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Open Access Publications from the University of California



Copper Catalyzed Oceanic Methyl Halide Production

Methyl halides are found in all of Earth’s biomes, produced naturally or through manmade means. Their presence in the atmosphere is problematic, as they catalyze depletion of stratospheric ozone. To understand the full environmental impact of these compounds, it is important to identify their chemical cycling processes. Iron increases methyl halide production in soils and oceans, yet copper’s influence remains unknown despite its similar chemical oxidation properties to iron. I experimentally tested the effect of copper sulfate and sunlight on methyl halide fluxes in San Francisco Bay seawater. Samples exposed to copper sulfate and sunlight averaged higher positive flux rates than other treatments. Copper sulfate also increased carbon dioxide production and acidification of the water. The interaction of copper sulfate and sunlight in seawater suggests a new mechanism for methyl halide production, most likely via a photochemical reaction or through suppression of normal uptake processes causing overabundant concentrations.

Phylogenetic Diversity and Endemism: Metrics for Identifying Critical Regions of Conifer Conservation in Australia

Accurately and sufficiently quantifying biodiversity is integral for conservation. Traditional metrics for measuring biodiversity, species richness (SR) and weighted endemism (WE), do not take into account the evolutionary history of organisms. Phylogenetic diversity (PD) addresses the shortcomings of SR by quantifying the evolutionary connections among the species present in an area. Phylogenetic endemism (PE) addresses the shortcomings of WE and represents the ranges of the branches of the evolutionary tree connecting the species in an area. Australia, with its advanced digitization of spatial reference data is the best model system for quantitative studies of biodiversity at present. I created a phylogeny for the 39 indigenous Australian conifer species using matK and rbcL sequences from GenBank and sequencing the 4 species for which there were no existing data. I used spatial data from Australia’s Virtual Herbarium. More precise estimates of biodiversity can be used by conservation policy-makers.