Photoautotrophic marine ecosystems can lock up organic carbon in their biomass and the associated organic sediments they trap over millennia and are thus regarded as blue carbon ecosystems. Because of the ability of marine ecosystems to lock up organic carbon for millennia, blue carbon is receiving much attention within the United Nations' 2030 Agenda for Sustainable Development as a nature‐based solution (NBS) to climate change, but classically still focuses on seagrass meadows, mangrove forests, and tidal marshes. However, other coastal ecosystems could also be important for blue carbon storage, but remain largely neglected in both carbon cycling budgets and NBS strategic planning. Using a meta‐analysis of 253 research publications, we identify other coastal ecosystems—including mud flats, fjords, coralline algal (rhodolith) beds, and some components or coral reef systems—with a strong capacity to act as blue carbon sinks in certain situations. Features that promote blue carbon burial within these ‘non‐classical’ blue carbon ecosystems included: (1) balancing of carbon release by calcification via carbon uptake at the individual and ecosystem levels; (2) high rates of allochthonous organic carbon supply because of high particle trapping capacity; (3) high rates of carbon preservation and low remineralization rates; and (4) location in depositional environments. Some of these features are context‐dependent, meaning that these ecosystems were blue carbon sinks in some locations, but not others. Therefore, we provide a universal framework that can evaluate the likelihood of a given ecosystem to behave as a blue carbon sink for a given context. Overall, this paper seeks to encourage consideration of non‐classical blue carbon ecosystems within NBS strategies, allowing more complete blue carbon accounting.

中文翻译：

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是时候扩大我们所认为的“蓝碳生态系统”了

光自养海洋生态系统可以将有机碳锁在其生物量和相关的有机沉积物中数千年，因此被视为蓝碳生态系统。由于海洋生态系统能够锁定有机碳数千年，蓝碳作为气候变化的基于自然的解决方案 (NBS) 在联合国 2030 年可持续发展议程中受到广泛关注，但传统上仍然关注海草草地、红树林和潮汐沼泽。然而，其他沿海生态系统对于蓝碳储存也可能很重要，但在碳循环预算和国家统计局战略规划中仍然很大程度上被忽视。通过对 253 份研究出版物的荟萃分析，我们确定了其他沿海生态系统，包括泥滩、峡湾、珊瑚藻（红石）床以及珊瑚礁系统的一些组成部分，在某些情况下具有强大的蓝色碳汇能力。在这些“非经典”蓝碳生态系统中促进蓝碳埋藏的特征包括：（1）通过个体和生态系统层面的碳吸收来平衡钙化所释放的碳； (2) 由于颗粒捕集能力高，因此外来有机碳供应率高； (3)碳保存率高，再矿化率低； (4)沉积环境中的位置。其中一些特征是与环境相关的，这意味着这些生态系统在某些地方是蓝色碳汇，但在其他地方则不然。因此，我们提供了一个通用框架，可以评估给定生态系统在给定环境下充当蓝色碳汇的可能性。总体而言，本文旨在鼓励在国家统计局战略中考虑非经典蓝碳生态系统，从而实现更完整的蓝碳核算。