Oceanographic Conditions in Prince William Sound, CTD, Chlorophyll-a, and Zooplankton Data: 2017-2023, Gulf Watch Alaska Environmental Drivers Component

This dataset includes Conductivity, Temperature, and Depth (CTD) measurements, chlorophyll-a, and zooplankton concentrations from multiple stations and at various depths in Prince William Sound (PWS) in 2017 through 2021.

CTD cast data are presented as .zip files containing collections of CTD casts by year. Each zip file contains the CTD data, gps track, event log, archived paper logs, and instrument calibration files (as separate zipped files for each year. The CTD data is presented in various formats following routine processing using the SeaBird electronics SBE Data Processing software, and custom software written in MATLAB. Raw XML HEX data formats and converted ASCII CNV files are included in a file directory prefaced with a number indicating the processing step and text indicating what processing was done. Event logs contain station metadata for each cruise. Chlorophyll-a concentration data are presented as a single comma-separated values (csv) file containing values of extracted chlorophyll-a concentrations at various depths and stations in PWS. Zooplankton concentrations are presented as a single csv file containing values of zooplankton concentrations, by species and stage, at stations in Prince William Sound.

Vessel surveys in PWS were conducted several times per year to conduct CTD, water nutrient and cholorphyll-a, and zooplankton measurements. Surveys were timed around the “productivity season” to attempt to capture the spring and autumn blooms (i.e. pre-bloom, bloom and post-bloom). The surveys visited four PWS bays to maintain ongoing Exxon Valdez Oil Spill Trustee Council (EVOSTC) funded time series measurements. The related historic datasets are from CTD surveys conducted by various agencies from the 1970s to 2009, and surveys conducted from 2010 to 2012 under the EVOS Herring Program. The major PWS entrances (Hinchinbrook Entrance and Montague Strait) were also surveyed from 2013 to 2016.

These data are part of the Gulf Watch Alaska (GWA), Environmental Drivers component of the EVOSTC, project numbers 17120114-G, 18120114-G, 19120114-G, 20120114-G and 21120114-G. GWA is the long-term ecosystem monitoring program of the EVOSTC for the marine ecosystem affected by the 1989 oil spill.