2006 Richard Barrett Scholarships
Danielle Eastman, Geology Student
Investigation of Sulfur-Utilizing Microbial in the Frasassi Cave System, Italy
The Frasassi cave system is located in Jurassic-aged Calcare Massiccio limestone in the Apennine Mountains of the Marches Region of Central Italy (Macalady, 2005). This cave system is rich in microbial communities that thrive in the hydrogen sulfide–rich waters. Much of the research on the caves focuses on the study of these microbes in an effort to better understand their role in cave formation, as well as their abilities to utilize the sulfur compounds in their environment. This focus will allow us to investigate the fundamental interactions between microbes and their chemical surrounding.
Microbial communities of sulfur-reducing and sulfur-oxidizing organisms in the aqueous regions of the caves, as well as on the walls and ceilings, are catalysts for the majority of the oxidation-reduction reactions that corrode the limestone. Using In Situ voltammetry to measure specific redox reactions we can be better understand the significance of the microbial communities to the sulfur chemistry of the cave environment. This research may be further applied to more chemically complex environments in which sulfur is a constituent, such as those found in groundwater contaminant plumes, fertilizer in agricultural areas, and in petroleum reserves for desulfurization.
Ryan Foster, CE Student
Investigation of Soil Parameters and their Effects on Stream Bank Stability
When spring run-off or heavy rain occurs, the soils in the stream banks become saturated and heavy. The increase in water levels result in a reduction in shear strength of the soil. The combination of increased weight and reduced strength make the stream banks unstable and they collapse. The moving water in streams gradually transports sediments and phosphorus particles downstream until they reach their final destination at the Lake. Here, they settle out permanently and allow the algae to flourish.
A growing concern over the past few decades is the rapidly accelerating eutrophication of Lake Champlain. An even bigger concern is the recently increasing amounts of algae disturbing the ecosystem balance of the Lake . High phosphorus levels in the Lake are being held mainly responsible for this occurrence (Meals and Budd, 1998). The streams and rivers that feed the Lake carry massive amounts of sediments and phosphorus which are deposited on the lake bottom. High phosphorus levels allow the algae to flourish because phosphorus is often the limiting nutrient for growth. As shown in Figure 1, there is a large algae bloom that extends several hundred meters out into the water. No one wants to look at a green lake, and furthermore no one wants to swim in one either. Fish are the species that are most affected by the algae growth because it takes away food sources and clouds up the lake. Erosion of stream banks is believed to be one of the most essential nonpoint sources of sediments and phosphorus in Lake Champlain (VTDEC and NYSDEC, 2002), as well as in lakes elsewhere.
Aaron Hartmann, Geology Student
Assessment of the Speciation and Concentration of Limiting Nutrients Nitrogen and Phosphorous in Missisquoi Bay as a Driving Force of Species Composition in Cyanobacterial Algal Blooms
Loading of nutrients from external non-point sources has led to increased eutrophication in areas of Lake Champlain, most dramatically in Missisquoi and St. Albans Bay in the north (Rosen et al., 2001; Druschel, Hartmann, et. al., 2005). Consistent with the influx of nutrients has been an increase in the occurrence of secondary algal blooms consisting of diverse phytoplankton species (Watzin, 2005). Missisquoi Bay, a shallow, highly eutrophic water mass, produces some of the most intense algal blooms of any site in the lake (Watzin et al. 2005). Concern was raised in 1999 when two dogs died after consuming large amounts of toxic cyanobacteria in Missisquoi Bay (Rosen et al., 2001). Subsequent monitoring has observed a dominance of toxic cyanobacterial blooms in Missisquoi Bay during the summer months (Watzin et al. 2005). A shift to a cyanobacterially dominated state with high potential for toxic blooms threatens recreational use, human health, and the local economy surrounding Missisquoi Bay.
The movement of nutrients across the sediment/water interface will be measured as nutrients trapped at different levels in the sediment become mobile during the summer months. This study proposes to test the hypothesis that species composition of cyanobacterial blooms in Missisquoi Bay is related to the concentration and speciation of nitrogen and phosphorous coming from lake sediments.
Chris Palombini, EE Student
Development of a Wireless Sensor Platform for Environmental Monitoring Projects
To make sound scientific conclusions, it is requisite that data supports results. Laboratory experiments along with instrumentation are often used to collect such data. However, when the project is field based a unique problem is introduced in that data must be collected away from laboratory instrumentation and staff. A solution to this problem is a network of wireless instrumentation that can be used at remote sites for purposes of long-term environmental monitoring. Having a wireless sensor system means the researchers potentially need only go to site twice, once to setup the equipment and a second time to disassemble the system. The use of wireless sensor networks enables spatially distributed collection of real time data from remote sites.
Wireless sensor networks have been employed in environmental monitoring in order to provide real-time data to researches either on-site or remotely. One example of remote data acquiring is when researches at Berkeley had interest in monitoring the environmental habitat of sea birds on Great Duck Island off the coast of Maine; in this case 3,000 miles separated the researchers and their data. This classic case study demonstrated the power of wireless sensor networks for habitat monitoring. The end result of the network was a system of wireless nodes that streamed real time data to the Internet for researchers to analyze. Applying this wireless network to this specific application allowed for habitat monitoring well after the biologists studying the case were no longer able to go out to the island because of weather. For the first time in the studies on Great Duck Island consistent data was collected in the fall and winter. Our work, with the assistance of other Barrett Scholars, will research the area of wireless sensor networks of interest to environmental monitoring. The goal of this work is to build and demonstrate in the field, a wireless sensor network for monitoring stream bank erosion along with other soil parameters including: soil suction, water level and flow.
Nathan Shaffer, CE Student
An Experimental Study to Classify Erodibility of Soils in Dams, Embankments, and Levees
Embankment dams are used for a variety of purposes: to create reservoirs, contain canals, filter out tailings (refuse) from mines, and to protect from flood water. While the makeup of these levees and dams seems to be quite straightforward, what remains to be discussed is the type of soil that should be used to create such a structure. Embankment dam failures result in destruction not only of human-made structures, but also lead to severe environmental damage. Many laboratory methods such as the flume test, jet erosion test, rotating erosion test, double hydrometer test, Pin Hole test, etc., have been developed to study erosion (Wan and Fell, 2004). Our study is in collaboration with the U.S. Bureau of Reclamation (USBR). The USBR recently modified the Australian Hole Erosion Test (HET) apparatus and conducted some preliminary tests. We visited the USBR in Denver, Colorado, in February 2006. Our visit had two purposes: (1) develop an apparatus very similar to the USBR's apparatus; and (2) learn testing techniques to ensure that both laboratories are following the same procedures.
So far, we have developed the basic HET apparatus. We have obtained soil samples from dam sites in Vermont from state's Dam Safety Program and conducted basic index testing on these soils (grain size analysis, consistency indices, density). Presently, we are working on incorporating electronic transducers to measure water pressures more accurately. Soil testing using the apparatus has begun however there is some trouble shooting that needs to be addressed before accurate results can be obtained.