Nitrogen fixation along the freshwater to marine continuum: state of the science and research needs

Document Type

Conference Proceeding

Publication Date



Interest in nitrogen (N) fixation is as old as ecology itself, and past research efforts have concluded that N fixation rates are low in aquatic habitats compared to reactive N inputs from land and from anthropogenic activities. Yet, more recent studies have identified measurable and ecologically relevant rates of N fixation in lake, stream, river and coastal habitats. Here, we will outline key questions regarding the consequences of this process for ecosystem productivity and food web interactions, including the influence of N fixation on small scale microbial processes, the lability and reactivity of organic nutrient pools, and coupled element cycling across a range of spatial and temporal scales. We will also discuss examples where new techniques and perspectives have revealed that N fixation is an important, previously underestimated, source of N. Finally, we will present a conceptual model regarding past and current understanding of controls and constraints of N fixation, and discuss how more accurate estimates of N fixation may change our understanding of the ecology and biogeochemistry of aquatic ecosystems.

Publication Title

Joint Aquatic Sciences Meeting 2014