Erosion microcosm experiments inform lake and reservoir benthic sediment stability and nutrient dynamics

Benthic sediment resuspension influences boundary layer nutrient dynamics, the ability of substrates to support rooted vegetation, and other factors impacting water quality health (e.g., suspended sediment) and aquatic ecosystems. In response, a benthic boundary layer microcosm system examined potential sediment erosion impacts in 2 independent intact sediment core case studies from diverse geographic locations (Michigan and Texas, USA). The first study investigated the effects of lake sediment erosion on wildrice bedforms, potential impacts to root stability, seed bank displacement, and suspended solids. Results indicate highly erodible sediments exhibit reduced wildrice abundance, underscoring the role of benthic sediment dynamics in maintaining ecosystem resilience. The second study evaluated increases in suspended solids and turbidity in reservoirs at risk from harmful algal blooms. Reservoirs with elevated sediment total phosphorus concentrations exhibited higher levels of total suspended solids during erosion experiments, highlighting potential erosion-induced internal benthic nutrient loading. Collectively, these studies illustrate how erosion microcosms inform the complex interactions between benthic sediment processes and factors influencing aquatic health, allowing natural resource managers to target sediment stabilization activities (e.g., no wake zones) or alter reservoir operations. Future studies should strengthen causal relationships between benthic boundary erosion, watershed characteristics, and water quality outcomes.