The past decades have seen remarkable changes in key arctic variables. The decrease of sea-ice extent and sea-ice thickness as well as changes in temperature and salinity, and associated shifts in nutrient distributions in Arctic waters will directly affect the marine biota, consequently altering food-web structures and ecosystem functioning. To detect and track the impact of large-scale environmental changes in a the transition zone between the northern North Atlantic and the central Arctic Ocean, the German Alfred Wegener Institute for Polar and Marine Research established the deep-sea long-term observatory HAUSGARTEN in the eastern Fram Strait.Multidisciplinary studies at HAUSGARTEN cover almost all compartments of the marine ecosystem from the pelagic zone to the benthic realm, with some focus on benthic processes. The observatory includes 15 permanent sampling sites along a depth transect (1000-5500 m) and along a latitudinal transect following the 2500 m isobath, crossing the central HAUSGARTEN station. Repeated water and sediment sampling, and the deployment of long-term moorings and bottom-landers, has taken place since the observatory was established in summer 1999. Visual observations with towed photo/video systems will allow to assess variations in large-scale distribution patterns of larger epibenthic organisms. At regular intervals, a ROV is used for targeted sampling, the positioning and servicing of autonomously measuring instruments, and the performance of in situ experiments.First results from the time series exhibited interesting trends from which, at the moment, we do not know whether these already indicate lasting alterations or simply reflect natural variability on multi-year time-scales. Water temperatures in Fram Strait significantly increased over the last years; a slight temperature increase could still be detected even at 2500 m water depth. Analyses of various biogenic sediment compounds between the summers of 2000 and 2005 revealed a generally decreasing flux of phytodetritial matter to the seafloor, and subsequently, a decreasing trend in sediment-bound organic matter and the total microbial biomass in the sediments. An ongoing trend in decreasing organic matter input will certainly affect the entire deep-sea ecosystem in this region.
AWI Organizations > Biosciences > Joint Research Group: Deep Sea Ecology and Technology
Helmholtz Research Programs > MARCOPOLI (2004-2008) > POL7-From permafrost to deep sea in the Arctic