Study of faunal assemblages and interactions at a cold seep in the Lofoten-Vesterålen region: using imagery within a GIS.

Supervisor: Arunima Sen (The Arctic University of Tromsø).
Deep sea exploration in the past was relatively limited due to reduced accessibility and difficulty in sampling. Chemosynthesis based ecosystems were discovered only forty years ago but are now acknowledged to be quite a common kind of deep-sea ecosystem. They also hold significance because they often contain specialized fauna, which are able to survive in harsh conditions. Such systems are independent of sunlight as the main source of energy and instead rely on sulfides and other reduced compounds. The goal of this study was to assess and characterize a chemosynthesis based ecosystem, specifically, a cold seep site in the Lofoten-Vesterålen region. Community composition and faunal distributions were characterized and possible interactions were described using imagery within a Geographic Information System (GIS). The Lofoten-Vesterålen region is known for its biological productivity and biodiversity, and is thus central to Norway’s model ecosystem based approach of resource management and environmental policy. However, this is the first time a cold seep system in this particular region was studied. Certain unexpected trends were observed, such as high sulfide concentration in the bottom water, along with the presence of several non-seep specialist species, that likely have elevated tolerances for the toxic sulfidic conditions. Nonetheless, the site displayed low taxonomic richness, with only 14 living taxa. The most abundant of these living taxa included Oligobrachia haakonmosbiensis frenulates, Nymphon hirtipes sea spiders, sipunculids, snails, rissoid snails, and bryozoans. Numerous skate egg cases of the Arctic skate, Ambylraja hyperborea were seen throughout the site, and appeared to be associated with areas of active seepage. A large amount of trash was also seen at the study site, which could be affecting the benthic fauna negatively. Since the site seems to exhibit certain peculiar features, and is impacted by human activity in terms of littering, further research and studies are required to study seep systems and help preserve this type of ecosystem.