Characterizing a refractory DOC sink in the deep northern North Pacific

长期以来，海洋中的难溶有机碳(RDoC)一直被认为是高度抵抗去除的。它在海洋中的平均寿命为数千年，因此通常被认为是一个顽固的水池，主要通过热盐环流保守地输送。但与今天海洋中的RDoC不同，这个巨大的水库被古海洋学研究认为是与过去气候变化有关的相对快速周转的碳源/碳汇。因此，古代海洋中的RDoC水库有时肯定比今天大得多，而且这个巨大的水库必须被迅速动员起来，将其碳释放到大气中。为了了解RDoC在过去或未来海洋中的潜在作用，显然有必要了解RDoC源和汇过程在现代海洋中的运作方式。在这个项目中，迈阿密大学罗森斯蒂尔海洋和大气科学学院的一名研究人员希望填补RDoC与气候联系方面的知识空白。由于在过去几年中才完成了对其全球分布的测绘，因此几乎没有关于控制RDoC池的进程的确凿事实。一个特别重要的RDoC下沉位于北太平洋北部。PI认为，从南大洋到远北的底层水域携带的RDOC是保守的，但一旦进入太平洋深水地层附近，碳就会相当突然地损失。他在这个项目中的直接目标是描述北太平洋的RDOC沉没的特征，这一目标是了解海洋RDOC在全球气候中的作用的更大目标的一部分。更广泛的影响：对现代海洋碳循环的拟议研究将使我们对海洋DOC在地球过去和未来气候中的作用有新的见解。这项研究的主题也与首席研究员目前在帮助实施新的美国碳循环科学计划方面的领导责任密切相关。

Refractory dissolved organic carbon (RDOC) in the ocean has long been recognized as highly resistant to removal. It has a mean lifetime in the ocean of thousands of years, so it is generally thought of as a recalcitrant pool that is transported mostly conservatively with the thermohaline circulation. But unlike RDOC in the present-day ocean, this vast reservoir has been implicated by paleoceanographic research as a relatively rapid-turnover carbon source/sink involved in past climate changes. Accordingly, the RDOC reservoir in ancient oceans must at times have been much larger than today, and that large reservoir must have been rapidly mobilized to release its carbon to the atmosphere. There is a clear need to understand how RDOC source and sink processes operate in the modern ocean in order to understand its potential role in past or future oceans.In this project, a researcher at the Rosenstiel School of Marine and Atmospheric Science of the University of Miami hopes to fill knowledge gaps in the RDOC-climate connection. Inasmuch as mapping of its global distribution was accomplished only within the past few years, few solid facts about processes controlling the RDOC pool have been established. One particularly important RDOC sink is in the northern North Pacific. The PI believes that RDOC carried in bottom waters from the Southern Ocean to the far north is conserved, but once in the vicinity of Pacific Deep Water formation there is a rather abrupt loss of carbon. His immediate goal in this project is to characterize the RDOC sink in the North Pacific, an objective that is one part of the larger goal of understanding the role of ocean RDOC in global climate.Broader Impacts: The proposed studies of the modern ocean carbon cycle will give us new insights on the role of marine DOC in Earth's past and future climates. The topic of this research is also closely related to the principal investigator's current leadership responsibilities in helping to implement the new U.S. Carbon Cycle Science Plan.