Tidal pulsing alters nitrous oxide fluxes in a temperate intertidal mudflat

Authors

  • A. M. Vieillard,

    Corresponding author
    1. Boston University Department of Earth and Environment, 685 Commonwealth Avenue, Boston, Massachusetts 02215 USA
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  • R. W. Fulweiler

    1. Boston University Department of Earth and Environment, 685 Commonwealth Avenue, Boston, Massachusetts 02215 USA
    2. Boston University Department of Biology, 5 Cummington Mall, Boston, Massachusetts 02215 USA
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  • Corresponding Editor: B. Z. Houlton.

Abstract

Environmental pulses, or sudden, marked changes to the conditions within an ecosystem, can be important drivers of resource availability in many systems. In this study, we investigated the effect of tidal pulsing on the fluxes of nitrous oxide (N2O), a powerful greenhouse gas, from a marine intertidal mudflat on the north shore of Massachusetts, USA. We found these tidal flat sediments to be a sink of N2O at low tide with an average uptake rate of −6.7 ± 2 μmol·m−2·h−1. Further, this N2O sink increased the longer sediments were tidally exposed. These field measurements, in conjunction with laboratory nutrient additions, revealed that this flux appears to be driven primarily by sediment denitrification. Additionally, N2O uptake was most responsive to dissolved inorganic nitrogen with phosphorus (DIN+DIP) addition, suggesting that the N2O consumption process may be P limited. Furthermore, nutrient addition experiments suggest that dissimilatory nitrate reduction to ammonium (DNRA) releases N2O at the highest levels of nitrate fertilization. Our findings indicate that tidal flats are important sinks of N2O, potentially capable of offsetting the release of this potent greenhouse gas by other, nearby ecosystems.

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