Climate change and its effects on marine life in Kongsfjorden
Kongsfjorden situated in western Spitsbergen is a Mecca for marine biologists and climatologists. Consequences of global change become apparent fast and are clearly visible on a small scale.
“As the fjord opens to the Fram Strait, it is exposed to inflow of relatively warm Atlantic water from the West Spitsbergen Current. At the same time, also the cold water from the Arctic Sørkapp Current influences the water masses of the fjord. So, marine life in the fjord is constantly exposed to alternating climate signals and thus it is an exciting natural laboratory for us," explains AWI biologist Inka Bartsch.
She is part of an international team of 60 scientists who compiled the current knowledge on impact of climate change on life in Kongsfjorden over the past months and published it in two special issues of the journal Polar Biology, edited by the AWI Kongsfjorden expert Christian Wiencke and Haakon Hop of the Norsk Polarinstitutt. "The contribution of AWI scientists is remarkable," says Christian Wiencke. 31 colleagues from AWI Bremerhaven, Helgoland and Sylt co-authored the 34 scientific papers.
"The two special issues contain many impressive results. Without any doubt they represent a scientific milestone," says Christian Wiencke. One new finding describes large shoals of zooplankton at the deep seabed of the fjord. "If these shoals are not considered, we underestimate the contribution of the pelagic zooplankton to the food web," says the scientist. Similarly he is impressed by the considerable increase of brown algae (kelp) biomass at shallow coastal sites which now became inhabited as a result of continuous ice-free winters while the algae had been regularly scraped off by drift ice formerly. As a consequence, the biomass of algae associated animals also multiplied, and both changes may have a lasting effect on the food web structure. Quite frequently, large algae are torn off from the ground, carried away by water currents, and sink to the ground at a different stretch of the coast "disrupting" the associated benthic community there. "Until recently, nobody had ever been able to show that loose kelp thalli can significantly alter the structure and diversity of soft bottom communities," says Christian Wiencke.
The two special issues include papers on almost all processes important for the fjord ecosystem and major groups of organisms – including pelagic heterotrophic microbes and zooplankton, benthic micro- and macro-algae, macrozoobenthos, fish and seabirds. Some of the papers focus on the effects of global climate change on biological communities; others compare changes observed in Kongsfjorden with those in other, still colder fjords and by this way provide a perspective for future scenarios. Another major part of the papers cover sedimentation processes and provide insights into sediment pollution. "We very much hope that these new scientific insights provide a good starting point for future work," says editor Christian Wiencke.
Due to its proximity to the research village of Ny-Ålesund, Kongsfjorden is one target region for long-term biodiversity research and observations. Numerous international and multidisciplinary research projects on Polar marine biology have been carried out here since decades. AWI researchers and their national and international partners use the German-French Arctic research station AWIPEV as their base camp for measurements and sampling in the Arctic.
The two special issues of the journal Polar Biology are published under the following titles: