scholarly journals Zooplankton Community Responses to Oxygen Stress

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 706 ◽  
Author(s):  
Maciej Karpowicz ◽  
Jolanta Ejsmont-Karabin ◽  
Joanna Kozłowska ◽  
Irina Feniova ◽  
Andrew R. Dzialowski
Keyword(s):  
Zooplankton Community ◽  
Oxygen Depletion ◽  
Zooplankton Biomass ◽  
Oxygen Stress ◽  
Carbon Transfer ◽  
Oxygen Conditions ◽  
Anoxic Layer ◽  
Zooplankton Communities ◽  
The Impact

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.

scholarly journals Contribution and pathways of diazotroph-derived nitrogen to zooplankton during the VAHINE mesocosm experiment in the oligotrophic New Caledonia lagoon

2016 ◽  
Vol 13 (10) ◽  
pp. 3131-3145 ◽  
Author(s):  
Brian P. V. Hunt ◽  
Sophie Bonnet ◽  
Hugo Berthelot ◽  
Brandon J. Conroy ◽  
Rachel A. Foster ◽  
...  
Keyword(s):  
N2 Fixation ◽  
New Caledonia ◽  
Austral Summer ◽  
Zooplankton Community ◽  
Zooplankton Biomass ◽  
Diazotrophic Cyanobacteria ◽  
Subtropical Oceans ◽  
Isotope Mixing Models

Abstract. In oligotrophic tropical and subtropical oceans, where strong stratification can limit the replenishment of surface nitrate, dinitrogen (N2) fixation by diazotrophs can represent a significant source of nitrogen (N) for primary production. The VAHINE (VAriability of vertical and tropHIc transfer of fixed N2 in the south-wEst Pacific) experiment was designed to examine the fate of diazotroph-derived nitrogen (DDN) in such ecosystems. In austral summer 2013, three large ( ∼  50 m3) in situ mesocosms were deployed for 23 days in the New Caledonia lagoon, an ecosystem that typifies the low-nutrient, low-chlorophyll environment, to stimulate diazotroph production. The zooplankton component of the study aimed to measure the incorporation of DDN into zooplankton biomass, and assess the role of direct diazotroph grazing by zooplankton as a DDN uptake pathway. Inside the mesocosms, the diatom–diazotroph association (DDA) het-1 predominated during days 5–15 while the unicellular diazotrophic cyanobacteria UCYN-C predominated during days 15–23. A Trichodesmium bloom was observed in the lagoon (outside the mesocosms) towards the end of the experiment. The zooplankton community was dominated by copepods (63 % of total abundance) for the duration of the experiment. Using two-source N isotope mixing models we estimated a mean  ∼  28 % contribution of DDN to zooplankton nitrogen biomass at the start of the experiment, indicating that the natural summer peak of N2 fixation in the lagoon was already contributing significantly to the zooplankton. Stimulation of N2 fixation in the mesocosms corresponded with a generally low-level enhancement of DDN contribution to zooplankton nitrogen biomass, but with a peak of  ∼  73 % in mesocosm 1 following the UCYN-C bloom. qPCR analysis targeting four of the common diazotroph groups present in the mesocosms (Trichodesmium, het-1, het-2, UCYN-C) demonstrated that all four were ingested by copepod grazers, and that their abundance in copepod stomachs generally corresponded with their in situ abundance. 15N2 labelled grazing experiments therefore provided evidence for direct ingestion and assimilation of UCYN-C-derived N by the zooplankton, but not for het-1 and Trichodesmium, supporting an important role of secondary pathways of DDN to the zooplankton for the latter groups, i.e. DDN contributions to the dissolved N pool and uptake by nondiazotrophs. This study appears to provide the first evidence of direct UCYN-C grazing by zooplankton, and indicates that UCYN-C-derived N contributes significantly to the zooplankton food web in the New Caledonia lagoon through a combination of direct grazing and secondary pathways.

