Copper and iron are essential micronutrients that are required by marine primary producers for a variety of metabolic processes. Over 99% of both copper and iron are bound within organic complexes in the marine environment, however the molecular identity of many of these complexes remains unknown. The speciation of these...
Microplastics are widely distributed in aquatic environments. The term ‘microplastics’ encompasses a wide array of particles with unique polymer constituents, morphologies, and sources, such as automobile tire tread. Tire wear particles (TWP) can end up in waterways near densely populated municipalities, where they can interact with aquatic biota. Studying the...
Environmental archives provide records of natural and anthropogenic variation in the environment at different temporal and spatial scales. Lead (Pb) concentrations and isotopic ratios are useful tracers of anthropogenic emissions from industrial activities including mining, smelting, and leaded gasoline use, however, methods of measuring Pb are largely limited in low...
Maintaining the quality and quantity of water resources in light of complex changes in climate, human land use, and ecosystem composition requires detailed understanding of ecohydrologic function within catchments, yet monitoring relevant upstream characteristics can be challenging. In this study, we investigate how variability in riverine microbial communities can be...
We report a decadally resolved record of atmospheric CO₂ concentration for the last 1000 years, obtained from the West Antarctic Ice Sheet (WAIS) Divide shallow ice core. The most prominent feature of the pre-industrial period is a rapid ∼7 ppm decrease of CO₂ in a span of ∼20–50 years at...
Microplastics, plastic marine debris less than 5 mm in size, is a threat to the health of our oceans. One important way to reduce microplastics in our oceans is to educate people about the issue, particularly future decision-makers. In this study, a middle school curriculum was developed using current scientific...
The Pacific Arctic is undergoing rapid biogeochemical changes in response to warming air temperatures caused by climate forcing. This is manifesting as changes in seasonal sea ice thickness and sea ice extent, as well as changes in primary production within surface waters. The data and samples analyzed here were collected...
Wildfire greatly impacts the composition and quantity of organic carbon stocks within watersheds. Most methods used to measure the contributions of fire altered organic carbon–i.e. pyrogenic organic carbon (Py-OC) in natural samples are designed to quantify specific fractions such as black carbon or polyaromatic hydrocarbons. In contrast, the CuO oxidation...
This dissertation works towards determining the mechanisms driving the Mo isotopic composition of soils, and how these signals may be used to refine the use of Mo as a proxy of biogeochemical processes. The first step towards quantifying Mo fractionation in soils is to determine the mechanisms controlling Mo accumulation,...
This study evaluates ore transport and other mining activities on metal levels in the remote Arctic ecosystem of Cape Krusenstern National Monument (CAKR) in northwestern Alaska. This monument is 50 km SW of Red Dog Mine, one of the world’s largest Pb–Zn mines. The Delong Mountain Transportation System (DMTS) haul...