Inorganic geochemistry of Bering Sea sediments

2009年，综合大洋钻探计划（IODP）的第323远征队从白令海恢复了第一个连续的沉积物岩心，可追溯到500万年前。独特的IODP核心材料具有相当大的潜力，可以解开白令海的环境和气候历史。白令海是一个大型的，但开发不足的天然实验室，研究气候相关的地球化学元素循环的发展，在一个高生产力的半限制上升流系统的冰川-间冰期的时间尺度。此外，白令海具有全球意义，因为（a）它具有大气CO2序列形成的潜力，并在很长一段时间内作为有机物埋藏在海底，（B）由于低氧高营养冰川水向北太平洋的输出，以及对世界上最大的海洋盆地的生产力、分层和碳埋藏的相关影响。我们的主要目标是破译生物地球化学动力学和耦合，几乎没有在白令海和全球范围内的研究，但可能是重要的大气-海洋CO2交换，从而对冰川-间冰期时间尺度上的气候动力学：初级生产力之间的反馈，中，深氧化还原条件，和沉积物中的营养物质再循环。我们将重点研究白令海环境状况的两个代表性站点的沉积物，即开阔海洋站点U1341和大陆坡站点U1343。我们将构建无机地球化学沉积物记录（Ba，Fe，P，氧化还原敏感的微量金属），以追踪过去2-5百万年的营养，生产力和海洋氧化还原变化，同时也量化影响主要环境信号的成岩过程。为了在更全球范围内评估上新世-更新世地球化学动力学和相互作用的影响，我们将把我们在白令海的记录与北太平洋（例如ODP 145航次）公布的数据和解释进行比较。

In 2009, Expedition 323 of the Integrated Ocean Drilling Program (IODP) recovered the first continuous sediment cores from the Bering Sea extending back 5 Million years. The unique IODP core material has considerable potential to unlock the environmental and climatic history of the Bering Sea. The Bering Sea is a large, yet poorly explored natural laboratory to study the development of climate-relevant biogeochemical element cycles in a high-productivity semi-restricted upwelling system on glacial-interglacial time scales. Moreover, the Bering Sea is of global relevance (a) due to its potential for atmospheric CO2 sequentation and its burial in the sea floor as organic matter over long time scales, and (b) due to the export of low-oxygen high-nutrient glacial water to the North Pacific and related effects on productivity, stratification, and carbon burial in the world´s largest ocean basin. Our main goal is to decipher biogeochemical dynamics and coupling that have hardly been studied both in the Bering Sea and globally so far, but may be of importance for atmosphere- ocean CO2 exchange and thus for climate dynamics on glacial-interglacial time scales: The feedbacks between primary productivity, middle and deep redox conditions, and nutrient recycling from the sediment. We will focus on sediments from two sites representative for the environmental regimes of the Bering Sea, namely open marine Site U1341, and Site U1343 at the continental slope. We will construct inorganic geochemical sediment records (Ba, Fe, P, redox-sensitive trace metals) to trace nutrient, productivity and ocean redox variations over the past 2-5 million years, but also to quantify diagenetic processes that affected primary environmental signals. To evaluate the effects of Pliocene- Pleistocene biogeochemical dynamics and interactions on a more global scale, we will compare our records from the Bering Sea to published data and interpretations from the North Pacific (e.g. ODP Leg 145).