Replacement of herbivore zooplankton species along gradients of ecosystem productivity and fish predation pressure

1995 ◽  
Vol 52 (4) ◽  
pp. 733-742 ◽  
Author(s):  
Dag O. Hessen ◽  
Tom Andersen ◽  
Bjørn A. Faafeng

In general the pooling of major taxa did not provide a basis for classifying zooplankton communities in 342 large Norwegian lakes, as neither cladocerans nor calanoids varied systematically with lake productivity or fish predation pressure. At the species level, most herbivorous cladocerans and calanoids, which constituted three quarters of the metazoan zooplankton biomass, differed in their preference for lake productivity and fish community and could be distinctly grouped according to these variables by canonical correspondance analysis. The analysis pointed out one oligotrophic and one eutrophic specialist among the herbivorous cladocerans, while two of the calanoids were oligotrophic specialists. The biomasses of cladocerans, calanoids, or daphnids were poorly correlated with both lake productivity and fish predation, whereas shifts in average size and species distribution could be attributed to these variables. At low lake productivity, chemical variables such as pH and Ca, as well as the species' physiological adaptations, appear as the main determinants for the competitive advantage and relative success of herbivorous species. Fish community composition changes with increasing lake productivity, but only at very high fish predation intensity (cyprinid communities) did the effects of predation become the main determinant of the zooplankton community, superimposed on the lake productivity.

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 706 ◽  
Author(s):  
Maciej Karpowicz ◽  
Jolanta Ejsmont-Karabin ◽  
Joanna Kozłowska ◽  
Irina Feniova ◽  
Andrew R. Dzialowski

Recent changes in climate and eutrophication have caused increases in oxygen depletion in both freshwater and marine ecosystems. However, the impact of oxygen stress on zooplankton, which is the major trophic link between primary producers and fish, remains largely unknown in lakes. Therefore, we studied 41 lakes with different trophic and oxygen conditions to assess the role of oxygen stress on zooplankton communities and carbon transfer between phytoplankton and zooplankton. Samples were collected from each lake at the peak of summer stratification from three depth layers (the epilimnion, metalimnion, and hypolimnion). Our results revealed that freshwater zooplankton were relatively tolerant to anoxic conditions and the greatest changes in community structure were found in lakes with the highest oxygen deficits. This caused a switch in dominance from large to small species and reduced the zooplankton biomass in lower, anoxic layers of water, but not in the upper layers of water where the oxygen deficits began. This upper anoxic layer could thus be a very important refuge for zooplankton to avoid predation during the day. However, the reduction of zooplankton in the lower water layers was the main factor that reduced the effectiveness of carbon transfer between the phytoplankton and zooplankton.


1980 ◽  
Vol 37 (12) ◽  
pp. 2282-2293 ◽  
Author(s):  
N. D. Yan ◽  
R. Strus

Crustacean zooplankton data for 1973 to 1978 from Clearwater Lake, an acidic, metal-contaminated lake near Sudbury, Ontario, are presented and compared with data from four other contaminated lakes near Sudbury and six uncontaminated lakes in the Muskoka–Haliburton Region of Ontario. Species richness and community biomass were reduced in the contaminated lakes, the latter because of reductions in numbers and average size of community dominants. The greatest reductions were observed in the lake with the highest metal levels, Hannah Lake. Cladocera were much more important contributors to total biomass in the contaminated lakes, forming, for example, 80–96% of the average biomass for the ice-free period in Clearwater Lake. An average of 89% of all adult Crustacea observed in Clearwater Lake were Bosmina longirostris (O. F. Müller). Zooplankton biomass in the contaminated lakes, excluding Hannah Lake, was not significantly correlated with pH, with Cu, Ni, or TP concentrations, or with total phytoplankton biomass. While similarities existed, community structure was different from that of acidic lakes in the La Cloche Mountains that were not contaminated with Cu or Ni. Hypotheses relating to how acidification alters typical phytoplankton–zooplankton interactions were constructed. The scarcity of quantitative data required to test such hypotheses is emphasized.


