Global importance of nitrogen fixation across inland and coastal waters

Authors: FULWEILER, ROBINSON - Boston University; RINEHART, SHELBY - Drexel University; Taylor, Jason; KELLY, MICHELLE - Michigan Technological University; BERBERICH, MEGAN - Michigan Technological University; RAY, NICHOLAS - University Of Delaware; OCZKOWSKI, AUTUMN - Us Environmental Protection Agency (EPA); BALINT, SAWYER - Boston University; GEISSER, ALEXANDER - Boston University; BENAVIDES, MAR - Aix-Marseille University; CHURCH, MATTHEW - University Of Montana; LOEKS, BRIANNA - University Of Minnesota; NEWELL, SILVIA - University Of Michigan; OLOFSSON, MALIN - Swedish University Of Agricultural Sciences; OPPONG, JIMMY - Charles University, Czech Republic; ROLEY, SARAH - Washington State University; VIZZA, CARMELLA - Hawaii Pacific University; WILSON, SAM - Newcastle University; GROFMMAN, PETER - Cary Institute Of Ecosystem Studies; SCOTT, JEFFERSON - Baylor University; MARCARELLI, AMY - Michigan Technological University

Submitted to: Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/16/2025
Publication Date: 6/12/2025
Citation: Fulweiler, R.W., Rinehart, S., Taylor, J.M., Kelly, M.C., Berberich, M., Ray, N.E., Oczkowski, A., Balint, S., Geisser, A., Benavides, M., Church, M., Loeks, B., Newell, S., Olofsson, M., Oppong, J., Roley, S., Vizza, C., Wilson, S., Grofmman, P., Scott, J.T., Marcarelli, A. 2025. Global importance of nitrogen fixation across inland and coastal waters. Science. 12 June 2025:1205-1209. https://doi.org/10.1126/science.adt1511.
DOI: https://doi.org/10.1126/science.adt1511

Interpretive Summary: Understanding global contributions of different sources of nitrogen is important information that drives decisions for wise management of excess nitrogen in our environment. Biological nitrogen fixation is the primary natural pathway for nitrogen to become available to plants and animals on Earth. Researchers have a good understanding of the contribution of biologically fixed nitrogen from land and ocean systems to global nitrogen availability but no comprehensive examinations have been done to estimate the contribution from inland (lakes, rivers, wetlands) and coastal aquatic ecosystems. Researchers present results based on a global database that demonstrate these overlooked habitats contribute significant amounts of nitrogen through biological fixation to the global pool. In fact, estimated contributions approach approximately 20% of the biologically fixed nitrogen, despite only representing ~ 10% of the global surface area. This new information will help inform global nitrogen budgets and contribute to better management of excess nitrogen across the globe.

Technical Abstract: Biological nitrogen fixation is a key driver of global primary production and climate. Decades of effort have repeatedly updated nitrogen fixation estimates for terrestrial and open ocean systems, yet the other aquatic systems in between have largely been ignored. Here we present a new evaluation of nitrogen fixation for inland and coastal waters. We demonstrate that water column and sediment nitrogen fixation is ubiquitous across these diverse aquatic habitats, with rates ranging six orders of magnitude. Despite accounting for less than 10% of the global surface area, we conservatively estimate that inland and coastal aquatic systems fix 60 (28-167) Tg N y-1, roughly equivalent to 20% of the nitrogen fixed on land and in the ocean.