Analysis of optimal environmental conditions for Microcystis blooms in large, shallow, eutrophic lakes

Abstract

Harmful algal blooms caused by cyanobacteria have detrimental impacts on lake ecosystems. Uncovering the factors influencing such blooms could facilitate aquatic ecosystem conservation and early warning activities. The experiment simulated the environmental characteristics of shallow eutrophic Lake Ulansuhai in arid regions of China. The experiments were conducted at various temperatures (6, 10, 19, 25°C) and different nutrient conditions (N: 1∼6 mg/L, P: 0.05∼1.00 mg/L) and in the presence of water, algae, and sediment under various disturbance levels (0, 100, 200, 250, 300, 350, 400 rpm). In this study, The optimal Microcystis growth conditions observed in the study were as follows: 19°C ≤ temperature ≤ 25°C; 1.0 mg/L ≤ N ≤ 1.6 mg/L; 0.05 mg/L ≤ P ≤ 0.1 mg/L; 16 ≤ N/P ≤ 20; and lake flow velocity = 10 cm·s⁻¹ (200 rpm). The most suitable pH for the growth of Microcystis is 8.5. Investigating the environmental factors that affect the growth of bloom-forming cyanobacteria could aid the development of early warning systems and guide lake restoration activities under climate warming, N:P imbalance, and varying lake velocity scenarios.

KEYWORDS:

• Microcystis
• eutrophication
• disturbance intensity
• sediment
• lake restoration

Acknowledgements

We gratefully acknowledge Professor Xixi Lv for help with this paper and thank our classmates for their guidance on the experiments.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available in https://osf.io/j7hmp/?viewonly=2766b25af68a4a71911e53c75f59550b.

Additional information

Funding

This study was funded by the Key Scientific and Technological Project of Inner Mongolia (grant no. 2019GG019), Major Science and Technology Projects of Inner Mongolia Autonomous Region (grant nos. 2020ZD0009 and ZDZX2018054), National Natural Science Foundation of China (grant no. 51869014), National Key Research and Development Program of China (grant no. 2016YFC0500508), and Open Project Program of the Ministry of Education Key Laboratory of Ecology and Resources Use of the Mongolian Plateau (grant no. KF2020006).