Author(s):  
Elena Vital’evna Pishchenko ◽  
Irina Vladimirovna Moruzi ◽  
Valentina Sergeevna Osipova ◽  
Oksana Andreyevna Vorobyova

Quantitative characteristics of the zooplankton community in cyprinid growth ponds were studied. As a method of stimulating the growth and development of hydrobionts, the introduction of probiotic into water and feed was used. It was taken into account that zooplankton is the main and significant part of the natural food base for young carp grown in ponds. At the early stages of ontogenesis, the activity of digestive enzymes in carp is extremely low, the larva practically does not assimilate high-molecular compounds [7]. At the same time, zooplankton is a secondary link in the food chain of aquatic ecosystems, and plays an important role in their functioning and structure. Changes in plankton fauna can lead to modification of the aquatic ecosystem [18]. The development and existence of zooplankton pond communities during the growing season is influenced by a combination of abiotic and biotic factors, in particular: the composition and abundance of ichthyofauna, fluctuations in the water level in the reservoir, temperature, «flowering» of water, etc. Due to a set of indicators, and the strengthening or weakening of certain factors, it is possible to observe changes in the seasonal dynamics of zooplankton communities, which are more uneven than progressive. In the conducted research on the use of the probiotic Sibmos-Pro-antimicrobial feed concentrate based on mananoligosaccharides (obtained from yeast cell walls) in combination with the bacteria Bacillus Subtilis and Bacillus Licheniformis. Its introduction was carried out both in feed and in feed and water. Studies have shown that, judging by the productivity of carp and zooplankton biomass, the probiotic is absorbed by hydrobionts and affects the increase in the number and productivity of crustaceans. The level of development of the natural food supply increases, which ensures an increase in fish production. The structure of the zooplankton community changes under the influence of probiotics.


1998 ◽  
Vol 55 (2) ◽  
pp. 414-422 ◽  
Author(s):  
Hélène Cyr

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.


1999 ◽  
Vol 56 (10) ◽  
pp. 1865-1872 ◽  
Author(s):  
Eva Wahlström ◽  
Erika Westman

In order to study density-dependent effects of invertebrate planktivory, four different densities of Bythotrephes longimanus were inoculated into mesocosm enclosures with a mixed zooplankton community. Changes in size structure and abundance of zooplankton and phytoplankton communities were recorded over a period of 3 weeks. High densities of Bythotrephes were able to reduce total zooplankton abundance, which was mainly due to a decrease in the density of the relatively large species Holopedium gibberum. The density of the smaller species Bosmina longirostris was also reduced with increasing densities of Bythotrephes, whereas rotifer abundance remained largely unaffected. The mean size of Holopedium increased with increasing densities of Bythotrephes. Despite the decrease in total zooplankton biomass in high-Bythotrephes treatments, no effect of Bythotrephes density on primary producers was observed. Our experiment shows that predacious cladocerans may reduce macrozooplankton biomass, large as well as small species. Predation from invertebrate planktivores results in a zooplankton community consisting of larger individuals. Comparing our experimental densities with densities of Bythotrephes found in natural systems suggests that invertebrate planktivores may influence size structure and abundance of zooplankton communities even in lakes with planktivorous fish.


2021 ◽  
Author(s):  
Liubovi Lebedenco ◽  
◽  
Mykhailo Nabokyn ◽  
Nadejda Andreev ◽  
Svetlana Kovalyshyna ◽  
...  

The study focuses on zooplankton communities of the Lower Dniester. The quantitative indicators of plankton are given and the annual dynamics is described. An assessment of the current state of the river according to the state of zooplankton communities is presented, together with a comparison with historical data, at different stages of river regulation. The changes that occurred in the river zooplankton since the 1950s were analyzed. The relationships between individual characteristics of planktonic communities and the physical and chemical characteristics of the river was also investigated. A comparison of actual data with those collected during 70-80s revealed no significant changes in the structure of the zooplankton community. The proportion of different groups of zooplankton organisms changed insignificantly, the saprobity indices improved slightly, and the average zooplankton biomass did not change. However, compared to the period before 1950s, prior to river regulation for hydropower purposes the role of rotifers in the community was reduced. It might be difficult to identify the main factor determining the development of zooplankton in the Lower Dniester, in order to understand the processes taking place in planktonic communities, it is necessary to analyze the complex impact of hydrological and hydrochemical factors on planktonic communities.


