The Biological Pump in the Eastern Equatorial Pacific: in situ measurements of Oxygen and Nitrate

在阳光照射下的世界海洋表面沃茨，浮游植物将联合收割机的营养物质和二氧化碳结合，形成有机物并释放氧气。这些地表水生物产物中的一部分最终进入深海，导致碳从地表海洋和大气中净移除。一种估算这种向深海输出的碳的方法，也被称为“生物泵”，是通过仔细测量与有机物质一起产生的沿着的氧气量。溶解在海水中的氧气可以通过传感器非常精确地测量，这些传感器可以在诸如系泊设备、浮子或滑翔机等仪器平台上一次部署数年。在这个项目中，一个研究小组将在赤道太平洋部署12个浮标，以测量海洋的温度、盐度、氧气和硝酸盐（浮游植物的营养物质）。这些数据将通过卫星传输，并与海洋环流的计算机模型联合收割机结合，以了解海洋这一生产区的生物泵。该项目将支持两名早期职业研究人员：一名研究生和一名博士后研究员，该项目将把在专门装备的剖面浮标上现场测量氧气和硝酸盐与使用高分辨率全球环流模型（GCM）解释数据相结合。该计划将建造12个Argo浮标，专门安装Aanderaa Optode氧气传感器和ISUS硝酸盐传感器，并将其部署在北纬8度至南纬8度之间，西经95度至西经140度之间的区域;在基于卫星和基于GCM的全球碳出口地图中，碳出口量最大的位置。这些数据将被解释在净生物氧生产，这是化学计量相关的年度净群落生产（ANCP）和年度有机碳出口，使用区域海洋模型系统（ROMS）物理传输模型与生物地球化学元素循环（BEC）-类生态系统。美国国家科学基金会先前的研究表明，当浮标浮出水面向海岸传输数据时，通过校准浮标上的氧传感器与大气中的氧，可以使用剖面浮标上的氧传感器确定海-气pO 2差，精确度为± 0.2%。由于海气通量和净生物生产力通常是上层海洋氧气质量平衡的主导项，因此可以使用一维上层海洋模式确定亚北极和亚热带环流位置的ANCP。该项目的目标是确定强平流赤道区域的ANCP，并将其与迄今尚未经过观测测试的基于卫星和基于大气环流模型的方法确定的碳输出值进行比较。

In the sunlit surface waters of the world's oceans, phytoplankton combine nutrients and carbon dioxide to form organic matter and release oxygen. Some of this surface water biological production ends up in the deep ocean, resulting in a net removal of carbon from the surface ocean and atmosphere. One way to estimate this export of carbon to the deep ocean, also called the "biological pump," is by carefully measuring the amount of oxygen that is produced along with the organic matter. Oxygen dissolved in seawater can be measured very precisely by sensors that can be deployed for years at a time on instrument platforms like moorings, floats, or gliders. In this project, a team of investigators will deploy twelve floats in the equatorial Pacific Ocean to measure ocean profiles of temperature, salinity, oxygen, and nitrate (a nutrient for phytoplankton). The data will be transmitted by satellite and combine with computer models of ocean circulation to understand the biological pump in this productive area of the ocean. The project will support two early-career researchers: a graduate student and a postdoctoral research fellow.The project will be a combination of in situ measurements of oxygen and nitrate on specially-equipped profiling floats with data interpretation using a high-resolution Global Circulation Model (GCM). The plan is to construct 12 Argo floats with specially-mounted Aanderaa Optode oxygen sensors and ISUS nitrate sensors, and to deploy them in the region between 8 degrees N and 8 degrees S from about 95 degrees W to 140 degrees W; the location where carbon export is greatest in both satellite-based and GCM-based maps of global carbon export. The data will be interpreted in terms of net biological oxygen production, which is stoichiometrically related to Annual Net Community Production (ANCP) and annual organic carbon export, using a Regional Ocean Model System (ROMS) physical transport model with a Biogeochemical Elemental Cycling (BEC)-like ecosystem. Previous NSF research has shown that it is possible to determine the air-sea pO2 difference using oxygen sensors on profiling floats to an accuracy of plus or minus 0.2 % by calibrating the sensors against atmospheric oxygen when the floats surface to transmit data to shore. Since the air-sea flux and net biological production are usually the dominant terms in the upper ocean oxygen mass balance, it has been possible to determine ANCP in subarctic and subtropical gyre locations using a one-dimensional, upper-ocean model. The goal in this project is to determine the ANCP in the strongly advective equatorial region, and compare it to carbon export values determined from satellite-based and GCM-based methods that so far have not been tested with observations.