Posted on 15.09.2011 - 14:00 UTC in GENERAL NEWS by Rons_ROV_Links
On August 9th an international team of scientists lead by the Kiel Leibniz Institute for Marine Sciences (IFM-Geomar) is starting a four week expedition on the Research Vessel Poseidon to the Arctic Ocean off the coast of Spitsbergen. The purpose of the research expedition is to explore the stability of gas hydrates and the intensity of methane gas emissions. The biogeochemical transformation processes of methane in the water column and the release of the greenhouse gas into the atmosphere will be evaluated.
RV Poseidon. Photo: K. LackschewitzEnvironmental change caused by global warming is especially dramatic in the area of the Arctic, as the rapid shrinking of polar ice and the Greenland glaciers in recent years demonstrates. These regions are expected to continue to change quickly and profoundly in the future. Large areas of the shallow shelf seas and the continental margin of the Arctic Ocean are characterized by the submarine permafrost and the existence of gas hydrates. As a result of increasing warming of seafloor waters these hydrates could dissolve and large amounts of the greenhouse gas methane contained therein could escape, contributing to accelerated warming. The most recent observations from more than 250 gas emissions sites west of Spitsbergen in a border area of the gas hydrate stability zone support the concern that the dissolution of gas hydrates as a result of global warming has already begun.
An international team of researchers led by Dr. Olaf Pfannkuche from the Kiel Leibniz Institute for Marine Sciences (IFM-Geomar) wants to investigate, how much of the released methane gas is broken down through biological and biogeochemical processes in the water column and estimate how much makes its way into the atmosphere. "We know that microbial decomposition of methane in sediment and in the water column functions as a natural filter of methane emissions", explains Dr. Pfannkuche. "However, we don't yet know how quickly and how effectively this filter will function in the face of massive dissolution of gas hydrates and what potential secondary consequences, for example ocean acidification and oxygen minimum zones, exist," he adds.
Scientists from the EU project HERMIONE and the Cluster of Excellence "Future Ocean" with participation from the institutes IFM-Geomar, NIOZ (Netherlands) and the University of Tromsø (Norway) are taking part in the expedition, which starts on August 9th and is the 419th voyage of the research vessel Poseidon.
Work area off Spitzbergen (BSR: suspected Gas hydrate deposits, red regions of concentrated gas emission points). Click image to enlarge. Photo: O. Pfannkuche, IFM-Geomar.The investigations will concentrate on two working areas off Spitsbergen. Investigations of the spatial distribution and the quantification of methane plumes in the water column will be carried out using acoustic as well as classic CTD/rosette water sampler methods. Planned are seafloor measurements of substance conversions with a BIGO lander (biogeochemical observatory). In addition sediment samples for microbiological examination will be collected using various procedures. Gas hydrate deposits and gas emission points can be located and new areas explored with a deep towed camera sled (OFOS).
"The measurements taken on this expedition will be compared with previously gathered observations to evaluate the rate of change in this very sensitive area of the world's ocean," says the expidition leader Pfannkuche.