2007 ◽  
Vol 64 (3) ◽  
pp. 516-529 ◽  
Author(s):  
Kerri Finlay ◽  
Beatrix E Beisner ◽  
Alain Patoine ◽  
Bernadette Pinel-Alloul

The relative effects of top-down and bottom-up drivers of zooplankton size structure were examined in three limnologically diverse regions of Quebec, Canada. Lake productivity drove biomass of small-sized zooplankton (300–1000 µm) in the Eastern Townships and Laurentian regions, which have high total phosphorus gradients, but was not significant in the low-productivity region, Gouin. Fish species composition was found to affect biomass of large-sized (>1000 µm) zooplankton and was the primary factor affecting zooplankton size structure in the low productivity region. When size structure of the zooplankton communities were described as normalized biomass size spectra, only bottom-up factors were significant, as increasing productivity resulted in higher curve peaks and increased parabola curvature. No factors were significantly related to any parameter of the Pareto distribution to describe size spectra. Overall, bottom-up forces were stronger drivers of zooplankton size structure, particularly in regions with wide ranges in lake trophy, while fish predation was more important in regions with low productivity variability.


2015 ◽  
Vol 115 (2) ◽  
pp. 24 ◽  
Author(s):  
Meghan C.W. Williams ◽  
Joseph D. Conroy ◽  
Jeffrey G. Miner ◽  
John R. Farver

Municipal water managers use copper sulfate (CuSO4) to control algae, predominantly phytoplankton, in water supply reservoirs. In multiple-purpose upground reservoirs in northwestern Ohio, CuSO4 application regimens vary from no application to over 600 µg Cu/L/year. Whereas CuSO4 effectively suppresses phytoplankton growth, it also has documented toxicities to zooplankton, which serve as forage for stocked sport fish. Consequently, CuSO4 application benefits one upground reservoir use (water supply) while potentially negatively affecting another (sport fishing). This research sought to directly compare copper concentrations ([Cu]) in dissolved and particulate fractions with corresponding zooplankton community composition and abundance both before and after CuSO4 application in Ohio upground reservoirs. Copper concentrations and zooplankton community characters were measured at four upground reservoirs (n = 2 treated with CuSO4 and n = 2 untreated) over multiple weeks during summer 2010. Total [Cu] in treated reservoirs increased by as much as 428% from pre- (mean = 16.5 µg/L) to post-application (mean = 70.7 µg/L); concomitantly, zooplankton biomass and density decreased by as much as 93%. Post-application zooplankton communities shifted to dominance by small copepod nauplii from a mixed community that included larger cladocerans. Copepod nauplii represent a less-suitable food source for stocked juvenile yellow perch Perca flavescens. Thus, short-term negative effects to the zooplankton community may result from CuSO4 applications, indirectly affecting stocked sport fish success.


2011 ◽  
Vol 68 (5) ◽  
pp. 795-811 ◽  
Author(s):  
Ora E. Johannsson ◽  
Kelly L. Bowen ◽  
Kristen T. Holeck ◽  
Maureen G. Walsh

We investigated population responses of Mysis to ecosystem changes induced by invasion of dreissenids and predatory cladocerans, Cercopagis and Bythotrephes . Lake productivity declined as dreissenids invaded the offshore region. Whole-lake mysid biomass was compared before (early 1990s) and after (2002–2007) the invasion period; it declined 40%–45%. Abundance of young mysids and presence of a summer cohort increased with summer, epilmnetic, nighttime zooplankton biomass (i.e., food biomass index). Cercopagis + Bythotrephes biomass was negatively correlated with this index, implicating them in the mysid decline. Eggs per gravid female increased with autumn, total-water-column zooplankton biomass, reflecting the greater use of hypolimnetic waters by adults. Reproductive success was below replacement during the period 2002–2005. First-year mysid growth rate was maintained while population abundance declined, suggesting selection for individuals that feed effectively at low food concentrations. Mortality rates in the first and second years were dependent on cohort density, indicating that competition for food limited abundance in the first 2 years. Fish predation indices (smelt and alewife combined) were correlated positively with mortality rates and negatively with abundance in the third year. Thus, mysids cannot support as many fish in invaded compared with non-invaded lakes. They may also not be a stable food resource; unusual cohort losses occurred in some years.


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