Distribution Of Zooplankton Species Research Articles

A comparison of zooplankton communities in saline lakewater with variable anion composition

Although salinity and aquatic biodiversity are inversely related in lake water, the relationship between types of salts and zooplankton communities is poorly understood. In this study, zooplankton species were related to environmental variables from 12 lakes: three saline lakes with water where the dominant anions were SO4 and CO3, four saline lakes with Cl-dominated water, and five dilute, subsaline (0.5–3 gl −1 total dissolved solids) lakes of variable anion composition. Although this study comprised only 12 lakes, distinct differences in zooplankton communities were observed among the two groups of chemically defined saline lakes. Canonical correspondence analysis identified total alkalinity, sulphate, chloride, calcium, sodium, potassium, and total phosphorus as all contributing to the first two ordination axes (λ1 =0 .97 andλ2 = 0.62, P< 0.05). The rotifer Brachionus plicatilis and the harpactacoid copepod Cletocamptus sp. prevailed lakes with Cl-dominated water. In contrast, the calanoid copepods Leptodiaptomus sicilis and Diaptomus nevadensis were dominant in the SO4/CO3-dominated lake water with elevated potassium (79–128 mg l −1 ) and total phosphorus concentrations (1322-2915 µ gl −1 ). The contrasting zooplankton species distribution among these two saline lake types is likely explained by variable selective pressure on zooplankton and their predators from differing physiological tolerances to salt stress and specific ions. While inland saline lakes with Cl as the dominant anion are relatively rare in Canada and SO4/CO3 are the common features, our study provided an opportunity to compare zooplankton communities across the two groups of lakes.

Winter distribution of phytoplankton and zooplankton around some sandbanks of the Belgian coastal zone

The distribution of phytoplankton and zooplankton around three sandbanks (Gootebank, Westhinder and Buitenratel sandbank) off the Belgian Coast was investigated in February 1994. The abundance of phytoplankton taxa was significantly different between the sandbanks. Community analysis using TWINSPAN resulted in a clear separation of clusters corresponding to the different sandbanks. The zooplankton community analysis, on the contrary, showed a rather indistinctive division of the sandbank stations. This was due to the omnipresence of three dominant copepod species (Temora longicornis, Pseudocalanus elongatus and Centropages hamatus) . When these species were excluded from the analysis, a clearer distinction between the different sandbanks was found. The observed differences in phyto- and zooplankton species distribution could be explained by the position of the sandbanks. Westhinder is positioned further fromthe coast than Buitenratel, while Gootebank has an intermediate position. Buitenratel and Gootebank harbour typical coastal plankton communities, while the plankton community over Westhinder is clearly influenced by the Atlantic current penetrating the southern North Sea from the English channel. More phyto-benthic species were found at Buitenratel than at Gootebank, probably because of its limited depth. Thus, the Belgian coastal zone, which is considered as one box in most spatial descriptions of the North Sea plankton, in fact harbours heterogeneous plankton communities at the end of winter.

Zooplankton Assemblages in Crater Lake, Oregon, USA

ABSTRACT The zooplankton community in Crater Lake was comprised of 11 rotifer species and 2 species of cladocerans. Most zooplankton taxa were distributed in winter and spring from the lake surface to a depth of about 200 m, the maximum depth of mixing of lake waters by wind energy. The distribution of zooplankton species was partitioned in the water column to a depth of 200 m during summer and fall, which corresponded to the period when the lake was thermally stratified. At that time of year, zooplankton density in die upper 20 m of the water column was very low, whereas highest densities were found in the depth interval between 80 and 120 m. Closely related or competing species were found in different portions of the water column. Daphnia pulicaria the largest cladoceran species, was cyclic in abundance, and its density corresponded to patterns of lake productivity and fish predation. When D. pulicaria was abundant, abundances of rotifers and Bosmina longirostris declined and changes in the vertical dis...

Metalimnetic Oxygen Depletion: Organic Carbon Flux and Crustacean Zooplankton Distribution in a Quarry Embayment

Metalimnetic Oxygen Depletion: Organic Carbon Flux and Crustacean Zooplankton Distribution in a Quarry Embayment

