水盐变化对滨海湿地土壤有机碳累积与碳排放的影响综述

Soil organic carbon accumulation and decomposition in coastal wetlands in the changing water and salinity conditions:a review

滨海湿地作为海岸带蓝碳生态系统的重要组分,具有巨大的碳捕获和碳封存潜力,在减缓气候变暖方面具有重要意义.水盐变化通过影响滨海湿地土壤有机碳的累积和排放过程实现对滨海湿地生态系统碳收支的调控.本文综述了水盐变化对滨海湿地土壤有机碳累积和碳排放过程的影响,以及滨海湿地土壤碳排放研究方法等方面的研究进展,分析了水盐驱动下滨海湿地土壤有机碳分解的微生物作用机制.针对当前研究存在的不足,提出今后应重点关注滨海湿地土壤有机碳分解的温度、湿度和盐度敏感性及其水盐-温度的协同作用机制,氮磷输入和多重污染胁迫对滨海湿地土壤有机碳排放的作用机制,以及滨海湿地土壤微生物碳代谢过程与氮磷硫代谢过程的耦合作用及其水盐驱动机制等方面的研究,以期揭示水盐变化对滨海湿地土壤碳循环的作用机制,为气候变化背景下滨海湿地的碳汇功能提升与管理提供科学依据.

Coastal wetlands are an important component of blue carbon ecosystems, have great potential for carbon capture and storage, and play a significant role in mitigating climate warming. Soil organic carbon accumulation and decomposition can change greatly along a hydrological and salinity gradient in coastal wetlands.This review summarized the progresses on the soil organic carbon accumulation, carbon emission, microbial mechanisms of soil organic carbon decomposition and the methodology of carbon fluxes in coastal wetlands in a changing water and salinity environment. Finally,the future key researches on the soil organic carbon processes in coastal wetlands under different water and salinity should focus on these following aspects, including(1) the temperature,moisture and salinity sensitivities of soil organic carbon mineralization in coastal wetlands and integrated influencing mechanisms of water, salinity and temperature,(2) the influencing mechanisms of nitrogen and phosphorus inputs and multi-pollutant stresses on soil organic carbon decomposition and carbon emissions from coastal wetlands, and(3) the coupling of microbial carbon metabolism and nitrogen, phosphorus and sulfur metabolisms and the driving mechanisms of water and salinity. This review can provide a scientific and theoretical basis for revealing the influencing mechanisms of changing water and salt conditions on carbon cycle of coastal wetlands,and for evaluating the improvement and management of carbon sink function of coastal wetlands in context to climate change.