Collaborative Researchl: A Quantitative Assessment of Mineral Ballasts in Carbon Export and Remineralization

ABSTRACTOCE-0136370 / OCE-0136387 / OCE-0136318下沉颗粒物是将碳从海面输出到海洋内部的主要载体。在向海底迁移的过程中，大多数颗粒有机碳 (POC) 会返回到无机形式并重新分布在水体中。这种重新分布决定了溶解二氧化碳的表面浓度，从而决定了海洋从大气中吸收二氧化碳的速率。因此，定量预测再矿化深度剖面的能力对于预测全球碳循环对环境变化的响应至关重要。 在这项研究中，纽约州立大学石溪分校、华盛顿大学和斯基德威海洋学研究所的研究人员将与摩纳哥和法国的同事合作，检验生物体产生的矿物质或通过风引入表层海洋的矿物质对向深海和沉积物的碳输出产生严重影响的假设。 他们将采用多示踪剂方法来明确考虑不同的矿物“压载物”类型，以及相关的有机物和放射性同位素。 他们的第一个假设是，压载矿物从物理上保护了与其相关的总有机物的一部分，该有机物在水柱下部（1000 m）中仍然占主导地位，而不是未受保护的部分。了解此类过程的机制基础需要了解特定化合物水平上的有机矿物相互作用。 其次，他们假设有机碳与压载物的比率是预测使用放射性示踪剂估计的有机碳出口通量和下沉速度变化的关键。 总体目标是对整个水体的碳通量和相关矿物压载通量进行无缝描述。为了实现这一目标，研究小组将同时测量一系列被认为可以指示通量的特性。 他们将使用各种建模和统计技术综合从水柱顶部到沉积物的这些测量结果。 该战略旨在整合多个学科的力量：（i）有机地球化学，用于表征受保护和未受保护形式的有机物并确定其降解状态； (ii) 放射化学，用于评估粒子动力学和传输所涉及的过程和时间尺度； (iii) 浮游动物生态学，用于评估放射性同位素分配和有机生物标志物改变； (iv) 微生物学在有机物分解中的作用，以及 (v) 建模和统计分析，以提供从富光区到海底的通量的基于过程的模型。

ABSTRACTOCE-0136370 / OCE-0136387 / OCE-0136318Sinking particulate matter is the major vehicle for exporting carbon from the sea surface to the ocean interior. During its transit towards the sea floor, most particulate organic carbon (POC) is returned to inorganic form and redistributed in the water column. This redistribution determines the surface concentration of dissolved CO2 , and hence the rate at which the ocean can absorb CO2 from the atmosphere. The ability to predict quantitatively the depth profile of remineralization is therefore critical to predicting the response of the global carbon cycle to environmental change. In this study, researchers at the State University of New York at Stony Brook, the University of Washington, and the Skidaway Institute of Oceanography will collaborate with colleagues in Monaco and France to test the hypothesis that minerals produced by organisms, or introduced into the surface ocean by winds, critically influence carbon export to the deep ocean and sediments. They will carry out a multi-tracer approach to explicitly consider different mineral "ballast" types, along with the associated organic matter and radioisotopes. Their first hypothesis is that ballast minerals physically protect a fraction of their associated total organic matter, which persists to predominate over the unprotected fraction in the lower (1000 m) part of the water column. Understanding the mechanistic basis of such processes will require an understanding of organic-mineral interaction at the compound-specific level. They hypothesize secondly that the ratio of organic carbon to ballast is key to predicting variability in the export fluxes and sinking velocities of organic carbon as estimated using radiotracers. The overall goal is to develop a seamless description of carbon fluxes and associated mineral ballast fluxes throughout the water column. To achieve this goal, the research team will measure simultaneously a suite of properties that are thought to be indicative of fluxes. They will synthesize these measurements from the top of the water column to the sediments using a variety of modeling and statistical techniques. The strategy is to unite the power of several disciplines: (i) organic geochemistry for characterizing organic matter in protected and unprotected forms and determining its degradation state; (ii) radiochemistry for assessing processes and time-scales involved in particle dynamics and transport; (iii) zooplankton ecology for assessing radioisotope partitioning and organic biomarker alteration; and (iv) microbiology for its role in organic matter decomposition, and (v) modeling and statistical analyses to provide a process-based model of flux out of the euphotic zone to the sea floor.