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New Project: Effects of climate change and invasive mussels on the benthic-pelagic coupling in shallow lakes

Xuifeng Zhang, Xueying Mei, Lars Rudstam (Chinese National Science Foundation visiting scholar support). 

Benthic–pelagic coupling refers to the dependence of processes in sediments on those in the water column and vice versa. The coupling between the benthic and pelagic realms works in both downward and upward directions. The most prominent directional effect of pelagic habitats on benthic systems (downward coupling) involves interception of light in the water column before it reaches the benthic habitats. Pelagic algal biomass can be sufficiently high in lakes with high nutrient concentrations to effectively shade out benthic algae, while growth of benthic algae can substantially reduce the growth of pelagic algae and contribute to maintaining clear-water conditions. This coupling between the benthic and pelagic habitats differs and is key to the dynamics of shallow lakes. 

However, the coupling between benthic and pelagic habitats is affected by warming and/or invasive species, such as mussels. In this study, eight-week mesocosm experiments were conducted with quagga mussel as mussel treatments and increased temperature (+4℃) as warm treatments and without mussel with ambient temperature as controls. The experiments were conducted in plastic tanks containing sediment and water collected from Oneida Lake to investigate the effects of warming and invasive mussels on the benthic-pelagic coupling in shallow lakes. We hypothesized that warming may enhance eutrophication by accelerating growth of pelagic algae, while invasion by mussels may improve water quality by filtering on particles in the water column and stimulating the growth of benthic algae. The main aim of the study is to evaluate the effects of climate change and invasive mussels on the benthic-pelagic coupling in shallow lakes.