厦门港疏浚物海洋倾废评价试验研究 Ⅱ.疏浚物倾倒对围隔海水初级生产力的影响

MESOCOSM ASSESSMENT OF DUMPING DREDGED MATERIALS FROM XIAMEN HARBOUR AT SEA Ⅱ .EFFECT ON PRIMARY PRODUCTIVITY IN MESOCOSM

讨论了围隔海水中初级生产力的变化及其与主要有害物质释放、营养盐溶出和悬浮物质增加引起的光照度变化之间的关系。初步结论认为,在疏浚物的浓度为150mg/L的情况下,尽管其中某些有害物质和营养盐有不同程度的释放,但对初级生产力不产生明显影响。然而,当混合作用使得疏浚物悬浮颗粒的浓度维持在130±30mg/L时,真光层光照度降低到表层光照度的十分之一以下,浮游植物光合作用受到抑制,初级生产力大约只有对照袋的三分一。

The mesocosm technique was used to study the release of some important harmful substances from the dredged materials from the Xiamen Harbour after dumped into seawater and its effect on primary productivity.The changes of primary productivity in the mesocosm and the relationship to the release of the harmful substances and nutrients and to the light intensity changes due to the increase of SPM are discussed in this paper.It was priliminarily found out that although release of some substances and nutrients occures to different extent after dredged materials from the harbour dumped with concentration of 150 mg/L into the mesocosm,the primary productivity was not obviously influenced.When SPM was kept at a concentration of 130*********+30 mg/L in the water column,however,the light intensity at 0.5m layer reduced to less than one tenth of that at water surface,and photosynthesis of phytoplankton was inhibited resulting in that the primary productivity decreased by a factor of 3 compared with the control bag.