Chin J Plant Ecol ›› 2023, Vol. 47 ›› Issue (8): 1171-1181.DOI: 10.17521/cjpe.2022.0181

Special Issue: 光合作用

• Research Articles • Previous Articles     Next Articles

Chlorophyll a variation and its driving factors during phase shift from macrophyte- to phytoplankton-dominated states in Caohai Lake, Guizhou, China

LI An-Yan1,2, HUANG Xian-Fei1,2, TIAN Yuan-Bin1,2, DONG Ji-Xing1,2, ZHENG Fei-Fei1,2, XIA Pin-Hua1,2,*()   

  1. 1Key Laboratory for Information System of Mountainous Areas and Protection of Ecological Environment of Guizhou Province, Guizhou Normal University, Guiyang 550001, China
    2Guizhou Caohai Wetland Ecosystem National Observation and Research Station, Bijie, Guizhou 553199, China
  • Received:2022-05-07 Accepted:2022-09-12 Online:2023-08-20 Published:2022-09-13
  • Contact: *XIA Pin-Hua(
  • Supported by:
    Science and Technology Plan Project of Guizhou Province(2021470);National Natural Science Foundation of China(41867056)


Aims In recent years, the aquatic ecosystem of Caohai Lake, in Guizhou Province in southwest China, has shown a trend of phase shift from macrophyte- to phytoplankton-dominated states, which indicates the weakening ecological functioning of the lake. The chlorophyll a (Chl a) concentration is an important indicator of phytoplankton biomass. It is of great significance to clarify the variation of Chl a concentration in comprehensively understanding the ecological status and developing feasible restoration measures for the Lake.

Methods Surface water samples were collected from the Lake in summers and autumns of 2020-2021 to analyze the variation of Chl a concentration. The generalized additive model (GAM) was applied to explore the relationship between each environmental factor and Chl a concentration.

Important findings The results showed that, the Chl a concentration in surface water of Caohai Lake increased during phase shift, with an average up to (17.96 ± 10.62) μg·L-1(during the monitoring period in 2021), which was 2.5 times greater than that before the phase shift (during monitoring period in 2020). The comprehensive trophic state of the Lake changed from mesotrophic state to eutrophic state, and the water quality presented an obvious trend of deterioration. Results from the single-factor GAM analysis showed that permanganate index (CODMn), total nitrogen (TN) concentration and water temperature (WT) had significant effects on Chl a concentration, which among all investigated environmental factors, account for 26.70%-33.30% of the concentration variation of Chl a, with WT, CODMn, TN concentration exhibiting the largest, intermediate, and smallest impact respectively. Based on the present study, it is concluded that CODMnand TN concentration were important factors driving the variation of Chl a concentration in Caohai Lake, and WT was an inducing factor. The massive extinction of submerged macrophyte and the significant increase of Chl a concentration indicated that the Lake is in phase shift from macrophyte- to phytoplankton-dominated state. Feasible measures should be developed timely to promote the restoration of submerged macrophyte, and further studies on phase shift mechanisms and restoration measures for the Lake should be carried out.

Key words: Caohai Lake, Guizhou, chlorophyll a concentration, regime shift, environmental factor, GAM model