The CTD on the deck of the R/V Endeavor is a hub of activity at 1:00 am on the last day of the 6 day Particulate Carbon Gulf of Maine Biogeochemistry research cruise (April 7th – 12th, 2021), led by Chief Scientist Adam Subhas (WHOI, Marine Chemistry and Geochemistry). Scientists included groups from WHOI (MC&G and PO), the University of Maine, and Lamont-Doherty Earth Observatory. The primary purpose of the cruise was to test a new instrument developed by Dr. Subhas to study in-situ, biogenic carbonate saturation states. Phytoplankton and water samples were also collected from three different stations in the Gulf of Maine to look at various biogeochemical characteristics of the water column. Photo by Nina Whitney.