Acadia National Park (Maine) & Isle Royale National Park (Michigan) Determine critical nitrogen loads to boreal lake ecosystems using the response of phytoplankton Jasmine Saros, Carmen Daggett, Heather Arnett Air pollution has affected and continues to threaten many boreal lake ecosystems in the U.S. national parks. The lakes of Acadia and Isle Royale National Parks read more Determine Critical Nitrogen Loads to Boreal Lake Ecosystems Using the Response of Phytoplankton