Phytoplankton and Cyanotoxin Data for Coastal and Shoreline Areas of National Parks, 2021-2024

This U.S. Geological Survey (USGS) data release contains phytoplankton classification and enumeration results from near-surface water samples collected during a nationwide harmful algal bloom (HAB) monitoring effort in partnership with the National Park Service (NPS) Water Resources Division. Samples were collected during the 2021-2024 monitoring seasons from 26 National Parks across the United States. In 2021, samples were analyzed using traditional light microscopy, while 2022 samples were analyzed using imaging flow cytometry. Data include phytoplankton and cyanobacterial taxa identified to the lowest possible taxonomic level, along with estimates of abundance (reported as both natural units and cells), biovolume; supporting cyanotoxin and water quality data are also included. Cyanotoxin data were also collected during the 2021-2024 monitoring seasons through the Cyanobacteria Monitoring Collaborative CyanoMonitoring Program. These data include cyanotoxin concentrations, as measured by Enzyme-Linked Immunosorbent Assay (ELISA) for anatoxins, beta-methylamino-L-alanine (BMAA), cylindrospermopsins, microsystins plus nodularins, and saxatoxins. All data are reported as raw calculated values and comply with USGS open data requirements to ensure public accessibility of research data.