Nitrogen fixation: a poorly understood process along the freshwater-marine continuum
Amy M Marcarelli1, Robinson W Fulweiler2,3, J Thad Scott4
1Department of Biological Sciences, Michigan Technological University.
Limnology and Oceanography Letters
|May 9, 2022
Summary
Nitrogen (N₂) fixation rates in aquatic ecosystems are poorly understood, despite its importance in the global nitrogen cycle. Research is needed on diazotroph diversity, stoichiometry, and upscaling to integrate N₂ fixation into aquatic ecology.
Area of Science:
- Aquatic Ecology
- Biogeochemistry
- Microbial Ecology
Background:
- Nitrogen (N₂) fixation is a critical process in the global nitrogen cycle.
- N₂ fixation rates and ecological dynamics are largely unknown in inland and coastal aquatic ecosystems.
- Previous research focused on open-ocean and terrestrial environments, overlooking diverse aquatic habitats.
Purpose of the Study:
- To highlight the knowledge gaps in aquatic N₂ fixation.
- To propose key research themes for advancing the understanding of N₂ fixation in aquatic ecosystems.
- To integrate N₂ fixation into the broader ecological dynamics of aquatic systems.
Main Methods:
- Identification of three major research themes: diazotroph diversity and N₂ fixation rate variability, ecological stoichiometry of N₂ fixation, and upscaling N₂ fixation rates.
- Emphasis on interdisciplinary approaches combining microbial ecology, biogeochemistry, and ecosystem science.
- Focus on diverse aquatic ecosystems including lakes, wetlands, rivers, streams, and estuaries.
Main Results:
- N₂ fixation rates and ecological dynamics in inland and coastal waters are significantly understudied.
- Diversity of diazotrophs and variability in N₂ fixation rates are key areas requiring investigation.
- Ecological stoichiometry and upscaling methods are crucial for understanding N₂ fixation impacts.
Conclusions:
- Advancing the study of aquatic N₂ fixation requires coordinated research across biological, chemical, and ecological disciplines.
- Integrating N₂ fixation into limnology and oceanography is essential for a comprehensive understanding of aquatic ecosystem functioning.
- Future research should focus on the proposed themes to bridge knowledge gaps from genes to ecosystems.
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