Effects of nutrient enrichment on the trophic structure and species composition of freshwater nematodes—a microcosm study

Species and trait compositions of freshwater nematodes as indicative descriptors of lake eutrophication

“…In fact, nematodes characterized by a small body size (<500 m), a slender body shape, or which were classified as chewers were highly represented under oligotrophic conditions, whereas the feeding type suction feeder was more dominant at eutrophic lake sites. These results partly confirm those of an own previous 16-month laboratory study designed to explore changes within nematodes' trophic structure and species composition in response to nutrient enrichment (range 7 to 250 g TP L −1 ), in which small-sized species with a low average dry mass ultimately peaked in nutrientpoor microcosms and suction feeders became most abundant at intermediate nutrient levels (Ristau et al, 2013). In accordance with our study, the analysis of the benthic marine assemblage in a Mediterranean harbor (Italy) suggested the morphological trait body shape as indicative for changes in the sediment quality (Losi et al, 2013).…”

“…M. paludicula, D. stagnalis, B. stefanskii, and E. filiformis were often stated to be predominant at littoral sites in eutrophic water bodies (Prejs, 1977;Michiels and Traunspurger, 2004;Wu et al, 2004;Bert et al, 2007;Ristau et al, 2013), but were in a few cases also detected at lower enriched conditions (Traunspurger, 1996a,b;Michiels and Traunspurger, 2005a). Furthermore, M. cf.…”

Short-term effects of nutrient enrichment on river biofilm: N–NO3 − uptake rate and response of meiofauna

“…These findings suggest that meiofaunal responses are rather slow and can take months to years to develop (Hillebrand et al, 2002;Posey et al, 2002;Mitwally & Fleeger, 2013), and that long-term impacts of nutrient enrichment on density and/or biomass of meiobenthic invertebrates are context-dependant and comparatively weaker than the responses of meiofauna to other factors, such as temperature and biotic constraints (e.g. resource availability) (Hulings & Gray, 1976;Majdi et al, 2011;Ristau et al, 2013).…”

“…Recently, Mitwally & Fleeger (2013) reported inconsistent and variable responses of densities of saltmarsh meiofauna to long-term (5 years) nutrient enrichment in marine muddy sediments. In contrast, nematodes responded to nutrient enrichment by increasing their density in marine sediments after 38-70 days (Wormald & Stirling, 1979) and in lake sediments during a 16-month experiment (Ristau et al, 2013). These findings suggest that meiofaunal responses are rather slow and can take months to years to develop (Hillebrand et al, 2002;Posey et al, 2002;Mitwally & Fleeger, 2013), and that long-term impacts of nutrient enrichment on density and/or biomass of meiobenthic invertebrates are context-dependant and comparatively weaker than the responses of meiofauna to other factors, such as temperature and biotic constraints (e.g.…”

“…Moreover, recent studies report that nutrient enrichment can induce increase in the density of marine and freshwater sediment-dwelling meiofauna, although the observed functional responses are slow and highly variable (e.g. Hillebrand et al, 2002;Posey et al, 2002;Mitwally & Fleeger, 2013;Ristau et al, 2013). As detailed above, since it has been shown that meiofauna can influence primary productivity and stimulate bacterial growth, we hypothesized that biofilm-dwelling meiofauna could indirectly influence biofilm functions related to nutrient uptake.…”