Search results for "Cladocera"
showing 10 items of 62 documents
Epizooic ciliates (Vorticella sp.) compete for food with their host Daphnia longispina in a small polyhumic lake.
1987
Clearance rates of epizooic ciliates (Vorticella sp.) were measured together with their host, a planktonic cladoceran Daphnia longispina by using fluorescent latex beads as tracers of food. Vorticellans and their host graze on food of same size range (nanoplanktonic algae and bacteria). Individual clearance rates of Vorticella averaged 6.9 and 7.0 μl ind-1 h-1 and those of Daphnia 463 and 708 μl ind-1 h-1 for beads with diameter 2.00 and 3.92 μm. On the average, epizooic vorticellans together on the carapace of Daphnia cleared particles with rates representing 25–33% of that the host cleared, the maximum rates being 50–80%. In a steeply stratified polyhumic lake vorticellans take advantage …
Diet-specific biomarkers show that high-quality phytoplankton fuels herbivorous zooplankton in large boreal lakes
2014
SUMMARY 1. The zooplankton is a key link in the transfer of energy from primary producers up through aquatic food webs. Previous efforts to quantify the importance of basal resources to aquatic consumers have used stable isotopes (SI) and simple ternary models, including only ‘bulk’ phytoplankton, bacteria or terrestrial particulate organic matter (t-POM). 2. We used a novel Bayesian mixing model based on fatty acids (FA) to quantify the dietary assimilation of seven basal resources, including five phytoplankton groups, pelagic bacteria and t-POM, to Cladocera in large boreal lakes in Finland. To account for trophic enrichment of FA from the diet to consumers, we parameterised the model wit…
Effects of the filter-feeding benthic bivalve corbicula fluminea on plankton community and water quality in aquatic ecosystems: A mesocosm study
2021
The influence of filter-feeding bivalves on plankton communities, nutrients, and water quality in a given aquatic ecosystem is so profound that they can be considered ecosystem engineers. In a 70-day mesocosm experiment, we tested the hypothesis that Corbicula fluminea would change plankton community structure by reducing small zooplankton and large phytoplankton and improve water quality by reducing nutrients. We monitored levels of nitrogen and phosphorus, organic suspended solids (OSS), and light at the sediment surface. Within the plankton, phytoplankton biomass (as Chl a, >
Lake restoration influences nutritional quality of algae and consequently Daphnia biomass
2020
AbstractFood quality is one of the key factors influencing zooplankton population dynamics. Eutrophication drives phytoplankton communities toward the dominance of cyanobacteria, which means a decrease in the availability of sterols and long-chain polyunsaturated fatty acids (EPA and DHA). The effects of different restoration measures on the nutritional quality of the phytoplankton community and subsequent impacts on zooplankton biomass have rarely been considered. We analyzed the nutritional quality of phytoplankton in the eutrophic Lake Vesijärvi in southern Finland over a 37-year period, and studied the impacts of two restoration measures, biomanipulation and hypolimnetic aeration, on th…
Trematode cercariae as prey for zooplankton: effect on fitness traits of predators.
