Numerical Study of the Three Gorges Dam Influences on Chlorophyll-a in the Changjiang Estuary and the Adjacent East China Sea  

作　　者：CHEN Dongxing LIU Qianqian YIN Kedong 

机构地区：[1]School of Marine Sciences/Guangdong Key Laboratory of Marine Resources and Coastal Engineering,Sun Yat-sen University,Guangzhou 510275,China [2]Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 510275,China [3]Department of Physics and Physical Oceanography,University of North Carolina Wilmington,Wilmington,NC 28403,USA

出　　处：《Journal of Ocean University of China》2021年第1期10-22,共13页中国海洋大学学报（英文版）

基　　金：supported by grants from the GuangdongNSFC Joint Theme Project(No.U1701247);the National Natural Science Foundation of China(No.91328203);the Southern Marine Science and Engineering–Guangdong Laboratory(Zhuhai)(No.311019006);the Sun Yat-sen University Supercomputing Funding(No.42000-52603700)。

摘　　要：The impoundment of the Three Gorges Dam(TGD)has altered downstream hydrological characteristics and sediment discharge,and it has caused ecological impacts,such as changes in chlorophyll-a(Chl-a)in estuaries and coastal oceans.To investigate the TGD's influence on Chl-a's interannual and seasonal variations in the Changjiang Estuary and the adjacent coastal East China Sea,a physical-biogeochemical model was developed with numerical experiments covering a decade,including TGD's preperiod(pre-TGD,1999–2003)and post-period(post-TGD,2004–2008).The modeling results demonstrate an annual increase in the regional average Chl-a from pre-to post-TGD,with the largest increase reaching up to 20.8%in spring in the nearshore region beyond the Changjiang mouth.The spatial variations in Chl-a are high,with the largest variation being observed around the 20–40 m isobaths.The increase in Chl-a is influenced by improved light and nutrient conditions,which is attributed to dam construction and fertilization by human activities.A decline in nitrogen-phosphorus fertilizer usage ratio along the Changjiang River watershed after the TGD's impoundment is another factor that influences the Chl-a's variation.The modeling results also show severe NO3 and PO4 imbalances with a larger N/P ratio during the post-TGD period,especially in regions with large Chl-a increases.Moreover,the greater increase in the usage of phosphorus fertilizer than nitrogen fertilizer influences Chl-a's variation and has potential promotion effects on the outbreak of harmful algal bloom events.

关 键 词：physical-biogeochemical model CHL-A coastal ecosystem East China Sea 

分 类 号：X143[环境科学与工程—环境科学] TV632[水利工程—水利水电工程]