科研成果Results


南海北部的多环芳烃研究：陆架区的水平输送与向下输出
PAHs in the Northern South China Sea: Horizontal transport and downward export on the continental shelf
发布日期：2018-3-23      浏览次数：1988

2018年3月23日，课题组在南海的论文成果《PAHs in the Northern South China Sea: Horizontal transport and downward export on the continental shelf》被Marine Chemistry期刊接收。

为探究陆架或边缘海海域半挥发性有机污染物的水平输送和颗粒输出，本研究对南海北部海域（SCS）的表层海水与水柱样品中的多环芳烃（PAHs）进行了分析。海水中Σ15PAH含量范围为1.6〜14 ng·L-1（平均5.5 ng·L-1）。PAHs沿岸减少的趋势表明在陆架区域的陆源输送强烈，且大多源于燃烧。其在海水中的分布，颗粒物相中PAHs表现为表面富集和深度亏损的特点，且在生物量最大值处PAHs浓度最高（2.9 ng·L-1），而溶解的PAH浓度最低（1.5 ng·L-1）相同的深度。本研究亦通过天然放射性同位素238U/234Th估算PAHs的输出通量为24-195 ng m-2 d-1，表明海洋生物泵高效地驱动了PAHs在南海的垂直向下输送。

 图1 南海东北部海域表层海水多环芳烃分布

 

 图2 各站位颗粒态多环芳烃浓度

Abstract

 To investigate horizontal transport and particulate export of semivolatile pollutants on the continental shelf or marginal sea, surface and depth water samples were collected across the northern South China Sea (SCS) and analyzed for polycyclic aromatic hydrocarbons (PAHs). The total concentrations of Σ15PAH in seawater were in the range of 1.6-14 ng·L-1 (mean 5.5 ng·L-1), and the offshore decreasing trend of PAHs revealed intense terrigenous transport on the continental shelf, which was originated from combustion activity. Vertically, PAHs in the particulate phase followed surface-enrichment and depth-depletion pattern with a concentration maximum (2.9 ng·L-1) at the biomass maximum, while the dissolved PAH concentrations showed a minimum (1.5 ng·L-1) at the same depth. Particulate export fluxes of PAHs were between 24 to 195 ng·m-2·d-1 in the northern SCS based on 238U/234Th equilibria, which is suggested appropriate to quantify their downward flux in the upper water column. Efficient oceanic biological pump drives PAHs downward export to the deep ocean in the northern SCS.

Keywords: Northern South China Sea; Polycyclic Aromatic Hydrocarbons; Export flux; Biological Pump

作者：蔡明刚、段梦姗、郭建青、刘萌阳、齐安翔、林嫣、梁俊华

通讯作者：蔡明刚