2015 Grant Recipients

Justin N. Carlson ($2500)
Ph.D. Candidate
Department of Anthropology
University of Kentucky

Assessing Human Activities, Sediment Deposition, and Pedogenesis at Crumps Cave Vestibule and Sink, Warren County, Kentucky

Abstract - Excavations in Crumps Cave, Kentucky, to collect archaeological and geoarchaeological data to refine the chronology of occupation, determine the range of prehistoric activities, and assess the geomorphological and pedological history of cave and sinkhole sites in the south-central Kentucky karst. Document evidence of anthropogenic forest impacts by fire and its timing in relation to intensive cave use in central Kentucky. The Late Archaic-Early Woodland transition (ca. 3500-2500 BP) in central Kentucky is a critical period for changes in land use, adoption of new subsistence technologies, and socio-economic reorganization. The work at Crumps Cave is significant to cave and karst studies in three ways: (1) developing a model of hunter-gatherer and early horticultural utilization of holokarst terrains; (2) contributing to contemporary forest management literature by considering long-term history of karstic barrens and cedar glades ecosystems; and (3) elucidating the Holocene history of geogenic, biogenic, and anthropogenic sediment deposition in Crumps Cave sink and vestibule, and the effects of prehistoric human land use on cave systems.

Mara L. Cashay ($2500)
M.S. Student
Department of Biology
Appalachian State University

Impact of exogenous nutrients on Mn-oxidizing microbial consortia among caves of the southern Appalachian Mountains

Abstract- Manganese-oxidizing microbes are common in a variety of environments, including cave and karst systems, and can act as indicators of water quality and/or bioremediators in their natural habitats. The microbial ecology of Mn oxide deposits is not well understood and even less is known about the factors that stimulate Mn-oxidizing microbes in situ. Previous studies suggest that biological Mn oxidation is carbon limited. Preliminary results from the proposed research however, have shown that fungal growth can be stimulated without inducing biotic Mn oxidation the addition of simple sugars (i.e. glucose and malt extract), as well as complex carbohydrates (i.e. wood, cotton and cellulose). This lack of simple correlation between Mn oxidation and additional exogenous carbon suggests that other environmental factors need to be considered in order to define the biotic role of Mn oxidation within cave systems. The aim of this study is to identify the range of factors that stimulate biotic Mn-oxidizing activity in situ and to identify how anthropogenic impacts may alter biogeochemical cycling and contaminant trapping within these ecosystems. This work has far reaching implications for water quality within karst aquifers that house a significant portion of the drinking water for the eastern United States.

Aaron Covey ($3000)
Ph.D. Candidate
Department of Earth and Environmental Sciences
Vanderbilt University

Quantifying Parameters of Climate Variability on Soil and Speleothem Carbon Isotopes: Coupling Modern Cave Monitoring with Multicomponent Reactive Transport Model

Abstract - Speleothem carbon isotope values (δ13C) have potential to record past variability in hydroclimate, vegetation, and soils. Yet, these data are often not interpreted in a paleoclimate context due to the multiple and complex environmental factors controlling δ13C. Radiocarbon (14C) can provide insight into water-soil/rock interaction in the epikarst, but it is also complicated by input from multiple subsurface carbon pools. By using a reactive transport model that has been ground-truthed with observations of modern systems, the factors controlling drip water carbon isotope systematics can be constrained, providing the basis needed to build an interpretive framework for speleothem δ13C and 14C records. I propose to couple monitoring of a modern cave system with a thermodynamically and kinetically driven multiphase reactive transport model, CrunchFlow. Monitoring of surface temperature and precipitation, soil temperature and moisture gradients, and cave temperature and pCO2 will set the initial boundary conditions for the model. Monthly δ13C and seasonal 14C samples in soil (gas and water) and cave (air and drip water) will constrain the factors controlling drip water δ13C and 14C, providing data for a best-fit model of the soil-epikarst environment. Once the model has been parameterized, I will conduct a series of experiments to determine how changes in temperature, precipitation, seasonality, vegetation, and soil thickness influence δ13C and 14C of drip water over varying timescales. These model simulations will help determine the fundamental factors that control δ13C in drip waters and should thus provide an innovative and powerful tool for future interpretations of speleothem δ13C records

Charles D. R. Stephen ($1500)
Ph.D. Student
Department of Biological Sciences
Auburn University

Reassessment of the cave pseudoscorpion Hesperochernes mirabilis (Pseudoscorpiones: Chernetidae)

Abstract -The karst regions of Tennessee, Alabama, and Georgia are well known as a biodiversity hotspot for cave life. Pseudoscorpions represent some of the best examples of this phenomenon, but their true diversity throughout the Appalachian karst has likely been underestimated. Few people are working on the group worldwide, and there are no active workers based in North America. Our knowledge of Appalachian cave pseudoscorpions is restricted to species lists, species descriptions, and unsupported hypotheses of the genealogical relationships between species. In most Appalachian troglobitic pseudoscorpions, the distribution of an entire species is restricted to a single cave system. The biggest exception to this pattern is Hesperochernes mirabilis. This species is known from at least 145 caves located from Alabama to Ohio and on either side of significant geographic barriers to dispersal. It may represent a complex of several species, of which some may be rare and deserving of protection. Alternatively, it may represent an extreme example of phoresy (or "hitching rides"), in which it is tracking the distribution of larger animals. Using phylogenetics, I will identify the boundaries of populations and test their genetic connectivity. If analyses support the hypothesis that H. mirabilis is a species complex, the species will be redefined, and distinct lineages will be described as new species. Results from this work will affect either the conservation status of currently unprotected H. mirabilis populations and the caves they inhabit, or provide compelling evidence for the impact that migrant mammals have on the genetic diversity of cave-inhabiting arthropods.

Gilles Tagne ($2500)
Ph.D. Student
Department of Geological Sciences
Ball State University

Using geochemical and isotopic data to partition sources of groundwater in epigenic karst aquifers

Abstract -This research comprises two related objectives in the study of epigenic karst aquifers: 1) to better constrain the flux of carbon through a detailed study of inorganic and organic carbon, including the temporal variation, reaction pathways, and relation to overlying land use; and 2) to examine the source and transport of sulfur and the impact of this sulfur upon water-rock interactions.

This study juxtaposes two primary geochemical pathways for carbonate dissolution in karst aquifers, carbonic acid conveyed by meteoric recharge and the oxidation of reduced sulfur entrained into groundwater flow. I will attempt to quantify the magnitude of each pathway and additionally assess the influence of petroleum-associated brines from deeper groundwater upon on the chemistry of these karst aquifers. This study will contribute to a mixing model to partition contributions of surface and deeper sources to nutrient and carbon flux in karst aquifers. It will also provide new insights in the geochemistry of karst waters in area impacted by agriculture and historic oil exploration.