2019
AbstractRemoval of parasite free-living stages by predators has previously been suggested an important factor controlling parasite transmission in aquatic habitats. Experimental studies of zooplankton predation on macroparasite larvae are, however, scarce. We tested whether trematode cercariae, which are often numerous in shallow waters, are suitable prey for syntopic zooplankters. Feeding rates and survival of freshwater cyclopoids (Megacyclops viridis, Macrocyclops distinctus), calanoids (Arctodiaptomus paulseni), cladocerans (Sida crystallina) and rotifers Asplanchna spp., fed with cercariae of Diplostomum pseudospathaceum, a common fish trematode, were studied. In additional long-term e…
Leptodora kindti (Focke) (Crustacea; Cladocera) bioloģija un loma saldūdens ekosistēmās
1993
Ievads 1. Leptodora kindti populācijas sezonālā dinamika un vertikālās migrācijas 1.1. Materiāli un metodika 1.2. Rezultāti un to apspriešana 1.2.1. L. kindti dzīves cikls, izmēri un auglība 1.2.2. L. kindti populācijas sezonālā dinamika 1.2.3. L. kindti diennakts vertikālās migrācijas 2. Leptodora kindti lineārā augšana un populācijas produktivitāte 2.1. Materiāli un metodika 2.2. Rezultāti un to apspriešana 2.2.1. L. kindti lineārās augšanas ātrums 2.2.2. L. kindti augšanas procesu īpatnības un populācijas produktivitātes rādītāju analīze 3. Leptodora kindti barošanās 3.1. Materiāli un metodika 3.2. Rezultāti un to apspriešana 3.2.1. Pieaugušo L. kindti barošanās 3.2.2. Juvenīlo L. kindti…
Climate controls on the Holocene development of a subarctic lake in northern Fennoscandia
2015
International audience; Climate exerts strong control over the functioning of northern freshwater ecosystems, yet their resilience and responses to climate forcing may vary. We examined postglacial development patterns in subarctic Lake Varddoaijavri to discern the impact of direct climate controls, catchment influence, and ontogenic processes on the ecological functioning of the lake over the Holocene. Subfossil diatom assemblages together with the elemental and stable isotopic (delta C-13, delta N-15) composition of sediment organic matter were used to examine climate-induced changes in the structure of the phototrophic community and transport of terrestrial organic matter from the catchm…
Meiofauna ratios as environmental indicators in the profundal depths of large lakes.
1995
Two sets of samples from Lake Paijanne and one from Lake Ladoga were used to examine the relations between the meiofauna and environmental variables. The most obvious indicators of an unpolluted environment were, in order of importance, the true meiofauna/total meiofauna ratio, the proportion of Aeolosomatidae, the proportion of Harpacticoida (excluding C. staphylinus), the meiofauna/macrofauna biomass ratio, the proportion of Naididae and the A. crassa + P. schmeili/true meiofauna ratio. Conversely, the clearest indicators of a polluted environment were the proportion of resting stages of Cyclopinae, the Nematoda/non-resting Copepoda ratio, and the proportions of Tubificidae, Oligochaeta, …
A redescription of the Mediterranean endemic cladoceran Daphnia chevreuxi Richard, 1896 (Cladocera: Daphniidae)
2022
The Mediterranean area is a biodiversity and endemism hotspot. “Circum-Mediterranean” taxa are known among different hydrobionts, including the water fleas. Some Mediterranean endemic cladoceran taxa have been described or redescribed according to modern taxonomical standards, but accurate drawings are missing for others. Here we redescribe the Mediterranean endemic Daphnia chevreuxi Richard, 1896 (Crustacea: Cladocera) and briefly review available data on its distribution and ecology. The species is confirmed to be a typical inhabitant of the temporary ponds of the central Mediterranean area, whereas its populations from the eastern Balkans and the Middle East should be studied in order to…
EFFECTS OF THIOBENCARB HERBICIDE TO AN ALGA (NANNOCHLORIS OCULATA) AND THE CLADOCERAN (DAPHNIA MAGNA)
2001
Chronic toxicity studies were conducted with an algae (Nannochloris oculata) and the cladoceran (Daphnia magna) to determine their relative sensitivities to the thiocarbamate herbicide thiobencarb (S-4-chlorobenzyl diethylthiocarbamate). Most of the algal populations were initially affected by exposure to the herbicide. Thiobencarb concentrations higher than 0.5 mg/L significantly reduced algal densities after 24-h exposure. The 24-h static EC50 in D. magna was 3.01 mg/L. The sublethal effects of 0.3, 0.37, 0.5, 0.75, and 1.5 mg/L of thiobencarb concentrations on the survival, reproduction, and growth of D. magna were monitored for 21 days. The parameters used to determined the effect of th…