Biodiversity and functioning of polar deep-sea ecosystems
Over centuries the deep sea was considered as a vast, desert-like environment with low numbers of species able to survive the harsh conditions. However, in recent years knowledge about the biodiversity of deep-sea life has increased and today we know that the deep ocean hosts enormously diverse communities. Biodiversity in the deep sea depends among other factors on water depth, which in turn is linked to food availability, but also influences dispersal and zonation of species.
In contrast to past assumptions that deep-sea organisms live in very stable conditions, it is nowadays accepted that the various abiotic and biotic factors governing deep-water ecosystems are highly dynamic and variable both, in space and time. For example, in addition to energy availability, the diversity of the benthos is linked to the complexity of the seafloor morphology.
Since polar organisms are strongly adapted to extreme environmental conditions with strong seasonal forcing, the acceleration of recent climate change in the Arctic challenges the resilience of its communities. The entire system is likely to be severely affected by the sea ice retreat, a changing hydrography, the warming and acidification of the ocean, a varying primary production and food availability, an increase in contaminants, and possibly also increased UV irradiance. A number of Arctic populations and ecosystems are probably not stable enough to withstand the sum of these changes, which might lead to a shift of communities.
To detect and track the impact of large-scale environmental changes in the transition zone between the northern North Atlantic and the central Arctic Ocean, and to determine the factors controlling deep-sea biodiversity, the Alfred Wegener Institute for Polar and Marine Research established the Deep-Sea Observatory HAUSGARTEN, representing the first, and by now only open-ocean long-term station in a polar region.