Spatial distribution and filtering efficiency of Daphnia in a deep subtropical reservoir  

作　　者：ZHANG Man SMYTH Rebecca Ashley ZHU Weixia ZHANG Li LI Yuncong WANG Yifan LI Xuejun GU Qianhong GAO Yunni 

机构地区：[1]College of Fisheries, Henan Normal University, Xinxiang 453007, China [2]Tropical Research and Education Centre, University of Florida, Homestead 33031, U.S. [3]Henan Entry-Exit Inspection and Quarantine Bureau, Zhengzhou 450003, China

出　　处：《Journal of Oceanology and Limnology》2019年第4期1277-1288,共12页海洋湖沼学报（英文）

基　　金：Supported by the National Natural Science Foundation of China(Nos.31400397,31700405);the Foundation of He’nan Science and Technology Department(No.172102210345)

摘　　要：Studies of Daphnia distribution and function could help people manage and protect water quality. We investigated how spatial distribution and filtering efficiency of Daphnia in the transition and lacustrine zones of the Nanwan Reservoir (China). Samplings were conducted seasonally for 2 years from six sites in the reservoir. Daphnia abundance and biomass were significantly higher in the lacustrine zone than in the transition zone. Similar composition and biomass of edible phytoplankton were found in the two zones, suggesting that food quantity could not explain high Daphnia distribution in the lacustrine zone. The variations of water velocity and food quality could help explaining Daphnia patchy distribution in the reservoir. On the one hand, rapid water velocity can cause the Daphnia decrement in the transition zone. On the other hand, the ratio of particulate organic carbon (POC) to chlorophyll a (chl a) concentration was significantly higher in the transition zone, indicating more allochthonous material constituted the food source for Daphnia. The lower quality food likely suppressed Daphnia development in the transition zone. A linear regression between Daphnia abundance and Secchi depth (SD) may suggest a cause-effect relationship where increased filtering efficiency was responsible for increased water clarity to some extent.Studies of Daphnia distribution and function could help people manage and protect water quality.We investigated how spatial distribution and filtering efficiency of Daphnia in the transition and lacustrine zones of the Nanwan Reservoir(China).Samplings were conducted seasonally for 2 years from six sites in the reservoir.Daphnia abundance and biomass were significantly higher in the lacustrine zone than in the transition zone.Similar composition and biomass of edible phytoplankton were found in the two zones,suggesting that food quantity could not explain high Daphnia distribution in the lacustrine zone.The variations of water velocity and food quality could help explaining Daphnia patchy distribution in the reservoir.On the one hand,rapid water velocity can cause the Daphnia decrement in the transition zone.On the other hand,the ratio of particulate organic carbon(POC)to chlorophyll a(chl a)concentration was significantly higher in the transition zone,indicating more allochthonous material constituted the food source for Daphnia.The lower quality food likely suppressed Daphnia development in the transition zone.A linear regression between Daphnia abundance and Secchi depth(SD)may suggest a cause-effect relationship where increased filtering efficiency was responsible for increased water clarity to some extent.

关 键 词：DAPHNIA LACUSTRINE ZONE transition ZONE water CLARITY Nanwan RESERVOIR 

分 类 号：P[天文地球]