High-resolution spatiotemporal dynamics of nitrous oxide and methane in fjords under global change

Emissions of the potent climate-forcing trace gases nitrous oxide (N2O) and methane (CH4) are far from being resolved, especially in remote marine areas such as fjords. My preliminary results suggest that productive fjords may be emission hotspots, but budgets remain undeveloped.

Here I aim to test whether eutrophication, the enrichment of waters with excessive nutrients, enhances climate-forcing trace gas emissions by revealing fluxes of N2O and CH4 from fjords along nutrient pollution gradients.

The work is organized in three work packages to: (1) determine seasonal variation in N2O and CH4 emissions in fjords; (2) resolve spatial patterns of N2O and CH4 benthic and pelagic cycling; (3) create fjord budgets for extrapolating the obtained fluxes globally.

Underway laser detectors, stable isotope tracers and molecular tools will be used to resolve emissions, geochemical pathways and the microbial drivers of N2O and CH4 cycling. This will allow me to construct the first global assessment of the importance of fjords in oceanic trace gas budgets.

By crossing the boundaries between biogeochemistry, microbiology and oceanography, this project will close significant gaps in our understanding of coastal N2O and CH4 dynamics and resolve imbalances in current budgets.

It will reveal whether chronic, widespread eutrophication represents a positive feedback for climate change, and ultimately build arguments for managing nutrient enrichment while minimizing climate-forcing gas emissions.