De-icing of Arctic Coasts: Critical or new opportunities for marine biodiversity and Ecosystem Services?

In this project, we have put together a strong pan-Arctic and interdisciplinary team from Norway, Poland, Canada, USA and Denmark to determine the biodiversity and socio-ecological consequences of the change from frozen to ice-free coasts in the Arctic. The authorities, business, environmental organizations, and society in general are increasingly demanding knowledge on the biodiversity and ecosystem status in Arctic coastal areas. In this project, we have organized workshops with various users of the coastal areas to gain closer contact and communication across researchers, managers and stakeholders in Svalbard. Arctic coastal ecosystems are under growing pressure as climate change and human activities increase. In this project, we had a major focus on Svalbard in a pan-Arctic perspective with focused studies on coastal areas in Canada and Greenland as well. Despite COVID challenges, the project has carried out most of the planned field activities, meetings and workshops. The ACCES project was also awarded two cruises of one week duration onboard the Norwegian Coast Guard ship “Barentshav” during the pandemic, which made it possible to study coastal regions in East Svalbard which still has extensive sea ice exposure in winter. Here we carried out important mapping of macroalgae and biological diversity along the heavily ice scoured coastline which contrast the ice-free coasts in western Svalbard. In Svalbard, macroalgae are rarely found below 30 m depth, while in Canada and Greenland macroalgae can show dense meadows at depths between 30-37 m where water is clear. In ACCES, we have worked actively on optimizing remote sensing algorithms to monitor the dynamic coastal areas in Svalbard, and elsewhere in the Arctic. New and improved methods thanks to validation data from the field show that Arctic coastal waters received around 23% more light for primary production in the period 2003-2020 compared to earlier due to less sea ice. However, the recent increase in melting and river run-off, combined with increased coastal erosion have increased the turbidity and thus the light attenuation, which counteract the positive trend, resulting in only a small overall (+ 1%) increase in light for primary production if we compare present situation with older records. Macroalgae are important as food and nursery grounds for invertebrates and fish. The shallower occurrence of macroalgae in the intertidal zone combined with more inflow of Atlantic water and warmer sea temperatures, has a positive effect on the total biodiversity and biomass in shallow coastal areas. So far boreal and Arctic species do not seem to suffer from competition – the carrying capacity has not yet been reached. For plants and animals that live inside the sea ice, however, the large reduction in landfast sea ice is bad news. New calculations show that land-based sea ice on Svalbard with a duration of 2 months or more has been reduced by 50% in the period 2003-2019 compared to 1973-2000, and by the year 2040 there may only be sea ice in a few fjords in East Svalbard if the winter air temperatures continue to increase. The Arctic Council and the coastal expert group have defined 7 coastal nature types (=coastscapes) to make it easier to compare coastal biodiversity across the Arctic – an ongoing work that shall result in a comprehensive status report on the biodiversity in Arctic coastal areas. In the ACCES project, we have followed the recommendations and guidelines to the Arctic Council and used existing images with a resolution of 1 km to map the distribution of the 7 different coastscapes in Svalbard. Tidal glaciers comprise about 10-12% of the coastline, while Rocky shores and Sea Cliffs make up around 30%. Coasts dominated by various types of soft shores constitute 30-35%, while 23% of the coastline remains to be mapped. Most marine research take place in the fjords of Svalbard. The shallow coastal areas are in comparison poorly known, especially the biological diversity and ecological significance of lagoons and river deltas. The environmental status of the nearshore areas in Svalbard with recommendations for future research and management has been summarized in a popular scientific report for stakeholders - a result of a workshop where researchers, managers and stakeholders met and discussed the various coastal issues. The rapid changes we see in the coastal zone were also the main topic in a scientific session ACESS co-led at the Arctic Frontiers conference in Tromsø in May 2022. So far, 18 ACCES papers have been published with more publications on its way. A special issue “Arctic Coasts in Transition” is planned highlight the urgent need for more knowledge. The Arctic coastline makes up 30% of the global coastline and here 95% of the people in the Arctic live and work. The coastal areas are much more productive than the deep Arctic Ocean and are among the regions experience the fastest climate change in the world today.

The ACCES project had a clear added value to ongoing Norwegian, Polish, Canadian, US and Danish national marine research projects across the Arctic by linking expertise and efforts across national teams, diciplines and across study sites. This allowed for matching needs of stakeholders and research products at local and regional levels, optimization and standardization of methods, and general increase in comparable and ecosystem-relevant understanding of the levels and consequences of changing biodiversity, spanning both the Pacific and the Atlantic sides of the Arctic. Further, the ACCES project has involved many young researchers, post docs, Phd-candidates and master students. The project would not have been so successful without their large effort. Results from this project have been published in peer-reviewed journals and communicated at international scientific conferences. Popular scientific publications, news paper reports, videos have also been prioritized made as well as meetings/workshops to ensure that the project knowledge reach out to stakeholders, policy- and decision-makers. In May 2022, ACCES co-led a science session on "Arctic Coasts in Transition" at the international Arctic Frontiers Conference in Tromsø, Norway, the largest Arctic annual conference where scientists, industry, and policy makers interact. A special issue is under planning from this conference and collaborative coastal projects. Further we are currently working hard on publishing our data in an open coastal database that will be searchable on the SIOS platform.

Nearshore waters are among the most productive regions in the Arctic and the coastal zone has always been the preferred ecotype for humans in the area. Melting of permafrost, shrinking of ice pack and retreat of glaciers are already subjects of intensive research, while the reduction of landfast ice and ice foot (seasonal coastal ice) has received much less attention. De-icing and continued warming will allow colonization of the intertidal zone by Arctic and boreal flora and fauna. Disappearance of coastal sea ice may, however, also result in habitat loss. Increased coastal erosion and sediment loads will physically change the nearshore bottom habitats and thus the biodiversity of these regions with cascading effects in food webs. Consequently, the coastal ecosystem goods and services (provisional, regulatory, socio-cultural) will also encounter changes. Arctic coastal biodiversity is therefore under growing pressure as climate change and human activities increase, necessitating that government managers, industries, conservation organisations and communities have access to timely and complete biodiversity status and trend data. In this project we have put together a strong multidisciplinary team from Norway, Poland, Canada, US and Denmark to Determine biodiversity- and socio-ecological consequences of the change from seasonal ice-covered to ice-free Arctic coasts. We will be studying a wide geographical range of Arctic coastal sites with contrasting ice regimes: Arctic coast with extensive seasonal sea ice coverage (iced) and Arctic coasts with limited or no seasonal sea ice (semi-iced to ice-free). For these two scenarios we will consider both rocky and soft sediment shores. Knowledge generated in this project will be communicated and discussed with relevant stakeholders, and be incorporated in Coastal management plans.