DataSheet_1_Early diagenesis and benthic fluxes of redox-sensitive metals in eastern China shelf sediments.pdf

Thirteen Short sediment cores (30-50 cm) were collected from Bohai Sea, Yellow Sea and Changjiang Estuary in China, and the early diagenesis of several redox sensitive metals (Fe, Mn, Mo, U and V, referring to as RSMs) in sediment were studied. The recycling process of Mo and Mn was closely correlated with each other, generating benthic fluxes diffusing upward from sediment to overlying water column, and the flux rates are related to the organic carbon oxidation rates. The recycling of U and V were more tightly coupled with Fe oxides, generating benthic fluxes going downward into the sediment in most cores. Significant authigenic accumulation of U, in contrary to little to no accumulation of Mo and V, were found in the study region, even in Changjiang Estuary where hypoxic condition was often found during summer. Benthic diffusive fluxes were compared with authigenic mass accumulate rates (MAR), which indicated that, besides the benthic diffusion process, there are other processes controlling the authigenic accumulation of the RSMs. The close relationships between authigenic accumulation of RSMs with OCburial and OCburial with Sburial, indicating the authigenic accumulation of RSMs is a consequence of redox environment in shelf sediment, which directly influencing the organic carbon degradation process. Compared with other continental margin, moderate enrichment of U was found in China continental sediment. The authigenic U accumulation in BS and NYS sediments accounted for 20 - 68% of the Yellow River input, whilst in SYS sediments accounted for ~ 64% of the Yellow River and Changjiang River input, which acting as important U sinks that cannot be ignored.

在中国渤海、黄海及长江口收集了十三组短沉积岩心（30-50厘米），对其中的多种氧化还原敏感金属（Fe、Mn、Mo、U和V，统称为RSMs）的早期成岩作用进行了研究。Mo和Mn的循环过程紧密相关，产生自底向上扩散至上覆水柱的底栖通量，而通量速率与有机碳氧化速率相关。U和V的循环与铁氧化物更为紧密地耦合，在大多数岩心中产生向沉积物中下行的底栖通量。研究发现，U的成岩积累显著，与Mo和V的微弱或无积累形成鲜明对比，即使在夏季常出现缺氧条件的长江口区域。底栖扩散通量与成岩质量积累率（MAR）进行了比较，这表明除了底栖扩散过程外，还有其他过程控制着RSMs的成岩积累。RSMs的成岩积累与有机碳埋藏（OCburial）以及OCburial与Sburial之间的密切关系表明，RSMs的成岩积累是 shelf 沉积氧化还原环境的结果，该环境直接影响了有机碳降解过程。与其他大陆边缘相比，中国大陆沉积物中U的富集程度适中。在渤海和北黄海沉积物中，成岩U积累量占黄河输入量的20%-68%，而在苏北沉积物中，该比例约为黄河和长江输入量的64%，这使其成为不可忽视的重要U汇。