Research Interests
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Emerging & Legacy Contaminants
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Aquatic - Terrestrial Linkages
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Ecotoxicology
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Microbiome
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Multivariate Data Analysis
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Eutrophication
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Ecological Stoichiometry
PhD Projects
Nanoparticle and Metal Exposure Alter Algal Biomass, Algal Nutrient Assimilation and Microbiome Structure of Consumers
During my PhD in the Aquatic Ecology Lab at Baylor University, I studied the effects of chronic nanoparticle and nutrient dosing on nitrogen and phosphorus nutrient dynamics in algal communities, consumer (snail) mediated nutrient recycling and snail gut microbiome communities during a 46 day indoor microcosm study.
Copper and gold nanoparticle exposures alter insect emergence and result in flux of metals from aquatic ecosystems into riparian food webs
During my PhD, I was a part of the large, NSF funded CEINT mesocosm study. We conducted a 9-month outdoor mesocosm experiment on the effects of chronic NP and Nutrient dosing at environmentally realistic concentrations and exposures. I collected emerging insects monthly and measured flux of copper and gold NPs from aquatic ecosystems to adjacent terrestrial environments. We found insect emergence decreased by 20% in NP treatments and both NPs exhibited trophic transfer into riparian predators. We found no effect of Nutrient on insect emergence. Further, we assessed the transfer of NPs from emerging insects into two riparian spider genera, Tetragnatha and Dolomedes. These results demonstrate an ecosystem-level transfer of NPs from aquatic to terrestrial ecosystems via emergence of aquatic insects and predation by riparian spiders and a potential of transfer of contaminants to other insectivorous predators.
Copper and gold nanoparticles increase nutrient excretion rates of primary consumers
During the CEINT mesocosm study, we measured the excretion rates of nitrogen and phosphorus of Physella acuta, a ubiquitous pulmonate snail that grazes heavily on periphyton, exposed to either copper or gold engineered nanoparticles for six months in an outdoor wetland mesocosm experiment. Chronic nanoparticle exposure doubled nutrient excretion when compared to the control. Gold nanoparticles increased nitrogen and phosphorus excretion rates more than copper nanoparticles but overall, both nanoparticles led to higher consumer excretion, despite contrasting particle stability and physio-chemical properties. These results suggest that low concentrations of engineered nanoparticles could alter the metabolism of consumers and increase consumer-mediated nutrient recycling rates, potentially intensifying eutrophication in aquatic systems, e.g. the increased persistence of algal blooms as observed in our mesocosm experiment.
