Biological nitrogen fixation is considered the major input of reactive nitrogen in low latitude open ocean regions, fuelling primary productivity and carbon export. For decades, nitrogen fixation had been assumed to be absent in the temperate shelf seas and high latitude ocean. However, there is now growing evidence that nitrogen-fixers are active in these systems, but the magnitude, environmental drivers, players and ecological implications are poorly known. This evidence is accumulating at a time when these systems are rapidly changing, underscoring the need for a focused effort in the scientific community to accelerate understanding of nitrogen fixation beyond the low latitudes. Compared to open oceans, temperate shelf and high latitude regions are heterogeneous and highly dynamic, limiting observations and challenging modelling efforts. Current models that include nitrogen fixation parametrise the geographical extent as a function of reactive nitrogen and/or temperature, excluding cold and nutrient-rich temperate shelf and high latitude oceans. In late March, Mar Benevides and colleagues attended a workshop at the ALSO 2025 conference in Charlotte, North Carolina to bring together the communities working on modelling nitrogen fixation with those of the physical oceanography, biogeochemical and molecular observational communities. The aim was to identify the data types and mechanistic understanding needed to parametrise nitrogen fixation beyond low latitude regions. It is hoped the workshop will provide a path forward to further develop models that incorporate nitrogen fixation in temperate shelf and high latitude oceans, to enable quantifying its contribution to the global nitrogen inventory, hypothesis testing and forecasting changes in nitrogen fixation in the future ocean. The workshop has also led to a proposal for a SCOR working group on this theme. 

The Author of this Article Mar Benavides (National Oceanography Centre)