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

合作研究：河流流量和风暴的时间变化如何影响河流主导边缘沉积有机碳的来源和年龄分布

基本信息

批准号：
0223334
负责人：
Thomas Bianchi
金额：
$ 27.5万
依托单位：
Tulane University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2002
资助国家：
美国
起止时间：
2002-10-01 至 2005-03-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=0223334&HistoricalAwards=false
关键词：
Collaborative Research How temporal changes

项目摘要

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.

大陆边缘是动态区域，这些区域接收来自陆地和海洋来源的有机碳的输入。一旦由密西西比州引入或固定在路易斯安那州的架子上，POC沿着架子携带，分解，埋葬或运送到墨西哥湾的更深层次地区。根据沿海初级生产估计和河流投入，密西西比州沿海水域中有机碳的20％实际上被埋葬在路易斯安那州的货架沉积物中，而埋藏的碳的40％是陆地。因此，密西西比州在货架沉积物中无法解释的碳分数的50-80％仍然是制定北美碳预算的关键问题。在这笔资金下，PI提出了一种合并的方法，即复合特异性稳定和放射性碳同位素技术和生物标志物分布，以评估密西西比河三角洲架子和坡度中有机碳的命运和运输。这项研究的工作假设是，路易斯安那州架子/坡度的SOC组成和年龄的季节性变化很大程度上取决于陆地和海洋来源的有机碳的脉冲，这是在密西西比河排放和风暴能源的变化控制下在不同时间内发生的。