A multi-parameter physical-chemical sensor suite on SeaCycler for determining the carbonate system, net community production, and air-sea fluxes

每年净流入海洋的二氧化碳流量有助于缓解气候变化，而氧气和有机碳转移到深海为其庞大的生态系统提供动力。与此相关的同样重要的是净群落生产量(NCP)，因为它代表着生态系统食物链底部的源输入，控制着向深海的垂直碳出口，也对大气-海洋二氧化碳和O2的通量有很大的控制影响。碳和氧在水柱中的转移、它们与大气的交换以及NCP都受到物理和生物过程的控制，这些过程在季节和较短的时间尺度上变化很大，而且年际变化也很大。高纬度的速度和控制过程具有特殊的意义，但研究和了解很少，部分原因是后勤和技术上的困难。为了通过现场测量限制或甚至完全确定海-气通量和NCP，通常需要做出假设，因为自主传感器目前无法观测到完成相关预算所需的全套数量。然而，最近和正在进行的发展现在提供了混合的传感器，部分是原型形式，可以部署在系泊剖面系统“Seaccle”上，并能够同时确定净群落生产量、二氧化碳的海-气通量，以及在全球海洋的重要区域建立预算。这项研究将获得并制造一套创新的商用和原型传感器和设备，以便在SeaCycler上进行集成和测试。目标是利用SeaCycler上的这些传感器收集足够的数据，以证明a)它们的可靠性，b)SeaCycler在剖面模式下的功能，c)它们的准确性，d)确定总溶解无机碳(DIC)和钙化(去掉通常对Redfield比率的假设)的能力，e)湍流轮廓在区分混合层和混合层方面的效用(对预算和水华的作用很重要)，f)SeaCycler本身的稳健性。这些努力将为SeaCycler为期一年的公海部署奠定基础，使用一套准确和经过测试的传感器来确定拉布拉多海等高纬度地区二氧化碳和O2的海气通量的大小和变异性，以及新形成的水团中DIC和O2的储存/输出。新的能力将允许完全使用生物地球化学预算来计算NCP的大小，并捕捉其亚季节到年际变化的物理/化学控制。通过高时间分辨率观测CO2/pH和DIC/AT的变化，可望量化钙化对碳收支和海气通量的影响。这项工作将利用NSF OTIC赠款下开发的几项技术，并利用NSF OOI技术。这项新技术将允许实验开发算法，以减少浮标和卫星观测中的不确定性。实现的观测对于测试模拟生物地球化学过程、大气-海洋通量和NCP.的数值模型也是至关重要的。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The net annual flux of CO2 into the ocean helps mitigate climate change, and the transfer of oxygen and organic carbon into the deep sea fuels its vast ecosystem. Linked to that, and equally important, is the net community production (NCP) since it represents the source input at the bottom of the ecosystem food chain, governs the vertical carbon export into the deep ocean, and also has a large controlling influence on the air-sea fluxes of CO2 and O2. The transfers of carbon and oxygen in the water column, their exchange with the atmosphere, and NCP are controlled by both physical and biological processes which vary greatly on seasonal and shorter time-scales, and also interannually. Rates and controlling processes at high latitudes have special significance but are poorly studied and understood, in part due to logistical and technological difficulties. In order to constrain or even fully determine the air-sea fluxes and NCP with in-situ measurements, usually assumptions need to be made since autonomous sensors currently cannot observe the full suite of quantities required for closing the relevant budgets. However, recent and ongoing developments now offer a mix of sensors, partially in prototype form, which could be deployed on the moored profiling system "Seacycler" and which could allow simultaneous determination of net community production (NCP), of the air-sea flux of CO2, and the construction of budgets in important regions of the global ocean. This research will acquire and fabricate an innovative suite of commercially available and prototype sensors and equipment, in order to integrate and exercise them on SeaCycler in a hierarchy of tests. The goal is to collect sufficient data with these sensors on SeaCycler to demonstrate a) their reliability, b) the functioning in profiling mode on SeaCycler, c) their accuracy, d) the ability to determine total dissolved inorganic carbon (DIC) and calcification (removing the normally made assumptions about Redfield ratios), e) the utility of turbulence profiles in distinguishing mixing vs mixed layers (important for budgets and the role of blooms), f) the robustness of SeaCycler itself. These efforts will lay the foundation for year-long open-ocean deployments of SeaCycler with a suite of accurate and tested sensors to determine the magnitude and variability of the air-sea flux of CO2 and O2 in high-latitude regions such as the Labrador Sea and of the storage/export of DIC and O2 in newly formed water masses. The new capabilities would allow calculation of the magnitude of NCP entirely using biogeochemical budgets, and to capture the physical/chemical controls of its sub-seasonal to inter-annual variability. It is expected that the effects of calcification on carbon budgets and air-sea fluxes can be quantifiable, by observing both CO2/pH and DIC/AT changes with high temporal resolution. The work will bring to bear several technologies developed under NSF OTIC grants, and leverage NSF OOI technology. The new technology will allow experiments to develop algorithms to reduce uncertainty in float and satellite observations. The observations enabled would also be crucial for testing numerical models which simulate biogeochemical processes, air-sea fluxes, and NCP.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.