I-CRYME: Impact of CRYosphere Melting on Southern Ocean Ecosystems and biogeochemical cycles

Global warming is transforming Antarctica; melting the cryosphere (the ice caps, the glaciers and the sea ice); affecting the Southern Ocean physical dynamics and elemental cycles; and impacting the marine ecosystems and their capacity to absorb the atmospheric CO2 emitted by men. The Southern Ocean is both home to rich ecosystems and a place where atmospheric CO2 is efficiently absorbed by the Ocean. A large part of this atmospheric CO2 is absorbed by phytoplankton and sea-ice algae which are limited by the availability of iron, a bio-essential element. Iron and other nutrients are highly concentrated within the cryosphere. The release of these elements and changes in the ocean dynamics linked to the melting cryosphere will have large consequences on marine ecosystems, their biodiversity and productivity. These consequences are not yet understood and research to improve our understanding is critical to predicting future changes. This project aims to understand and quantify the impact of the melting cryosphere on the marine ecosystem of the Kong Håkon VII Sea, in the Southern Ocean. Towards this goal, I-CRYME combines field, laboratory and modelling activities that will generate novel datasets. The project utilizes the Research Vessel Kronprins Haakon, the Supply Vessel Silver Arctica that is commissioned annually by NPI to carry out research in the Southern Ocean; innovative technologies such as the TRIAXUS towed vehicle and long-term monitoring by deep-sea moorings in the area. The research activities will allow us to quantify the physical and biogeochemical properties during a time of rapid environmental change and to measure the response of the microbial community to the biogeochemical enrichment caused by the melting cryosphere. The project outcomes will shift our understanding of key processes in the Southern Ocean and improve our predictions of the future of its physical dynamics, its ecosystems and elemental cycles. Since the beginning of the project in January 2023, 3 scientific campaigns have taken place on board the vessel that resupplies the Norwegian Antarctic Station Troll. In January 2023 and January 2025, both campaigns’ objectives were to study the ocean physics, biogeochemistry and biology in connection with the ice shelves bordering the Kong Haakon VII Hav and extending North into the sea ice zone. Both years proved to be years with strong phytoplankton blooms. In 2023, the phytoplankton bloom was strongest at the continental shelf break, linking ocean physics and turbulence to deep and possibly sedimentary iron sources that fuelled the phytoplankton bloom. In 2025, the phytoplankton bloom was strongest where the sea ice had recently receded and proved to be a so-called sea-ice edge phytoplankton bloom. In January 2024, the focus of the scientific campaign was to link sea ice biology and biogeochemistry with ocean turbulence and, thus, nutrients fluxes to the sea ice. In addition, both in 2023 and 2025, the researchers and engineers onboard retrieved the deep ocean moorings that are maintained as part of a long-term time series by the Norwegian Polar Institute since 2019. These moorings include several sensors and devices to study the ocean physics and biogeochemistry, as well as 2 sediment traps placed at 500 m depth to study the Biological Carbon Pump. Finally, in early 2025, the Australian partners of I-CRYME conducted a scientific voyage to the Denman Glacier on board RSV Nuyina. This interdisciplinary voyage focused on studying the trace metal in close proximity of the Denman Glacier and Shackleton Ice Shelf. Several publications are in preparation relating the results of these campaigns as well as that of the mooring data and samples. These publications are led by the Early Career Researchers hired by and associated with the I-CRYME project (i.e., 4 PhD students). In the upcoming years of the I-CRYME project, more data and samples will be retrieved from annual oceanographic cruises to the area to achieve all the project’s objectives.

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This project improves our understanding of how the melting cryosphere of the Kong Håkon VII Sea (KHS), in the Southern Ocean (SO) impacts the marine ecosystem surrounding Antarctica. By doing so, this project focuses on the pressing research question; what are the consequences of climate change on the Earth’s cryosphere and associated polar marine ecosystems? Such knowledge is of primary importance to objectives of the Southern Ocean Decade, the SO task force of the United Nations decade of Ocean Science for Sustainable Development. The project brings together a multidisciplinary team with broad expertise on the SO (e.g. physical oceanography) and its associated cryosphere, as well as expertise on the microorganisms, trace metals and biogeochemical cycling that occurs within these systems. The main hypothesis of this project is that the melting cryosphere (i.e. ice sheets, glaciers and sea ice) of the SO and Antarctic continent have a profound impact on marine biogeochemical dynamics (nutrients, bio-essential trace metals, and ecosystem productivity). To investigate this hypothesis, we focus on the poorly studied region of the KHS in the SO. This innovative project utilizes world-class Norwegian research infrastructure, including the Research Vessel Kronprins Håkon (KPH), the Supply Vessel Silver Arctica (SA) and deep-sea moorings in KHS. Combined field and laboratory activities will generate novel datasets to answer the suite of objectives articulated in this proposal, which focus around quantifying the physical and biogeochemical properties of the KHS during a time of rapid environmental change. This project is led by a gender-balanced and experienced team of early career researchers and professors; their mentoring skills will ensure the training of a next generation of polar leaders in this emerging discipline. Outcomes of this project will bolster Norwegian leadership in this climate sensitive region of strategic national and international importance.