Most of our projects involve tracking the movement of mercury through ecosystems. Sediment cores from lakes and reservoirs can provide temporal records of the deposition of mercury and other metals deposited on the landscape from atmospheric deposition. We have also used sediment cores as archives of primary productivity and oxygen depletion in reservoirs. Our current activities include analyzing lichens as natural biomonitors of atmospheric pollution.
Sediment archives of environmental change
Sediment coring and analysis in Watson Lake, Arizona. Accordion Closed
Sediment coring and bathymetric mapping to support Total Maximum Daily Load development of Watson Lake. Sediment cores were used to reconstruct histories of nutrient loading and primary productivity. Funded by Arizona Department of Environmental Quality. $22,300. May 2011 to May 2012. Executive Summary.
Analysis of Lyman Lake sediments to detect power plant emissions. Accordion Closed
High-resolution analysis of sediment cores for mercury and indicators of high-temperature combustion. Funded by Arizona Department of Environmental Quality. $18,318.
Mercury source fingerprinting in arid lands ecosystems Accordion Closed
Investigation of techniques to quantify mercury stable isotopes. Funded by the US Geological Survey 104(b) program through the University of Arizona Water Resources Research Consortium. 2008. $10,900. Final report.
Developing the capability to trace sources of mercury in the environment using stable Hg isotopes Accordion Closed
Development of instrumental techniques to detect mercury stable isotopes using inductively coupled plasma mass spectrometry (ICPMS). Funded by the NAU Technology and Research Initiative Fund. 2008. $25,000.
Total maximum daily load support for Parker Canyon Reservoir, Arizona Accordion Closed
A comprehensive assessment of mercury in the lake system, including spatial distribution of mercury in watershed soils, mercury bioaccumulation in the food web, spatial distribution of mercury in surface sediments, history of mercury accumulation through sediment core analysis, and modeling of mercury in the water column. Funded by the Arizona Department of Environmental Quality. 2006. $29,600.
Effects of wildfire suppression on mercury sequestration and release from watersheds Accordion Closed
Analysis of long-term (several thousand year) sediment records from lakes in Arizona and New Mexico to compare mercury release from watersheds under varying wildfire regimes. Funded by the Merriam Powell Center for Environmental Research at NAU. 2005. $10,000.
The relevance of fire and erosion on mercury availability in Lyman Lake, Arizona Accordion Closed
High resolution analysis of sediment cores collected from Lyman Lake, Arizona to detect mercury responses to fire and erosion events. Funded by the Intramural Faculty Grant Program at NAU. 2005. $9,000.
Histories of metals deposition in northern Arizona reservoirs Accordion Closed
Comparative analysis of metals accumulation in sediment cores collected in 11 northern and central Arizona reservoirs. Funded by the Arizona Department of Environmental Quality. 2004. $32,626. Final report.
Mercury in aquatic food webs
Variations in mercury bioaccumulation in fish along the river continuum of four Arizona freshwater ecosystems Accordion Closed
An examination of changes in fish bioaccumulation of mercury with changing food base. At river headwaters ultimate carbon sources are more associated with detrital matter (leaf litter). Farther downstream a greater influx of carbon derived through photosynthesis (algal biomass) occurs. Carbon sources were measured with deuterium isotopes and trophic position was measured with nitrogen stable isotopes. Results indicated increased mercury bioaccumulation is associated with downstream reaches, although it is not certain that this is related to carbon source, or if other factors contributed to increased mercury. Unfunded research. 2010. Thesis.
Caudal fin clippings of fish as non-lethal mercury indicators Accordion Closed
For this study, we sampled the archive of fish collected by the Arizona Department of Environmental Quality for their mercury advisory program. We compared total mercury contained in muscle tissue with that found in caudal fins to determine whether non-lethal sampling of fish for mercury was possible. We found a positive correlation between muscle-mercury and fin-mercury, although this relationship needs to be calibrated for each fish species. Unfunded research. Environmental Chemistry article.
Metals and trophic position of fish in mercury-contaminated Arizona reservoirs Accordion Closed
The use of nitrogen stable isotopes to quantify trophic position in the aquatic food webs of Arizona reservoirs as a strategy for evaluating mercury bioaccumulation. Funded by the Intramural Faculty Grant Program at NAU. 2005. $7,500.
Mercury concentrations in lichen near Drake Cement, LLC Accordion Closed
A baseline study of spatial variability in the mercury content of lichens in the Verde Valley. Funded by Watershed Research & Education Program at NAU. $3,200. May 2013 to April 2014.
Lichen as biomonitors for mercury deposition in Arizona Accordion Closed
Initial research to quantify the variability of mercury in the lichen Xanthoparmelia at one location in northern Arizona. Funded by the National Science Foundation, Research Experiences for Undergraduates. 2006. $4,000.
Reservoir mapping & geophysics
Analysis of sediment dynamics in the Bill Williams River, Arizona. Accordion Closed
Sediment cores, seismic profiling, and bathymetric mapping in Alamo Lake and Lake Havasu, Arizona were used to evaluate changes in sediment delivery due to impoundment of Alamo Lake on the Bill Williams River. Funded by the US Fish & Wildlife Service. $45,000. November 2010 to September 2011.
Seismic profiling of Lakeside Lake, Tucson, Arizona Accordion Closed
Evaluation of spatial extent of sediment thickness in an urban stormwater management facility using seismic sub-bottom profiling equipment. Funded by the City of Tucson, Arizona. 2008. $4,500.
Advanced techniques for sediment mapping in western reservoirs Accordion Closed
Field testing and development of data processing protocols to apply seismic profiling equipment for mapping bathymetry and sediment thickness in U.S. western reservoirs. Funded by the Intramural Faculty Grant Program at NAU. 2006. $9,500.
Bathymetric survey of northern Arizona reservoirs Accordion Closed
Development of bathymetric maps and curves for volume and surface area as a function of elevation for nine northern Arizona reservoirs to support total maximum daily load studies. Funded by the Arizona Department of Environmental Quality. 2005. $11,571.