生态调水驱动下富营养化湖泊溶解氧与叶绿素a动态耦合响应研究OA

Taihu Lake was selected as a representative eutrophic lake for this investigation.Focusing on the"Diverting Yangtze River Water to Taihu"ecological water diversion project,we set two sampling points in the water diversion area(Gonghu Bay)and a reference area(lake center)to conduct monthly field investigations in 2011(high-intensity water diversion period),2014(medium-intensity water diver-sion period),and 2016(low-intensity water diversion period).Based on the monitoring data,the tempo-ral and spatial variation characteristics of chlorophyll-a(Chl-a),dissolved oxygen(DO),and key envi-ronmental factors under different water diversion intensities were systematically analyzed and the cou-pling response laws and driving mechanisms of Chl-a and DO concentrations were identified.We aimed to clarify the regulatory mechanism of ecological water diversion on the dynamic coupling relationship between Chl-a and DO in eutrophic lakes,and provide a quantitative basis and scientific support for opti-mizing lake water diversion schemes and enhancing the long-term effectiveness of ecological restora-tion.The concentration of Chl-a in the water body and the risk of cyanobacterial blooms significantly de-creased(P<0.01)after the water diversion scheme was implemented and the concentration of Chl-a in the water diversion area(Gonghu Bay)decreased from 24.35 μg/L to 12.51 μg/L.Ecological water diversion also altered the algal growth environment in the water diversion area and reshaped the restrictive environ-ment for algal growth so that total phosphorus might not be the main influencing factor for Chl-a concen-tration.During the ecological water diversion period DO increased,but DO saturation decreased from 96%to 85%,indicating that water diversion could decrease photosynthetic oxygen production by lower-ing algal biomass,thereby changing the balance of DO production and consumption.Ecological water di-version not only changed the coupling relationship between Chl-a and DO,but indirectly affected DO by increasing the input of exogenous nutrients.This study clarified the regulatory mechanism of ecological water diversion on the coupling process of lake algal biomass and DO production/consumption and pro-vides quantitative scientific support for optimizing lake water diversion schemes and enhancing the long-term effectiveness of ecological restoration.