In situ measurements of surface chlorophyll and zooplankton concentration are compared with in situ hydrographic measurements and infrared satellite images of the west coast of British Columbia for early winter and midsummer study periods. Maximum winter concentrations ofchlorophyll (1.0 mg m-3) and zooplankton (2900 counts m-3) were found in colder, more stratified nearshore water. Warmer wate...

Migratory grazing of zooplankton between non-toxic phytoplankton (NTP) and toxic phytoplankton (TPP) is a realistic phenomena unexplored so far. The present article is a first step in this direction. A mathematical model of NTP–TPPzooplankton with constant and variable zooplankton migration is proposed and analyzed. The asymptotic dynamics of the model system around the biologically feasible eq...

[1] Zooplankton in the California Current had large anomalies in biomass and composition in 2005. The zone most strongly affected extended from northern California to southern British Columbia, where zooplankton biomass was low from spring through autumn, community composition showed reduced dominance by northern origin taxa, and life cycles of some species shifted to earlier in the year. Altho...

The transparency-gradient hypothesis argues that ultraviolet radiation (UV) is a primary determinant of the vertical distribution of zooplankton in transparent lakes with fewer fish, while fish predation is the primary driver in less transparent lakes where fish are more abundant. We measured vertical profiles of UV, photosynthetically active radiation (PAR, essentially visible light used as a ...

Scleractinian cold-water corals (CWC) represent key taxa controlling deep-sea reef ecosystem functioning by providing structurally complex habitats to a high associated biodiversity, and by fuelling biogeochemical cycles via the release of organic matter. Nevertheless, our current knowledge on basic CWC properties, such as feeding ecology and key physiological processes (i.e. respiration, calci...

The dynamics of two plankton population models are investigated to examine sensitivities to model complexity and to parameter values. The models simulate concentrations of nutrients, phytoplankton, zooplankton and detritus in the oceanic mixed layer. In Model 1, zooplankton can graze only upon phytoplankton, whereas in Model 2 zooplankton can graze upon phytoplankton and detritus. Both feeding ...

The influence of physico-chemical properties of Oyun Reservoir, Offa, Nigeria (a shallow tropical African reservoir) on its zooplankton composition and abundance were investigated at three stations for two years between January 2002 and December 2003. Diversity is not high: only three groups of zooplankton were found: Rotifera with eight genera; and Cladocera and Copepoda with three genera each...

Recent studies have demonstrated that Daphnia, a cladoceran (anomopod) zooplankton species with a high phosphorus content, can become P limited when fed algae deficient in phosphorus. Bosmina is another common anomopod zooplankter, but its body has a lower percentage of P than does that of Daphnia, and Bosmina might therefore be less susceptible to P mineral limitation. To test for this hypothe...

Open ocean zooplankton often have been viewed as slowly evolving species that have limited capacity to respond adaptively to changing ocean conditions. Hence, attention has focused on the ecological responses of zooplankton to current global change, including range shifts and changing phenology. Here, we argue that zooplankton also are well poised for evolutionary responses to global change. We...

It is widely accepted that predation plays a critical role in determining zooplankton community structure in ponds and lakes. The relationship between fish planktivory and zooplankton species composition has been discussed since the early work of HRBACEK et al. (1961) and BROOKS & DODSON (1965). Size-selective predation by fish may produce changes in zooplankton community structure. Phenomena f...