Faculty Research

Paleoenvironmental reconstruction of ancient land environments

Jennifer Elick

My recent research has involved studying Devonian (408-354 million years old) age rock in Pennsylvania, New York, and Québec to better understand how early terrestrial (land) environments expanded and influenced the world. I study sedimentary rock containing plant and root traces, fish, insect, and marine fossils/traces, and sedimentary structures in order to produce paleoenvironmental reconstructions for the Devonian. My research with Susquehanna students has shown that Late Devonian plants from Selinsgrove exhibit dissimilar morphologies to plants from the Early Devonian plants from Québec.

I have also worked with students in geologic mapping projects. Most recently, I have worked with a student to map the geology (bedrock and geologic structures) of the region around Centralia. This effort was made in order to update an older map and add new details to our understanding of the structure in that region.

A clay-lined plant root trace from Hepburnville, PA that is in the Catskill Formation from the Late Devonian age (plastic ruler for scale).

 

Stratigraphic and Sedimentologic Evidence for High-elevation Proglacial Lakes, in SW Michigan

Andrew Kozlowski

Proglacial lakes are common physiographic features in modern temperate glacial environments and were equally common at glacial margins during the late Pleistocene. In many locations low-relief plains composed of laminated silt-clay often typify the sediment-landform relationships and are easily recognized as former proglacial lake settings. Multiple low relief plains composed of fine-grained sediment extend through several counties in southwestern Michigan, USA. These northeast southwest trending plains have been previously identified as former proglacial lake basins of the Lake Michigan Lobe of the Laurentide Ice Sheet. Previous studies in this region have suggested that most of these shallow proglacial lakes resulted as retreating ice episodically formed ice dams and impounded meltwater. My research uses sedimentologic and stratigraphic data from multiple exposures that indicate that deep high elevation proglacial lakes were also present along the margin of the Lake Michigan Lobe in areas previously interpreted as end moraines (ridges). Consistent stratigraphic profiles at high elevations on the landscape indicate that the former lake deepened prior to draining and that complex depositional mechanisms were operating along the proximal margin of the ice while the lake was in place. These findings alter previous interpretations, and have implications for understanding the drainage history, land use policy, groundwater management and aggregate exploration.

Dr. Kozlowski with a "bullet boulder" in Iceland.

 

Combustion gas contributions to microbial ecology

Daniel Ressler

My recent research has been to characterize the surface environment at the Centralia PA mine fire. Studies of microbial ecology have been conducted at sites of different temperature. Soils have been analyzed to determine the nutrient content and to investigate how the fire affects soil chemistry and thus the conditions that affect the microbial ecology. Water relations have been recently examined and experiments that detail the gas composition and contribution to the soil environment are about to get underway.

I have also recently completed an urban tree inventory in Sunbury, Pennsylvania as well as experiments that examine microbial ecology and nutrient interactions in natural wetlands.

A vent at the Centralia mine fire.

 

Measured and predicted concentrations of sulfur dioxide in the plume of a coal-fired power plant

Derek Straub

One of my current student-involved research projects is the examination of elevated sulfur dioxide (SO2) concentrations in the vicinity of a local coal-fired power plant. SO2 is a colorless gas that can reduce lung function and lead to other health effects as a result of long term, high concentration exposure. In addition, SO2 contributes to regional visibility impairment and acid deposition. During the 2004 summer, we set up SO2 monitoring equipment and began measuring SO2 levels at a location that was periodically influenced by the plume of a coal burning electrical generation plant located 6 km to our northeast. While background concentrations were relatively low, we measured peak concentrations exceeding 100 to 200 ppb for brief periods, reflecting the influence of the power plant plume. As part of this project, we used a computer-based dispersion model to predict SO2 concentrations during these peak events. Comparison between the measured and modeled concentrations showed reasonably good agreement. SO2 was also sampled from a department vehicle on two days to help characterize power plant emissions over a wide area during a relatively stagnant period and during a windy period. Future studies will focus on the conversion of SO2 to sulfate in the SO2 rich plume during the frequent fog episodes experienced in this region.

Katie Beem '06 adjusts the mobile SO2 monitor before a day of measurements.

 

Surface precipitation in the Madden-Julian Oscillation

Katherine Straub

I recently competed a study with Donna Strahan '05 on observations of precipitation in the Madden-Julian Oscillation (MJO). The MJO is an oscillation in tropical cloudiness, rainfall, winds, and other meteorological variables with a period of 30-60 days and a spatial scale of 10,000 km. As the MJO moves eastward from the Indian Ocean to the central Pacific, it strongly influences rainfall and cloudiness in locations such as India and Australia. In this study, we analyzed daily rainfall data for 700+ tropical stations to determine changes associated with the MJO. Specifically, we contrasted the in-situ rainfall data with a more commonly used dataset, satellite-derived outgoing longwave radiation (OLR) data, which measures the temperature of cloud tops. Previous studies have used OLR as a proxy for precipitation, but this study suggests that actual precipitation patterns are in some cases vastly different from those inferred from OLR. The results of this study point to a need for further analysis of in-situ precipitation data to determine the true rainfall and heating patterns within the MJO.

A map of OLR (shading) and precipitation (circles) associated with one phase of the MJO.