Unraveling the controls of inorganic carbon dynamics in the Gulf of Alaska with a regional three-dimensional biogeochemical model

利用区域三维生物地球化学模型揭示阿拉斯加湾无机碳动力学的控制

• 批准号: 1459834
• 负责人: Claudine Hauri
• 金额: $ 50.25万
• 依托单位: University of Alaska Fairbanks Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1459834&HistoricalAwards=false
• 关键词: Unraveling; controls; inorganic; carbon; dynamics

The Gulf of Alaska ecosystem provides significant socio-economic benefits through tourism and through subsistence and commercial fisheries. However, the combined effects of climate change and ocean acidification, which is caused by the oceanic uptake of anthropogenic carbon dioxide, are altering the habitat of commercially important species. Climate induced enhancement of glacial melting may accelerate the progression of ocean acidification in the Gulf of Alaska even further. Due to a limited number of measurements in the Gulf of Alaska, little is known about the current state and rate of change of the chemical habitat of key species. Researchers from the University of Alaska Fairbanks propose to develop models of the ocean circulation, chemistry and biology for this region that will enable better understanding of environmental controls on ocean acidification in the Gulf of Alaska. In addition to communicating the science through a collaboration with the Alaska Ocean Observing System, the project will support a field course called "Girls in Icy Fjords", which is designed to inspire young women who have had limited opportunities due to life circumstances to pursue college educations and, possibly, careers in science. This project will identify the dominant controls and patterns of high carbon dioxide environments in the northern Gulf of Alaska. The few available observations document a seasonal manifestation of aragonite undersaturation in subsurface waters on this continental shelf. Particularly if it expands in time and space, such undersaturation could engender detrimental consequences for carbon dioxide sensitive organisms and potentially lead to altered food web structures, ultimately imparting large ecosystem and socio-economic consequences. However, the currently limited spatial and temporal data coverage precludes a detailed conceptual understanding of the physical and biological mechanisms controlling the local carbon dynamics and thus impedes our ability to anticipate and mitigate future changes. In this study, researchers will conduct high-resolution physical-biogeochemical hindcast model integrations and use neural networks, dye tracers and Lagrangian floats to detangle the complex interplay of mechanisms that drive aragonite undersaturation in the study region. The proposed physical-biogeochemical model configuration, which uses carbon and nitrate as model currencies, has been extensively evaluated for the greater North Pacific region at moderate (10 km) resolution. This model will be tailored to the Gulf of Alaska with a high (1.5 km) horizontal resolution, explicit forcing of coastal freshwater discharges, and modeled iron limitation. Such improvements will make this setup an attractive choice as a foundation for many other high-latitude biogeochemical modeling applications. The proposed experiments and analytical methods will take advantage of the three-dimensional model output and will provide insights into seasonal and interannual variability of enhancing and inhibiting controls of ocean acidification.

阿拉斯加湾生态系统通过旅游业和自给渔业和商业渔业提供了巨大的社会经济效益。然而，气候变化和海洋酸化（由海洋吸收人为二氧化碳引起）的综合影响正在改变具有重要商业价值的物种的栖息地。气候导致的冰川融化加速可能会进一步加速阿拉斯加湾海洋酸化的进程。由于在阿拉斯加湾的测量数量有限，人们对关键物种的化学栖息地的现状和变化速度知之甚少。阿拉斯加费尔班克斯大学的研究人员建议为该地区开发海洋环流、化学和生物学模型，以便更好地了解阿拉斯加湾海洋酸化的环境控制。除了通过与阿拉斯加海洋观测系统的合作交流科学知识外，该项目还将支持一门名为“冰雪峡湾中的女孩”的实地课程，旨在激励那些由于生活环境而机会有限的年轻女性接受大学教育，并可能从事科学事业。该项目将确定阿拉斯加湾北部高二氧化碳环境的主要控制因素和模式。为数不多的观测记录了该大陆架地下水文石不饱和的季节性表现。特别是如果它在时间和空间上扩大，这种不饱和可能对二氧化碳敏感的生物产生有害后果，并可能导致食物网结构的改变，最终造成巨大的生态系统和社会经济后果。然而，目前有限的时空数据覆盖范围妨碍了对控制当地碳动态的物理和生物机制的详细概念理解，从而阻碍了我们预测和减轻未来变化的能力。在这项研究中，研究人员将进行高分辨率的物理-生物地球化学后投模型集成，并使用神经网络、染料示踪剂和拉格朗日浮子来解开驱动研究区域文石欠饱和的复杂机制的相互作用。提出的物理-生物地球化学模型配置，使用碳和硝酸盐作为模型货币，已在大北太平洋地区以中等（10公里）分辨率进行了广泛评估。该模型将适用于阿拉斯加湾，具有高水平分辨率（1.5公里）、沿海淡水排放的明确强迫和模拟的铁限制。这些改进将使这种设置成为许多其他高纬度生物地球化学建模应用的一个有吸引力的选择。拟议的实验和分析方法将利用三维模型的输出，并将深入了解加强和抑制海洋酸化控制的季节和年际变化。