NITROGEN-FIXING DIATOMS AS INDICATORS OF HISTORICAL NITROGEN LIMITATION IN LAURENTIAN GREAT LAKES COASTAL WETLANDS
The purpose of this study was to examine historical nitrogen limitation in Great Lakes coastal wetlands. Previous research has suggested that the presence of nitrogen-fixing diatoms can indicate nitrogen scarcity in wetlands. We obtained herbarium macrophytes from the University of Michigan Herbarium, acid-digested macrophyte material to isolate attached diatoms, and determined the relative abundance of the nitrogen-fixing diatoms Epithemia and Rhopalodia. Present-day nutrient enrichment experiments with a concurrent collection of epiphytic diatoms and water samples were also used to validate the relationship between diatoms and nitrogen scarcity. Preliminary analysis of present day data suggest that benthic algae in some Great Lakes coastal wetlands are nitrogen limited, and analysis of historical samples is ongoing. Understanding the prevalence of nitrogen limitation in Great Lakes coastal wetlands from 1896 to 2018 will shed new insights on wetland ecology and nutrient cycling, and may suggest the need for new nutrient management policies in the Great Lakes region.
Matthew Cooper (Co-Presenter/Co-Author), Burke Center for Freshwater Innovation, Northland College, firstname.lastname@example.org;
Laura Moore (Co-Presenter/Co-Author), Central Michigan University, email@example.com;
Donald Uzarski (Co-Presenter/Co-Author), Institute for Great Lakes Research, Central Michigan University, firstname.lastname@example.org;
Steven Francoeur (Co-Presenter/Co-Author), Eastern Michigan University, email@example.com;
Willow Newman (Primary Presenter/Author), Eastern Michigan University, firstname.lastname@example.org;