As part of Arizona State University’s net-zero carbon initiative, 1000 mesquite trees were planted on a vacant plot of land at West Campus to sequester carbon from the atmosphere. Urban forestry is typically a method of carbon capture in temperate areas, but it is hypothesized that the same principle can be employed in arid regions as well. To test this hypothesis a carbon model was constructed using the pools and fluxes measured at the Carbon sink and learning forest at West Campus. As an ideal, another carbon model was constructed for the mature mesquite forest at the Hassayampa River Preserve to project how the carbon cycle at West Campus could change over time as the forest matures. The results indicate that the West Campus plot currently functions as a carbon source while the site at the Hassayampa river preserve currently functions as a carbon sink. Soil composition at both sites differ with inorganic carbon contributing to the largest percentage at West Campus, and organic carbon at Hassayampa. Predictive modeling using biomass accumulation estimates and photosynthesis rates for the Carbon Sink Forest at West Campus both predict approximately 290 metric tons of carbon sequestration after 30 years. Modeling net ecosystem exchange predicts that the West Campus plot will begin to act as a carbon sink after 33 years.

The Philippines relies on a vast biodiversity of fishes as a staple food, but like many countries around the globe, experiences severe “leakages” of contaminants and pollutants in the environment. In order to better understand the relationship between environmental pollutants and public health, this research project measured the concentration of pollutants in a commonly consumed local fish (Siganus fuscescens), and then evaluated the potential health risks of eating this fish based on estimated average consumer weight and consumption levels. Fish sampled from four different sites located in Negros Oriental, Philippines were analyzed for organic contaminants using gas chromatography and mass spectroscopy. Pollutants quantified included polycyclic aromatic hydrocarbons (PAHs), pesticides, phthalates, and polychlorinated biphenyl (PCBs). Across the four study sites, fishes from Manjuyod showed the highest frequency of detection of different pollutants. However, phthalates and PAHs were found in similar concentrations in all four sites, with fishes from Dumaguete showing the highest level of PCBs compared to the other sampled sites. The U.S. Environmental Protection Agency’s guide for fish contaminants pinpoints several health risks associated with the chronic ingestion of these contaminants. Based on estimated average body weights of Filipino adult men, adult women, and children, and various consumption levels, people who eat the fish at or above the national average consumption level may be at increased risk for chronic health outcomes, such as cancer and/or other adverse effects. Specifically, due to the high concentration of PCBs in Dumaguete, selected populations who eat local fish from this site may be at higher risk than the citizens who eat the fish from other sites at similar consumption rates. These results can help to inform local and national policies on water quality, waste disposal, and fish consumption advisory programs.

Summer daytime cooling efficiency of various land cover is investigated for the urban core of Phoenix, Arizona, using the Local-Scale Urban Meteorological Parameterization Scheme (LUMPS). We examined the urban energy balance for 2 summer days in 2005 to analyze the daytime cooling-water use tradeoff and the timing of sensible heat reversal at night. The plausibility of the LUMPS model results was tested using remotely sensed surface temperatures from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) imagery and reference evapotranspiration values from a meteorological station. Cooling efficiency was derived from sensible and latent heat flux differences. The time when the sensible heat flux turns negative (sensible heat flux transition) was calculated from LUMPS simulated hourly fluxes. Results indicate that the time when the sensible heat flux changes direction at night is strongly influenced by the heat storage capacity of different land cover types and by the amount of vegetation. Higher heat storage delayed the transition up to 3 h in the study area, while vegetation expedited the sensible heat reversal by 2 h. Cooling efficiency index results suggest that overall, the Phoenix urban core is slightly more efficient at cooling than the desert, but efficiencies do not increase much with wet fractions higher than 20%. Industrial sites with high impervious surface cover and low wet fraction have negative cooling efficiencies. Findings indicate that drier neighborhoods with heterogeneous land uses are the most efficient landscapes in balancing cooling and water use in Phoenix. However, further factors such as energy use and human vulnerability to extreme heat have to be considered in the cooling-water use tradeoff, especially under the uncertainties of future climate change.