A new study provides the most comprehensive and clearest picture yet of where nitrogen fixation is happening in our inland and coastal waters. Sarah Roley, a WSU Tri-Cities associate professor of environmental science who co-authored the research. Our study underscores the underrated importance of these ecosystems in increasing global nitrogen supply. It includes excellent chapters from Carmella Vizza, an assistant professor at Hawai’i Pacific University and a former post-doctoral research associate at WSU Tri-Cities.
The research team compiled data from over 4,793 nitrogen fixation rate measurements across hundreds of inland and coastal sites worldwide. Their findings suggest that these water bodies collectively sequester the equivalent of nearly 60 billion pounds of digestible nitrogen each year. This represents about 15% of the global total. This intelligence is extremely important. It provides fascinating insights into the environmental and ecosystem interactions of biological nitrogen fixation, one of the most important processes for supporting life on Earth.
Comprehensive Data Collection
Our research team brought together transportation and health data during an intense workshop. Their aim was to combine studies already done into something like a unified dataset. The researchers expanded their research to include lakes, rivers, wetlands and coastal waters. They found that each of these environments sequesters about 40 million tons of nitrogen annually.
This exciting collaboration brings to the forefront a notable omission in past literature—inclusion of aquatic ecosystems in global nitrogen estimates.
“This research will help improve environmental models and predictions by giving us a more complete picture of where nitrogen is coming from.”
Nitrogen is one of the four atomic elements that comprise all living organisms. For the most part, it exists in an atmospheric layer that few are able to tap into. With the help of specialized microbes, nitrogen fixation converts this atmospheric nitrogen into forms that plants and other organisms can utilize. Roley emphasized the findings’ implications for ecological health:
Importance of Nitrogen Fixation
The new research focuses on the important part that rivers, lakes and estuaries play in this vital process. Regrettably, these contributions have frequently been dismissed in wider environmental reviews.
“Often, a lack of nitrogen limits algae and plant growth, especially in coastal ecosystems. These global nitrogen fixation estimates can help us better understand algal growth in freshwater and coastal ecosystems, which are clearly producing more of their own nitrogen than we previously understood.”
According to the study’s authors, we completely missed the boat by failing to include inland and coastal aquatic ecosystems in global nitrogen estimates. Together, they point out a number of reasons for this neglect. They hope that this work will ignite more research focused on understanding nitrogen fixation mechanisms in these ecosystems. Robinson W. Fulweiler and colleagues noted:
Future Research Directions
These findings further our understanding of how anthropogenically altered ecosystems mediate nitrogen dynamics. More importantly, they can point us to where we need the most conservation action to protect these irreplaceable waters.
“We anticipate that this study will motivate future research to improve detection techniques, expand monitoring across underrepresented climate zones, and better understand what drives nitrogen fixation in these environments.”
These insights aim to foster a deeper understanding of how various ecosystems contribute to nitrogen dynamics and could inform conservation efforts aimed at protecting these critical water bodies.