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: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=716368
• 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 () 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 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.

北冰洋在大气二氧化碳吸收中扮演着不成比例的大角色。这在一定程度上是由于其冷水中二氧化碳的高溶解度，以及与大陆架下方的广阔海洋区域相关的物理和生物过程。北冰洋的海冰正在减少，由于海水融化和河流流入的增加，北冰洋正在变得新鲜。我们不确定这些变化将如何影响海洋作为一个强大的二氧化碳汇的作用。北冰洋从河流中获得了大量的淡水和碳(有机和无机)，碳的输送对区域碳循环产生了非常大的影响。这是因为从河流获得的有机碳大部分通过生物过程转化为二氧化碳(二氧化碳分压，pCO2w)。海洋系统中的河水也有降低海水pH值的趋势，并增加了水对碳酸钙的溶解度。这样做是因为它的总碱度(TA)较低，即缓冲能力较低。随着碳酸钙在水中溶解度的增加，碳酸钙的饱和状态()降低。这些过程的结合(低pH和低饱和状态)导致了海洋酸化(OA)。许多生物为贝壳和骨骼产生各种类型的碳酸钙，如果海水中的碳酸钙不饱和，生物将更难产生贝壳，和/或它们的贝壳可能会溶解。因此，日益加剧的海洋酸化会对海洋生态系统产生负面影响。 我研究的基本思路是了解加拿大北极沿海水域的碳循环。我建议的研究有三个目标，即： (I)了解pCO2w、DIC、TA和在河口从河流到海洋的演变方式和程度； (2)描述陆架海气-海二氧化碳通量和海洋酸化的空间模式，了解物理和生物过程对观测到的变化的影响；(3)制定经证明适用于沿海水域生物地球化学模式的pCO2w、DIC、Ta的参数。 研究将在哈德逊和詹姆斯湾(以下简称HBC)进行，并将涉及对河流、河口和邻近海岸海洋的水进行采样。将对水样进行水碳化学分析。该项目将为6名学生、3名博士生和3名硕士学生提供机会。 与我的目标相关的研究将使我和我的学生能够量化河流对HBC当代和未来无机碳系统的作用，包括其二氧化碳源/汇以及OA的现状和进展。由于其对海洋生态系统的潜在影响，OA对粮食安全构成了潜在威胁。该计划所产生的信息将对联邦和省级政策制定者以及地区和共同管理机构具有无价的价值。