CPR data from Cook Inlet and Cook Shelf 2012-2023

CPR abundance counts and Phytoplankton Colour within the Cook Inlet and Cook Shelf region of the Gulf of Alaska from 2012-2023. NOTE: Only selected taxa have been included in this data extract, for specific taxa requirements please email [e-mail]. The excel file consists of samples in rows, with the following information in columns - A: midpoint of sample local date and time B: midpoint of sample latitude in decimal degrees C: midpoint of sample longitude in decimal degrees D:GeographicRegion E:chlorophyll index F:onwards = abundance counts per CPR sample ~3m3 of seawater. NaN = taxa was not looked for. The taxa_info sheet give more information on the taxa included; the counting method (1=eyecount, 2=traverse, 3=phytoplankton) and if the category is a grouping that includes other categories (to avoid double counting in your analyses). The Continuous Plankton Recorder (CPR) is a marine sampler that is towed behind volunteer ships of opportunity at speeds of up to ∼20 knots and samples at a depth of ∼7 m below the surface. The CPR unit is a metal casing in the shape of a ∼1 m torpedo that houses a roll of silk which automatically rotates using a geared propeller system. The seawater enters the front aperture where plankton and small particles are captured onto the rotating silk, which has a mesh size of 270 µm. This silk is stored in 4 % buffered formalin to preserve the sample until microscopic analysis at the laboratory in Plymouth. The silk is cut into pre-defined sections that represent one sample and equate to 10 nautical miles of tow. Phytoplankton and zooplankton are identified and counted at different stages of the microscopic analysis: semi-quantitative count of phytoplankton across 20 fields of view per sample, quantitative count of all zooplankton >= 2 mm (these are picked off the silk for identification), and semi-quantitative traverse count of all zooplankton 2 mm. For a more in-depth description of the sampling methodology please refer to Richardson et al. (2006). The Phytoplankton Colour Index is a record of the colour gradient of the mesh as one of 4 colour categories (0,1,2,6.5) and has been shown to relate to the chlorophyll content of the water, including organisms not visible in the sample (Raitsos et al., 2013, Raitsos, D.E., Walne, A., Lavender, S.J., Licandro, P., Reid, P.C., and Edwards, M. 2013. A 60-year ocean colour data set from the Continuous Plankton Recorder. Journal of Plankton Research, 35(1):