氮输入对河口高、低潮滩沼泽土壤甲烷产生和氧化潜力的影响及驱动因子
- Nitrogen addition differently alters potentials of soil methane production and oxidation of tidal marshes in estuarine high and low tide flats and driving factors
- 基金项目：国家自然科学基金资助项目(No. 42177213),国家重点研发计划项目(No.2022YFC3105401), 中央专项财政支持项目([No. 350182]FJYHZB[GK]2024001 )
- 摘要：氮素是影响湿地甲烷(CH4)代谢的重要驱动因子之一,然而湿地CH4产生、氧化对氮输入的响应具有复杂性和不确定性,氮输入对河口不同潮滩位沼泽湿地CH4产生和氧化速率的影响尚不清晰。本研究采集闽江河口鳝鱼滩高、低潮滩分布的短叶茳芏沼泽湿地表层土壤,运用厌氧和有氧微宇宙(microcosm)培养实验,并添加不同计量的铵态氮和硝态氮,研究不同形态、不同剂量的氮输入对河口高、低潮滩沼泽湿地CH4产生潜力和氧化潜力的影响及主要驱动因子。氮输入对高、低潮滩短叶茳芏沼泽湿地 CH4产生潜力和氧化潜力的影响不同。施加高、低浓度的硝态氮均显著抑制高潮滩沼泽湿地CH4产生潜力(P <0.05),与对照组(5.75±2.85) ng g?1 d?1相比,CH4产生潜力分别降低79.5%和75.3%；高、低浓度铵态氮和硝态氮添加均显著增加高潮滩CH4氧化潜力(P <0.05),与对照组(0.42±0.06) ng g?1 d?1相比,施加高、低浓度铵态氮和硝态氮后高潮滩沼泽湿地CH4氧化潜力分别增加126.2%和211.9%及104.8%和233.3%；高、低浓度的铵态氮和硝态氮输入对低潮滩CH4产生和氧化潜力均无显著影响(P >0.05)。施氮处理后土壤TC、电导率和TN含量是影响土壤CH4产生潜力的主要土壤环境因子；土壤电导率是影响土壤CH4氧化潜力的主要土壤环境因子。本研究结果表明：潮滩位是科学评价和预测氮负荷增加对河口沼泽湿地CH4代谢的影响必须考虑的重要因素之一。
- Abstract：Nitrogen is one of important drivers of wetlands methane (CH4) metabolism, however, responses of wetlands CH4production and oxidation to nitrogen input demonstrate complexity and uncertainty, and effects of nitrogen input on soil CH4production and oxidation of estuarine tidal marshes in different tidal flats are unclear. In our study, we collected surface soil samples from the Cyperus malaccensis marshes in the high and low tidal flats of Shanyutan in the Minjiang River estuary. In order to study the effects of different forms and doses of nitrogen input on the potentials of CH4 production and oxidation, as well as the main driving factors behind these effects, we carried anaerobic and aerobic microcosm incubation experiments, and combining the different levels of ammonium and nitrate nitrogen additions. Nitrogen input demonstrated different impacts on the CH4 production and oxidation potential between the marshes in high and low tidal flats. Both high and low levels of nitrate nitrogen input significantly inhibited CH4production potential in the high tidal marsh (P < 0.05), reducing it by 79.5% and 75.3%, respectively, compared to the control group (5.75 ± 2.85 ng g?1 d?1). In contrast, high and low levels of ammonium and nitrate nitrogen input significantly increased CH4 oxidation potential in the high tidal flats marshes (P < 0.05). Compared to the control group (0.42 ± 0.06 ng g?1 d?1), CH4 oxidation potential increased by 126.2% and 211.9% with ammonium nitrogen imput, and by 104.8% and 233.3% with nitrate nitrogen imput, respectively. However, the input of both high and low levels of ammonium and nitrate nitrogen showed no significant effects on CH4 production or oxidation potential in the low tidal flat marshes (P > 0.05). Following nitrogen imput, total nitrogen(TN), soil electrical conductivity (EC) and total carbon (TC) were the key factors driving CH4 production potential, while EC was the primary factor influencing CH4 oxidation potential. .The results indicated that in order to scientifically evaluate and predict the effects of nitrogen enrichment on estuarine tidal marshes CH4 metabolism, location of tidal flat must be considered.