Grazing by a river zooplankton community: Importance of microzooplankton

1996 ◽  
Vol 47 (8) ◽  
pp. 1025 ◽  
Author(s):  
T Kobayashi ◽  
P Gibbs ◽  
PI Dixon ◽  
RJ Shiel
Keyword(s):  
Surface Temperature ◽  
Phytoplankton Community ◽  
Size Fraction ◽  
Zooplankton Community ◽  
Zooplankton Biomass ◽  
Regulated River ◽  
Grazing Impact ◽  
Total Biomass ◽  
Community Grazing ◽  
The Impact

Grazing rates by a zooplankton community were measured in situ by a radiotracer cell method at depths of 1 m and 4 m at the upper tidal freshwater portion of a regulated river over a year. The objectives were to evaluate the likely grazing impact on the river phytoplankton community and to produce predictive models by regressing the measured grazing rates against zooplankton biomass, temperature and food concentrations (represented by chlorophyll a). Grazing attained rates (overall average 0.2 day-1, range 0.01-0.59 day-1, expressed as instantaneous mortality rates of algal cells) comparable to those reported for lentic zooplankton communities. The measured community grazing rates were predictable largely as a function of total biomass or rotifer biomass and surface temperature for 1 m depth, and as a function of total biomass or juvenile copepod biomass and surface temperature for 4 m depth, with all-positive regression coefficients in the models. Owing to the predominance of microzooplankton in the river, the impact of zooplankton community grazing appears likely to be linked to a small-size fraction of the phytoplankton community all year. Management strategies for river water quality may need to take account of possible functional demarcation of grazing by river zooplankton.

Hyperbenthic and pelagic predators regulate alternate key planktonic copepods in shallow temperate estuaries

2014 ◽  
Vol 65 (9) ◽  
pp. 791 ◽  
Author(s):  
R. J. Wasserman ◽  
T. J. F. Vink ◽  
R. Kramer ◽  
P. W. Froneman
Keyword(s):  
Population Regulation ◽  
Zooplankton Community ◽  
Copepod Species ◽  
Benthic Fish ◽  
Predator Diversity ◽  
Predatory Impact ◽  
Experimental Treatments ◽  
Zooplankton Communities ◽  
Predatory Pressure

Although predation has been identified as an important community driver, the role of predator diversity in structuring estuarine zooplankton has not been assessed. As such, we investigated the effects of two different zooplanktivorous fish species on the estuarine zooplankton community during a 12-day mesocosm study. Three experimental treatments were established, whereby natural zooplankton communities were subject to either (1) no predatory pressure, (2) predation by a pelagic predator (Monodactylus falciformis) or (3) predation by a hyper-benthic predator (Glossogobius callidus). The pelagic feeding M. falciformis fed largely on the numerically dominant mid-water copepod species, Paracartia longipatella. In contrast, the hyper-benthic fish had a greater predatory impact on the less numerically dominant copepod, Pseudodiaptomus hessei, which demonstrates strong diel vertical migration. Variations in prey-population regulation are ascribed to the distinct behavioural differences of the predators, and mediated by the differences in behaviour of the copepod species.

Development of the zooplankton community in the growing ponds of the Novosibirsk region when growing carp fingerlings using the probiotic “Sibmos-PRO”

2020 ◽  
pp. 44-57
Author(s):  
Elena Vital’evna Pishchenko ◽  
Irina Vladimirovna Moruzi ◽  
Valentina Sergeevna Osipova ◽  
Oksana Andreyevna Vorobyova
Keyword(s):  
Zooplankton Community ◽  
Zooplankton Biomass ◽  
Natural Food ◽  
Reservoir Temperature ◽  
Structure Changes ◽  
Quantitative Characteristics ◽  
Abiotic And Biotic Factors ◽  
Zooplankton Communities ◽  
Molecular Compounds ◽  
Secondary Link

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.

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.

