Climate change in the Arctic has led to dramatic changes in benthic ecosystems of the two fjords of Spitsbergen — in particular, in the last 30 years, the area of algal cover their increased five to eight times, say the authors of an article published in the journal Proceedings of the National Academy of Sciences.
The team, led by Suzanne Korch (Susanne Kortsch) from the University of Tromso (Norway) analyzed data on the state of benthic ecosystems Kongsfjord Smeerenburgforda and the west of the island Spitsbergen in 1980-2010 years. In this period, according to their data, the average surface temperature of water in the region increased by 0.5 degrees, and the length of the summer season, when this part of the island is free of ice, grew an average of 3.3 days per year.
The researchers found that abrupt changes in ecosystems fjords began in the last 15 years, until that time the structure of benthic communities has remained relatively unchanged. Until 1995, the algal cover in Kongsfjord had an average of 8% of the area, but in 1996 kelp suddenly "seized" at once 80% of the area, and since then their share is around the level of 40%.
In Smeerenburgforde "capture" the ecosystems brown and red algae was recorded five years later, in 2000, when the area of algal cover increased from about 3% to 26%. Scientists note that these observations are consistent with studies in the south of the archipelago, in the Hornsund fjord, where in the years 1988-2008 algal biomass increased by about three times.
According to the authors, in Kongsfjord kelp strongly pushed dominated there anemones, or sea anemones. In Smeerenburgforde where groundfish were more changes in the ecosystem began with "regime change" within the invertebrate community. A greater variety of algae inhabitants left less space, so the absolute increase in the area of algal cover in the second fjord was not as significant to the scientists.
The study's authors believe that climate change in the Arctic could reduce the stability of two benthic ecosystems and lead them out of balance, "open", so to thermophilic species.
"According to forecasts, the warming in the Arctic will continue to pace up to twice the average, and one of the consequences (of the process) can be a full release of the region of ice during the summer prior to 2050. Moreover, in the near future we can expect new ecosystem changes that will lead to borealizatsii marine communities in the Arctic, and their convergence with ecosystems lower latitudes of the Northern Hemisphere "- write the authors.