Quantifying the Ocean's Carbon Pumps with Dissolved Gas Measurements

海洋自然地从大气中去除二氧化碳，将其输送到深海，并将其储存在那里，从而降低大气水平和更温和的气候。随着人类燃烧燃料并向大气中添加二氧化碳，我们需要了解海洋的天然碳运输机制如何工作，它们的工作速度以及它们如何变化，以便对未来气候做出准确的预测，我们的社会可以用来做出决策。我的研究旨在通过对溶解气体的新测量来揭示和量化这些机制。我们的研究小组已经开发出高精度测量溶解惰性气体（氖、氩、氪和氙）浓度的方法。这些气体没有生物功能，只对海洋中的物理过程做出反应。我们将使用惰性气体测量来量化影响海洋中所有气体的物理过程的速率，例如空气-海洋气体交换和温度驱动的溶解度变化。这些过程控制着当稠密的沃茨沉入深海时携带多少碳。通过与大规模气候建模者的直接合作，我们将改进这些过程在气候预测模型中的表现方式。我们的研究还侧重于生物过程，特别是光合作用产生的有机碳从海洋表面下沉，这是一种重要但量化不佳的碳运输机制。我们已经开发出了使用溶解气体的氧/氩比的高精度测量来量化从表面的这种“输出”速率的方法。我们现在将扩展我们的技术，以量化来自传感器的碳输出，这些传感器检测海洋浮子和滑翔机上的氧气浓度，这些浮子和滑翔机在水柱中自主上下移动。这项工作将扩大进行这些估计的空间和时间尺度。我们的总体目标之一是建立一个基线，据此可以发现海洋生产力的未来变化。任何变化不仅会影响海洋对大气二氧化碳的吸收，还会影响海洋生态系统和依赖海洋的渔业。我们的第三个研究重点是从海洋中提取植物光合作用所需的生物可利用氮的反应。这些反应被称为脱氮作用，发生在没有氧气的海洋区域。这些缺氧区正在扩大，这意味着脱氮作用可能会影响未来全球海洋生物生产力的速度。我们已经开发了使用溶解在海洋中的N2气体的高精度测量来检测这种反应的方法。我们将在当地的萨尼奇湾，这提供了一个方便的天然实验室，研究缺氧区，并在北冰洋，这些反应是最不好量化的反硝化作用。

The ocean naturally removes carbon dioxide from the atmosphere, transports it to the deep, and stores it there, resulting in lower atmospheric levels and a more moderate climate. As humans burn fuels and add carbon dioxide to the atmosphere, we need to understand how the ocean's natural carbon transport mechanisms work, how fast they work, and how they are changing in order to make accurate projections of future climate that our society can use to make decisions. My research seeks to uncover and quantify these mechanisms using novel measurements of dissolved gases.******Our research group has developed methods to make high precision measurements of dissolved noble gas concentrations (neon, argon, krypton, and xenon). These gases have no biological function, responding only to physical processes in the ocean. We will use our noble gas measurements to quantify the rates of physical processes that impact all gases in the ocean, such as air-sea gas exchange and temperature-driven solubility changes. These processes control how much carbon is carried as dense waters sink into the deep sea. Through direct collaborations with large-scale climate modellers, we will improve the way these processes are represented in the models from which climate projections are made.******Our research also focuses on biological processes, particularly the sinking of organic carbon created by photosynthesis out of the surface ocean, an important but poorly quantified carbon transport mechanism. We have developed ways of quantifying this “export” rate from the surface using high precision measurements of the oxygen/argon ratio of dissolved gases. We will now expand our techniques to quantify carbon export from sensors that detect oxygen concentrations on ocean floats and gliders that autonomously move up and down through the water column. This work will expand the space and time scales over which these estimates are made. One of our overall goals is to establish a baseline against which future changes in ocean productivity can be detected. Any changes could affect not only ocean uptake of atmospheric carbon dioxide but also the ocean ecosystem and fisheries that rely on it.******Our third research focus is on reactions that strip bioavailable nitrogen, which plants need to photosynthesize, out of the ocean. These reactions, known as denitrification, take place in regions of the ocean with no oxygen. These oxygen deficient zones are expanding, which means that denitrification could affect global rates of ocean biological productivity in the future. We have developed methods to detect this reaction using high precision measurements of N2 gas dissolved in the ocean. We will quantify denitrification both in local Saanich Inlet, which provides an accessible natural laboratory to study oxygen deficient zones, and in the Arctic Ocean, where these reactions are least well quantified.