The ocean–atmosphere exchange of carbon largely depends on the balance between carbon export of particulate organic carbon (POC) as sinking marine particles, and POC remineralization by attached microbial communities. Despite the vast spectrum of types, sources, ages, shapes, and composition of individual sinking particles, they are usually considered as a bulk together with their associated microbial communities. This limits our mechanistic understanding of the biological carbon pump (BCP) and its feedback on the global carbon cycle. We established a method to sample individual particles while preserving their shape, structure, and nucleic acids by placing a jellified RNA-fixative at the bottom of drifting sediment traps. Coupling imaging of individual particles with associated 16S rRNA analysis reveals that active bacterial communities are highly heterogenous from one particles origin to another. In contrast to lab-made particles, we found that complex in situ conditions lead to heterogeneity even within the same particle type. Our new method allows to associate patterns of active prokaryotic and functional diversity to particle features, enabling the detection of potential remineralization niches. This new approach will therefore improve our understanding of the BCP and numerical representation in the context of a rapidly changing ocean.

中文翻译：

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一种对单个海洋雪颗粒进行采样以进行下游分子分析的新方法

海洋-大气碳交换很大程度上取决于沉降海洋颗粒的颗粒有机碳（POC）的碳输出与附着微生物群落的 POC 再矿化之间的平衡。尽管单个下沉颗粒的类型、来源、年龄、形状和成分多种多样，但它们通常与相关的微生物群落一起被视为一个整体。这限制了我们对生物碳泵（BCP）及其对全球碳循环的反馈的机制理解。我们建立了一种方法，通过将胶状 RNA 固定剂放置在漂流沉积物陷阱的底部，对单个颗粒进行采样，同时保留其形状、结构和核酸。单个颗粒的耦合成像与相关 16S rRNA 分析表明，活性细菌群落从一个颗粒来源到另一个颗粒来源具有高度异质性。与实验室制造的颗粒相比，我们发现即使在相同的颗粒类型内，复杂的原位条件也会导致异质性。我们的新方法允许将活性原核生物和功能多样性的模式与颗粒特征相关联，从而能够检测潜在的再矿化生态位。因此，这种新方法将提高我们对快速变化的海洋背景下的 BCP 和数值表示的理解。