The zooplankton of the north sea

This review summarizes available knowledge on herbivorous and omnivorous zooplankton of the North Sea. After an introductory chapter on history and general approach of zooplankton studies, the four main contributions review distribution patterns, cycles and trends in temporal variation, trophic interactions and population dyamics and production. The distribution of zooplankton species in relation to hydrography and origin of watermasses is described for copepods. It highlights the influence of Atlantic Ocean influx from the northwest, which to a large extent dominates the species composition and its seasonal variation in the summer-stratified waters. In contrast, the more neritic communities in the southeast region mainly depend on the local populations of the species abundant in coastal mixed waters. The chapter on cycles and trends in temporal variation discusses the differences in seasonal variation with respect to species, area, and community structure in terms of herbivores, omnivores and carnivores. The year-to-year changes are considered as dependent on the overwintering stocks and strategies. Patterns in long-term variation appearing from long-term data series are related to climatic changes, leading to two hypotheses with respect to the effects of changes in wind regime. The chapter on trophic interactions deals with the utilization of primary particulate production by planktonic herbivores and its variation in time and space. Emphasis is put on differences between north and south, which are partly due to differences in species composition, community structure and seasonal variation already discussed in foregoing chapters. The various aspects of copepod grazing are reviewed, but also the role of microzooplankton as both grazers and food organisms is brought to attention. The last chapter deals with population dynamics and production of key species. Seasonal fluctuations in abundance and biomass are discussed and related to underlying population processes and characteristics such as reproduction and life strategy, growth and development, and mortality. Secondary-production estimates inferred from biomass and growth rate estimates are discussed.

The influence of predation on horizontal distribution of zooplankton species

SUMMARY. 1. The horizontal distributions of Daphnia longispina and Bosmina tongispina in Lake Kvernavatn (Norway) were investigated twice in 1982. In late spring, when populations were small, the two species inhabited the same areas, and they were evenly distributed from the littoral to the pelagic. At high population densities, during midsummer, the species were spatially segregated, D. longispina being pelagic and B. longispina littoral in distribution.2. The distribution and feeding of three‐spined sticklebacks (Gasteros‐teus aculeatus) were also studied. The sticklebacks were apparently forced into littoral areas by larger piscivorous predators in the pelagic and they were consequently restricted to foraging primarily on B. longispina, which formed dense swarms during daytime in summer.3. We suggest that predation and competition influence the spatial distribution of zooplankton species. The feeding efficiency of fish foraging on high‐density zooplankton populations can be reduced by spatial segregation of zooplankton species. Where high local densities occur, due to swarm formation, predation is changed from size‐selective feeding to consumption of spatially isolated individuals.

Distribution of zooplankton in a coastal upwelling in New Zealand

Abstract Species composition and biomass of plankton samples taken on transects across an upwelling plume off Farewell Spit in February 1981 are presented. Copepods were numerically dominant, particularly Oithona similis and Paracalanus indicus. Also abundant were large phytoplankters (Chaetoceros sp. and Trichodesmium sp.), crustacean faecal pellets, and euphausiid larvae. The distribution of zooplankton species suggests mixing of inshore waters and neritic populations with upwelled waters. These data are discussed with respect to an interpretation of the upwelling system as a northwards transport of zooplankton and its enhanced productivity into the South Taranaki Bight.

Prey Field of Larval Herring Clupea harengus on a Continental Shelf Spawning Area

The predator-prey relationships of larval Clupea harengus L. were investigated on a continental shelf spawning area, Georges Bank-Nantucket Shoals, off the northeastern coast of the United States during 3 autumn-winter spawning seasons. Our observations are based on examination of the alimentary tracts (guts) of over 8,000 larval herring. Feeding was concentrated into 2 peaks during the daylight hours, and larvae averaged 1 to 7 prey (0.5 to 48 ~g dry weight) per gut. Larvae preyed on the synchronously developing juvenile and adult stages of the dominant copepods of this area (Pseudocalanus sp.. Paracalanus parvus, Centropages typicus, C. hamatus, Oithona spp.. and Calanus finmarchicus). During 1974, Centropages spp. and Pseudocalanus sp. dominated the larval diet; during 1975 and 1976, Pseudocalanus sp. and Paracalanus parvus were dominant. This shift in diet reflects a shift in zooplankton species distribution in the area. Larger, more robust larvae were collected in 1976 than in 1974 and 1975; survival was greater during this season, and a higher percentage of feeding larvae was observed.

Arctic Zooplankton Community Structure: Exceptions to Some General Rules

Commonly accepted theories of zooplankton species distribution hold that: 1) large-bodied zooplankton species are excluded by fish predation and so are found only in lakes and ponds without fish; and 2) because small-bodied species are unable to compete successfully against large ones and also are preyed upon heavily by invertebrate predators, they exist primarily in lakes with fish. This pattern is not followed in a group of lakes and ponds in arctic Alaska. Some of these lakes were found to support both large and small zooplankton species along with populations of facultative planktivorous fish. Other lakes that had no fish had a small-bodied zooplankton species co-existing with a more typical large-bodied community. Close analysis of these unusual distributions reveals that the mechanisms affecting zooplankton community dynamics are more subtle and complex than generally recognized, particularly in such harsh environments as the Arctic.