Collaborative Research: How Temporal Changes in River Discharge and Storms Affect the Source and Age Distribution of Sedimentary Organic Carbon Across a River-Dominated Margin

大陆边是动态区域，接受来自陆地和海洋来源的有机碳输入。一旦被密西西比引入或固定在路易斯安那州大陆架上，POC就会被沿着大陆架携带，分解，掩埋或运输到墨西哥湾的更深区域。根据沿海初级生产力的估计和河流输入，只有20-50%的有机碳在沿海沃茨关闭密西西比实际上是埋在路易斯安那州大陆架沉积物，40%的埋碳是陆地来源。因此，由密西西比输送的50-80%的碳组分在陆架沉积物中的去向仍然是制定北美碳预算的一个关键问题。在此资助下，PI提出了化合物特定的稳定和放射性碳同位素技术和生物标志物分布的综合方法，以评估有机碳在密西西比河三角洲大陆架和斜坡的命运和运输。这项研究的工作假设是，季节性变化的组成和年龄的SOC在路易斯安那州的货架/斜坡主要是由脉冲在陆地和海洋来源的有机碳发生在不同的时间段控制的变化，密西西比河流量和风暴能量。

Continental margins are dynamic regions that receive inputs of organic carbon derived from both terrestrial and marine sources. Once introduced by the Mississippi or fixed on the Louisiana shelf, POC is carried along the shelf, decomposed, buried, or transported to deeper regions in the Gulf of Mexico. Based on coastal primary production estimates and riverine inputs, only 20-50% of the organic carbon in coastal waters off the Mississippi is actually buried in Louisiana shelf sediments, and 40% of that buried carbon is of terrestrial origin. Thus, the fate of 50-80% of the carbon fraction delivered by the Mississippi that cannot be accounted for in shelf sediments remains a key question in developing a North American carbon budget. Under this funding, the PIs propose a combined approach of compound-specific stable and radiocarbon isotopic techniques and biomarker distributions to evaluate fates and transport of organic carbon in the Mississippi River delta shelf and slope. The working hypothesis of this study is that seasonal changes in the composition and age of SOC across the Louisiana shelf/slope are largely determined by pulses in terrestrially- and marine-derived organic carbon which occur at distinct time periods controlled by changes in Mississippi River discharge and storm energy.