Biomass Size Spectra and Plankton Diversity in a Shallow Eutrophic Lake

Abstract

Biomass size spectra collate structural and functional attributes of plankton communities enabling standardised temporal and cross-system comparisons and may be rapidly obtained by automated particle counters. To examine how differences in plankton communities from highly eutrophic and more oligotrophic lakes are reflected in size spectra, a three-year time series of biomass size spectra was established for polymictic, eutrophic Lake Müggelsee, based on approximately weekly sampling and microscopic enumeration. The continuous but often bumpy size spectra reflected appropriately the seasonal and trophy-related variations in the plankton composition and growth conditions and the potential impact of daphnids on smaller plankton. We tested the hypothesis that more diverse plankton communities have smoother size spectra than impoverished ones. The spectra of Lake Müggelsee and other more or less eutrophic lakes covaried roughly with the functional diversity in total plankton composition but were unrelated to taxonomical diversity within the phyto-or mesozooplankton. The slopes of the normalised size spectra of Lake Müggelsee were generally more negative than -1, exhibited a recurrent seasonal pattern and were strongly correlated with crustacean biomass. In contrast to less eutrophic systems, slopes could not be used to quantify energy fluxes within the food web due to highly variable algal P/B ratios and frequently bumpy size distributions. The latter indicated stronger deviations from the ideal concept of a steady energy flow along the size gradient than found in e.g. large, mesotrophic Lake Constance.

Seasonal variation of microbial eukaryotic community composition in the large, shallow, subtropical Taihu Lake, China

“…In addition, the abundance of ciliate was significantly correlated with TN concentration at Lake Center in this study (r = 0.62, P = 0.032). Many other studies have demonstrated that the composition of microbial eukaryotic communities is related to trophic status (Gaedke et al 2004;Lefranc et al 2005;Lepère et al 2006;Moore et al 2008). For example, Lepère et al (2006) found that nutrients, especially nitrogenous nutrients and total phosphorus, play a significant role in structuring small eukaryotic communities.…”

“…The result suggests that cladocera and copepoda may exert differential top-down regulation of microbial eukaryotes in the microbial food web (Lepère et al 2006). The preferred food size for the filtering cladocera is less than 40-50 lm; therefore, they could exert a pronounced effect on the whole protist community (Auer and Arndt 2001;Gaedke et al 2004;Jürgens and Stolpe 1995). Copepoda select a larger particle size than cladocera and are known to be efficient selective grazers of larger Aquat Ecol (2010) 44:1-12 9 planktonic ciliates (Auer and Arndt 2001;Sommer et al 2003;Zöllner et al 2003) and are probably of minor importance as grazers of nanoplankton (Jür-gens and Stolpe 1995).…”

Plankton food web structure in a eutrophic polymictic lake with a history of toxic cyanobacterial blooms

“…Additionally, there should be a higher vulnerability of heterotrophic nanoplank- ters to high daphnids abundance than that of the equally sized autotrophs. A precondition for both circumstances is a high abundance of large daphnids (Tittel et al 1998;Gaedke et al 2004). However, in Lake Kastoria, the overall size composition of zooplankton was dominated by sizes up to 300 m (Fig.…”

Fish community size structure of small lakes: the role of lake size, biodiversity and disturbance

“…There is relatively little information available on how species richness influences fish community size distributions, particularly in small lakes (Duplisea 2000;Gaedke et al 2004;Sprules 2008). It is possible that even single species lakes show a predicable size structure as long as there is competition for limited food resources and size-based predation.…”

“…This suggests that species diversity has little effect on size spectra slope in large systems, or beyond some yet undetermined number of species. Similarly, Gaedke et al (2004) found that diversity of plankton had little effect on the shape of size spectra in a large (730 ha), shallow eutrophic lake. Contrary to the aforementioned studies, Duplisea (2000) suggested that size spectra of the Baltic Sea benthos may be altered when one or two ecologically important species are reduced in abundance; these results suggest that as species richness decreases the likelihood of single (ecologically important) species population dynamics having a strong influence on CSS increases, as will the variability in size structure (i.e., tend toward stochastic structure).…”