Short-term variability in coastal community and ecosystem dynamics in northern Lake Michigan

AbstractDespite their ecological and economic importance, coastal biological communities and ecosystem processes in large lakes have been understudied compared to those offshore. We investigated temporal variability in the abundance and assemblage composition of coastal organisms in northern Lake Michigan. We sampled nutrients, phytoplankton, zooplankton, periphyton, benthic invertebrates, and fish along the east coast of Beaver Island, Michigan, USA, with high temporal frequency (every d to every 2 wk) over 2 summers. We also examined connectivity between coastal and offshore habitats with both hourly water current data from the Great Lakes Coastal Forecasting System and sampling offshore 2 to 3× per summer. The abundance of littoral zone organisms varied markedly on daily to weekly timescales for both benthic invertebrates and water-column organisms (phytoplankton, zooplankton, fish). For example, zooplankton abundance changed by a mean of 297% between sampling dates at the same location. Within-season ...