The Lake Ontario Nearshore Study: Introduction and summary

Intensive sampling of seven 100-km2 nearshore sites and a lake circumnavigation using geo-spatially linked, continuous-measuring sensors allowed unprecedented detail on the structure of the nearshore of Lake Ontario in the post-dreissenid era. The 23 manuscripts describe the wide variability in nearshore nutrients, suspended solids, and organic wastewater correlated with proximity to the shoreline and among geographic areas. Although 7.71 × 105 mT of dreissenids exist in the nearshore, phosphorus regenerated was not enough to sustain populations of Cladophora. The phosphorus load of tributaries to Lake Ontario was 234% higher than of wastewater treatment plants and 67.5% of the 1982 Niagara phosphorus load. Phosphorus loading from local watersheds appeared to be the underlying driver for the spatial nearshore variability in Cladophora biomass. Such research has implications for the nearshore of other large lakes and is a necessary prerequisite to more fully understand how the nearshore functions in the post-dreissenid era. Consistent monitoring should be conducted on the major tributaries and representative smaller water courses in Ontario and New York to obtain ongoing information on the spectrum of influences that shoreline runoff has on the nearshore and the lake as a whole. We believe, however, that this falls short of what is needed to effectively manage nearshore water resources. We suggest that nearshore management might be advanced by a more purposeful coupling of the knowledge that exists in the field of watershed science with that of the limnology of large lakes to predict explicit nearshore conditions in the face of potential future environmental management regimes.

► In 2008 an intensive study of the nearshore of Lake Ontario was undertaken.
► Chemistry, Cladophora, phytoplankton, gobies, dreissenids results are presented.
► Variability in nutrients and suspended solids were correlated with land use.
► P regenerated by mussels was not enough to sustain populations of Cladophora.
► Watershed P loading was the driver for the spatial variability in Cladophora.