Succession of phytoplankton functional groups and their driving factors in a subtropical plateau lake

Jing Cao; Zeying Hou; Zekun Li; Zhaosheng Chu; Pingping Yang; Binghui Zheng

doi:10.1016/j.scitotenv.2018.03.026

Succession of phytoplankton functional groups and their driving factors in a subtropical plateau lake

Sci Total Environ. 2018 Aug 1:631-632:1127-1137. doi: 10.1016/j.scitotenv.2018.03.026. Epub 2018 Mar 16.

Authors

Jing Cao¹, Zeying Hou¹, Zekun Li², Zhaosheng Chu³, Pingping Yang², Binghui Zheng¹

Affiliations

¹ National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
² Environmental Monitoring Station of Dali Prefecture, Dali 671000, China.
³ National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China. Electronic address: chuzssci@yeah.net.

PMID: 29727939
DOI: 10.1016/j.scitotenv.2018.03.026

Abstract

The present study was carried out in a mesotrophic subtropical plateau lake, Erhai, located in southwest of China. The succession of phytoplankton functional groups and the environmental variables in the lake were investigated from January 2013 to December 2015. The lake had strong radiation levels and a low-temperature amplitude because of its high elevation and strongly mixed water. It was highly affected by the subtropical monsoon precipitation, and its pollution sources were from diffuse pollution caused by rainfall runoff. Altogether 112 genera, 16 functional groups and 4 predominant functional groups, L_M (Microcystis), P (Melosira, Fragilaria, Closterium), T (Mougeotia), T (Psephonema aenigmaticum) and Y (Cryptomonas), were identified, and the predominant functional groups demonstrated strong seasonal variations. Group T (Mougeotia) dominated from the winter to early spring, with strong lake water mixing. Group P replaced group T (Mougeotia) as the dominate group of the phytoplankton community in the spring (March to May), with clear water and increased temperature. With the arrival of the monsoon rainy season in the summer, large amounts of external pollutants were brought into the lake via rainfall runoff, allowing group L_M (Microcystis) to become dominant. Meanwhile, the intensive nutrient inputs after the rainstorm in the summer, combined with high temperatures and decreased radiation, led to the sustained growth of group L_M in the autumn and even ultimately triggered Microcystis blooming. Group T (P. aenigmaticum) was a particular phytoplankton genus predominant in the autumn, which displayed a seasonal variation similar to that of group L_M. This study underscores the usefulness of phytoplankton functional groups in studying phytoplankton succession in subtropical plateau lakes impacted by diffuse pollution, in which the succession of phytoplankton functional groups can be significantly affected by rainfall runoff, which altered variables such as nutrients, high temperatures and radiation.

Keywords: Driving factors; Microcystis blooms; Phytoplankton functional groups; Precipitation; Subtropical plateau lake; Succession.