Organic matter and trace gas turnover in northeast Siberian permafrost: First soil studies on the impact of climate change on carbon mineralization

拟议研究项目的目的是提高我们对富含碳的西伯利亚东北部永久冻土中有机质周转及其对全球变化的潜在响应的理解。永久冻土(永冻层)是北半球约四分之一的地貌特征。在西伯利亚东北部，永久冻土沉积物中含有大量的有机物。目前观察到的全球气温上升导致更深的永久冻土融化，使以前冻结的有机物质暴露在微生物降解之下。目前对多年冻土深层有机质碳矿化率的估计是高度不确定的，北部多年冻土地貌的微量气体排放测量也很少。计划进行野外和实验室实验，以量化西伯利亚东北部不同深度、不同年龄和不同成分的永久冻土中的碳矿化和痕量气体周转。将使用不同的孵化方法和基于稳定同位素的技术来量化在缺氧和缺氧条件下的矿化率。这一结果将增加我们对多年冻土退化对痕量气体通量影响的了解。

The objective of the proposed research project is to improve our understanding of organic matter turnover in the carbon rich northeast Siberian permafrost soils and its potential response to global change. Permanently frozen ground (permafrost) characterises the landscape of about one quarter of the northern hemisphere. In northeast Siberia, permafrost deposits contain huge amounts of organic matter. The currently observed global temperature rise results in deeper permafrost thawing exposing formerly frozen organic matter to microbial degradation. Current estimates about carbon mineralization rates of deep permafrost organic matter are highly uncertain and trace gas emissions measurements from northern permafrost landscapes are scarce. Field and laboratory experiments are planned to quantify carbon mineralization and trace gas turnover in northeast Siberian permafrost of different depth, age, and composition. Mineralization rates will be quantified under oxic and anoxic conditions using different incubation methods and stable isotope based techniques. The results will increase our knowledge about the impact of permafrost degradation on trace gas fluxes.