东海内陆架表层沉积物中黑碳的分布及来源

对东海内陆架表层沉积物中黑碳含量进行了分析,探讨了黑碳在东海内陆架不同区域的分布特征、影响因素及来源,并与长江口徐六径悬浮颗粒物中的黑碳进行了对比。结果显示,长江口徐六径悬浮颗粒物中黑碳的含量平均为1.68±0.51mg/g,且枯季浓度要高于洪季,这反映了燃烧活动的季节变化。黑碳在东海内陆架表层沉积物的分布具有明显的区域特征,近岸区域沉积物中的黑碳含量接近,且与粒径成负相关,并低于徐六径悬浮颗粒物中黑碳的含量,说明来自长江输入的黑碳主要以烟炱为主,并且部分粒径极小的颗粒未完全沉积下来;在123°E以东区域的表层沉积物中的黑碳含量分布较广,并与平均粒径成正相关,说明该区域主要以石墨态黑碳为主。另外,东海内陆架表层沉积物BC/TOC在0.11～0.55之间,因此在研究该区域碳循环过程中,不可忽视BC在不同区域的分布特征及类型差别。

Distribution and Source of Black Carbon in the Surface Sediments of the Inner Continental Shelf of the East China Sea

This paper studied the contents of black carbon(BC) in the surface sediments of the inner continental shelf of the East China Sea,focusing on the distribution,influence factors and source of BC in different areas.In addition,the BC contents were compared with those in suspended particulate matter(SPM) derived from Xuliujing in the Yangtze River estuary.The results showed that the average BC content in SPM of Xuliujing was 1.68±0.51 mg/g,and the content in the dry season was higher than that in the flood season,which is related with seasonal change of combustion.The distribution of BC in the surface sediments of the inner continental shelf of the East China Sea was characterized by regional difference.The BC contents in nearshore varied over a narrow range and were negatively related with size,and lower than those in SPM of Xuliujing,which showed that BC came from river input and was dominated by soot in this area,and partial small-sized BC was not completely deposited.The BC contents in the east of 123°E were extensively high and positively correlated with size,indicating that BC was dominated by graphitic black carbon.Moreover,the BC/TOC values range from 0.11 to 0.55 in the sediments,so we should not ignore the difference in distribution and species from one area to another,when investigating the carbon cycle in this area.