LONG-TERM RECORDS OF GREAT LAKES PHYTOPLANKTON REVEAL MULTIPLE STRESSORS AFFECTING FOOD WEBS

The Laurentian Great Lakes are the world’s largest surface freshwater resource, so it is worth considering the implications of changes at the base of the food web. Monitoring and paleoecological assessments of the Great Lakes phytoplankton flora reveal changes in whole-lake conditions in each of the lakes. Trends indicate impacts from invasive species, agriculturally derived nutrients, and climate change. Those responsible for tracking and maintaining ecosystem services on the Great Lakes are concerned about the ecological trajectories of the lakes, and phytoplankton data from monitoring and paleolimnological programs provide an early warning tool to uncover impacts. Major changes from the last two decades include: unicellular flagellated algae are increasing in relative abundance while diatoms are being lost; the substantial loss of phytoplankton biomass due to the quagga mussel invasion; and densities of cyanophytes are increasing in vulnerable coastal systems. Monitoring data complement paleolimnological data by providing a contemporary ecological context for fossil phytoplankton species. The implications of climate, nutrients and invasive species drivers on recent changes will be discussed in the context of future management of the Great Lakes.

Presentation Preference: Oral

Primary Presenter: Euan Reavie, University of Minnesota Duluth (ereavie@d.umn.edu)

Authors:

Euan Reavie, University of Minnesota Duluth  (ereavie@d.umn.edu)

Elizabeth Alexson, University of Minnesota Duluth  (alexs005@d.umn.edu)

Katya Kovalenko, University of Minnesota Duluth  (ekovalen@d.umn.edu)

Holly Wellard Kelly, University of Minnesota Duluth  (hwellard@d.umn.edu)