic state in the artificial freshwater lake JUST, in a semi-arid area. The high concentrations of nutrients and the trophic level index (TLI) classified the lake as eutrophic–hypertrophic. The zooplankton in the JUST lake were composed of twenty-six species, with eleven Rotifera, ten Copepoda, and five Cladocera. Copepoda was numerically the most abundant taxon, accounting for 64% of the total zooplankton abundance, in both seasons. However, the second most abundant taxon in summer was Rotifera (28.26%) while in winter it was Cladocera (25.88%). The community structure seemed to be influenced, most likely, by trophic state, phytoplankton abundance, water temperature, dissolved oxygen, and nutrient loading. The zooplankton were largely dominated by bioindicator species of high trophic levels. Zooplankton could be used as a tool to monitor the trophic state of the lake. For sustainable development, the introduction of phytoplanktivorous, aquaculture species, such as carp and koi, will strengthen the top-down control of the phytoplankton concentration, leading to a reduced trophic state.

EDNA of zooplankton reveals the ecological community thresholds for key environmental factors in the Baiyangdian Lake aquatic ecosystem

BackgroundThe drastic change in an ecosystem as a threshold phenomenon caused by abrupt changes in environmental conditions is a focus of current ecological research. However, the study of ecological thresholds has generally been limited to estimating the threshold values of single factors. Using eDNA metabarcoding technology, we collected zooplankton data from Baiyangdian Lake, the largest freshwater lake in the North China Plain, to explore the zooplankton community distribution characteristics and the relevant environmental factors. We used Threshold Indicator Taxa Analysis (TITAN) to determine the thresholds of key environmental factors and to identify the factors influencing biological diversity.ResultsBy comparing previous studies, we found that the zooplankton community composition based on eDNA metabarcoding was similar to that based on morphological methods, and that the data could be used to estimate ecological thresholds and assess risk conditions. Temperature (T), electrical conductivity (EC), and turbidity were the major environmental factors affecting the zooplankton community structure. The composition and structure of zooplankton communities in rivers and lakes were significantly different due to the influence of specific environmental factors. The results of TITAN analysis showed that there were different indicator species for T and EC in rivers and lakes. The protection thresholds of zooplankton in rivers were T = 19.0 °C and EC = 795 μS/cm, whereas the protection thresholds of zooplankton in lakes were T = 14.3 °C and EC = 1920 μS/cm. The overall values for the Baiyangdian watershed were T = 15.5 °C and EC = 1073 μS/cm. Compared with the field monitoring results, approximately 50% of the water quality index values at the sampling points in the Baiyangdian watershed exceeded the negative response threshold, indicating that Baiyangdian Lake was disturbed.ConclusionsThe validity of eDNA technology in biodiversity analysis was confirmed by the zooplankton community data from Baiyangdian Lake. The ecological thresholds derived by combining eDNA technology with Threshold Indicator Taxa Analysis (TITAN) are beneficial to the biological conservation of the region.

Do submerged macrophytes facilitate the development of large crustacean zooplankton in tropical shallow lakes?

Do submerged macrophytes facilitate the development of large crustacean zooplankton in tropical shallow lakes?

Statistical modelling of aquatic size spectra: integrating data from multiple taxa and sampling methods

Abstract Size spectra are used to assess the status and functioning of marine and freshwater ecosystems worldwide. Their use is underpinned by theory linking the dynamics of trophic interactions to a power-law decline of abundance with body size in ecological communities. Recent papers on empirical size spectrum estimation have argued for Maximum Likelihood Estimation of power-law probability distributions as a more accurate alternative to traditional linear regression approaches. One major limitation of currently used size spectrum estimators from Maximum Likelihood Estimation is that they cannot account for the use of multiple sampling protocols, nor the distortions caused by gear size selectivity, and therefore they become restricted to a relatively narrow taxonomic group and size range. Further progress in the field requires new methods that are flexible enough to combine multiple trophic groups and sampling gears into a single size spectrum estimate, while taking advantage of more accurate distributional approaches. The method we propose in this paper fills this gap by deriving the distribution of observed sizes explicitly from the underlying power-law spectrum and gear selectivity functions. It specifies likelihoods as a product of two components: (i) the probability of belonging to a given group and (ii) the probability distribution within the group. Using Bayesian estimation, we applied the method to surveys of phytoplankton, zooplankton, and fishes in lakes of Quetico Provincial Park, northwestern Ontario, using Van Dorn samplers, zooplankton nets, gillnets, and hydroacoustics. The results show that the spectra estimated from subsets of trophic groups or gears are weak predictors of more complete spectra, highlighting the importance of using more inclusive community data. The two-component partitioning of likelihoods also helped demonstrate the existence of between-group spectrum slopes that were overall steeper than within-group slopes, indicating that heterogeneity of trophic transfers across the size spectrum is an important factor structuring these ecosystems.

Costs of Daphnia diel vertical migrations under forecasted increase of lake temperature

The aim of our work was to experimentally test the hypothesis that changes in the thermal stratification in lakes of the temperate zone, expected as a result of progressive global warming, will cause an increase in fitness costs in a planktonic cladoceran Daphnia, associated with diel vertical migrations. In a programmable thermostatic chamber, Daphnia magna have been cultured from the first juvenile instar till the first reproduction, in thermal regimes corresponding to the conditions experienced by non-migratory (remaining in epilimnion day and night) and migrating (spending nights in epilimnion and days in hypolimnion) animals. We exposed Daphnia to thermal regimes: corresponding to the temperatures typically reigning stratified lakes nowadays (20 °C in epilimnion and 8 °C in hypolimnion), and expected at the end of this century (28 °C and 12 °C, respectively). The analysis of life-history parameters confirmed the assumption of an increase in metabolic costs resulting from vertical migration of Daphnia along with the expected increase in temperature differences between epilimnion and hypolimnion, which is a daily anti-predator refuge for migrating animals. This may consequently lead to significant changes in the composition of lake zooplankton communities, i.e., to an increase in the share of non-migrating species with small body sizes.