This dataset contains algal identification and enumeration data for phytoplankton samples collected by the U.S. Geological Survey (USGS) between July 2019 and November 2019 at seven reservoirs across the United States. Reservoirs sampled included Lake Koshkonong, Wisconsin, Pelican Lake, Minnesota, Lake Ida, Minnesota, Pomme de Terre, Minnesota, Lake Emily, Minnesota, Milford Lake, Kansas, and Jordan Lake, North Carolina. The samples were analyzed at the Caribbean - Florida Water Science Center (CFWSC) Phycology Laboratory using morphology-based microscopy methods. This data is part of a larger multi-agency project between the U.S. Environmental Protection Agency, the National Aeronautics and Space Administration, the National Oceanic and Atmospheric Administration, and USGS called the Cyanobacteria Assessment Network (CyAN). The goal of the CyAN project is to develop a satellite-based, early warning system to detect harmful algal blooms (HABs) in freshwater systems.

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.

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.

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 October 2018. 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 cyanobacteria and cyanotoxin occurrence in the Nation's large rivers. Phytoplankton were identified to the lowest possible taxonomic level and abundance (reported as both natural units and cells) is reported.

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 October 2018. 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 cyanobacteria and cyanotoxin occurrence in the Nation's large rivers. Phytoplankton were identified to the lowest possible taxonomic level and abundance (reported as both natural units and cells) is reported.

This U.S. Geological Survey (USGS) Data Release provides phytoplankton data collected from Milford Lake, Kansas, during July 27 and August 31, 2015. This data release was produced in compliance with the federal open-data requirements as a way to make scientific products associated with USGS research efforts and publications available to the public. The dataset includes all samples collected at three long-term U.S. Army Corps of Engineers (USACE) sites on Milford Lake. Phytoplankton were identified to the lowest possible taxonomic level and abundance (density) and biovolume are reported.

This U.S. Geological Survey (USGS) Data Release provides phytoplankton data collected from Milford Lake, Kansas, during July 27 and August 31, 2015. This data release was produced in compliance with the federal open-data requirements as a way to make scientific products associated with USGS research efforts and publications available to the public. The dataset includes all samples collected at three long-term U.S. Army Corps of Engineers (USACE) sites on Milford Lake. Phytoplankton were identified to the lowest possible taxonomic level and abundance (density) and biovolume are reported.

This U.S. Geological Survey (USGS) Data Release provides the phytoplankton tally sheet, including photomicrographs, for samples collected from eleven large river sites throughout the United States, from June through September 2017. All data are raw tallies, not calculated abundances or concentrations. 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 ocurrence in the Nation's large rivers. Phytoplankton were identified to the lowest possible taxonomic level and abundances (density reported as natural units) are reported.

This U.S. Geological Survey (USGS) Data Release provides the phytoplankton tally sheet, including photomicrographs, for samples collected from eleven large river sites throughout the United States, from June through September 2017. All data are raw tallies, not calculated abundances or concentrations. 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 ocurrence in the Nation's large rivers. Phytoplankton were identified to the lowest possible taxonomic level and abundances (density reported as natural units) are reported.

This U.S. Geological Survey (USGS) Data Release includes phytoplankton data collected from four reservoirs in Kansas, during August 2020 through August 2022. 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 at twenty-five locations within Marion Reservoir, Milford Lake, Perry Lake, and Hillsdale Lake. Phytoplankton were identified to the lowest possible taxonomic level and densities and biovolumes are reported. This data is part of a larger multi-agency project between the U.S. Environmental Protection Agency, National Aeronautics and Space Administration, National Oceanic and Atmospheric Administration, and USGS called the Cyanobacteria Assessment Network (CyAN). The goal of the CyAN project is to develop a satellite-based, early warning system to detect harmful algal blooms (HABs) in freshwater systems.