GOS 2020113

Abstract

The cruise GOS 2020113 (6 October 2020 Longyearbyen, 27 October 2020 Tromsø) aboard the Research Vessel G.O. SARS is a mooring service/deployment and process studies cruise of the Nansen LEGACY project. The study region covered 24-35E and 75-79N, with objectives to deploy moorings for process studies (1 year duration), service and redeploy accessible gateway moorings (long term), deploy underwater gliders (cruise duration as well as 3-4 months missions), conduct ocean mixing and water transformation process studies in the Barents Sea Polar Front region east of Svalbard, and sample for biology, nutrients and the carbonate chemistry in the water column at selected stations. The cruise contributes to tasks T1-1 on the Atlantic Water inflow to the northern Barents Sea at key gateways, T1-2 on processes that control sea ice and stratification in the northern Barents Sea, T2-1 on ocean acidification, T3-2 on timing of critical biological processes. Overall, we deployed 7 process moorings with physical oceanography focus, recovered and redeployed gateway moorings M3, M5 and M5-bioac and recovered the gateway mooring M6. We collected measurements of ocean stratification, currents, and microstructure from the vessel as well as from transects using ocean gliders. From the vessel we obtained 212 microstructure profiles down to 0-20 m above seabed; 64 CTD (32 with bottle sampling) and 63 LADCP profiles down to 5 m above seabed, and 20 days of underway current profiles. From gliders we obtained 801 profiles (16 days) including 266 profiles (6 days) using microstructure sensors in the polar front region north of Hopen Trench, and 678 profiles (10days) between the Great Bank and the Central Bank. Using the CTD’s water sampler, we collected 149 water samples for nutrient and carbonate chemistry analyses, 136 for POC/PON analyses, 68 for dissolved oxygen analyses, 52 for chlorophyll analyses, and 48 for phytoplankton analyses. We used multinet and bongo net for mesozooplankton sampling. We performed 4 hauls with Multinet (2 with 64 µm and 2 with 180 µm meshed net) and 29 hauls Bongo net (18 profiles with the 180 µm and 40 profiles with the 64 µm meshed net).