模拟SO42-沉降对闽江河口潮汐淡水湿地温室气体排放通量的影响

为了探究SO₄2-沉降对潮汐淡水湿地温室气体排放通量的影响，在闽江河口短叶茳芏（Cyperus malaccensis）潮汐淡水湿地模拟SO₄2-沉降，采用静态箱法测定样地环境因子与3种温室气体（CH₄、CO₂、N₂O）通量随SO₄2-添加量和不同月份的变化，采用多元逐步回归分析影响温室气体通量的关键因子.结果表明:①各环境因子和3种温室气体通量均具有显著的月际变化. ②添加SO₄2-显著增加了短叶茳芏种群密度和间隙水ρ（SO₄2-）、ρ（NH₄+-N），但对其他环境因子无显著影响. ③添加SO₄2-显著抑制了CH₄排放，当SO₄2-添加量（以SO₄2--S计，下同）为40和120 kg/（hm2·a）时，CH₄通量分别减少了33.8%、69.9%；CO₂和N₂O通量随SO₄2-添加量的变化不显著，但分别趋于减小和增加，其中，SO₄2-添加量为40和120 kg/（hm2·a）时，CO₂通量分别减少了5.2%、11.8%，N₂O通量则分别增加了98.0%、103.0%. ④相关分析和多元逐步回归分析结果显示，沉积物温度及间隙水ρ（SO₄2-）、ρ（NH₄+-N）、ρ（NO_x--N）（NO_x--N主要包括NO₃--N和NO₂--N）是影响样地3种湿地温室气体排放通量的关键因子. ⑤当SO₄2-添加量为40和120 kg/（hm2·a）时，3种温室气体排放产生的综合温室效应呈减小趋势，分别降低了5.5%和13.5%.研究推断，SO₄2-沉降速率的升高有助于缓解潮汐淡水湿地对全球气候变暖的贡献. 

Effects of Simulated SO42- Deposition on the Greenhouse Gas Fluxes in a Freshwater Tidal Marsh in Minjiang River Estuary

In order to investigate the effect of SO₄2- deposition on the greenhouse gas emissions from freshwater tidal marsh, simulated SO₄2- deposition was carried out in a Cyperus malaccensis freshwater tidal marsh in Minjiang River Estuary. The enclosed static chamber technique was used to determine the environmental factors and the greenhouse gas fluxes (included CH₄, CO₂ and N₂O) in different months and under different SO₄2- application rates. The stepwise regression was performed to determine the influential environmental factors to the greenhouse gas fluxes. The results showed that the environmental factors and the greenhouse gas fluxes in the plots exhibited distinct monthly variations. The additional sulfate concentration significantly promoted the plant density, and ρ(SO₄2-) and ρ(NH₄+-N) in pore water. The additional sulfate significantly suppressed the CH₄ flux; the CH₄ flux decreased by 33.8% and 69.9%, respectively, when the SO₄2- application rate (by SO₄2--S) reached 40 and 120 kg/(hm2·a). The CO₂ flux decreased with increasing SO₄2- while the N₂O flux increased, though the changes were not significant; the CO₂ flux decreased by 5.2% and 11.8%, respectively, while the N₂O flux increased by 98.0% and 103.0%, respectively, due to 40 and 120 kg/(hm2·a) SO₄2- applications. Sediment temperature, and ρ(SO₄2-), ρ(NH₄+-N) and ρ(NO_x--N) (included NO₃--N and NO₂--N) in pore water were the influential factors to the greenhouse gas fluxes. The overall greenhouse effect from the emissions of the 3 greenhouse gases decreased with the application of 40 and 120 kg/(hm2·a) SO₄2-; the reduction was 5.5% and 13.5%, respectively. Our research concluded that the increase in sulfate deposition rate might be conducive to the reduction of the contribution of tidal marsh to the global warming.