Marsh-Dominated Ocean Margins as a Source of CO2 to the Atmosphere and Open Oceans: A Field Study in the U.S. Southeastern Continental Shelf

摘要-0425153最近对位于中高纬度地区的几个大型大陆架的研究表明，大气中的CO2向海洋的转移是显著的。据推测，吸收的二氧化碳被转移到公海。如果这一结论在全球适用，那么这样的大陆架CO2汇将在全球碳循环研究中发挥重要作用。在这个项目中，格鲁吉亚大学的研究人员将通过量化低至中纬度海洋边缘的海气CO2通量来测试这一假设，美国东南大陆架（也称为南大西洋湾，SAB），初步证据表明相反的（海-气）CO2通量。 研究人员假设，SAB是大气和公海的二氧化碳来源，这种二氧化碳释放是由潮间带盐沼输出的有机碳（OC）的呼吸驱动的。将通过覆盖整个SAB的四个跨大陆架样带和一个沿岸样带，并通过五次季度巡航，确定整个大陆架表面pCO 2和水柱总溶解无机碳（DIC）和碱度（Alk）的分布。DIC的向海输出通量将根据区域综合过量DIC库存和淡水平衡确定的陆架水停留时间进行估计。这DIC通量的开放的海洋，预计将远远高于河流通量在这一地区。同时量化海气CO2通量和DIC输出到公海，这是以前很少尝试过的，将大大提高我们对海洋边缘在全球海洋碳循环中的作用的理解。除了确定总体向海DIC通量外，该小组还将利用最近出版的SAB三维气候学模型和该地区其他正在进行的数值模型活动，更好地了解跨大陆架和沿岸流携带的DIC通量的相对重要性。还将采用类似的方法，估算Alk和溶解有机碳的向海通量。更广泛的影响。该项目的结果有望提高我们的理解和能力，以预测大气中人为CO2的命运。 该项目还将以若干重要方式促进涉及研究生、本科生和高中生的教学、培训和学习。

ABSTRACTOCE-0425153Recent studies in several large continental shelves located in mid-to-high latitude areas indicate significant air-to-sea CO2 transfer. Presumably the absorbed CO2 is transferred into the open ocean. If this conclusion is globally applicable, such a continental shelf CO2 sink would be very important in the study of global carbon cycling. In this project, researchers at the University of Georgia will test this hypothesis by quantifying air-sea CO2 fluxes in a low-to-mid latitude ocean margin, the U.S. Southeastern Continental Shelf (also known as the South Atlantic Bight, SAB), where preliminary evidence indicates an opposite (sea-to-air) CO2 flux. The researchers hypothesize that the SAB is a source of CO2 to the atmosphere and to the open ocean and that this CO2-release is driven by the respiration of organic carbon (OC) exported from intertidal salt marshes. Shelf-wide distributions of surface pCO2 and water column total dissolved inorganic carbon (DIC) and alkalinity (Alk) will be determined with four cross-shelf transects and one alongshore transect covering the entire SAB and through five quarterly cruises. The seaward export fluxes of DIC will be estimated based on an area-integrated excess DIC inventory and the shelf water residence time determined by freshwater balance. This DIC flux to the open ocean is expected to be much higher than the riverine flux in this area. The simultaneous quantification of air-sea CO2 flux and DIC export to the open ocean, which has rarely been attempted before, will significantly improve our understanding of the role that ocean margins play in the global ocean carbon cycle. In addition to the determination of overall seaward DIC flux, the team will also seek a better understanding of the relative importance of DIC fluxes carried by cross-shelf and alongshore flows by taking advantage of a recently published SAB 3-dimensional climatology model and other ongoing numerical model activities in this region. In a similar approach, seaward fluxes of Alk and dissolved organic carbon will also be estimated. Broader Impacts. The results of this project are expected to enhance our understanding and ability to predict the fate of anthropogenic CO2 in the atmosphere. This project will also promote teaching, training and learning in a number of important ways that involve graduate, undergraduate and high school students.