New biogeochemical sensors deployed in the Fram Strait

The Fram Strait 2025 expedition team on board RV Kronprins Haakon during the Norwegian Polar Institute annual cruise
The Fram Strait 2025 expedition team on board RV Kronprins Haakon during the Norwegian Polar Institute annual cruise

Report from the Fram Strait cruise 27 July – 14 August 2025

New biogeochemical sensors have been deployed in the Fram Strait as part of the 2025 annual cruise conducted by the Norwegian Polar Institute (NPI), with the science team from the UK’s National Oceanography Centre (NOC) installing autonomous Lab-on-Chip (LoC) sensors on long-term moorings in the East Greenland Current.

These compact instruments measure pH, total alkalinity, nitrate and phosphate directly in the ocean, at high resolution and over many months.

Why Fram Strait biogeochemical monitoring matters

Fram Strait is the one of the two main pathways where Arctic waters flow into the Nordic Seas and the Subpolar North Atlantic –with the Davis Strait on the west side of Greenland being the other main one. These Arctic waters carry a unique chemical “fingerprint” — rich in phosphate relative to nitrogen and already strongly affected by ocean acidification in the Arctic Ocean due to disappearing sea ice and freshening surface waters. While the NPI has monitored the Arctic freshwater, sea ice and returning Atlantic Water in the East Greenland Current via the Fram Strait Arctic Outflow Observatory since the 1990s, biogeochemical properties have only been measured in late summer through the water sampling programme implemented during their annual cruises since 2010.  Furthermore, tracking biogeochemical properties helps us understand not only what is happening in the Arctic, but also how it influences ecosystems and carbon cycling further south.

Diagram of the Fram Strait mooring array maintained by the Norwegian Polar Institute and Alfred Wegener Institute for biogeochemical and oceanographic monitoring
The mooring array in Fram Strait maintained by the Norwegian Polar Institute (NPI) and Alfred Wegener Institute (AWI). Image courtesy NPI.

By combining carbonate chemistry and nutrient measurements in this remote gateway, the newly installed LoC sensors will provide year-round data that has never been captured before. These observations will improve estimates of Arctic nutrient and carbon exports, support international ocean acidification monitoring, and demonstrate how UK-developed autonomous technology can extend our reach in challenging environments.

NOC scientist Pablo Trucco Pignata preparing a Lab-on-Chip biogeochemical sensor for deployment in the Fram Strait, 2025
NOC's Pablo Trucco Pignata preparing the LoC for deployment. Image L. de Steur (NPI)
LoCs ready for action. Image L. de Steur (NPI)
Deploying the LoCs into the Fram Strait. Image L. de Steur (NPI)
RV Kronprins Haakon. Image Kit Kovacs (NPI)

The Fram Strait biogeochemical sensors will return their first full annual dataset in summer 2026, providing an unprecedented year-round picture of Arctic outflow chemistry.

Reporting by Pablo Trucco Pignata (NOC) and Laura de Steur (NPI)

For more on EPOC’s Arctic research, see our EPOC in the Arctic page.