Algal blooms: Proactive strategy

CYANOBACTERIAL HARMFUL algal blooms (CHABs) are increasing in severity on a worldwide basis. Combining nutrientsource control with post-bloom control is currently considered the best strategy for dealing with CHABs (1). However, huge investments in this strategy have proven ineffective in China, as demonstrated by yet another massive bloom last summer in Lake Tai despite over 100 billion RMB (more than US$16.25 billion) invested since 2007 (2). Further afield, four decades of strict phosphorus loading regulations have not prevented massive CHAB events in Lake Erie of the Laurentian Great Lakes of North America and the adjacent water bodies (3).

The current strategy apparently has limited effectiveness. Furthermore, nutrient-source control may not be feasible for many developing countries because of increasing population pressure and pollution, and elevated CO2 influx into aquatic systems and climate change will intensify algal blooms (4). Once CHABs have occurred, even the most effective methods to date of removal of cyanobacteria and cyanotoxins cannot eliminate their adverse impacts on ecosystems and human health (5).

We firmly believe that the missing key component in the current strategy is proactive CHAB control. By implementing this approach over the past 15 years, we have achieved effective long-term prevention of CHABs in several severely eutrophic lakes and reservoirs in Eastern China (6), thus showing that this approach is entirely possible and practical. Our strategy also affords valuable time for the implementation of nutrient-source control.

Proactive CHAB control requires appropriate technical expertise aimed at inhibiting algal growth during the spring season, when cyanobacteria is vulnerable to foraging species. This would involve developing new tools to trace pre-bloom algal distribution so that proactive treatments only need to be implemented within algae concentrated areas and in a costeffective manner. Continuous monitoring
and assessment of water bodies would maximize treatment efficacy.

Moreover, supportive laws and government policies are necessary. In particular, governments from different jurisdictions should reallocate resources to where CHABs originate; implement an appropriate merit system for proactive CHAB prevention and other measures related to eco-service enhancement; and curtail counterproductive human practices such as illegal fishing by enhancing law enforcement and providing alternative livelihoods and social learning to affected communities.

Mingzhi Qu,1 Daniel D. Lefebvre,1
Yuxiang Wang,1Yunfang Qu,2 Donglin
Zhu,3 Wenwei Ren4*

Department of Biology, Queen’s University, Kingston, ON, K7L 3N6, Canada. 2Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, School of Life Sciences, Fudan University, Shanghai, 200433, China. 3Jiangsu Engineering Consulting Center, Nanjing, Jiangsu Province, 210003, China. 4Key Laboratory of Yangtze Water Environment, Ministry of Education, The College of Environment Science and Engineering,

Tongji University, Shanghai, 200092, China.
*Corresponding author.