Biochemical investigations into the ecology and ecotoxicology of algal toxins
Thursday June 7, 2012
Redfield Auditorium - 12:00 Noon
Dr. Juliette Smith
Woods Hole Oceanographic Institution
Worldwide, harmful algal blooms (HABs) negatively impact human health, marine and freshwater ecosystems, fisheries resources, and local economies. I focus on a diverse group of HABs (cyanobacteria, dinoflagellates and diatoms) along the freshwater-estuarine-oceanic gradient that produce biotoxins with neurotoxic or carcinogenic attributes. I have shown that the bioactive compounds produced by these dynamic organisms range greatly over temporal and spatial scales with respect to chemical structure, concentrations, uptake kinetics, and stability in animal tissue, sediments and surrounding waters. As such, my research into the ecotoxicology of these algal toxins involved the development of sensitive techniques that take into account the chemical and biochemical properties of these toxins. I then implemented these tools to study critical aspects of toxin production, extracellular release, foodweb transfer, toxicity, detoxification, and degradation in both lab and field applications. As ecosystems can be concurrently exposed to numerous toxin groups and toxin congeners (i.e., compounds with similar chemical structure), I utilized, and will continue to use, sophisticated analytical methods to quantitate complex toxin profiles. For example, my research characterized variations in toxin production and toxin profiles using tandem mass spectrometry that were dependent upon algal growth stage, food quality, dissolved nutrient availability, prey type and physical environment. I also paired LC-MS with biochemical techniques to identify novel mechanisms for the transfer of algal toxins through the foodweb. I am currently developing algal extraction methods to quantitate co-occurring toxin groups and congeners for AUV and moored instrumentation with the aid of HPLC-ox-FLD. With an apparent regional and global increase in the duration, frequency, and geographic span of HABs, there is an urgent need to better understand factors that promote the production and degradation of co-occurring algal toxins in these systems, the potential for additive or synergistic effects of these toxins on ecosystems and humans, and how these effects may be altered by expanding coastal development.