大亚湾柱状沉积物中C、N、P的分布特征及其环境意义

Distribution characteristics and environmental significance of carbon,nitrogen and phosphorus in core sediments of Daya Bay

对大亚湾典型柱状沉积物中C、N、P的含量及其分布特征进行了研究。结果表明,大亚湾柱状沉积物中C、N、P含量的变化范围分别为（0.48～1.53）×10-2、（316.24～570.47）×10-6、（206.02～342.02）×10-6,C与N的垂直分布具有由深层向浅层增加的趋势,而P含量随深度的增加而增大。根据沉积物中TOC/TN比值及两者的相关性,可以判断沉积物中有机质一直以陆源输入为主,其比值垂向变化主要受控于TOC含量的变化。另外,沉积物中TN和TN/TP的垂直变化也和近年来大亚湾水体中营养盐含量的变化相一致。低沉积速率是导致大亚湾沉积物中各生源要素埋藏通量小的主要因素。从20世纪80年代中期开始,随着沿岸工农业的快速发展和排污的增加,TN和TOC的埋藏通量有所增加;近年来,随着治污措施发挥作用,TN和TOC的埋藏通量有所降低,大亚湾的整个生态环境有所改善。

Biogeochemical observations were carried out to determine TOC,TN and TP contents and their distribution characteristics in sediments of the Daya Bay. The results showed that,the content of TOC,TN and TP ranged from0. 48 × 10- 2to 1. 53 × 10- 2,from 316. 24 × 10- 6to 570. 47 × 10- 6,from 206. 02 × 10- 6to 342. 02 × 10- 6,respectively. Both TOC and TN in sediments had an increasing trend from bottom to surface,and TP content increases with core depth. According to the ratios between TOC and TN and also their correlation,organic matter mainly came from terrene,and the vertical variation was mainly controlled by TOC content. The vertical distribution of TN,TP contents and the ratios between TOC and TN were in accordance with the increased trend of nutrient content in seawater of the Daya Bay. Low deposition rate was the main factor leading to low burial fluxes of biogenic elements. Since twenty mid-1980 s,the burial fluxes of TN and TOC increased due to increased human activities. However,the efforts of controlling pollution in recent years had improved the environment of the Daya Bay. Our investigation confirms that the burial fluxes of biogenic elements can be a good proxy indicating environment changes of the Daya Bay.