三峡水库香溪河库湾夏季水华期间浮游植物的初级生产力

PHYTOPLANKTON PRIMARY PRODUCTION DURING SUMMER BLOOM IN XIANGXI BAY,BRANCH OF THE YANGTZE RIVER

用黑白瓶法调查了香溪河库湾夏季水华期间浮游植物的初级生产力,探讨了浮游植物初级生产力的分布格局、光照强度对初级生产力的影响以及香溪河库湾浮游植物群落的代谢类型。结果表明:河口、峡口、吴家湾和平邑口总初级生产力最大值分别为6.33、3.89、6.51和4.67 gO2/(m2.d);平邑口、吴家湾、峡口、河口0~5 m水柱日生产量分别为6.95、6.78、5.17和4.65 gO2/(m2.d)。除平邑口的最大生产力出现在水下0.5 m以外,其余3个样点的生产力垂直变化均表现为表层最高,随水深增加而逐渐降低。吴家湾、峡口、河口三位点总初级生产力和净初级生产力与相对应水层的平均光照强度呈显著正相关,而平邑口位点相关性不明显。香溪河库湾1 m水深以内的群落代谢率平均值为4.0,推测夏季水华期间该水体1 m水深以内的浮游植物群落为自养代谢类型。

The characteristics of phytoplankton primary production in summer in Xiangxi Bay were estimated by means of dark and light bottle method(Winkler method).The region distribution,vertical profile of primary production,together with the relationship between light intensity and primary production were studied.The results showed that the maximum of gross primary production in HK,XK,WJW and PYK was 6.33,3.89,6.51 and 4.67 gO2/(m2·d),respectively.The maximum production layer in PYK was found below 0.5 m,however,a decrease trend was observed with increase of the water depth in the other three site.The primary production of 0~5m water column per day in PYK、WJW、XK and HK were 6.95,6.78,5.17 and 4.65 gO2/(m2·d),respectively.A postive correlation was found between gross and net primary production and avergae light intensity of corrsponding water layers in HK,XK,WJW sites.While,no significant correlation was found in PYK site.The average metabolic rate of plankton community within 1 m depth was 4 in the whole Xiangxi Bay,which probably showed that the type of plankton community within 1 m depth was autotrophic metabolism.