Constraints on Precambrian ocean chemistry are dependent upon sediment geochemistry. However, diagenesis and metamorphism can destroy primary biosignatures, making it difficult to consider biology when interpreting geochemical data. Modern analogues for ancient ecosystems can be useful tools for identifying how sediment geochemistry records an active biosphere. The Middle Island Sinkhole (MIS) in Lake Huron is an analogue for shallow Proterozoic waters due to its low oxygen water chemistry and microbial communities that exhibit diverse metabolic functions at the sediment–water interface. This study uses sediment trace metal contents and microbial abundances in MIS sediments and an oxygenated Lake Huron control site (LH) to infer mechanisms for trace metal burial. The adsorption of trace metals to Mn‐oxyhydroxides is a critical burial pathway for metals in oxic LH sediments, but not for the MIS mat and sediments, consistent with conventional understanding of Mn cycling. Micronutrient trace metals (e.g., Zn) are associated with organic matter regardless of oxygen and sulfide availability. Although U and V are conventionally considered to be organically complexed in suboxic and anoxic conditions, U and organic covary in oxic LH sediments, and Mn‐oxyhydroxide cycling dominates V deposition in the anoxic MIS sediments. Significant correlations between Mo and organic matter across all redox regimes have major implications for our interpretations of Mo isotope systematics in the geologic record. Finally, while microbial groups vary between the sampling locales (e.g., the cyanobacteria in the MIS microbial mat are not present in LH sediments), LH and MIS ultimately have similar relationships between microbial assemblages and metal burial, making it difficult to link trace metal burial to microbial metabolisms. Together, these results indicate that bulk sediment trace metal composition does not capture microbiological processes; more robust trace metal geochemistry such as isotopes and speciation may be critical for understanding the intersections between microbiology and sediment geochemistry.

中文翻译：

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氧化还原敏感的微量金属与元古代海洋类似物中的微生物群落之间的关联。

前寒武纪海洋化学的制约因素取决于沉积物地球化学。但是，成岩作用和变质作用会破坏主要的生物特征，因此在解释地球化学数据时很难考虑生物学。古代生态系统的现代类似物可能是确定沉积物地球化学如何记录活跃生物圈的有用工具。休伦湖的中岛污水池（MIS）是浅元古代水的类似物，因为它的低氧水化学性质和微生物群落在沉积物-水界面处表现出多种代谢功能。这项研究利用MIS沉积物中的沉积物微量金属含量和微生物丰度以及氧化的休伦湖控制点（LH）来推断痕量金属埋葬的机理。Mn-羟基氢氧化物对痕量金属的吸附是有氧LH沉积物中金属的关键埋葬途径，但对于MIS垫层和沉积物而言则并非如此，这与对Mn循环的常规理解一致。微量元素微量金属（例如Zn）与有机物相关，而与氧气和硫化物的可用性无关。尽管通常认为U和V在低氧和缺氧条件下是有机络合物，但在LH含氧沉积物中，U和有机化合物的存在以及Mn-羟基氧化循环主导了MIS缺氧中V的沉积。在所有氧化还原方式下，Mo与有机物之间的显着相关性对我们对地质记录中Mo同位素系统学的解释具有重要意义。最后，虽然微生物组在采样地点之间有所不同（例如，（LH沉积物中不存在MIS微生物垫中的蓝细菌），LH和MIS最终在微生物组合和金属埋葬之间具有相似的关系，因此很难将痕量金属埋藏与微生物代谢联系起来。总之，这些结果表明，大量沉积物中的痕量金属成分无法捕获微生物过程。对于了解微生物学和沉积物地球化学之间的交叉点而言，更强大的痕量金属地球化学（例如同位素和物种形成）可能至关重要。