Effects of Temperature increase on N2O Emissions from Intertidal Area along the East China Coast

Coasts and estuaries are key contributors to atmospheric nitrous oxide (N₂O) emissions. Here, we used laboratory incubation experiments to investigate temperature (12, 25, and 35 °C) and tidal effects on N₂O fluxes in sediments sampled from three contrasting latitudinal subareas along the East China Coast (ECC) (North, Mid, and South). Overall, responses of N₂O emissions to increasing temperature varied among the three climatic zones. During non-flood and flooding, mean N₂O fluxes in sediments sampled from the North subarea increased exponentially with temperature (49.0 ±40.6 nmol m^-2 h^-1 at 12 °C to 3160 ±3960 nmol m^-2 h^-1 at 35 °C, and 741 ±518 nmol m^-2 h^-1 at 12 °C to 1020 ±1400 nmol m^-2 h^-1 at 35 °C, respectively). However, mean N₂O fluxes in sediments sampled from the South subarea decreased at higher temperatures during flooding (977 ±306 nmol m^-2 h^-1 at 12 °C to 68.0 ±47.5 nmol m^-2 h^-1 at 35 °C) and non-flood (233 ±292 nmol m^-2 h^-1 at 12 °C to 183 ±142 nmol m^-2 h^-1 at 35 °C). Under ongoing global warming, intertidal areas at temperate may act as potential sources of N₂O, whereas the contribution of low latitude coastal sediments to N₂O budget may decrease. In addition, there is a combined impact of temperature and tidal fluctuation on N₂O emissions that controls N₂O production and consumption. Our results improve understanding of the diverse feedbacks of N₂O emissions from coastal area to global climate change.