【作者】 柳铮铮；

【导师】 曾从盛；

【作者基本信息】 福建师范大学 ， 自然地理学， 2009， 硕士

【摘要】 湿地是一个巨大的碳库,它是温室气体的源或汇。最近研究表明酸沉降可以刺激硫酸盐还原细菌活性增加,并与产甲烷（CH₄）菌争夺基质,从而抑制CH₄气体的产生。国外关于酸沉降抑制泥炭沼泽和水稻田等湿地的CH₄产生、排放的研究已经很多,但在河口湿地缺还很少开展相关研究,相关机制不是很清楚。地处东南沿海区的闽江河口湿地具有其典型性和代表性,咸草是闽江河口湿地最主要的植被类型之一,故而研究酸沉降对闽江河口咸草湿地甲烷排放影响的具有重要理论意义和实践价值。闽江河口湿地是我国东南沿海最具代表性的河口湿地之一。本文采用室内培养法—原位静态箱法—气相色谱法,探讨了酸沉降对闽江河口湿地CH₄排放的影响,闽江河口咸草湿地CH₄产生可能的竞争性基质来源和非竞争性基质来源,以及酸沉降对湿地土壤碳输出的影响。研究成果填补了我国在该方面研究的不足本文研究结果如下:1、咸草湿地CH₄排放通量具有明显的季节变化。CH₄排放通量的变化模式为单峰模式,温度变化和植物生长状况是造成这一规律的主要原因。2、温度在一定范围内与CH₄排放成正相关,盐度与CH₄排放负相关;酸碱度（pH）和氧化还原电位（Eh）在室内控制条件下显著相关,在自然状态下,由于湿地CH₄排放的影响机制相当复杂,Eh和pH的变化对CH₄排放的影响并不是很明显3、室内培养的理想状态下,硫酸根的增加可以刺激硫酸根还原菌同产甲烷菌竞争底物,从而达到抑制CH₄产生的效果。4、模拟酸沉降对闽江河口湿地CH₄排放的影响,结果表明:（1）从相对变化率看,增加硫酸根可以抑制一定程度的闽江口鳝鱼滩湿地CH₄排放。但CH₄排放在绝对量上抑制不明显。（2）大剂量的酸沉降处理实验也同样说明增加酸沉降在一定范围内还是可以增加抑制效果的。但是由于半日潮的冲刷作用,处理组的CH₄排放通量也迅速恢复到了施加前的水平。（3）证实了Gauci等（2004）在美国宇航局戈达德航天飞行中心通过模拟实验中的假设。5、闽江口鳝鱼滩湿地CH₄产生的基质来源不是H₂/CO₂,而施加醋酸、甲醇、三甲胺都对CH₄产生都有促进作用。同时发现CH₄氧化随着CH₄浓度的增加而增加,并且在微氧情况即可以发生。6、从室内培养实验看,硫酸根的存在在短期内是增加了CO₂和CH₄总的碳输出。而在闽江口鳝鱼滩湿地,土壤中的硫酸根浓度已经超过饱和浓度,再增加酸沉降并没有增加硫酸根还原的速率。因此在闽江口鳝鱼滩湿地,增加酸沉降并不会增加CH₄和CO₂这两种碳输出。更多还原

【Abstract】 Wetlands represent large carbon reservoirs that can act as a source or sink for greenhouse gases. Recent research has shown that that SO₄²-from acid rain can stimulate sulfate-reducing bacteria into a population capable of outcompeting methanogens for substrates, thereby can suppress Methane Emission from wetland. Now there are a lot of research about acid deposition inhibiting production of methane from peatland and rice fields.But few research are carry out at estuary marsh, so the relevant mechanism is not very clear. Minjiang River Estuary wetland located in the southeast of coastal area,has its typical and representative.Cyperus malaccensis is one of the most important vegetation types in Minjiang River Estuary wetland,so study effect of acid deposition on the Cyperus malaccensis wetland methane emissions has important theoretical and practical value.Using laboratory incubation, the enclosed chamber technique and gas chromatograph methods,we investigate the effects of sulfur deposition on methane emission and carbon cycling of estuarine eediments and methanogenesis competitive and noncompetitive substrates in estuarine sediments. The results of studies will make up the blank of the research in China.The results showed:1.Cyperus malaccensis wetland CH₄ emission flux has obvious seasonal variation. The mode that CH₄ flux change is single peak.The temperature and plants are main causation.2.At certain range,temperature and CH₄ emissions were positively correlated.And salinity is negatively correlated with the CH₄ emissions; when under culture conditions,pH and Eh is significant correlation with CH₄ production.3.when under culture conditions, The increase in sulfate can stimulate sulfate-reducing bacteria compete with methanogen for substrate, so as to achieve the effect of inhibiting CH₄.4. Simulated acid deposition on the Minjiang estuary wetland CH₄ emissions, the results showed: （1） from the relative changes rate, increase sulfate can inhibit a certain degree of Minjiang River Estuary wetland CH₄ emissions;（2）Sigle-dose treatment of acid deposition experiments also indicate that increase of acid deposition at a certain range can increase the inhibitory effect. But because of tidal flushing, CH₄ emission flux of treatment group is rapidly restored to the level before the imposed.（3） Approve the assumptions of Gauci.5. CH₄ source of Minjiang River Estuary wetland is not generated by H2/CO₂, imposed acetate, methanol, trimethylamine enhance CH₄ production.CH₄ oxidation was found simultaneously with the CH₄ concentration increased,and at micro-oxygen situations can happen.6. When under culture conditions, the existence of sulfate can increase total carbon output of CO₂ and CH₄. In Minjiang River Estuary wetland, soil sulfate concentration has exceeded saturation concentration, increase the acid deposition did not increase the rate of sulfate reduction. Therefore, in Minjiang River Estuary wetland,increase acid deposition will not increase the total output of CH₄ and CO₂.更多还原