Phytoplankton data for samples collected at eleven large river sites throughout the United States, June through September 2017

This U.S. Geological Survey (USGS) Data Release provides phytoplankton data for samples collected from eleven large river sites throughout the United States, from June through September 2017. All data are reported as raw calculated values and are not rounded to USGS significant figures. The dataset includes all routine and quality assurance/quality control samples collected as part of a National Water Quality Assessment Project pilot study to describe the potential for cyanobacteria and cyanotoxin occurrence in the Nation's large rivers. Phytoplankton were identified to the lowest possible taxonomic level and abundances (density reported as natural units) are reported.