Seagrass ecosystems are globally-significant ‘blue carbon’ sinks; however, there is concern that this capacity will decline if rising ocean temperatures accelerate microbial decomposition. Decomposition of plant litter is a key process in the global carbon cycle—it influences how much carbon is available for sequestration. Therefore, understanding the biogeochemistry underlying decomposition is essential to predicting the capacity of seagrass ecosystems to act as carbon sinks in the future. Here, we tracked the breakdown of standardised and natural litter of varying chemical recalcitrance (rooibos tea > seagrass leaves > green tea) combined with highly-sensitive microsensor technology to test (a) how elevated water temperatures affect short-term microbial turnover, and (b) provide novel information on how the decay dynamics of the tea litter compare to those of natural litter. We found that increased temperatures (+ 5–10 °C) boosted microbial activity for all substrates, exhibited as enhanced decay, oxygen consumption and sulphate reduction. Within the 1-month experiment, the green tea litter had a rapid Q10 response to the temperature increase, quickly exhausting the resources for microbes, while the response of the rooibos tea and seagrass litters became more apparent toward the end of the experiment. Our results suggest that the tea litters capture a range of decomposition traits and can be compared with natural litter using traditional exponential decay models. The enhanced temperature-driven organic matter turnover, even under anoxic conditions, highlights the vulnerability of fresh litter to microbial attack during the early stages of decay and the potential weakening of blue carbon accumulation rates under future climatic conditions.

中文翻译：

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升高温度对海草叶和茶凋落物生物量微生物分解的影响

海草生态系统是具有全球意义的“蓝碳”汇；然而，有人担心，如果海洋温度上升加速微生物分解，这种能力将会下降。植物凋落物的分解是全球碳循环中的一个关键过程——它会影响可用于封存的碳量。因此，了解分解背后的生物地球化学对于预测未来海草生态系统作为碳汇的能力至关重要。在这里，我们跟踪了具有不同化学反抗性（路易波士茶 > 海草叶 > 绿茶）的标准化和自然垃圾的分解情况，并结合高度敏感的微传感器技术来测试 (a) 水温升高如何影响短期微生物更新，(b) 提供关于茶垫的衰减动力学与天然垫料的衰减动力学相比如何的新信息。我们发现升高的温度（+ 5–10 °C）会提高所有底物的微生物活性，表现为腐烂、耗氧量和硫酸盐还原度增加。在为期 1 个月的实验中，绿茶垃圾对温度升高有快速的 Q10 响应，迅速耗尽微生物资源，而路易波士茶和海草垃圾的响应在实验结束时变得更加明显。我们的结果表明，茶垫具有一系列分解特征，可以使用传统的指数衰减模型与天然垫进行比较。即使在缺氧条件下，增强的温度驱动的有机物周转率，