Current research in my research laboratory focuses on detecting and quantifying the sublethal molecular, biochemical and physiological responses of fish and aquatic invertebrates to anthropogenic environmental stressors, in particular elevated temperature and neurotoxic insecticides, and interpreting these in an ecological context. The overall goal is to provide information and develop tools to protect and manage aquatic ecosystems.
Field and laboratory investigations for my projects are designed to investigate the relationship of acute versus chronic effects of toxic compounds or temperature stress in aquatic organisms by measuring a combination of conventional toxicity test endpoints and cellular responses. One area of emphasis has been the investigation of heat shock (or stress) proteins as indicators of exposure and/or effect in various fish, bivalve, insect and amphipod species. Stress proteins are involved in cellular protein synthesis, transport and repair, and play an important role in cellular receptor activation. Their cellular functions make them good candidates as indicators of cellular protein damage and receptor related disruption, caused by the action of xenobiotic compounds or physical stressors such as pH or temperature changes. In addition, we have studied developmental aspects of stress protein expression in fish and their relationship to temperature stress and tolerance. This research is important for the understanding of when a particular organism is most susceptible to physiological insult.
Ultimately, such cellular endpoints will only be meaningful tools if they can be linked to deleterious effect at the organism or population level. Recent advances in molecular biology allow a broader approach to detecting and understanding the sublethal effects of environmental stressors on organisms using DNA microarray and quantitative PCR technology. Immediate goals of our ongoing research are to select candidate biomarker genes, and establish quantitative links between molecular and cellular responses, and effects on physiology, behavior, and survival of fish. This should ultimately lead to the establishment of mechanistically based suites of molecular biomarkers.
Other areas of interest are the influence of metabolic energy reserves on cellular stress responses, the effect of temperature change due to global warming on the physiology of coldwater fish species, and the effect(s) of multiple stressors.
My students and postdoctoral scholars work closely with the UC Davis - Aquatic Toxicology Laboratory (UCD-ATL), whose director I am. The UCD-ATL is a State-certified toxicity testing laboratory with over 20 years of experience in investigating surface water quality and aquatic ecosystem health in watersheds throughout California. Components of this research include aquatic monitoring studies to assess impact and efficacy of alternative pest control methods in agriculture and urban areas.
