Dissolved inorganic carbon, total alkalinity, pH on total scale, and other variables collected from discrete samples and profile observations during the R/V F. G. Walton Smith cruise WS24205 (EXPOCODE 33WA20240723) in the North Atlantic Ocean, Gulf of Mexico from from 2024-07-23 to 2024-07-30 (NCEI Accession 0298978)

Near-shore estuarine and coastal regions are where most recreational fishing and tourism occur, yet they are vastly under-sampled. Their susceptibility to OA is not well understood due to their high biogeochemical variability. These regions are affected by land-side processes such as river discharge and run-offs and ocean-side processes through slope water exchange. A full determination of the carbonate system in these regions in conjunction with open ocean measurements is needed to increase our understanding of the effects of OA on ocean health and fisheries and our ability to predict them. In this project, we propose to augment several observational campaigns by 1) adding a carbonate component to the harmful algal blooms (HABs) monitoring cruises conducted periodically on the Western Florida Shelf in order to study potential links between HABs and OA, 2) renewing our collaboration with select National Parks to complement and enhance our near-shore data collection on the Northern Gulf of Mexico and US East Coast, and 3) complementing our underway surface pCO2 measurements in the Gulf of Mexico and US East Coast with underway total alkalinity measurements to help us improve our fundamental understanding of nearshore OA processes. The addition of these measurements to the current assets already present in the region would enhance our understanding of the linkage between nearshore and open ocean processes and better assess the mechanisms and impacts of OA on the biogeochemistry, biology and their economic consequences.

近岸河口与近岸海域是休闲垂钓与旅游业的核心聚集地，但其观测采样却严重不足。由于该区域生物地球化学过程高度复杂多变，人们对其受海洋酸化（Ocean Acidification, OA）影响的敏感性尚未形成充分认知。此类区域同时受陆源与海源两类过程的调控：陆源过程包括河流排放与地表径流，海源过程则通过陆坡水交换实现。为加深对海洋酸化对海洋健康与渔业的影响的理解，并提升相关预测能力，亟需结合远洋观测数据，对该区域的碳酸盐系统开展全面测定。在本项目中，我们拟对多项现有观测计划进行扩充：其一，在佛罗里达陆架西部定期开展的有害藻华（Harmful Algal Blooms, HABs）监测航次中增设碳酸盐组分观测，以探究有害藻华与海洋酸化之间的潜在关联；其二，与遴选的部分国家公园续签合作协议，以补充并完善墨西哥湾北部与美国东海岸的近岸数据采集工作；其三，在墨西哥湾及美国东海岸的走航表层二氧化碳分压（partial pressure of carbon dioxide, pCO2）观测基础上，补充走航总碱度测量，从而深化对近岸海洋酸化过程的基础认知。将上述观测项目纳入该区域现有观测体系，将有助于我们进一步厘清近岸与远洋过程间的关联，并更精准地评估海洋酸化对生物地球化学循环、海洋生态系统及其经济后果的作用机制与实际影响。