人类活动对海南省小海泻湖沉积环境的影响

ANTHROPOGENIC IMPACT ON THE SEDIMENTARY ENVIRONMENT OF XIAOHAI LAGOON,HAINAN ISLAND

根据小海泻湖XHK04-01沉积物柱状样的210Pb定年以及总有机碳和总氮含量分析,探讨了人类活动对小海沉积环境的影响.分析表明:1988年以前,总有机碳和总氮的含量稳定在0.6%和0.04%,TOC/TN为14左右,沉积物的有机质主要来自陆地,陆源有机碳的含量占到总有机碳含量的80%,人类活动对沉积环境的影响变化较小;而1988年之后,由于人类活动的加剧,小海沉积物中总有机碳和总氮的含量迅速上升,到表层时总有机碳和总氮的含量均达到最高值,分别为1.2%和0.13%,TOC/TN下降到9,沉积物中小海自生来源的有机碳的比例显著增加,陆源有机碳的比例相对下降到45%.小海沉积物中营养元素的增加,导致小海水质的恶化.人类活动的影响在沉积速率上也有反映,在18cm以下沉积速率为0.46cm.a-1,0—18cm沉积速率为1.26cm.a-1.

Based on ^210pb chronology, sediment YOC/TN ratio were used to indicate the an core profiles of total organic carbon c impacts on the sediment （ TOC ）, total nitrogen （ TN）, environment of Xiaohai lagoon. The profiles with time reveal that： （1） before 1988, the concent of TOC and TN were quite stable, about 3. 6% and 0. 04%, respectively. TOC/TN was about 14, The organic matter of Xiaohai Lagoon was mainly terrigenous provenance. （2） since 1988, the concent of TOC, TN have risen rapidly with the local development. The concent of TOC, TN in the surface are the top values in the sediment core profiles, about 1.2% and 0. 13%, respctively. TOC/TN is 9. The relative proportion of autogenous organiccarbon has risen obviously , and the terrigenous organic carbon has been correspondingly decreased to 45%. Water quality of Xiaohai lagoon has deteriorated for increase of its nutrition element content. The change of sedimentation rate also indicates anthropogeni 1.26cm·a^-1 from 18cm siltation in Xiaohai lagoon. c impact. The sedimentation rates are 0. 46cm·a^-1 from 160 cm to 18cm, and to surface. The increased sedimentation rate in recent years has accelerated the siltation in Xiaohai lagoon.