Large increase in diffusive greenhouse gas fluxes from subtropical shallow aquaculture ponds during the passage of typhoons

• Tropical cyclones are extreme perturbations that can affect the biogeochemical cycles in tropical and temperate coastal ecosystems. Yet, whether typhoon events would affect the magnitude of greenhouse gas (GHG) emissions from shallow aquaculture ponds in the subtropical coastal regions is still poorly understood. In this study, we estimated and compared the diffusive fluxes of CO2, CH4, and N2O in the mariculture ponds at a subtropical estuary in southeast China before, during, and after the passage of three typhoons. Our results indicate that the average diffusive CO2, CH4, and N2O fluxes during typhoon passage were one to two orders of magnitude higher than those observed during both the pre-typhoon and post-typhoon periods. We estimated conservatively that the estuarine aquaculture ponds emitted GHGs at a rate of about 3145 mg CO2-eq m(-2) h(-1) into the atmosphere during the passage of typhoons, which was substantially higher than the average emission rates of 30.8 and 35.2 mg CO2-eq m(-2) h(-1) observed during the pre- and post-typhoon periods, respectively. Our findings demonstrated that the typhoon passage period can be a hot moment of GHG emissions from aquaculture ponds in the subtropical estuaries, and highlight the importance of capturing short-term disturbance events such as typhoons to accurately assess the annual GHG balance and hence the climatic impacts on these shallow water ecosystems.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Naturgeografi (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Physical Geography (hsv//eng)

Nyckelord

Tropical cyclones; Greenhouse gas; Agricultural ecosystem; Aquaculture ponds; Subtropical estuary; China

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