Research in our laboratory has two main areas of focus: a. The microbial ecology of the interactions of microbes with mercury We are looking at microbial transformations of mercury (Hg) and how they affect metal toxicity and accumulation patterns in the environment. As part of this research, we study the genetics and physiology of Hg resistance and transformations in microbes from various environments, such as industrially contaminated sites and geothermal environments that naturally contain high concentrations of Hg.
Figure 1. The geochemical cycle of mercury in the environment. The major public health concern with mercury is the bioaccumulation and biomagnification in the aquatic food chain which are determined by rates of Hg transformations and transport in the environment. Black arrows depict transformations and gray arrows depict transfer pathways. The
biogeochemistry of Hg has received considerable attention because
of the toxicity of methylmercury, the accumulation of methylmercury
in biota, and its biomagnification in aquatic food chains.
Knowledge of the concentration, transport, and dynamics of
Hg in its various chemical forms in ecosystems is needed to predict
its potential impact on human being and ecosystems. Our
research combines biogeochemical, microbiological, and molecular investigations
of the transformations of mercury (and of the microbes that carry
them out) to study factors that control Hg cycling and transport of
Hg in the environment. Our
studies combine examinations of intact environmental samples and of
microorganisms in pure cultures that we have isolated from various
environments. Specific
projects currently in progress in the lab are: a. Mercury mycorrhizae fungi-plant interaction b. Molecular characterization of Methylmercury production in wetland soils c. Stable isotope fractionation during Hg transformations d. Interactions between mercury and anaerobic microorganisms in subsurface sediments e.Interactions of microbes with mercury in the geothermal environments
b. Horizontal gene transfer among microorganisms and its effect on the competence of microbial communities in stressed environments. Specifically, we examine the role of horizontal gene transfer among bacteria in the evolution of metal resistance in microbial communities that inhabit metal and radionuclei impacted subsurface soils. Such genetic spread facilitates microbial survival and activities in metal contaminated environments.
Publications If you would like to get acquainted with our work in greater detail click the titles above. Links to our recent publications are provided with each project description. If you would like to look at the list of our publications in the last three years you may click here. For comprehensive list of publications by Tamar, look at her Curriculum Vitae.
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