The Arctic Ocean Ecosystem - Polhavets økosystem

Strategic Initiative from the Institute of Marine Research (IMR): The Arctic Ocean Ecosystem Understanding and being able to quantify key physical and biological processes of the Arctic Ocean is imperative to reveal and forecast future ecosystem change. The innate coupling between pelagic resources and bottom living organisms, between shelf, slope and deep water communities needs to be understood and quantified. The consequences of a warming Arctic on the ocean carbonate system, lower trophic level productivity, fish migrations and distribution, and further implications for top predators such as seals and whales is critical to understand the fate of the ecosystem in a changing Arctic Ocean. In such a dynamic and rapidly changing physical environment, (ice retreat, light conditions and ocean chemistry) it is hard to know precisely why some species can cope while others do not - obtaining a better understanding of this will allow us to better predict how particular species, trophic structures, productivity and energy pathways in the Arctic Ocean can be affected. We therefore examine the underlying mechanisms and potential long term impact of changes in the physical characteristics, phytoplankton, mesozooplankton, fish, marine mammals and benthic communities of the Arctic Ocean ecosystem in the region under Norwegian jurisdiction, i.e. the region north of Svalbard. The project is based on new field investigations in combination with utilization of historical data. Surveys to the study area were conducted in 2014, 2015, 2016 and 2017. Outreach from the surveys and a summary of the 2014 survey can be found at the project web-site: http://siarctic.imr.no/. Some information (in Norwegian) about the 2015 survey can also be found at Aftenposten #klodenvår http://mm.aftenposten.no/kloden-var/torsken-elsker-global-oppvarming. Blog text from the 2016 survey can be found at forskning.no (under the term ?Polhavstoktet?). More information of the project can be found at: http://siarctic.imr.no/. The project started with conducting a synthesis on historical data and present knowledge, enlightening the possibilities and limitations for the ecosystem in the region. To understand the consequences of a warming Arctic Ocean in more detail, the project thereafter focused on comparative studies between the eastern Fram Strait and the region north of Svalbard. The results so far show pronounced differences between the regions. While the eastern Fram Strait is dominated by fish species and to a lesser degree marine mammals like seals and whales, the situation is opposite north of Svalbard. However, in both regions there is a mesopelagic layer, i.e. a layer of plankton and fish in 300-500 m depth. The layer is connected to the flow of Atlantic Water. Investigations of this flow show distinct branches near the shelf-break, and that some of the Atlantic Water flow into the shelves in deeper trenches making favourable conditions for the ecosystems in those regions. The investigations conducted in the four years also show that the inter-annual variability in the region is large. More analyses are necessary to identify the causes behind these variations, and the results will be published in a special issue in the scientific journal Progress in Oceanography. The new data west and north of Svalbard, together with data from the rest of the Barents Sea, showed that some areas are more vulnerable towards climate and trawling than others. In addition, new data will improve model simulation capabilities with respect to key species, both native and immigrants, their distribution and production in present and tentatively new habitats, and aid the exploration of potential options for providing ecosystem-based advice. Results from the project is being included in assessment work in ICES, and a long-term monitoring program will be developed suited for present and future monitoring of the region.

Prosjektet har bidratt til å bygge opp kompetanse på Nordområdene. I tillegg til å øke kompetansen på oseanografi, arktisk planteplankton, dyreplankton og fisk, arktiske bunndyr og sjøpattedyr, har også gitt bedre forståelse av vekselvirkningene i økosystemet. Prosjektet har dessuten bidratt til Arktisk rådgivning gjennom kunnskapsoppbygging relevant for mange ulike fora (ICES, miljøkommisjoner, forvaltningsplanarbeid, Arktisk råd aktivitet o.a.). Dette inkluderer bedre forståelse av hvordan økosystembasert forvaltning bør gjennomføres i et vanskelig tilgjengelig og datafattig område som Polhavet. Resultatene fra prosjektet bidrar dessuten til bedre langtidssovervåkning av Polhavet. Prosjektet har bidratt til internasjonalt samarbeid gjennom deltagelse av internasjonale partnere på tokt, møter og i fagfellevurderte artikler, og gjennom deltagelse på internasjonale konferanser og møter. Mer enn 50% av de publiserte artiklene er tverrfaglige og med en internasjonal forfattergruppe.

Understanding and being able to quantify key physical and biological processes of the Arctic Ocean is imperative to reveal and forecast future ecosystem change. The innate coupling between pelagic resources and bottom living organisms, between shelf, slop e and deep water communities needs to be understood and quantified. The consequences of a warming Arctic on the ocean carbonate system, lower trophic level productivity, fish migration and distribution, and further implications for top predators like seal s and whales is critical to understand the fate of the ecosystem in a changing Arctic Ocean. In such a dynamic and rapidly changing physical environment, (ice retreat, light conditions and ocean chemistry) it is hard to know precisely why some species c an cope and others not - arriving at a better understanding of this will allow us to better predict how particular species, trophic structure, productivity and energy pathways in the Arctic Ocean can be affected. We propose to examine the underlying mech anisms and potential long term impact of changes in the physical characteristics, phytoplankton, mesozooplankton, fish, marine mammals and benthic communities of the Arctic Ocean ecosystem in the region under Norwegian jurisdiction. We will do so by using historical data, traditional surveying, process and experimental studies, and to some degree numerical modeling. A long-term monitoring program will be developed suited for present and future monitoring of the region. New data will also improve model sim ulation capabilities with respect to key species, both native and immigrants, their distribution and production in present and tentatively new habitats, and aid the exploration of potential options for providing ecosystem-based advice. This Strategic Ini tiative will enable IMR to significantly improve its abilities to give better advice on the ecosystem effects of climate change, through a collaborative national effort.