Indirect effect of environmental factors on interactions between microbial and classical food webs in freshwater ecosystems

Abstract

-The role of environmental factors in aquatic ecosystems results from basic lake characteristics, human disturbances ('cultural eutrophication') and climate-related trends in the physical and chemical components of lakes. Although the influence of environmental factors on the abundance of aquatic animals is fairly well documented, less has been done to research their influence on food web interactions. The aim of the study was to evaluate microbial and classical food webs in lakes, with special emphasis placed on the role of environmental factors as influencing strengths. Variation partitioning, based on redundancy analysis, revealed that environmental factors played the most important role in structuring aquatic communities by accounting for 87.5% of their variation. Among all the factors measured, total solids (TS), transparency (Secchi disc) and temperature were most closely related to the variation in trophic communities. The analyses of food web interactions under low and high levels of those factors revealed that they differently influenced strengths among food web components. The strongest relations among distinct trophic levels were found under conditions of low TS, the lowest number of relations was found under conditions of low temperature. Only in low TS did bacteria correlate significantly with biogenes. Under high TS, bacteria positively influenced plenty of higher trophic levels. Top-down control was observed under conditions of high temperature. Conditions of low and high transparency did not diversify food web interactions. The obtained results can broaden our knowledge of the response of food webs to environmental factors in advanced stages of global eutrophication of water bodies and in the early stage of projected trends of global climate change.

The effect of epiphytic macroinvertebrates on microbial communities in different types of macrophyte-dominated shallow lakes

“…Both species richness and abundance of algae and epiphytic fauna reached their highest values in the Stratiotes-dominated lake, while the species richness and abundance of microbial communities and Metazoa increased in the Ceratophyllum-dominated lakes and reached their highest values in the Potamogetondominated lakes. Similar patterns have been observed in planktonic microbial communities inhabiting these water bodies (Adamczuk et al, 2015). The structure of periphyton communities on the substrates studied was correlated with the productivity of the lakes.…”

How to mitigate cyanobacterial blooms and cyanotoxin production in eutrophic water reservoirs?

“…In this lake, water outputs and subsequent inputs are frequent, and depend on the needs of fish farming in neighbouring pounds (personal communication; manager of Fish Farm ''Polesie'' in Sosnowica). Characteristics of biological communities of the lakes were presented previously (Adamczuk et al, 2015).…”

Distribution of Archaeal and Bacterial communities in a subtropical reservoir

“…Eutrophication in reservoirs and lakes, such as increased organic matter and nutrients, can also alter the structure of the microbial community, which may lead to water pollution and changes in ecosystems (Adamczuk et al, 2015).…”