Journal article
Nitrous oxide fluxes in estuarine environments: response to global change
Global Change Biology, Vol.21(9), pp.3219-3245
09/03/2015
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Abstract
Nitrous oxide is a powerful, long-lived greenhouse gas, but we know little about the role of estuarine areas in the global N2O budget. This review summarizes 56 studies of N2O fluxes and associated biogeochemical controlling factors in estuarine open waters, salt marshes, mangroves, and intertidal sediments. The majority of in situ N2O production occurs as a result of sediment denitrification, although the water column contributes N2O through nitrification in suspended particles. The most important factors controlling N2O fluxes seem to be dissolved inorganic nitrogen (DIN) and oxygen availability, which in turn are affected by tidal cycles, groundwater inputs, and macrophyte density. The heterogeneity of coastal environments leads to a high variability in observations, but on average estuarine open water, intertidal and vegetated environments are sites of a small positive N2O flux to the atmosphere (range 0.15–0.91; median 0.31; Tg N2O-N yr−1). Global changes in macrophyte distribution and anthropogenic nitrogen loading are expected to increase N2O emissions from estuaries. We estimate that a doubling of current median NO3− concentrations would increase the global estuary water–air N2O flux by about 0.45 Tg N2O-N yr−1 or about 190%. A loss of 50% of mangrove habitat, being converted to unvegetated intertidal area, would result in a net decrease in N2O emissions of 0.002 Tg N2O-N yr−1. In contrast, conversion of 50% of salt marsh to unvegetated area would result in a net increase of 0.001 Tg N2O-N yr−1. Decreased oxygen concentrations may inhibit production of N2O by nitrification; however, sediment denitrification and the associated ratio of N2O:N2 is expected to increase.
Details
- Title
- Nitrous oxide fluxes in estuarine environments: response to global change
- Creators
- Rachel H Murray - Southern Cross UniversityDirk V Erler - Southern Cross UniversityBradley D Eyre - Southern Cross University
- Publication Details
- Global Change Biology, Vol.21(9), pp.3219-3245
- Publisher
- Wiley-Blackwell Publishing Ltd.
- Grant note
- This review was supported by ARC Linkage Project LP110200975 and ARC LIEF projects LE130100153 and LE120100156.
- Identifiers
- 3579; 991012821228502368
- Copyright
- © 2015 John Wiley & Sons Ltd
- Academic Unit
- Science; Centre for Coastal Biogeochemistry; Faculty of Science and Engineering; School of Environment, Science and Engineering
- Language
- English
- Resource Type
- Journal article