Nitrogen fixation across the aquascape: current perspectives, future priorities

Abstract

Di-nitrogen (N 2 ) fixation rates, and the diversity of the organisms that fix N 2 , remain largely unconstrained in the aquatic landscapes or aquascapes (e.g., lakes, wetlands, streams, rivers, estuaries) between land and sea. As a result, we lack a mechanistic understanding of the controls and contributions of N 2 fixation across disparate aquatic environments, and cannot accurately incorporate this process into local and global nitrogen (N) budgets. This special issue brings together papers highlighting current advances in understanding of N 2 fixation within and across all aquatic habitats, integrating novel methodology for studying N 2 fixation, quantification of N 2 fixation fluxes in understudied habitats, the role of N 2 fixation in biotic assemblages, and the rate and fate of fixed N in heterogeneous landscapes. Together, these papers address important gaps in understanding and highlight the frontiers of research on N 2 fixation in aquatic habitats.