Together with 50 scientists, engineers, technicians and students, hypox scientists from the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, (AWI; www.awi-bremerhaven.de), and the Max Planck Institute for Marine Microbiology in Bremen (MPI; www.mpi-bremen.de) embarked in Longyearbyen, Svalbard. They will participate in the second cruise leg of RV „Polarstern“ during her 24th Arctic expedition. The aim of the hypox project work on board is to continue long term oxygen measurements at the deep-sea long term station "Hausgarten".
The "Hausgarten" station is situated west of Svalbard at 79 degrees northern latitude and comprises 16 sampling stations that cover a depth range of 1000 to 5500 meters. Although the water column is far from hypoxia the station was selected as one of the hypox project field sites: Previous oxygen data seemed to indicate a significant decline of oxygen concentrations in the bottom water that may be related to climate induced changes in deep water formation in the North Atlantic - Arctic Ocean transition.
The “Hausgarten” observatory is operated since 10 years. Since 2004 it carries out long term oxygen measurements, making it one of the first observatories to include this parameter. The “Hausgarten” observatory provides some 17000 data points on dynamics in oxygen concentration in Arctic bottom waters to the HYPOX data base.
Within the hypox project, research related to dynamics in oxygen concentrations and fluxes in the Arctic will be fostered by adding long-term optode oxygen sensors to moorings, and by additional measurements of various oxygen consumption parameters in the water column and sediments. The techniques applied include in situ chamber incubations and microprofiling as well as flux measurements in retrieved cores. The first project activity during the cruise is the deployment of a free falling lander at the Molloy Deep, a 5600 m deep depression and the deepest Hausgarten station that will do it’s pre-programmed monitoring mission over the coming twelve months. Weekly reports with more information on the cruise are found at www.awi.de/en/infrastructure/ships/polarstern/weekly_reports.
hypox lander equipped with oxygen optodes at the sea surface soon after release at Hausgarten (Photo: T. Soltwedel)
Oxygen microsensor profiles are measured in and next to starvation experiments. Here the benthic community has been closed off from sedimentation of fresh organic matter for one year (Photo: MARUM)
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