Denitrification in coastal Louisiana: A spatial assessment and research needs

摘要: Abstract By transforming fixed nitrogen (N) into gas, the biochemical processes that support denitrification provide a function critical to maintaining integrity of ecosystems subjected increased loading N from anthropogenic sources. The Louisiana coastal region receives high nitrate (NO3−) concentrations (> 100 µM) Mississippi–Ohio–Missouri River Basin and is also an area undergoing rates wetland loss. Ongoing anticipated changes in promise alter biogeochemical cycles including net rate by ecosystems. Projecting what these could mean for water quality natural resources requires understanding magnitude patterns variation their connection estuarine at large temporal spatial scales under current conditions. We compile review reported 32 studies conducted variety habitats across during period 1981– 2008. acetylene inhibition 15N flux were preferred techniques (95%); most used sediment slurries rather than intact cores. There are no estimates using N2/Ar ratio isotope pairing techniques, which address some problems limitations techniques. These have shown sediments estuaries, lakes, marshes, forested wetlands, shelf capable potential when exposed NO3− (> 100 µM). Maximum experimental settings can reach values > 2500 µmol m2 h− 1. lack contemporary understand interactions among transformations (e.g., organic matter mineralization, immobilization, aquatic plant assimilation, nitrification, fixation, dissimilatory reduction ammonium (DNRA) anaerobic oxidation (annamox) limits our cycling Louisiana, particularly role respiratory chemolithoautotrophic areas restoration.