Geoscience Colloquia for Spring 2010 Semester

Thursday February 25, 2010 4 PM
Dr. Neil C. Sturchio
University of Illinois at Chicago
Title: “Of Rockets, Radishes, and Cosmic Rays: Environmental Isotope Forensics of Perchlorate”
Lapham Hall 262

Abstract:

Contamination of water supplies with perchlorate has become increasingly apparent since the introduction of improved analytical methods in 1997. Isotopic analyses of oxygen and chlorine have identified three principal types of perchlorate that contribute to this contamination, including natural and anthropogenic sources.

Refreshments served prior to the colloquium at 3:30 in Lapham 380.


Thursday March 11, 2010 4 PM
Dr. J. Elmo Rawling
University of Wisconsin- Platteville
Geomorphology
Lapham Hall 262

Abstract

Refreshments served prior to the colloquium at 3:30 in Lapham 380.


Thursday April 1, 2010 4 PM
Dr. Nancy Hinman
University of Montana
Title: “Strategies for identifying signatures of life on early Earth and elsewhere"
Lapham Hall 262

Abstract:

This work seeks to better understand mineral-bio/organic compound interactions in laboratory-based, biologically induced, and natural samples and to understand bio/organic compound stability upon exposure to thermal, gamma, and UV radiation. This understanding will lead to improved ability to detect such compounds and determine their biogenicity, predict which landing sites are most likely to provide evidence for life, and detect bio/organic compounds for decontamination procedures for planetary protection.

This presentation includes results of experiments to determine mass spectral patterns for bio/organic compounds associated with different mineral salts, which are representative of secondary minerals that have been or might be found on Mars. Additionally, I will report results of natural, mineral terrestrial samples and how these might be related to extraterrestrial settings. Specifically, I emphasize the basalt and secondary minerals at Craters of the Moon (COM) National Park are that are analogous to martian basalt and that the secondary minerals associated with such basalts are a potential targets for finding bio/organic compounds derived from microbial activity.

Refreshments served prior to the colloquium at 3:30 in Lapham 380.


Thursday April 15, 2010 4 PM
Dr. Ken Bradbury
Wisconsin Geological and Natural History Survey
Title: “Viruses in Deep Groundwater in Wisconsin: Implications for Public Health, Water Treatment, and Groundwater Protection”
Lapham Hall 262

Ken_cropped2Abstract:

Among the many waterborne pathogens of humans, enteric viruses, because of their small size, have a high potential to move deeply through the subsurface environment, penetrate aquitards, and reach confined aquifers. In spite of this potential, until recently, most water utilities and researchers paid little attention to possible virus presence in deep aquifers and wells. Virus analyses were difficult and expensive, and transport times to deep wells were thought to exceed virus lifetimes. Recent research in Madison, Wisconsin shows that these past assumptions were false.

Over the past five years our group, working with researchers at the Marshfield Clinic, has repeatedly detected human viruses in water pumped from deep municipal wells in Madison, WI. Madison’s wells range in depth from about 700 to 900 feet and draw water from a series of Cambrian sandstones. Many of these wells are cased through a regional aquitard thought to protect the wells from surface contamination, but some of the wells have shallow casings. We also collected samples from local lakes and from untreated sewage.

Viruses were detected at least twice in each well sampled, but no well was virus-positive in every sampling round. Samples from several wells were positive for virus infectivity. Lake samples were positive over 75 percent of the time. Sewage samples were extremely high in viruses, with all samples positive. Virus results varied significantly with time, and there is apparent temporal correlation between virus levels in sewage, lakes, and groundwater.

Correlation between viral serotypes found in sewage, lakes, and groundwater suggests very rapid transport from the source(s) to wells. Water isotope analyses showed surface water to be an unlikely source of viruses; the most likely source of the viruses in the wells is leakage of untreated sewage from the Madison sewer system. Given the high concentrations of viruses in sewage, it would take very small volumes of sewage to produce the virus concentrations observed in the wells.

Potential pathways for virus transport from the surface to the wells include porous-media flow, rapid transport through fractures, transport down failed well casings, and flow through cross-connecting wells. Work to establish the pathways is continuing. Human enteric viruses might be excellent tracers of recently recharged groundwater in urban settings if virus sources exist.

Refreshments served prior to the colloquium at 3:30 in Lapham 380.


Thursday April 22, 2010 4 PM
Student Research Talks and Posters Part I
Lapham Hall 262


Thursday April 29, 2010 4 PM
Student Research Talks and Posters Part II
Lapham Hall 262