A combination of elemental analysis, bulk stable isotope analysis (bulk SIA) and compound-specific stable isotope analysis of amino acids (CSIA-AA) was used to assess and monitor carbon (C), nitrogen (N) and sulfur (S) cycling of a mangrove ecosystem that suffered mass dieback of trees in the Gulf of Carpentaria, Australia in 2015–2016, attributed to an extreme drought event. Three field campaigns were conducted 8, 20 and 32 months after the event over a period from 2016 to 2018 to obtain biological time-series data. Invertebrates and associated organic matter including mangroves and sediments from the impacted ecosystem showed enrichment in ¹³C, ¹⁵N and ³⁴S relative to those from an adjacent unimpacted reference ecosystem, likely indicating lower mangrove carbon fixation, lower nitrogen fixation and lower sulfate reduction in the impacted ecosystem. For example, invertebrates representing the feeding types of grazing, leaf feeding and algae feeding were more ¹³C enriched at the impacted site, by 1.7 ‰–4.1 ‰, and these differences did not change over the period from 2016 to 2018. The CSIA-AA data indicated widespread ¹³C enrichment across five essential amino acids and all groups sampled (except filter feeders) within the impacted site. The seedling density increased from 0.2 m⁻² in 2016 to 7.1 m⁻² in 2018 in the impacted forest, suggesting recovery of the vegetation. Recovery of CNS cycling, however, was not evident even after 32 months, suggesting a biogeochemical legacy of the mortality event. Continued monitoring of the post-dieback forest is required to predict the long-term trajectory of ecosystem recovery. This study shows that time-series SIA can track biogeochemical changes over time and evaluate recovery of an impacted ecosystem from an extreme event.

中文翻译：

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稳定的同位素追踪了澳大利亚卡彭塔里亚湾大面积红树林砍伐的生态和生物地球化学遗产

元素分析，本体稳定同位素分析（本体SIA）和氨基酸的化合物特定稳定同位素分析（CSIA-AA）的组合用于评估和监测碳（C），氮（N）和硫（S）循环由于极端干旱事件，2015-2016年澳大利亚卡彭塔里亚湾的红树林生态系统遭受了树木的大量毁灭。在事件发生后的8个，20个和32个月内，从2016年到2018年进行了三个野外运动，以获取生物时间序列数据。无脊椎动物和相关的有机物质（包括红树林和受影响生态系统的沉积物）在¹³ C，¹⁵ N和^34中富集相对于邻近的未受影响参考生态系统中的S而言，S可能表明受影响的生态系统中的红树林碳固着力降低，氮固着力降低和硫酸盐还原能力降低。例如，代表放牧，叶片进食和藻类进食类型的无脊椎动物在受灾地点的富集¹³ C的比例为1.7‰至4.1‰，这些差异在2016年至2018年期间没有变化。CSIA- AA数据表明，受影响部位中五个基本氨基酸和所有采样组（滤嘴除外）的¹³ C富集程度很高。幼苗密度从2016年的0.2 m ^-2增加到7.1 m ^-2于2018年在受影响的森林中，暗示植被已恢复。然而，即使在32个月后，CNS循环仍未恢复，这表明该死亡事件具有生物地球化学遗产。需要持续监测后折返森林，以预测生态系统恢复的长期轨迹。这项研究表明，时间序列SIA可以跟踪生物地球化学随时间的变化，并评估极端事件对受影响生态系统的恢复。