Current Research
Understanding transport and accumulation of microplastics in alpine environments and using spectroscopy techniques to measure microplastics!
Past Research
Mono Lake Population Age and Structure of Ephyra hians
Understanding how population dynamics vary over a three year period in alkaline (pH of ~9) and saline (~80 mg/L) Mono Lake. The purpose of this study was to develop a biomonitoring protocol where cement blocks would mimic the calcium carbonate tufas and Ephydra hians would be collected at intervals or cumulatively. Age and structure of the population are affected by seasonal, salinity, wind, and possibly other physiological stressors.
Climate Change in Alpine Reference Streams
Over an eight year period, 2010-2017, 12 sites (each having a catchment and tributary), were sampled for their geomorphology, water chemistry, Fine Particulate Organic Matter, Coarse Particulate Organic Matter, macroinvertebrates, and algae. It was showed that in drought, streams become more acidic, and have higher conductivity rates. They also begin to have more pools and have less riffles, ultimately lowering the biodiversity of streams drastically.
Site-directed Mutagenesis of Toluene/ortho-xylene mono-oxygenase
My college thesis focused on the site-directed mutagenesis of toluene/ortho-xylene monooxygenase’s (ToMO) second coordination sphere of the active site. The intention of the project is to mimic the behavior of a closely related enzyme that has increased amounts of terminal hydroxylation activity. Successful alteration of ToMO’s activity will lead to an industrial application of the enzyme and bioremediation possibilities.
Understanding the Cytotoxicity of Permalloy Disks used for Cancerous Tumor Treatments
Permalloy disks can trigger apoptosis in carcinogenic cells by attaching to over-expressed cell membrane receptors and vibrating at the surface of the cell. The vibration occurs when the magnetic domains of the permalloy disks align with an external alternating magnetic field. Permalloy disks could potentially leach nickel and iron, becoming toxic to the organism. Toxicity of iron-nickel permalloy microdisks were measured by fluorescence imaging of hydroxyl radicals. A summer of research suggested that there might be leaching of nickel from the disks, which would be harmful by reacting with peroxides to create hydroxyl radicals in the presence of in vivo cancer and healthy cells.
Microbial Community Metabolism Rates at Acid Mine Drainage Sites Downstream of Superfund Leviathan Mine
Leviathan mine is a former open pit sulfur mine in California that for over two decades has been leaching aluminum, selenium, iron, sulfur, and other heavy metals. There is a bioreactor that neutralizes the pools formed in the pit, in order to increase the pH and create an environment where metals precipitate. Seasonally, with snow and rain, the bioreactors do overflow and mine run off goes directly downstream. Following the seasonal patterns, Dr. David Herbst has collected macroinvertebrate data downstream of the mine for over 20 years. I have designed a protocol to understand if the microbial community composition and activity reflects the macroinvertebrate biodiversity at each of the sample sites downstream of the mine. Ecoplates, which have 32 carbon substrates in triplicate, were used to quantify metabolism rates by measuring the rate of tetrazolium dye accumulation in each of the wells. The photographs were used using Fiji/Image J.
Upstream Diversion and Drought Increasing the Salinity Levels of Walker Lake
Walker Lake is a saline and terminal lake in Nevada that has had it’s salinity increased due to upstream diversion for ranching. This study sampled macroinvertebrates seasonally at eight different sites around the lake. Sites varied in salinity level, proximity to freshwater runoff, and geomorphology of sediment/lake bed. It was found that species that had high affinity for salt did well, meanwhile midge Cricotopus, which has low salt tolerance, nearly disappeared during the drought years. It’s return was recorded at the site closest to the main freshwater run off in 2017, which was a high snow year. Lake ecosystems show resiliency IF provided the opportunity to be restored.
Hydrogen Production from
In a nanoscale system consisting of bacteriorhodopsin assembled onto Pt/TiO2 photocatalysts, a significant amount of visible-light generated hydrogen is created in the presence of methanol. Using bacteriorhodopsin as a proton-pumping enzyme that extends the spectrum of light reactivity of titanium dioxide. Instead of harvesting bacteriorhodopsin from Halobacterium salinarum, the focus of the project was to explore the potential use of a whole organism in the system.
Methane Production with an Electrochemical Fuel Cell with Methanogens
This project began as an electrolysis cell that hydrolyzed water molecules from a carbon-dioxide rich medium containing methanogens. The methanogens in the media formed a biofilm at the cathode, utilizing the hydrogen gas as a reducing agent for methane production and the dissolved carbon-dioxide in the medium as a carbon source. In order to optimize production and efficiency of methane we conducted experiments on different membrane materials, conditions, and fuel cell architectures experiments. Since I have graduated high school, the electrochemical cell has attracted industrial interest and now is the basis of two 10,000-liter bioreactors in Denmark that produce pipeline-grade methane for energy consumption.
Aleksandra Karapetrova 