The Expedition ARK-XXIV/2
Summary and itinerary
„Polarstern“ expedition ARK-XXIV/2 10.07. – 03.08.2009
Longyearbyen – Reykjavik
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, and to determine experimentally the factors controlling deep-sea biodiversity, the Alfred Wegener Institute for Polar and Marine Research (AWI) established the deep-sea long-term observatory HAUSGARTEN, which represents the first, and until now only open-ocean long-term station in a polar region. It is located west of Svalbard at 79 degrees northern latitude consisting out of 16 sampling stations covering a depth range of 1000 to 5500 meters. The planned research programme during the first half of the „Polarstern“ expedition ARK-XXIV/2 contributes to the time-series studies at this deep-sea long-term observatory where we investigate the impacts of Climate Change on an Arctic marine deep-sea ecosystem through field studies, observations and models since 1999. This research programme also contributes to the EU funded projects ESONET (European Seas Observatory NETwork), EMSO (European Multidisciplinary Seafloor Observatories), HERMIONE (Hotspot Ecosystem Research and Man’s Impact on European Seas) and HYPOX. Additionally, it is part of the StatoilHydro co-funded project KONGHAU (“Impact of climate change on Arctic marine community structures and food webs”).
The main aim of the second part of the expedition ARK-XXIV/2 is the implementation of a long-term observatory on the Norwegian margin to study mud volcanism, as a Demonstration mission of the 6th FP EU project ESONET. The Hakon Mosby Mud Volcano (HMMV), located at a water depth of 1250 m on the SW Barents Sea slope, is a priority target site of ESONET and EMSO. It is also a key site of the EU projects HERMIONE, MARBEF and the ESF EuroDeep program CHEMECO. Liquefied mud, gas, and geofluids rising from a subseafloor depth of at least 3 kilometres, form a highly active mud volcano with a diameter of 1.5 kilometer, characterized by permanent gas emission. Fluid flow velocities decrease radially towards the outer rim of HMMV, which is stabilized by gas hydrates. Earlier investigations of MPI, AWI and IFREMER at HMMV showed that fluid flow rates control the distribution of chemosynthetic communities, the stability of the hydrate system and gas emission. With the implementation of a long term observatory, we plan detailed investigations of the temporal variability at HMMV to follow the sequence of events before, during, and after an eruption, and to analyze their effects on gas hydrate stability, seafloor morphology and the distribution and colonization patterns of benthic communities.
For both areas of investigation the availability of a Remotely Operated Vehicle (ROV) is essential. Therefore, for the second time after 2007 the ROV QUEST owned by the Centre for Environmental Sciences (MARUM) at the University of Bremen is onboard “Polarstern”.