Today's MessagePosted: Thursday, December 7, 2017
GLC Seminar - 'Patterns of Long-Term Dynamics of Aquatic Communities and Water-Quality Parameters in the Great Lakes: Are They Synchronized?' - December 13
Please join the Great Lakes Center for the seminar "Patterns of Long-Term Dynamics of Aquatic Communities and Water-Quality Parameters in the Great Lakes: Are They Synchronized?" presented by Katya E. Kovalenko of the University of Minnesota Duluth's Natural Resources Research Institute, on Wednesday, December 13, from noon to 1:00 p.m. in Technology Building 258. All students, faculty, and staff are welcome.
Longtime series data can provide insights into dynamics of large lakes. We use the USEPA-GLNPO biological monitoring dataset (phytoplankton, benthos, zooplankton, and water quality), collected from 1996 through 2015, to identify whether there is evidence of concordant linear or non-linear trends in community composition, density/biomass/biovolume, and major environmental parameters. We show concurrent changes in some biotic assemblages and water quality variables, particularly in Lakes Michigan and Huron. These include changes in phytoplankton biovolume and zooplankton biomass, increasing invasive Dreissena abundance, and decreasing densities of other benthos. Biotic changes are accompanied by pronounced changes in water quality and nutrient ratios, indicating likely stoichiometric shifts affecting entire food webs. Species change-points, identified using threshold indicator taxon analysis, are often less abrupt, but there are clear shifts in most species in each assemblage. The concordance of breakpoints among assemblages or lack thereof provides valuable insight into potential drivers of ecosystem change.