环境科学
湿地
生态系统
生态系统呼吸
高原(数学)
植被(病理学)
水文学(农业)
土壤水分
土壤碳
降水
生产力
生态学
初级生产
土壤科学
地质学
地理
生物
数学分析
数学
岩土工程
医学
宏观经济学
病理
气象学
经济
作者
Jiangqi Wu,Haiyan Wang,Guang Li,Yanhua Lu,Xingxing Wei
出处
期刊:Catena
[Elsevier]
日期:2022-12-01
卷期号:219: 106629-106629
被引量:3
标识
DOI:10.1016/j.catena.2022.106629
摘要
Extreme rainfall amount and frequency can alter carbon dioxide (CO2) exchange between the soil and vegetation in wetlands. Seasonal redistribution of extreme rainfall events is one component of a hydrological regime that affects soil water content (SWC), but its impacts on ecosystem CO2 exchange in the Qinghai-Tibet Plateau (QTP) wetlands remain unclear. Here, we conducted field simulation experiments to understand the effects of extreme rainfall with high to low frequency once every-one, two, three, and four weeks on CO2 exchange of wet meadow ecosystem in QTP. The ecosystem absorbed more CO2 with high-frequency extreme rainfall (−1468.52 mg C m-2h−1) than with current natural amounts and frequency of rainfall (−1162.51 mg C m-2h−1) throughout local vegetation growing seasons. However, under low-frequency extreme rainfall (−916.72 mg C m-2h−1) the wetland absorbed less CO2 than under natural rainfall frequency. This difference comes from the changes in net ecosystem productivity (NEP) and ecosystem respiration (ER) in wet meadows due to soil temperature (ST) and soil nutrient content. In the rapid growth stage of plants, ER and NEP exhibited single-peak curves due to increases in ST and SWC, and they reached their maximum values in August. Our results indicate that the distribution pattern of extreme rainfall events plays a critical role in regulating ecosystem CO2 exchange in the wet meadows of the QTP. More research on the related changes between contents of soil nutrient contents and extreme rainfall events could improve the accuracy of C budget estimation in wet meadows. The predicted regional impacts of future climate extremes of rainfall will rely on changes in their frequency and timing.
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