This dataset includes CSV data files containing environmental data that may be associated with the occurrence and toxicity of the diatom Pseudo nitzschia in Frenchman Bay, Maine, that can form harmful algal blooms and produce the toxin domoic acid. The dataset covers the period 2010 through 2022 or shorter period depending on the variable. Elevated concentrations of domoic acid in Pseudo nitzschia can lead to the contamination of shellfish, threats to human health and closures of shellfish harvesting areas. This dataset was compiled in cooperation with the National Park Service.XXXXXXXXXXXXXXXXXXXXXXXXXXX The file “Site_Infomation_v4.csv” contains the latitudes and longitudes for the locations where Pseudo nitzschia cells were enumerated, water quality and mussel tissue samples were collected, nutrient loads were estimated, and ocean temperature and salinity were measured.XXXXXXXXXXXXXXXXXXXXXXXXXXX The file “Pn_Cells_Ancillary_vars_v2.csv” contains Pseudo nitzschia monitoring data (cells/liter) for two locations: the Mount Desert Island Biological Laboratory and the Bar Harbor Town Pier for large and small Pseudo nitzschia cells as well as ancillary data including timing of sampling in relation to the tides, sampling depth, air temperature, water temperature, and salinity (PSU). These data were collected with variable frequency, generally approximately weekly to monthly from 3/2007 through 12/2022.XXXXXXXXXXXXXXXXXXXXXXXXXXX The file “MDIBL_BHTP_Nutrients_Field_Parms.csv” contains nutrient concentration data (nitrate + nitrite, silica, ammonium and orthophosphate) for two locations: the Mount Desert Island Biological Laboratory (MDIBL) and the Bar Harbor Town Pier (BHTP). These data were collected with variable frequency generally from approximately weekly to monthly from May through October and less frequently and with fewer samples in other months. Data are available from samples from 2013 to 2018 and in 2021.XXXXXXXXXXXXXXXXXXXXXXXXXXX The file “Water-quality_data_from_Frenchman_Bay_coastal_locations.csv” contains nutrient concentration data (total nitrogen, ammonium, phosphorus, and silicate) and water temperature, air temperature, salinity, and rainfall in the past 48 hours for (Berry Cove, various sites at Hadley Point; Jordan River, Racoon Cove, Skillings River, Thomas Island East, Thomas Island West). These data were collected with variable frequency generally approximately weekly to monthly from June through September. The period of record varied by site: Berry Cove, 2010 to 2017; various sites at Hadley Point, 2007 to 2017; Jordan River, 2008 to 2017; Racoon Cove, 2010 to 2017; Skillings River, 2010 to 2015; Thomas Island East, 2011 to 2017; Thomas Island West, 2010 to 2017. The data were retrieved from the ANECDATA.org data archive. XXXXXXXXXXXXXXXXXXXXXXXXXXX The file “Trib_N_P_Runoff_Loads_v2.csv” contains monthly nutrient load (kilogram/month) for total dissolved nitrogen and total phosphorus as well as monthly mean air temperature, mean precipitation, and mean runoff data for 24 tributaries that drain into Frenchman Bay for January 2010 through December 2021. The 7-digit numbers in the column headers of the “Trib_N_P_Runoff_Loads_v2.csv” file refer to the reach ID as defined in the file “Static_N_P_Annual_Loads_SPARROW_Model.csv”. The computation of loads is based on the static loads from the Sparrow Model shown in the file “Static_N_P_Annual_Loads_SPARROW_Model.csv” that were adjusted for monthly runoff modeled using the Thornthwaite Water Balance Model that, in turn used precipitation and temperature data from the PRISM model 4-kilometer quadrant data derived from GRIDMET. The centroids for the PRISM quadrants that were included for the calculated runoff for each tributary watershed are listed in the file “Site_Infomation_v4.csv”.XXXXXXXXXXXXXXXXXXXXXXXXXXX The file “Solar_Radiation_Frenchman_Bay.csv” contains monthly average solar radiation data for Frenchman Bay for January 2010 through December 2021. The file “Ocean_T_PSU.csv” contains monthly average water temperature and salinity data at 1-meter depth for NERACOOS Buoy I01 for most months from January 2010 through December 2021. This file also contains water temperature data at 1 m depth from the Co-OPS station no. 8413320 at the pier in Bar Harbor, Maine, or most months from January 2010 through December 2021. XXXXXXXXXXXXXXXXXXXXXXXXXXX The file “Enterococci_Bacteria.csv” contains the fecal indicator bacteria Enterococci cell concentration data for Bar Harbor, Maine town beach during June, July, and August from 2003 through 2021.XXXXXXXXXXXXXXXXXXXXXXXXXXX The file “Mussel_Tissue_DA_Conc_USGS_Collected_2021.csv” contains the results for tissue analysis of mussel species Mytilus for domoic acid concentration for sentinel mussels in bags suspended 1 meter below the water surface at Mount Desert Island Biological Laboratory and the Bar Harbor Town Pier from June 2021 through December 2021.XXXXXXXXXXXXXXXXXXXXXXXXXXX The file “Static_N_P_Annual_Loads_SPARROW_Model.csv” contains the SPARROW Model estimated annual static nitrogen and phosphorus loads for 24 streams that drain into Frenchman Bay. The static loads are based on an “average hydrologic year” (1999 to 2014) and model estimated nutrient loading for each watershed.XXXXXXXXXXXXXXXXXXXXXXXXXXX The file "Wastewater_Point_Sources.csv" includes information about nine wastewater point sources identified by the Maine Department of Environmental Protection (ME DEP). The information includes facility names; National Pollutant Discharge Elimination System (NEPDES) license ID numbers, latitudes and longitudes; and other variables. Only the Bar Harbor Waste Water Treatment Facility (WWTF) is classified as a major site and no data are available for nutrient export from the other eight sites classified as minor.XXXXXXXXXXXXXXXXXXXXXXXXXXX The file "Data_Dictionary_v3.csv" describes the contents of each csv tile including information on the data source of laboratory where the data were analyzed, variable name, variable description, units, analytical method, and method citation.XXXXXXXXXXXXXXXXXXXXXXXXXXX