UK^(37)沉积地层记录:三门湾海表温度(SST)和EI Nio现象及其对大型底栖动物生命活动的影响

Stratigraohic record of U K^(37):sea surface temperature(SST) and EI Nio in the Sanmenwan bay and the effect of it on life activity in Macrobenthos communities

应用UK37估算三门湾(1916~2003年)表层海水温度,SST波动范围在15.97~18.00℃之间,年平均为17.03℃,此计算值比当年实测海水全年平均温度低3.52℃,与秋季海水实测温度相接近。研究显示出,三门湾的EI Nio事件在大尺度上与东太平洋一样,均受制于气候影响因素,但在变化尺度上又受到地理位置和地方性气候(季风)的影响,事件在形式和年代上相互对应,但其颤动幅度远不如东太平洋强烈。同时通过比较EI Nio期间(2003/2002)和非EI Nio期间(2006/2005)大型底栖生物的群落结构变动信号、生物量、栖息密度以及物种多样性等,研究显示出三门湾若干大型底栖生物对EI Nio事件产生响应迹象,若干大型底栖生物对EI Ni o的响应主要是通过海洋环流的影响来体现生命和生态效应的,主要表现在改变了底栖生物种类数和多样性、以及生命活动及栖息密度分布模式。在EI Nio影响下,台湾暖流入侵势力加强,2003/2002年底栖生物群落种类数减少与海流入侵及盐度密切相关;通过与同海域浮游动物对比研究,三门湾海域浮游动物和底栖生物对EI Nio的生态响应均较大,前者可能与三门湾海域水域较浅,外海暖水从底部入侵改变水温和盐度,直接影响底栖生物的生态环境,致使种类数大大减少有关;而后者由于入侵暖水强度增大,携带大量暖水性浮游动物,呈现出在EI Nio时期浮游动物种类数、生物量和丰度有偏高趋势。

Sea surface temperature （SST） was estimated by the index of U^K37 of organic compounds in the Sanmen bay sediment. It fluctuated between 15.97℃ and 18. 00 ℃ with an average of 17.03℃. The estimated SST was 3.52℃ lower than the annual average temperature measured in the same year but was close to the temperature measured in fall. The research indicated that like the climate in the Eastern Pacific Ocean, on a large scale, the climate in the Sanmen bay was similarly affected by the climate events to a different degree according to geographical location and local climate such as monsoon. Like the Eastern Pacific Ocean, in a similar way in chronological basis, the Sanmen bay responded to the climate events but in a weaker scale. By comparison of the community, biomass, inhabit density and biodiversity of macrobenthos during EI Nino （ between year 2002 and 2003 ） and non-EI Nifio （ between year 2005 and 2006 ） periods, the research indicated that certain macrobenthos communities in the Sanmen bay responded to EI Nino events by changing those biological features through oceanic circulation. During EI Nino period, warm Taiwan current strongly flowed into the bay.The species of the macrobenthos community during year 2002 and 2003 correlatively reduced with the intrusive current and with the salinity change. Compared to their correspondent in adjacent seas, both the macrobenthos communities and zooplankton in the Sanmen bay responded to EI Nino event more significantly. The macrobenthos community species decreased significantly because a warm water invaded into the shallow bay from the floor and thus changed the temperature and salinity in the bay. On the other hand, zooplankton species, biomass and abundance tended to increase in the period of EI Nino since the invaded warm current carried abundant zooplankton.