VERtical Transport in the Global Ocean (VERTIGO)

在这项研究中，伍兹霍尔海洋研究所、弗吉尼亚海洋科学研究所、加州大学圣克鲁兹分校、加州大学圣巴巴拉分校、塔斯马尼亚大学和niwa澳大利亚分校的研究人员将共同努力，回答海洋生物地球化学中的一个难题：是什么控制了表层和深海之间粒子传输的效率？更具体地说，离开上层海洋的下沉颗粒的命运是什么？不同下沉颗粒类别的再矿化长度尺度受到哪些因素的影响？了解粒子传输的效率对于准确评估海洋碳汇非常重要。在全球范围内，生物泵的规模和效率将在一定程度上调节大气中的二氧化碳水平。研究小组拟验证关于再矿化控制的两个基本假设，即：(1)颗粒源特征是颗粒输运效率的主要控制因素；和/或(2)浮游动物或细菌的中水处理控制了运输效率。为此，他们将在海上进行过程研究，重点关注海洋上层500-1000米的颗粒通量和成分变化。基本方法是使用多种方法（其中许多是该领域的新方法）来检查给定源区域内粒子组成和通量随深度的变化。这些包括中性浮力沉积物捕集器、颗粒泵、沉降柱和呼吸室，以及用于对生物泵进行综合生物地球化学评估的新生物和地球化学工具的开发。在为期三周的过程研究巡航中，将对两个地点进行广泛研究：夏威夷海洋时间序列地点（HOT）和西北太平洋亚北极地区的一个新的系泊时间序列地点（日本地点K2； 47oN 160oE）。这些地点在产量、出口量、颗粒组成和预期再矿化长度尺度方面有很大的差别。关于下沉粒子通量与深度关系的可变性的证据没有争议，但是对通过模糊带的粒子输运效率的控制仍然知之甚少。由于缺乏可靠的通量和粒子表征数据，这阻碍了我们在这一领域取得进展的能力，而且没有单一的方法可能解决这些问题。拟议的研究将应用定量建模来确定单个粒子过程对碳和其他元素有效运输的净影响，并将船上观测结果置于这些过程的时空变化背景下。除了对海洋和行星碳循环研究的明显贡献外，该项目还将产生更广泛的结果和影响。研究生和本科生将参与研究的各个方面，非美国pi的参与将鼓励不同国家实验室之间的学生和博士后交换。此外，各组成小组将继续维护为公共和科学交流而设计的科学网站，以便传播这项工作的更广泛和具体的目标和成果。本项目由美国国家科学基金会化学海洋学和生物海洋学项目共同支持。

In this study, researchers at the Woods Hole Oceanographic Institution, Virginia Institute of Marine Science, University of California - Santa Cruz, University of California - Santa Barbara, University of Tasmania, and NIWA-Australia will work collaboratively to answer a difficult question in marine biogeochemistry: What controls the efficiency of particle transport between the surface and deep ocean? More specifically, what is the fate of sinking particles leaving the upper ocean and what factors influence remineralization length scales for different sinking particle classes? Knowing the efficiency of particle transport is important for an accurate assessment of the ocean carbon sink. Globally, the magnitude and efficiency of the biological pump will in part modulate levels of atmospheric carbon dioxide.The research team intends to test two basic hypotheses about remineralization control, namely: (1) particle source characteristics are the dominant control on the efficiency of particle transport; and/or that (2) mid-water processing, either by zooplankton or bacteria, controls transport efficiency. To do so, they will conduct process studies at sea focused on particle flux and composition changes in the upper 500-1000m of the ocean. The basic approach is to examine changes in particle composition and flux with depth within a given source region using a combination of approaches, many of which are new to the field. These include neutrally buoyant sediment traps, particle pumps, settling columns and respiration chambers, along with the development of new biological and geochemical tools for an integrated biogeochemical assessment of the biological pump. Two sites will be studied extensively on three-week process study cruises: the Hawaii Ocean Time-series site (HOT) and a new moored time-series site in the subarctic NW Pacific (Japanese site K2; 47oN 160oE). There are strong contrasts between these sites in rates of production, export, particle composition and expected remineralization length scales. Evidence for variability in the flux vs. depth relationship of sinking particles is not in dispute, but the controls on particle transport efficiency through the twilight zone remain poorly understood. A lack of reliable flux and particle characterization data within the twilight zone has hampered our ability to make progress in this area, and no single approach is likely to resolve these issues. The proposed study will apply quantitative modeling to determine the net effects of the individual particle processes on the effective transport of carbon and other elements and to place the shipboard observations in the context of spatial and temporal variations in these processesBesides the obvious contributions to the study of the oceanic and planetary carbon cycles, there are broader outcomes and impacts forthcoming from this project. Graduate and undergraduate students will be included in all aspects of the research, and the involvement of non-US PIs will encourage exchange of students and post-docs between labs in different countries. In addition, the component groups will continue to maintain science web sites designed for both public and scientific exchange where the broader and specific goals and outcomes of this work can be communicated. This project is supported cooperatively by the NSF Chemical Oceanography and Biological Oceanography Programs.