Land use patterns, ecoregion and phytoplankton relationships in productive Ohio reservoirs

Abstract

We describe characteristics of phytoplankton communities of Ohio reservoirs with emphasis on the interrelationships among cyanobacterial populations, land use within 3 ecoregions, and associated environmental variables. We collected 59 phytoplankton samples from 25 mostly productive reservoirs located within 3 distinct ecoregions corresponding to intense agricultural land use (Eastern Corn Belt Plains), intermediate forestation and intermediate agricultural land use (Erie Drift Plain), and heavily forested land (Western Allegheny Plateau) between May and October 2008–2010 and May and June 2011. Cyanobacteria populations peaked in late summer months and were dominated by nitrogen-fixing taxa only in Western Allegheny Plateau and Erie Drift Plain sites, which commonly included Anabaena, Anabaenopsis, Aphanizomenon, and Cylindrospermopsis. Canonical correlation analysis suggests that the qualitative and quantitative characteristics of phytoplankton populations in Ohio reservoirs are strongly influenced by underlying land use practices. Coarse resolution at the ecoregion scale can be valuable in describing potential cyanobacteria composition where detailed nutrient budgets are not available for particular reservoirs and lakes.