The Great Lakes have multiple stresses acting on them, but offshore and nearshore systems may show different trends in relation to stresses. A new paper by NCCOS-supported researchers links these trends with invasive mussels. Mussels filter waters coming into coastal embayments, and can pull phosphorus out of the water column and deposit it into nearshore sediments.

Phosphorus retention close to shore is associated with nutrient enrichment, leading to blooms of noxious algae and decaying algal 'muck' on beaches. At the same time, the offshore food web is experiencing nutrient starvation and decreasing production of fish. This growing dichotomy between nearshore and offshore regions is a dilemma for resource managers trying to set target loads.

As Canada and the U.S. renegotiate the terms of the Great Lakes Water Quality Agreement in the near future, they must take these spatial differences into account when evaluating target loads.

Read more about the research and the research paper at http://cen.acs.org/index.html.