Increase in biodiversity in the arctic rocky littoral, Sorkappland, Svalbard, after 20 years of climate warming

Abstract

Rocky littoral macroorganisms that live between the high and low water marks were sampled in the summers of 1988 and 2007-2008 in Hornsund Fjord and along the adjacent Sorkappland coast (76-77°N). The same sampling stations and methodology were used to collect the samples. Over the last 20 years, the study area has been exposed to well-documented increases in air and sea temperature, increased windiness, and marked decreases in both the duration and extent of sea ice cover. The study revealed a twofold increase in the number of species found intertidally, a threefold increase in the biomass of macrophytes, and an upward shift in algae occurrence on the coast. Subarctic boreal species occupied new areas, while arctic species retreated. There were no species new to the area in 2007-2008, and all newcomers to the intertidal zone were noted in 1988 in the sublittoral zone. The relative stability of intertidal flora and fauna after 20 years is explained by the fact that the warm Atlantic waters (the main warming agent) are distant from the Sorkappland coast. Current observations show a marked change in the coastal belt biocenosis.

Climate-driven regime shifts in Arctic marine benthos

“…1073/pnas.1207509109/-/DCSupplemental. diversity was documented immediately after the macroalgae expanded (22), which is consistent with findings in previous studies from the area, where rocky bottom habitats with occurrences of macroalgae host higher diversity (20,23). The site in Smeerenburgfjord, with 36 benthic taxa (Table S1), was initially characterized by several sessile suspension feeders.…”

“…In Smeerenburgfjord, the shift occurred in 2000, 5 y later than in Kongsfjord, and resulted in a macroalgal (brown and red algae) increase from on average 3-26%. The observed increase in macroalgal cover is likely representative of a regional trend toward increased macroalgal biomass, as supported by a separate study in Hornsund, in the south of Svalbard, where a threefold increase in biomass was recorded between 1988 and 2008 (20). In addition, a study from West Greenland documented substantial increases in the productivity and depth extension of macroalgae (kelp beds) in relation to the retreat of sea ice and prolonging of the open water period (21).…”

Expansion of vegetated coastal ecosystems in the future Arctic

“…The continuity of coastlines between the temperate and polar zones facilitates the poleward migration of temperate macrophyte species and is unique to the Arctic Ocean because the Southern Ocean acts as a barrier for dispersal of southern temperate species to Antarctica (Wulff et al, 2009;Jueterbock et al, 2013). Northern Hemisphere intertidal biota are already moving northwards at speeds of up to 50 km per decade (Helmuth et al, 2006;Hawkins et al, 2008;Weslawski et al, 2010), and there are reports of northward range extensions of kelps (Müller et al, 2009 and references therein; Wilce and Dunton, 2014), and new eelgrass meadows in Greenland .…”

“…Research on arctic terrestrial vegetation has shown that Greenland's terrestrial woody flora has a great potential for future expansion but is strongly dispersal limited, with a potentially important role of unintentional introductions (Normand et al, 2013 -Jensen et al, 2012;Clausen et al, 2014;Olesen et al, 2014). Initial signs of positive responses of the vegetation to arctic warming and longer ice-free periods have also been reported (Weslawski et al, 2010;Kortsch et al, 2012;Krause-Jensen et al, 2012). Space-for-time substitutions along large spatial gradients have a limited ability to attribute the patterns to specific factors that may co-vary across these scales, such as light and temperature.…”

Algal pigments in Hornsund (Svalbard) sediments as biomarkers of Arctic productivity and environmental conditions

“…Spitsbergen fjords could be interesting areas for studying pigments so long as these are not decomposed to colourless products under conditions unfavourable to pigment preservation. Contemporary global warming has advanced, and its effects are more apparent in Arctic than in mid latitudes (Manabe and Stouffer 1980;Morata and Renaud 2008;Węsławski et al 2010;Kay et al 2012;Gervais et al 2016); environmental conditions in high latitudes have been greatly influenced as a result (Overpeck et al 1997;Post et al 2009;Wassmann et al 2011). The large inflow of freshwater from glacier melting lowers water salinity and increases turbidity, which may in turn affect phytoplankton composition (Wiktor and Wojciechowska 2005).…”