报告题目：The variability of cyanobacterial occurrence – Why? When? What? How?
报告人：Elke Reichwaldt教授（西澳大学）
报告时间：2017年4月28日9:00 - 11:00
报告地点：科技中心504
报告摘要：The variability of cyanobacterial occurrence – Why? When? What? How?
Freshwater cyanobacteria present a hazard for humans and the environment due to their ability to produce toxins. While there is some agreement on the key drivers responsible for bloom development and toxin production, the interactive effect of these drivers is less understood and it is still a challenge to predict blooms reliably. Due to the highly variable spatial and temporal bloom occurrence, management authorities are still often caught by surprise when blooms suddenly occur. It is even more difficult to predict the toxin production, which in addition depends on a number of factors, such as the presence of toxin producing species, the presence of toxin-producing strains within a species, and the level of toxin-geneexpression. To enable a sustainable management of cyanobacterial blooms, a holistic approach has to be used to understand the drivers of the variability of bloom occurrence and its effect on key players in the food web.
In this talk I will aim to answer some of the important questions in relation to cyanobacterial bloom management: Why do some lakes develop blooms and others don’t? Whenare toxins produced? What effectdoes the spatial bloom variability have on the zooplankton community? How can we improve mitigation and management of toxic cyanobacterial blooms?
Why? When? What? The data presented show that cyanobacteria and toxin dynamics are driven by complex, lake-specific interactions of environmental variables, making it unlikely that ONE-FITS-ALL management strategies can reliably be used to manage water bodies in the future. Instead this between-lake heterogeneity has to be taken into account. However, while the high spatial and temporal variability of bloom occurrence is a challenge for management, our study shows that it is a win situation for the zooplankton community, because it creates refuge sites that allow large grazers, that are easily affected by toxic cyanobacteria, to survive during blooms.
How? The unpredictability of cyanobacterial bloom occurrence,especially in drinking water reservoirs or ponds that treat wastewater to be reused for irrigation, might require immediate mitigation action. Results of a large scale in-situ study indicate that hydrogen peroxide (H2O2) is able to suppress cyanobacterial biomass and decrease toxin concentration for 3-4 weeks, highlighting its suitability as an environmentally friendly chemical to mitigate blooms.
How? A further problem for management stemming from the unpredictability of bloom occurrence is that blooms often go undetected, because not all waterbodies can be monitored regularly. This poses a problem for current risk assessment strategies because adequate actions to protect the public are only implemented when blooms are detected in the first place. We therefore developed a novel risk assessment model that allows the determination of the level of risk that a waterbody poses to the public even if blooms are not detected.
The talk will conclude with an outlook on how changes in the rainfall patterns (due to climate change) will impact cyanobacterial and toxin dynamics in the future. This will include an identification of some of the major knowledge gaps that need to be addressed to allow a sustainable management of toxic cyanobacteria in the future.
报告人简介：
Elke Reichwaldt has recently started an honorary research fellow appointment at the University of Western Australia (UWA) after having worked at as Research Fellow within the Aquatic Ecology and Ecosystems Studies Group at UWA since 2008. She completed her PhD at the University of Munich (2004) and was a Research Fellow at the Max-Planck Institute for Limnology, Plön, Germany.
Her research seeks to understand the ecological functioning of natural and engineered waterbodies, with a focus on microbial and grazer communities, to inform sustainable water resource management.
欢迎全校师生参加！
备注：本次报告纳入海洋生物学科继续教育课程。
汕头大学理学院/海洋生物研究所
2017年4月26日
