南海上层水体黑碳颗粒动力学的同位素示踪

项目名称： 南海上层水体黑碳颗粒动力学的同位素示踪

项目编号： No.41476061

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 天文学、地球科学

项目作者： 杨伟锋

作者单位： 厦门大学

项目金额： 90万元

中文摘要： 黑碳是全球碳循环中被忽略的碳失汇之一，近几年发现其在气候变暖中的作用仅次于CO2，故其排放和在大气中的扩散备受关注。但海水作为黑碳重要的归宿地，其中黑碳的信息极度匮缺，无法评估其对海洋碳循环的贡献。本项目立足已有研究基础，以黑碳的颗粒动力学为切入点，以颗粒态黑碳（PBC）的来源与输出为突破口，选择南海为研究区域，注重陆架区与海盆区的对比研究，通过核心科学问题聚焦-现场调查-受控模拟实验-综合分析，采用多种同位素（13C、14C、210Po、210Pb、234Th、137Cs、230Th）联合示踪的方法，研究南海上层水体PBC的同位素特征，揭示其主要来源、时空格局及其与水文动力条件关系，探明PBC循环与输出关键过程的速率与通量特征及主控因素，定量评估PBC对颗粒有机碳的贡献及其对评估生物泵效率的影响，综合研究黑碳对南海碳循环的贡献。项目可望在边缘海上层海水中黑碳的源汇研究方面取得突破。

中文关键词： 放射性同位素；颗粒动力学；海洋碳循环

英文摘要： Black carbon, representing one of the most important missing carbon sinks, has been proved to play a crucial role in driving global warming following CO2 in the last years. Its emission and diffusion in the atmosphere have been extensively investigated. However, its behaviors in the ocean are very poorly understanood although the ocean is the most important potential sink, resulting in the impossibility of evaluating the contribution of black carbon to marine carbon cycle. This project will focus on the particle dynamics of particulate black carbon (i.e. PBC) in the upper layer of the South China Sea (SCS). Strategically, specific scientific questions are firstly proposed, followed by field investigation accompanying simulation experiments. Finally, the data will be synthetically discussed to reach our goals. The sources of PBC and its export from the euphotic layer, in both shelf and basin regions, have been selected as the primary scientific questions of highlighting its basic cycling in the SCS. Methodologically, multiple isotopes, including stable isotope (13C) and radioactive nuclides (i.e. 14C, 210Po, 210Pb, 234Th, 137Cs, and 230Th) will be used to reveal the following information: (1) the sources of PBC in the upper layer of the SCS, (2) the temporal-spatial patterns of PBC and its relation with hydrological parameters, (3) the turnover rates, export fluxes of PBC with respect to the upper layer and the dominating factors, (4) the quantitative contribution of PBC to particulate organic carbon standing crop and its influence on evaluating the biological pump efficiencies. These forthcoming results would provide the foundation of evaluating the role of black carbon in the carbon cycling of the South China Sea.

英文关键词： Radioactive isotopes;Particle dynamics;Marine carbon cycle