Lake Erie & Eutrophication 1960’s: Harmful Algal Blooms (HABs); extreme eutrophication; hypolimnetic hypoxia 1972: Great Lakes Water Quality Agreement (GLWQA) signed; reduced phosphorus (P) entering Lake Erie; P detergents banned Late 1970’s-1980’s: Reductions in P recorded; decreased HABs and hypoxia Mid-1990’s: re-eutrophication of Lake Erie; increases in dissolved P; return of HABs and hypoxia Sandusky Bay in April (OhioLink Landsat 7)