EK80 Water Column Sonar Data Collected During PC2304

A total of 63 sites were targeted for sampling over a period of twelve days. At each station, a Craib corer was deployed, and a relatively undisturbed surface sediment core collected with a penetration depth of about 6-10 cm deep. The core was extruded onboard and sectioned into two layers; the top 0-1 cm and the underlying 1-3 cm layers. Two 5cc subsamples were collected from the 0-1 cm layer for cyst counting (by microscopy) and for molecular analysis (via qPCR). The remaining sediment from the 0-1 cm layer, and the sediment from the 1-3 cm layer were refrigerated and retained for later processing (if needed). Sediment below 3 cm deep in the core was discarded. The two 5cc subsamples were processed onboard using standard cyst techniques, including protocols for dilution of the raw sediment, sonifying and sieving the sample to yield a 20-100 μm particulate fraction. One subsample was initially preserved in 2% formalin for subsequent exchange onboard into 100% methanol until later counting at the Beaufort Lab. The second subsample was centrifuged to remove the overlying water and frozen pending analysis in Beaufort. At up to six stations (to be determined), additional sediment was collected using the Craib corer for a method development project.

At each station, a CTD provided by the ship was deployed to measure parameters such as salinity, pressure, chlorophyll, and temperature from the surface of the water to the bottom to characterize water masses moving within the Gulf of Maine.