Annual Net Community Production of Particulate and Dissolved Organic Carbon From a Decade of Biogeochemical Profiling Float Observations in the Northeast Pacific
Annual Net Community Production of Particulate and Dissolved Organic Carbon From a Decade of Biogeochemical Profiling Float Observations in the Northeast Pacific
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DOI：
10.1029/2020gb006599
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发表时间：
2020-10-01
影响因子：
5.2
通讯作者：
Plant, J. N.
中科院分区：
文献类型：
--
作者：
Haskell, W. Z., II;Fassbender, A. J.;Plant, J. N.
通过生物泵从海洋表面输出的碳是大气二氧化碳的关键汇。这一过程通过颗粒有机碳（POC）的下沉以及悬浮有机碳和溶解有机碳（DOC）的向下输送将有机碳输送到深海。每种途径的相对贡献的变化可以显著影响碳输出到深度的幅度和效率。净群落生产量（NCP）是稳态假设下碳输出的一种模拟，通常使用船上或自主平台观测约束的上层海洋生物重要化学示踪剂的预算来估计。在这项研究中，我们使用测量从地球化学剖面浮标，海洋站Papa系泊，和最近开发的算法碳酸盐系统参数约束预算的三个示踪剂（硝酸盐，溶解无机碳，总碱度）和估计NCP在东北太平洋从2009年到2017年。使用我们的多示踪剂的方法，并限制端员营养比的POC和DOC的生产，我们不仅计算区域NCP在整个年度周期和跨多个深度的视野，但也分区这个数量到颗粒和溶解部分。我们还使用了粒子后向散射为基础的方法来估计POC衰减与深度，并提出了一种新的方法来约束粒子出口更深的视野和估计原位出口效率。我们的研究结果与以前发表的区域每年碳输出的估计值吻合得很好，并表明这里提出的方法可以用于评估世界其他海洋区域碳输出的规模和效率。简明语言摘要“碳输出”是指海洋表层生物从大气中去除并随后输送到深海的二氧化碳的量，无论是通过下沉颗粒（效率更高的过程）还是向下混合（效率较低的过程），使海洋成为大气二氧化碳的天然汇，并对海洋化学产生重大影响。通过每种途径出口的相对比例显著影响这一过程的总体效率，并对全球碳出口模式产生影响。传统上，测量全年的碳排放量需要持续的船基观测，这对研究人员来说既昂贵又危险。相反，碳输出通常通过预算营养分布和随时间的变化来估计，因为它们也受到相同过程的控制。这些测量现在可以使用自主地球化学剖面浮标远程进行。在这里，我们提出了一种新的方法，利用多个化学预算，估计碳输出超过十年的东北太平洋，它可以结合到分区出口发生通过下沉颗粒和向下混合。我们的研究结果得到了先前发表的碳输出估计的支持，并表明这种方法有可能应用于海洋的其他部分。
Carbon export out of the surface ocean via the biological pump is a critical sink for atmospheric carbon dioxide. This process transports organic carbon to the deep ocean through sinking particulate organic carbon (POC) and the downward transport of suspended POC and dissolved organic carbon (DOC). Changes in the relative contribution of each pathway can significantly affect the magnitude and efficiency of carbon export to depth. Net community production (NCP), an analog of carbon export under steady state assumptions, is typically estimated using budgets of biologically important chemical tracers in the upper ocean constrained by ship-board or autonomous platform observations. In this study, we use measurements from biogeochemical profiling floats, the Ocean Station Papa mooring, and recently developed algorithms for carbonate system parameters to constrain budgets for three tracers (nitrate, dissolved inorganic carbon, and total alkalinity) and estimate NCP in the Northeast Pacific from 2009 to 2017. Using our multiple-tracer approach, and constraining end-member nutrient ratios of the POC and DOC produced, we not only calculate regional NCP throughout the annual cycle and across multiple depth horizons, but also partition this quantity into particulate and dissolved portions. We also use a particle backscatter-based approach to estimate POC attenuation with depth and present a new method to constrain particle export across deeper horizons and estimate in situ export efficiency. Our results agree well with previously published estimates of regional carbon export annually and suggest that the approaches presented here could be used to assess the magnitude and efficiency of carbon export in other regions of the world's oceans.Plain Language Summary "Carbon export" refers to the amount of carbon dioxide that is removed from the atmosphere by organisms in the surface ocean and subsequently transported into the deep sea, either through sinking particles (more efficient process) or downward mixing (less efficient process), making the ocean a natural sink for atmospheric carbon dioxide and significantly influencing ocean chemistry. The relative proportion of export through each pathway significantly affects the overall efficiency of this process and has implications for the pattern of carbon export globally. Measuring carbon export throughout the year traditionally requires persistent ship-based observations, which can be costly and perilous for researchers. Instead, carbon export is often estimated by budgeting nutrient distributions and changes through time, as they are also controlled by the same processes. These measurements can now be made remotely using autonomous biogeochemical profiling floats. Here, we present a new approach utilizing multiple chemical budgets to estimate carbon export over a decade in the Northeast Pacific, which can be combined to partition export occurring through sinking particles and downward mixing. Our results are supported by previously published estimates of carbon export and suggest that this method has the potential to be applied to other parts of the ocean.