Although the major focus of our research group is in the area of environmental geochemistry, the work done by members of my group is multidisciplinary and multifaceted. We have interests in the earth's chemical environment and how it is affected by physical, biological, geological and anthropogenic processes. Currently the research in our group focuses on a number of different research areas. As you can see on our people page, our research group includes professional scientists, graduate students, and undergraduate students.
Since my graduate student days, I have had an interest in the transport and fate of trace elements, especially trace metals in aquatic systems. Working with John Olesik at the Trace Element Research Laboratory in the School of Earth Sciences, my students and I continue this type of work. The research involves both the investigation of trace metals as "pollutants" and also as important micronutrients to biological systems. In addition, we use trace elements, stable isotopes, and even major elements to follow water movement through surface and near-surface systems. For example, the work of Chris Gardner in our group, along with colleagues from the University of Wyoming, utilized Ge/Si ratios along with Ba, Sr, δ18O and δD to track the various “hydrologic sources” of water in tropical rainforests and mixed land use catchments to streams in Panama. We have also used Cl, Si, and δ18O to investigate hyporheic zone dynamics in Antarctic streams.
With my colleague, Dr. Anne Carey, our group has been involved in the investigation of the relationship between chemical and physical weathering in alpine regions, especially on tectonically active oceanic islands such as New Zealand, Taiwan, and most recently Panama, northern Spain, and southern Italy. Results of these investigations suggest a strong correlation between chemical and physical erosion, and implies that tectonic uplift as well as rainfall are extremely important in driving chemical weathering.
Another area of interest lies in the impact of both agricultural and urbanization on surface water quality. The group has worked in such places as the Chattahoochie River in Atlanta, GA, as well as the Scioto River system here in Ohio, in order to quantify the impact of urban runoff and sewage input on river water quality. Here in Ohio, we have attempted to discern between agricultural impact and urban sources on the flux of many elements into the Scioto system. In the past decades we have also developed detailed watershed mass balances of nitrogen for rather large river systems like the Alabama-Mobile. We have worked on the trace metal geochemistry of small urban streams in order to assess how small variations in land type impact water quality. We also finished a large, interdisciplanary plot-scale project to assess how variations in agricultural practices impact chemical weathering and carbon transport. This work mimics the results of the entire Ohio River watershed in regard to the impact of acidification from N-fertilizer on soil weathering. We are continuing this wok by “mining” a multi-decade dataset that incorporates climatic, hydrologic, and geochemical data and investigating how the geochemical signature varies with land use and agricultural practices.
I have been involved in polar research since the 1980s, and our research group has been involved for 24 years in the McMurdo Dry Valleys Long-Term Ecological Research (MCM-LTER) project (www.mcmlter.org). We have worked with a group of glaciologists, hydrologists, soil scientists and ecologists in order to determine the structure and function of this polar desert ecosystem. This work is diverse and multi-disciplinary. For example, under the guise of MCM-LTER, I have had students investigating the atmospheric mercury flux in the Antarctic, the processes responsible for CaCO3 accumulation in polar desert soils, and the geochemistry and quantity of sediment transport from alpine glaciers into the closed-basin lakes of the Dry Valleys, and most recently the flux of Fe into the marine environment. We have also used non-traditional stable isotopes of Li and B to better understand solute sources to the aquatic environmets. Currently, we are using more traditional stable isotopes such as δD, δ18O, and δ13C to describe in-situ stream processes. This research is coming to an end, but the group continues to be involved in various geochemical and biogeochemical research projects in Antarctica. These projects are as diverse as examining the geochemistry of subglacial hydrologic systems in both West and East Antarctica. We have examined subglacial brine evolution, and the flux of subglacial water into the Southern Ocean off the Antarctic Peninsula. An upcoming project will entail working with a multidisciplinary team investigating the biology and biogeochemistry of a large West Antarctic subglacial lake. Another project will analyze soil geochemistry of locations in the Transantarctic Mountains and relate it to the distribution of soil organisms and their biogeography. We also continue to work with both our scientific and technology colleagues around the US to develop better, more efficient and environmentally friendly “tools” to sample subglacial environments. Finally, we hope to continue our on-going research on better quantifying the impact of micronutrients such as Fe into the Antarctic marine environment.
Although being director of the School of Earth Sciences and teaching introductory geochemistry keeps me very busy, I still find enough time to be involved in the research activities of our group. By reading the statements of our group of students and research staff, you will get a better understanding of the diversity and excitement of the work with which we are involved.