Abstract
Abstract. The rapid response of benthic foraminifera to environmental factors (e.g. organic matter quality and quantity, salinity, pH) and their high fossilisation potential make them promising bio-indicators for the intensity and recurrence of brine formation in Arctic seas. Such an approach, however, requires a thorough knowledge of their modern ecology in such extreme settings. To this aim, seven stations along a north–south transect across the Storfjorden (Svalbard archipelago) have been sampled using an interface multicorer. This fjord is an area of intense sea ice formation characterised by the production of brine-enriched shelf waters (BSW) as a result of a recurrent latent-heat polynya. Living (rose bengal-stained) foraminiferal assemblages were analysed together with geochemical and sedimentological parameters in the top 5 cm of the sediment. Three major biozones were distinguished. (i) The “inner fjord” zone, dominated by typical glacier proximal calcareous species, which opportunistically respond to fresh organic matter inputs. (ii) The “deep basins and sill” zone, characterised by glacier distal agglutinated fauna; these are either dominant because of the mostly refractory nature of organic matter and/or the brine persistence that hampers the growth of calcareous species and/or causes their dissolution. (iii) The “outer fjord” zone, characterised by typical North Atlantic species due to the intrusion of the North Atlantic water in the Storfjordrenna. The stressful conditions present in the deep basins and sill (i.e. acidic waters and low food quality) result in a high agglutinated ∕ calcareous ratio (A∕C). This supports the potential use of the A∕C ratio as a proxy for brine persistence and overflow in Storfjorden.
Highlights
The polar regions are sensitive to climate change, as evidenced from the several dramatic alterations in recent decades (Peings, 2018)
Living benthic foraminiferal fauna from the Storfjorden “sea ice factory” were studied in order to determine the response of foraminiferal communities to the major driving factors controlling the sea bottom ecology in this area
The benthic ambient conditions were further connected to brine-enriched shelf waters (BSW) production and persistence and indirectly to first-year sea ice formation
Summary
The polar regions are sensitive to climate change, as evidenced from the several dramatic alterations in recent decades (Peings, 2018). The ocean surface absorbs considerably more sunlight energy. This leads to further warming of the atmosphere and the ocean, enhancing sea ice melting, which, in turn, affects marine and continental ecosystems (Perovich and Richter-Menge, 2009). A recent review study compiling several high-resolution terrestrial proxies show that the modern decline in Arctic sea ice is unprecedented compared to at least the last few thousand years and is unexplainable by known natural variability To better understand how and how much natural and anthropogenic forcing factors control sea ice dynamics, there is a need for more high-resolution marine time series covering the historical period (i.e. hundreds of years) and for robust biological proxies in key areas from the circum-Arctic. Storfjorden, a semi-enclosed bay located in the Svalbard archipelago (Fig. 1a), is one of the Arctic re-
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
