Black Carbon (BC) and the Global Carbon Cycle: Assessing BC Inventories in Coastal Seawater and Burial in Margin Sediments off the Northeastern USA

黑碳 (BC) 和全球碳循环：评估美国东北部沿海海水和边缘沉积物中的 BC 库存

• 批准号: 0223441
• 负责人: Philip Gschwend
• 金额: $ 47.99万
• 依托单位: Massachusetts Institute of Technology
• 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: 2002-09-15 至 2006-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0223441&HistoricalAwards=false
• 关键词: Black; Carbon; BC; Global; Cycle

Black carbon (BC), the product of incomplete combustion of fossil fuels and biomass, has been increasingly formed and released to the environment for the last century. Presently, it is not possible to quantify (a) the rate of BC burial in the oceanic margin sediments (where most of the OC is buried), (b) the size of the BC reservoir in seawater, nor (c) riverine fluxes of BC to the sea. Consequently, it is not possible to ascertain how important BC is to the global carbon cycle. Under this award, the PIs address the following questions: (1)What is the contribution of BC burial relative to the organic carbon burial in the Gulf of Maine? (2) How has the input flux of BC to the region's bed sediments changed in the past century? (3) What is the inventory of BC in coastal seawater off the Northeast United States and what temporal and spatial variability does this reservoir exhibit? (4) What are riverine inputs of BC to the Gulf of Maine and how do they vary seasonally? (5) Can we identify the major sources of BC (e.g., fossil fuel combustion-produced soots, biomass-derived chars) for coastal seawater and sediment of the Gulf of Maine? In addition to measurement of the abundance of BC in various samples, the approach taken includes field sampling of water and sediments, and a variety of analytical measurements including: 234Th/238U disequilibria in water and unsupported 210Pb in sediments, carbon isotopes in BC and specific compounds as well as with key marker compounds (PAHs), and BC analyses in radiometrically dated sediment cores collected from within and beyond the Gulf of Maine.

黑碳（BC）是化石燃料和生物质不完全燃烧的产物，在上个世纪越来越多地形成并释放到环境中。目前，无法量化（a）大洋边缘沉积物（大部分 OC 埋藏在此处）中的 BC 埋藏率，（b）海水中的 BC 水库的大小，以及（c）BC 流入海洋的河流通量。因此，不可能确定碳黑对全球碳循环有多重要。根据该奖项，PI 解决了以下问题： (1) BC 埋藏相对于缅因湾的有机碳埋藏有何贡献？ (2) 近一个世纪以来，BC对该地区河床沉积物的输入通量发生了怎样的变化？ (3) 美国东北部沿海海水中的黑碳库存是多少？该水库表现出什么样的时间和空间变化？ (4) 不列颠哥伦比亚省对缅因湾的河流输入是什么？它们随季节如何变化？ (5) 我们能否确定缅因湾沿海海水和沉积物中BC的主要来源（例如化石燃料燃烧产生的烟灰、生物质衍生的炭）？除了测量各种样品中 BC 的丰度外，所采取的方法还包括对水和沉积物进行现场采样，以及各种分析测量，包括：水中的 234Th/238U 不平衡和沉积物中的无支撑 210Pb、BC 和特定化合物以及关键标记化合物 (PAH) 中的碳同位素，以及放射性测年中的 BC 分析 从缅因湾内外收集的沉积物岩心。