Planktivory by the predacious cladoceran Bythotrephes longimanus: effects on zooplankton size structure and abundance

1999 ◽  
Vol 56 (10) ◽  
pp. 1865-1872 ◽  
Author(s):  
Eva Wahlström ◽  
Erika Westman
Keyword(s):  
Size Structure ◽  
Zooplankton Community ◽  
Zooplankton Biomass ◽  
Zooplankton Abundance ◽  
Large Species ◽  
Bythotrephes Longimanus ◽  
Total Zooplankton ◽  
Natural Systems ◽  
Phytoplankton Communities ◽  
Zooplankton Communities

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.

Impact of Permethrin on Zooplankton Communities in Limnocorrals

1985 ◽  
Vol 42 (1) ◽  
pp. 77-85 ◽  
Author(s):  
N. K. Kaushik ◽  
G. L. Stephenson ◽  
K. R. Solomon ◽  
K. E. Day
Keyword(s):  
Acute Toxicity ◽  
Zooplankton Community ◽  
Exposure Concentration ◽  
Natural Conditions ◽  
Southern Ontario ◽  
Direct And Indirect Impacts ◽  
Indirect Impacts ◽  
Zooplankton Communities ◽  
The Impact

A series of in situ aquatic enclosures or limnocorrals (5 × 5 × 5 m deep) was used to evaluate the impact of the insecticide permethrin (3-phenoxybenzy[(1RS)-cis,trans-3-(2,2-dimethyl-3-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate) (50.0 and 5.0 μg∙L−1 in 1979 and 5.0 and 0.5 μg∙L−1 in 1980) on the pelagic zooplankton community in a 10-ha mesotrophic lake in southern Ontario. Permethrin was acutely toxic to the macrozooplankton (Cladocera and Copepoda) at all concentrations; microzooplankton (Rotifera) showed acute toxicity only at 50.0 μg∙L−1. Despite this initial toxicity, the density of microzooplankton increased dramatically 15–20 d post-treatment in all treated enclosures, and the rotifer populations dominated the zooplankton community for 3–4 wk. The high densities of microzooplankton were attributed to their inherent reproductive capabilities when released from competition and predation pressures. Resilience of the different zooplankton taxa was variable and depended upon both the species and the exposure concentration. Diversity of zooplankton was significantly reduced in communities exposed to permethrin. The limnocorral technique has proved to be an important tool for assessment of direct and indirect impacts of pesticides on and probable recovery of a zooplankton community under natural conditions.

scholarly journals Contribution and pathways of diazotroph derived nitrogen to zooplankton during the VAHINE mesocosm experiment in the oligotrophic New Caledonia lagoon

2016 ◽  
Author(s):  
B. P. V. Hunt ◽  
S. Bonnet ◽  
H. Berthelot ◽  
B. J. Conroy ◽  
R. A. Foster ◽  
...  
Keyword(s):  
N2 Fixation ◽  
New Caledonia ◽  
Austral Summer ◽  
Zooplankton Community ◽  
Zooplankton Biomass ◽  
Diazotrophic Cyanobacteria ◽  
Subtropical Oceans ◽  
Isotope Mixing Models

