Geochemical analyses reveal the importance of environmental history for blue carbon sequestration

Coastal habitats including saltmarshes and mangrove forests can accumulate and store significant blue carbon stocks, which may persist for millennia. Despite this implied stability, the distribution and structure of intertidal-supratidal wetlands is known to respond to changes imposed by geomorphic evolution, climatic, sea level and anthropogenic influences. In this study, we reconstruct environmental histories and biogeochemical conditions in four wetlands of similar contemporary vegetation in SE Australia. The objective is to assess the importance of historic factors to contemporary organic carbon (C) stocks and accumulation rates. Results from the four cores – two collected from marine influenced saltmarshes (WAP-M and POR-M) and two from fluvial influenced saltmarshes (WAP-F and POR-F) – highlight different environmental histories and preservation conditions. High C stocks are associated with the presence of a mangrove phase below the contemporary saltmarsh sediments in the POR-M an...包括盐沼（saltmarshes）与红树林（mangrove forests）在内的海岸生境，可积累并储存大量蓝碳（blue carbon）储量，且此类碳储量可留存数千年之久。尽管这类生境看似具备稳定性，但已有研究证实，潮间带-潮上带湿地（intertidal-supratidal wetlands）的分布与结构会响应地貌演化、气候变化、海平面变动以及人为活动带来的扰动。本研究针对澳大利亚东南部（SE Australia）4处现代植被类型相近的湿地，重建了其环境演化历史与生物地球化学（biogeochemical）条件。本研究的核心目标为评估历史成因因素对现代有机碳（C）储量及累积速率的影响程度。对4处岩芯（cores）的分析结果显示出迥异的环境演化历史与沉积保存条件：其中2处岩芯采自海洋影响型盐沼（marine influenced saltmarshes）WAP-M与POR-M，另外2处采自河流影响型盐沼（fluvial influenced saltmarshes）WAP-F与POR-F。高有机碳储量与POR-M站位现代盐沼沉积物下方存在的红树林阶段密切相关，而……