Time: 10:00, April 20, 2015

Venue: 8th Floor of the No. 1 Laboratory Building

Speaker: Prof. Rudolf Wu

                  University of Hong Kong

Title: Functional responses of marine ecosystem to hypoxia

Introduction to the Speaker: 

Professor Rudolf Wu received his PhD from the University of British Columbia and he worked in Canada, USA, Australia and Hong Kong afterwards. Currently, he is the Chair Professor and the Director of the School of Biological Sciences, the University of Hong Kong. He is the Director of the Centre for Marine Environmental Research and Innovative Technology (MERIT), one of the "Areas of Excellence” (AoE) in Hong Kong, and also the founding Director of the State Key Laboratory in Marine Pollution.

Professor Wu’s research primarily focuses on the molecular, biochemical, physiological and ecological responses of marine animals to environmental stresses, with a particular emphasis on hypoxia, xenobiotics and endocrine disrupting chemicals. Currently, he is researching into the trans-generational effects of hypoxia and endocrine disrupting chemicals on fish and the underlying epigenetic mechanisms. He has published one book, five book chapters, and over 240 papers in leading journals in environmental sciences, environmental toxicology and marine ecology. Professor Wu is the associated editor of four international journals and was the Chief Guest Editor of seven special issues of the journal “Marine Pollution Bulletin”.

Professor Wu has served on many working / expert groups of international organizations, including the United Nations, the International Maritime organization and the Intergovernmental Oceanographic Commission (IOC). He was one of the 24 members of the Coastal Ocean Observation Panel of the IOC, and is currently one of the 13 members of the “Group of Experts on Scientific Aspects of Marine Environmental Protection” of the United Nations, the Director of the “Regional Centre of Excellence in Marine Pollution” of the United Nation’s Regional Programme of the East Asian Seas, and also a member of the Scientific Advisory Panel of United Kingdom's Environment Agency.

In his career, Prof. Wu has secured over US$19 million competitive research grants. In the past five years, Professor Wu completed many milestone consultancy studies for the government of Hong Kong SAR. The total contract value of consultancy studies under his leadership exceeded US$5 million.

Speaker: Prof. Kenneth M. Y. Leung 
                  University of Hong Kong

Title: Temperature-dependent chemical toxicity models and their implications on derivation of water quality criteria and ecological risk assessment

Introduction to the Speaker: 

Kenneth Leung is Professor of Aquatic Ecology and Toxicology at the Swire Institute of Marine Science and School of Biological Sciences, in the University of Hong Kong (HKU) where he also acts as Associate Dean (Research & Graduate Studies) at the Faculty of Science. He obtained his PhD in marine ecotoxicology from University of Glasgow and received postdoctoral training in environmental risk assessment (ERA) of chemical pollutants at University of London. So far, he has published over 130 peer-reviewed articles which are principally related to the ecology, pollution, ecotoxicology and ERA in both marine and freshwater ecosystems. During 2010–2012, he was the elected President of the Society of Environmental Toxicology and Chemistry (SETAC) Asia Pacific Geographic Unit. He is a founding editor-in-chief of the Elsevier journal, Regional Studies in Marine Science and a subject editor for the SETAC journal, Integrated Environmental Assessment and Management. He is also an editorial board member for a number of SCI journals, such as Marine Pollution Bulletin, Environmental Science and Pollution Research, Scientific Reports, Integrative Zoology, and Canadian Journal of Zoology. At present, he serves as an expert member in various advisory committees for the Government of the Hong Kong Special Administrative Region, such as Advisory Council on Food and Environmental Hygiene, Marine Parks Committee, Endangered Species Advisory Committee, Red Tide/Harmful Algal Blooms Expert Advisory Group and Marine Mammal Conservation Working Group. Owing to his professional achievements and community services, he was selected as one of the “Ten Outstanding Young Persons” for Hong Kong by Junior Chamber International in 2010.

Introduction to the Lecture:

The anticipated anthropogenically-driven climate change not only can increase the average air and water temperatures and prolong the hottest period, but also result in increased incidents of temperature extremes that will have profound implications on the toxicity of chemical contaminants and hence their ecological impacts to aquatic organisms. This study aims to comprehensively examine and elucidate the mechanisms of temperature-dependent chemical toxicities to aquatic ecototherms based on both literature review and empirical laboratory studies. Examples will be drawn from an array of marine organisms upon chemical exposure at different temperatures. Our results suggest that most of the organisms have the highest tolerance to chemicals at their optimal temperature (OT) where they displayed the highest value of median lethal or effect concentration, and the chemical toxicity increased at temperatures departing from the OT. Such universal phenomena could be well explained by the thermal performance curve and the oxygen limited thermal tolerance theory. In contrast, small crustaceans could undergo metabolic depression and enter dormancy at low temperatures, and thus chemical toxicity generally declined with decreasing temperatures. The two hypothetical temperature-dependent chemical toxicity models are further verified through a comprehensive meta-analysis using temperature-based species sensitivity distributions. Moreover, the overall temperature-dependent toxicity profiles vary considerably amongst different chemicals. Such differences may be partially attributable to the differences in temperature-mediated modifications of their physicochemical properties, toxicokinetics and bioavailability. Recently, we have been conducting a novel meta-analysis to address whether an assessment factor of 10 (AF10) applied to fresh and salt water quality criteria (WQC) would be sufficient to account for variation in chemical toxicity brought by thermal extremes. Our results suggest that AF10 seems adequately protective to tropical species but not their temperate counterparts. The results will be discussed in relation to ecological risk assessment of chemical contaminants and WQC derivation for protecting aquatic ecosystems.