Abstract. In oligotrophic tropical and subtropical oceans, where strong stratification can limit the replenishment of surface nitrate, dinitrogen (N2) fixation by diazotrophs can represent a significant source of nitrogen (N) for primary production. The VAHINE experiment was designed to examine the fate of diazotroph derived nitrogen (DDN) in such ecosystems. In austral summer 2013 three large (~ 50 m3) in situ mesocosms were deployed for 23 days in the New Caledonia lagoon, an ecosystem that typifies the low-nutrient, low-chlorophyll environment, to stimulate diazotroph production. The zooplankton component of the study aimed to measure the incorporation of DDN into zooplankton biomass, and assess the role of direct diazotroph grazing by zooplankton as a DDN uptake pathway. Inside the mesocosms the diatom-diazotroph association (DDA) het-1 predominated during day 5-15 while the unicellular diazotrophic cyanobacteria UCYN-C predominated during day 15-23. A Trichodesmium bloom was observed in the lagoon (outside the mesocosms) towards the end of the experiment. The zooplankton community was dominated by copepods (63 % of total abundance) for the duration of the experiment. Using two source N isotope mixing models we estimated a mean ~ 30 % contribution of DDN to zooplankton biomass at the start of the experiment, indicating that the natural summer peak of N2 fixation in the lagoon was already contributing significantly to the zooplankton. Stimulation of N2 fixation BNF in the mesocosms corresponded with a generally low level enhancement of DDN contribution to zooplankton biomass, but with a peak of ~ 70 % in Mesocosm 1 following the UCYN-C bloom. qPCR analysis targeting four of the common diazotroph groups present in the mesocosms (Trichodesmium, het-1, het-2, UCYN-C) demonstrated that all were ingested by copepod grazers and that target abundance generally corresponded with their in situ abundance. 15N2 labeled grazing experiments provided evidence for direct ingestion and assimilation of UCYN-C-derived N by the zooplankton, but not for het-1 and Trichodesmium, supporting an important role of secondary pathways of DDN to the zooplankton for the latter groups, i.e., DDN contributions to the dissolved N pool and uptake by non-diazotrophs. This study appears to provide the first evidence of direct UCYN-C grazing by zooplankton, and indicates that UCYN-C-derived N contributes significantly to the zooplankton food web in the New Caledonia lagoon though a combination of direct grazing and secondary pathways.

scholarly journals The state of zooplankton communities in the lower Dniester area under the conditions of river regulation and actual climatic changes

2021 ◽  
Author(s):  
Liubovi Lebedenco ◽  
◽  
Mykhailo Nabokyn ◽  
Nadejda Andreev ◽  
Svetlana Kovalyshyna ◽  
...  
Keyword(s):  
Zooplankton Community ◽  
River Regulation ◽  
Zooplankton Biomass ◽  
Individual Characteristics ◽  
The State ◽  
Current State ◽  
Zooplankton Communities ◽  
Physical And Chemical ◽  
Quantitative Indicators ◽  
Planktonic Communities

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.

scholarly journals Impact of Bythotrephes invasion on zooplankton communities in acid-damaged and recovered lakes on the Boreal Shield

2005 ◽  
Vol 62 (11) ◽  
pp. 2450-2462 ◽  
Author(s):  
Angela L Strecker ◽  
Shelley E Arnott
Keyword(s):  
Community Structure ◽  
Zooplankton Community ◽  
Freshwater Ecosystems ◽  
Specific Response ◽  
Bythotrephes Longimanus ◽  
Aquatic Communities ◽  
Zooplankton Community Structure ◽  
Community Types ◽  
Zooplankton Communities ◽  
The Impact

Invasive species introductions into freshwater ecosystems have had a multitude of effects on aquatic communities. Few studies, however, have directly compared the impact of an invader on communities with contrasting structure. Historically high levels and subsequent reductions of acid deposition have produced landscapes of lakes of varying acidity and zooplankton community structure. We conducted a 30-day enclosure experiment in Killarney Provincial Park, Ontario, Canada, to test the effects of Bythotrephes longimanus, an invasive invertebrate predator, on two contrasting zooplankton communities at different stages of recovery from acidification: recovered and acid damaged. Bythotrephes significantly decreased zooplankton biomass and abundance in both communities but had a greater negative effect on the abundance of zooplankton in the recovered community. Bythotrephes reduced species diversity of the recovered zooplankton community but not of the acid-damaged community. Species richness of both community types was unaffected by Bythotrephes predation. The effect of Bythotrephes on small cladocerans, a preferred prey type, differed between the community types and appeared to be related to density-dependent predation by Bythotrephes. Both community- and species-level results suggest that recovered and acid-damaged zooplankton assemblages may be negatively affected by an invasion of Bythotrephes but that the specific response is dependent on the original community structure.

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