Nitrous Oxide (N₂O) Biogeochemistry in Baffin Bay
What is the motivation?
The Arctic nitrogen cycle remains poorly understood. In particular, the role of the Arctic Ocean and its marginal seas in producing or consuming atmospheric nitrous oxide (N₂O)—a potent greenhouse gas whose atmospheric concentrations continue to rise—needs to be better constrained.
Why does it matter?
Nitrous oxide (N₂O) is the third-largest human-driven greenhouse gas contributing to global warming since pre-industrial times. Understanding its global cycle is essential for designing effective mitigation strategies. Natural N₂O emissions may increase under current warming trends, making it critical to document and quantify potential amplifying factors, including those occurring in remote and harsh regions such as the Arctic Ocean and the Baffin Sea.
© Richard Mardens – FOREL
Project Focus
The project will measure dissolved N₂O in seawater from coastal Greenland to the open waters of Baffin Bay, alongside other indicators of the nitrogen cycle and the physical state of seawater (including water isotopes). It will assess whether glacial meltwater in Greenland’s fjords acts as a source or sink of N₂O and determine how sea-ice refreezing and its effects on ocean stratification might alter N₂O exchanges between the ocean and atmosphere in western Baffin Bay.
© Richard Mardens – FOREL
How will it be done?
The work will rely on an innovative instrument called SubOcean, capable of measuring dissolved N₂O in situ and in real time along vertical depth profiles. The instrument will be deployed during regular vessel stations. Water samples will also be collected for laboratory analyses of nitrogen species and phosphate. A second SubOcean system will continuously monitor water isotopes in surface waters to differentiate freshwater sources. The project team will participate in both legs of the CASCADES expedition.
© Sébastien Lavanchy
What will be collected?
SubOcean instruments will continuously record dissolved N₂O and water-isotope data every second, eliminating the need for direct sampling for these measurements. Additional water samples will be collected for discrete laboratory analyses of nitrogen compounds and phosphate once the expedition returns.
Members and partners
- Principal Investigator:
- Jérôme Chappellaz, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Other participants:
- Sofia Muller, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Sébastien Lavanchy, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Hugo Cruz, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Partners:
- Roberto Grilli, Institut des Géosciences de l’Environnement, CNRS, Grenoble, France