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长时间尺度的沉积记录可以提升对近岸低氧形成机制的理解,从而为预报、预测和发展减缓低氧措施等提供必要的依据。综述了近岸低氧发育与演化历史的主要研究进展,尤其侧重于沉积记录的研究。首先按水体受限程度将近岸低氧发育环境划分为半封闭型海盆/海湾和开阔陆架海2类,分别探讨了二者低氧发育的主要特征。其次分析总结了低氧沉积记录的替代性指标,包括对水体氧化还原环境具有较好指示意义的生物学、矿物学和地球化学指标,着重分析了各类替代性指标的适用性。最后对长江口外海域底层水体低氧发生机制与沉积记录的研究现状作了回顾与分析。目前长时间尺度的低氧沉积记录研究仍然较少,鉴于长江口外海域低氧的动态发育特征,提出了多钻孔、多参数结合的研究方案。
Sedimentary records on long time scales can enhance the understanding of the formation mechanism of near-shore hypoxia, so as to provide the necessary basis for forecasting, forecasting and developing measures to reduce hypoxia. The main research progresses on the development and evolution history of nearshore hypoxia are summarized, with particular emphasis on the study of sedimentary records. First, according to the limited degree of water body, the near-shore hypoxia development environment is divided into two types: semi-enclosed basin / bay and open shelf sea, and the main characteristics of hypoxia development are discussed respectively. Secondly, the paper summarizes the alternative indexes of low oxygen sedimentary records, including the biological, mineralogical and geochemical indicators that have a good indication of the redox environment of water body, and emphatically analyzes the applicability of various kinds of alternative indicators. Finally, the research status of hypoxia mechanism and sedimentary record in the bottom water of the Changjiang Estuary was reviewed and analyzed. At present, there are still few studies on the record of hypoxia sediments on long time scales. In view of the dynamic characteristics of hypoxia in the waters off the Changjiang Estuary, a multi-parameter and multi-borehole combination scheme is proposed.