Constraining Upper-Ocean Carbon Export with Biogeochemical Profiling Floats

化学海洋学的一个目标是促进我们对全球碳循环的理解，特别是量化碳从海洋表面到海洋深处通过海洋生物产生的颗粒下沉的转移。然而，现代全球对这一过程（通常称为碳出口）的估计相差超过100%。这些估计值通常来自海洋测量和卫星观测之间的区域关系，然后应用于全球。在整个海洋中发现，卫星和实地估算的碳排放量之间存在持续的差异，这表明需要改进。这个项目将决定配备化学传感器的剖面浮标是否可以用来估计海洋中的碳输出。浮标将部署在Papa海洋站，但该方法本质上是可扩展的，可用于验证和改进用于全球碳出口确定的卫星算法。该项目将支持一名女性、早期职业科学家和一名博士后，并促进与加拿大科学家的国际合作。此外，研究结果可能有助于美国国家航空航天局（NASA）的出口活动以及其他卫星碳出口开发工作。对生物泵的现代全球估计相差超过100%(~5至12 Pg C -1)，这使得确定海洋生物地球化学（BGC）循环在现代气候和气候变率中的作用具有挑战性。全球碳出口估计通常是根据实地观测和卫星观测之间的区域经验关系得出的，然后在全球范围内应用。独特的卫星算法和独特的地球化学方法之间的持续差异表明，准确量化生物泵仍然是一个基本的研究目标。该项目将评估利用BGC剖面浮标估算不同生物源碳库（溶解有机碳和颗粒有机碳以及颗粒无机碳）出口的能力。通过使用BGC浮标来关闭多个上层海洋示踪剂预算，该项目将解决其他地球化学方法常见的两个已知问题：关于(1)溶解有机碳循环的假设和(2)用于年度碳输出评估的整合深度。该方法将在Papa海洋站进行测试，但本质上是可扩展的，可用于开发一个碳出口数据库，适合于全球碳出口确定所需的卫星算法的验证和培训。浮标的结果将与卫星碳输出算法估计的浮标5年寿命进行比较。从剖面浮标和该地区的系泊中获得的10年现有BGC数据也将用于进一步提供年际变化的背景。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

A goal in chemical oceanography is to advance our understanding of the global carbon cycle, specifically to quantify the transfer of carbon from the surface ocean to depth through the sinking of particles produced by marine organisms. Yet, modern global estimates of this process (commonly called carbon export) differ by over 100%. These estimates are often derived from regional relationships between ocean measurements and satellite observations that are then applied globally. Persistent differences between the satellite and field-based estimates of carbon export have been found throughout the ocean, suggesting that improvements are needed. This project will determine whether profiling floats equipped with chemical sensors can be used to estimate the export of carbon in the ocean. Floats will be deployed at Ocean Station Papa, but the approach is scalable in nature and could be used to validate and improve the satellite algorithms used for global carbon export determinations. The project will support a female, early career scientist and a postdoc, as well as facilitate international collaboration with Canadian scientists. Additionally, the results may assist the National Aeronautics and Space Administration (NASA) EXPORTS campaign as well as other satellite carbon export development efforts. Modern global estimates of the biological pump differ by over 100% (~5 to 12 Pg C yr-1) making it challenging to determine the role of marine biogeochemical (BGC) cycling in modern climate and climate variability. Global carbon export estimates are often derived from regional empirical relationships between field and satellite observations that are then applied globally. Persistent discrepancies between unique satellite algorithms and unique geochemical approaches suggest that accurately quantifying the biological pump remains a fundamental research goal. This project will assess the capability of using BGC profiling floats to estimate the export of distinct biogenic carbon pools (dissolved and particulate organic carbon, and particulate inorganic carbon). By using BGC floats to close multiple upper ocean tracer budgets this project will address two known issues common to other geochemical approaches: assumptions about (1) dissolved organic carbon cycling and (2) the integration depth used for annual carbon export assessments. The method will be tested at Ocean Station Papa, but is scalable in nature and could be used to develop a carbon export database suitable for the validation and training of satellite algorithms required for global carbon export determinations. Results from the floats will be compared to satellite carbon export algorithm estimates over the 5-year float lifetimes. Ten years of existing BGC data from profiling floats and a mooring in the region will also be used to provide further context about interannual variability.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.