River influences on air-sea exchange of CO2 and carbon system dynamics in Canadian subarctic coastal waters

河流对加拿大亚北极沿海水域二氧化碳海气交换和碳系统动态的影响

• 批准号: RGPIN-2019-06736
• 负责人: Papakyriakou, Timothy
• 金额: $ 2.19万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=753240
• 关键词: River; influences; air; sea; exchange

The Arctic Ocean plays a disproportionally large role in the uptake of atmospheric CO2. This is due in part to the high CO2 solubility in its cold waters, and physical and biological processes associated with an expansive ocean area underlain by continental shelf. The Arctic Ocean is losing sea ice and is freshening through the combination of increased sea melt and river inflow. We are uncertain as to how these changes will impact the ocean's role as a strong CO2 sink. The Arctic Ocean receives an enormous amount of freshwater and carbon (both organic and inorganic) from rivers and the carbon delivery has a very strong influence on regional carbon cycles. This is because much the organic carbon received from rivers is converted to CO2 (CO2 partial pressure, pCO2w) by biological processes.  River water in the marine system also has the tendency to reduce the seawater's pH and increase in the water's solubility for calcium carbonate. It does this because it has a lower total alkalinity (TA), or buffering capacity. As the solubility increases in water, the saturation state (O) for the calcium carbonate decreases. The combination of these processes (lower pH and lower saturation state) leads to ocean acidification (OA). Many organisms produce types of calcium carbonate for shells and skeletons, and if the seawater becomes undersaturated in calcium carbonate, it will be more difficult for the organisms to produce shells, and/or their shells can dissolve. Hence intensifying ocean acidification can negatively impact the marine ecosystem. The underlying thread of my research is to understand the carbon cycle of coastal waters in the Canadian Arctic. The research that I propose has three objectives, namely: (i) Understand how, and the extent to which pCO2w, DIC, TA, and O evolve in estuaries from river to ocean; (ii) Characterize spatial patterns in the air-sea CO2 flux and OA within a shelf sea and understand what physical and biological processes contributed to the observed variability; (iii) Develop parameterizations for pCO2w, DIC, TA that are shown to be suitable for application in biogeochemical models for coastal waters. Research will be conducted in Hudson and James Bay (hereafter HBC), and will involve the sampling of water in rivers, along estuaries and in the adjacent coast ocean. Water samples will be analysed for  water carbon chemistry. The program will provide opportunity for 6 students, 3 PhD, and 3 MSc students. Research associated with my objectives will allow my students and I to quantify the role of rivers on contemporary and future inorganic carbon systems of the HBC, including its CO2 source/sink and status and progression of OA. Because of its potential impacts on marine ecosystem, OA represents a potential threat to food security. Information resulting from this program will be invaluable to federal and provincial policy-makers, as well as territorial and co-management bodies.

北极海洋在大气二氧化碳的吸收中起着不成比例的作用。这是由于其冷水中高二氧化碳溶解度的一部分，以及与连续架子下面的广泛海洋区域相关的物理和生物过程。北极海洋正在失去海冰，并通过增加的海融化和河流流入的结合而焕然一新。我们不确定这些变化将如何影响海洋作为强大的二氧化碳的作用。北极海洋从河流中获得了增强的淡水和碳（有机和无机），碳输送对区域碳周期的影响很大。这是因为通过生物过程，从河流收到的有机碳接收到的许多有机碳都被转化为CO2（CO2部分压力，PCO2W）。海洋系统中的河水还倾向于减少海水的pH值并增加碳酸钙的溶解度。之所以这样做，是因为它具有较低的总碱度（TA）或缓冲能力。随着水的溶解度的增加，碳酸钙的饱和状态（O）减小。这些过程（下pH和下饱和态）的组合导致海洋酸化（OA）。许多生物会为贝壳和骨骼产生碳酸钙的类型，如果海水在碳酸钙中变得不饱和，那么生物体会产生贝壳和/或它们的壳可以溶解更困难。因此，加强海洋酸化会对海洋生态系统产生负面影响。我的研究的基本线索是了解加拿大北极沿海水域的碳循环。我提出的研究具有三个目标，即：（i）了解如何以及从河流到海洋的河口的PCO2W，DIC，TA和O进化的程度； （ii）表征空气海洋二氧化碳通量和货架海中OA中的空间模式，并了解什么物理和生物过程导致了观察到的变异性； （iii）开发PCO2W，DIC，TA的参数，该参数适用于用于沿海水域的生物地球化学模型中。研究将在Hudson和James Bay（以下称HBC）进行，并将涉及沿河流，河口和邻近海岸海洋的水采样。水样将分析水碳化学。该计划将为6名学生，3位博士学位和3名MSC学生提供机会。与我的目标相关的研究将使我和我的学生能够量化河流在HBC的当代和未来无机碳系统中的作用，包括其二氧化碳源/水槽以及OA的状态和进展。由于其对海洋生态系统的潜在影响，OA代表了对粮食安全的潜在威胁。该计划产生的信息对于联邦和省级决策者以及领土和共同管理机构将是无价的。