An empirical analysis of zooplankton community size structure across lake trophic gradients1

Abstract

The hypothesis was tested that zooplankton community size structure shifts toward an increased relative biomass of microzooplankton with increased lake trophy at 12 sites in Quebec, The seasonal mean abundance and biomass of ciliates, rotifers, nauplii, cladocerans, and cyclopoid copepods were significantly (P < 0.1) related to lake trophy, but Calanoid copepod abundance and biomass varied independently of lake trophy. Regressions of microzooplankton and macrozooplankton biomass with total phosphorus (TP) were highly significant (P < 0.000 l), and TP explained a large proportion of the total variation (microzooplankton: Y* = 0.72; macrozooplankton: r2 = 0.86). The regression models for microzooplankton and macrozooplankton were not significantly different, refuting the hypothesis that relative biomass changes with lake trophy. Further analysis with a community structure index (the slope of the log weight-log abundance relationship) and mean lengths of various taxa indicated that zooplankton community size structure was not correlated with either TP or chlorophyll. On average, about 40% of the total zooplankton biomass is accounted for by microzooplankton in the Quebec lakes. The inverse relationship between body size and specific flux rates suggests that microzooplankton account for the major portion of zooplankton community rates.

The influence of a severe reservoir drawdown on springtime zooplankton and larval fish assemblages in Red Willow Reservoir, Nebraska

“…We observed an increase in the total zooplankton density as well as the density of several individual taxa À similar to a nearby reservoir during a drought-related drawdown (Olds et al 2014) À that could have resulted from the increase in Chl-a concentration (as a measure of phytoplankton biomass). The increase in Chl-a concentration, with a concurrent increase in cladoceran and cyclopoid copepod density and decrease in calanoid copepod density, is consistent with other studies (McNaught 1975;Allan 1976;Byron et al 1984;Pace 1986). The change in copepod densities could be caused by differences in feeding habits between calanoid and cyclopoid copepods.…”

Long-term changes of the crustacean zooplankton community in Lake Mjøsa, the largest lake in Norway

“…nanoplankton) and bacteria probably also increased along with increasing phytoplankton biovolume (Kjellberg et al 2001). Other studies have also demonstrated significant positive cor- relations between phytoplankton biomass, lake productivity, and zooplankton biomass (McCauley & Kalff 1981;Rognerud & Kjellberg 1984;Pace 1986;Hessen et al 1995a). The phytoplankton biomass seemed to be a decisive factor for the dominant herbivorous cladocerans D. galeata and B. longispina as well as for the omnivorous calanoid L. macrurus and cyclopoid C. lacustris.…”

“…Lack of significant correlation between biomass of calanoids and lake trophy have also been shown in 12 lakes in Canada (Pace 1986). The positive correlation between E. gracilis and epilimnion temperature observed from 1972-88 in Lake Mjøsa (Rognerud & Kjellberg 1990), disappeared when 12 more years were added in our study.…”

Effects of constant and stepwise changes in temperature on the species abundance dynamics of four cladocera species

“…Of course, the population dynamics of natural communities is also driven by other factors such as biotic interactions (e.g. Tilman et al, 1986), food availability (Starkweather and Bogdan, 1980;McCauley and Kalff, 1981;Stemberger, 1981;Pushchina and Verbitsky, 1983;Chow-Fraser and Knoechel, 1985;Chow-Fraser, 1986;Sarviro and Verbitsky, 1988;Zurek and Bucka, 1994) and fish predation (Brooks and Dodson, 1965;Verbitsky et al, 1980;Verbitsky and Verbitskaya, 1989;Cristoffersen et al, 1993;Ronneberger et al, 1993), as well as abiotic components such as turbidity (Zettler and Carter, 1986;Hart, 1988Hart, , 1990Kirk and Gilbert, 1990;Kirk, 1991), nutrient status (Bays and Crisman, 1983;Hanson and Peters, 1983;Pace, 1986;Verbitsky and Verbitskaya, 2007). But our researches of influence of others abiotic environmental factors (Verbitsky and Verbitskaya, 2007) and the analysis of the literature allows to assume, that the approach to define a real ecological optimum for ectotherms as described in this article may be applied to other environmental factors.…”