三峡水库香溪河初级生产力及其影响因素分析

2013 2014年采用黑白瓶测氧法对香溪河不同站点(上、中、下游及其支流库湾)和不同水深(0.5、1.0、2.0、5.0和10.0 m)的初级生产力进行原位测定.结果显示:(1)三峡水库蓄水后香溪河水域初级生产力具有显著的空间差异,支流和上游的总初级生产力大于中、下游,下游的初级生产力水平最低;初级生产力随着水深增加呈现逐渐减少的趋势;(2)初级生产力具有显著的季节差异,春、夏季显著高于秋、冬季;(3)光照强度、水温和天气对初级生产力有显著影响,水体叶绿素浓度与初级生产力极显著相关.结果显示,蓄水后改变的水文情势将香溪河的初级生产划分为明显不同的两个区域,水动力条件成为影响初级生产力的重要因子;依据初级生产力判断香溪河为富营养、自养代谢型水体.

Primary production and its influencing factors in Xiangxi River, Three-Gorges Reservoir

The dark and light bottle method of oxygen measurement was adopted to determine the primary production at different sites and different water depths (0.5, 1.0, 2.0, 5.0 and 10.0 m) in Xiangxi River, Three-Gorges Reservoir during 2013 and 2014.4 sites were located in the upper reaches (PYK), the middle reaches (XK), the anabranch (WJW) and the lower reaches (HK), respectively.There was a significant spatial difference in phytoplankton primary production.The gross primary production of the anabranch on the upper reaches was much higher than that on the middle reaches, but the least gross primary production appeared at the lower reaches.With the increase of the depth of the water, the primary production increased at 0-2 m depth, and then decreased at >2 m water depth.The primary production showed a significant seasonal variation.The light intensity, water temperature and weather have influenced the primary production of Xiangxi River significantly.There is a close relationship between the primary production and chlorophyll-a.It could be concluded that hydraulic regime was the important factor to influence the primary production and divided Xiangxi River into two different parts.Based upon the primary production, Xiangxi River was eutrophic with autotrophic metabolism.