AZTI adds two autonomous submarines to the Basque coastal observation network to study processes affecting marine ecosystems

• AZTI has included two gliders in the BIGFIS project to monitor the biogeochemical behaviour of the waters.
• This data will help to better understand how marine currents affect biogeochemical cycles, essential for the marine food chain and ecosystem.
• The Provincial Council of Gipuzkoa is backing the initiative through its support programme for the Gipuzkoa Science, Technology and Innovation Network.

Pasaia, 8 January 2025- Understanding the biogeochemical cycle – which involves the exchange and transformation of vital elements such as carbon, nitrogen and oxygen between organisms and their environment – is crucial. In this context, since 2024, AZTI has been coordinating a detailed analysis of how ocean circulation affects these essential cycles that maintain the production of nutrients by phytoplankton, the basis of the oceanic food chain, as part of the BIGFIS project.

The project, funded by the Provincial Council of Gipuzkoa, uses two innovative autonomous underwater vehicles, known as gliders, equipped with advanced sensors. These devices will be able to travel along the Basque coast to monitor marine biogeochemical processes and provide data to the existing observation network, which will help tracking the evolution of the effects of climate change on marine ecosystems. This information, together with additional observations from satellites or existing observation platforms in the area, such as high-frequency radars and mooring buoys, helps to improve understanding of the relationship between physics and biogeochemistry to better understand their impact on these ecosystems.

‘The task of monitoring biogeochemical changes in the water column is complex, but thanks to our gliders, we can take detailed and extensive measurements, covering up to 1,000 metres deep and more than 1,000 kilometres away, for periods of up to one or two months’, explains Iván Manso, an expert in marine technologies at AZTI and coordinator of the project.

Furthermore, these devices have a minimal environmental impact, as they operate in complete silence and move by means of changes in their buoyancy, making sawtooth-shaped trajectories. ‘Each time they surface, they transmit the collected data and receive instructions for their next movements,’ adds Manso.

The gliders offer a unique perspective, providing three-dimensional information that illustrates the interaction between ocean physics and biogeochemical cycling. The gliders are equipped with hydrographic sensors to measure water temperature and salinity. One of them includes additional sensors to measure oxygen, turbidity, chlorophyll, dissolved organic matter and nitrate levels. The other is equipped with an echo-sounder to detect schools of pelagic fish.

Complementing an advanced observation network of the Basque coast

These instruments not only enrich the advanced observing network of the Basque Country, but also provide data with wide spatio-temporal coverage in places that are difficult to sample. This network includes the Gulf of Biscay Marine Climate Change Observatory, OBSERVAMAR, and EuskOOS, the Operational Oceanography System, operated by AZTI in collaboration with Euskalmet, which provides real-time data on the state of the sea from the Basque coast up to 150 kilometres offshore.

The one-year BIGFIS project is financially supported by the Provincial Council of Gipuzkoa through its Support Programme for the Science, Technology and Innovation Network of Gipuzkoa.