The Philip M. Smith Graduate Research
Grant for Cave and Karst Research
2014 Grants
Ashley M. Bandy ($3,000)
Ph.D. Candidate
Department of Earth and Environmental Sciences
University of Kentucky
Mobility of Stable Isotope-Labeled Escherichia coli Karst Terrains
Abstract - Currently,
bacterial transport in karst aquifers is not well understood. Bacterial
contamination of karst aquifers is a large concern across the globe.
Groundwater tracers typically used in karst systems include fluorescent
dyes and latex microspheres. These tracers do not exhibit surface
properties and transport behaviors mimicking those of bacteria and
pathogens, and therefore are not good proxies for risk assessment
involving microorganisms. The proposed project will expand upon a
proof-of-concept study tagging nonpathogenic Escherichia coli (E. coli)
with stable isotopes (15N and 13C) to use as a tracer in a karst basin.
A trace will be conducted using labeled E. coli in conjunction with
fluorescent dyes and latex microspheres in the Cane Run karst aquifer
in central Kentucky and through epikarst above Cave Spring Caverns near
Bowling Green, Kentucky. It is hypothesized that dyes, microspheres,
and bacteria tracers will show differential transport times in the Cane
Run/Royal Spring basin under normal flow conditions, with
microorganisms arriving at the spring prior to microspheres or
conservative dyes. For the epikarst trace above Cave Spring Caverns,
the E. coli isolate that exhibits higher attachment efficiency in
saturated granular columns is expected to have higher attenuation and
emerge from the epikarst after the isolate that exhibits lower
attachment efficiency. These two types of E. coli will have different
transport times than microspheres or dyes and may take many storm
events before they are flushed through the epikarst. Isotope analysis
will be used in conjunction with genetic markers to monitor
breakthrough of tracer bacteria.
________________________________________
David Brankovits ($3,000)
Ph.D. Candidate
Marine Biology Interdisciplinary Program
Texas A&M University at Galveston
A Biogeochemical Investigation of a Methane-Dependent Anchialine Cave Ecosystem
Abstract- Energy limited
flooded coastal cave systems are likely to utilize similar processes as
those occurring in chemosynthesis-based oceanic ecosystems. Preliminary
data from my dissertation research suggests methane may be the primary
source of carbon and energy for a unique subsurface ecosystem in the
tropics. I propose advanced molecular biological, lipid biomarker, and
stable isotope techniques to test this premise. I will examine the
following hypotheses in a coastal cave system in the Yucatan Peninsula
in Mexico: (1) methane is seeping into the aquifer from overlying soils
and is being consumed by methanotrophic ('methane-eating') microbes in
the water column of a subterranean estuary; (2) methanotrophic bacteria
inhabiting the groundwater are being consumed by the unique
cave-adapted invertebrate community; (3) methanotrophic bacteria
contribute significant chemosynthetically-produced organic matter to
higher levels of the food web (i.e., cave-adapted shrimps).
The proposed study will provide a comprehensive biogeochemical
description of carbon cycling and the fate of methane in the water
column of a coastal cave system in the Yucatan Peninsula.
Characterizing the microbial community, biogeochemical pathways, and
carbon flow will expand our understanding on the ecology of anchialine
caves. This study will significantly increase the knowledge on
chemosynthetically-based ecosystems and the importance of methane for
certain subterranean food webs. Moreover, demonstrating that an
underground ecosystem is fueled by methane (powerful greenhouse gas)
will have potential implications in studying globally relevant
biogeochemical processes (e.g., methane sinks) for environmental
purposes.
________________________________________
Brian M. Carlson ($3,000)
Ph.D. Candidate
Department of Biological Sciences
University of Cincinnati
Creating High-Density GBS-Based Linkage Mapping Resources for Use in Astyanax mexicanus, the Blind Mexican Cavefish
Abstract - The ability to
conduct genome-level studies aimed at illuminating the genetic
underpinnings of traits of interest has led to significant advances in
our understanding of a wide variety of interesting and ecologically
relevant traits. In the past, however, the cost of sequencing-intensive
methodologies has made such studies difficult or impossible for those
working in non-model and emerging model systems. In such cases,
alternate approaches such as the construction and use of linkage maps
have proven both necessary and valuable. The blind Mexican cavefish,
Astyanax-mexicanus, is an emerging model fish system consisting of a
derived cave morphotype and an extant surface morphotype. Here, I
propose the use of cost-efficient next-generation sequencing
technologies to generate the data necessary to create high-density
linkage maps for use in this species, which has become the model of
choice for many researchers interested in the evolutionary consequences
of cave colonization. Additionally, I propose strategies that will
allow researchers to leverage genomic resources for a related model
fish species, as well as early drafts of genomic resources for Astyanax
mexicanus itself, to determine the genes and genomic intervals
associated with the anonymous markers from which these linkage maps are
constructed.
________________________________________
John Wall ($1,000)
Ph.D. Student
Department of Marine, Earth & Atmospheric Sciences
North Carolina State University
High-Resolution Morphometric Analysis of Sinkholes and Depressions within Karst Geology
Abstract -The proliferation of
Light Detection and Ranging (LiDAR) surveys conducted at the county and
state levels over the past decade provides increasingly high-resolution
topographic data that can be used to quantify the geomorphology of
karst terrains. Current methods to map sinkholes and depressions within
karst geology typically employ coarse resolution topographic data. From
this coarse data closed-contours are manually digitized which is time
intensive. We will show that sinkholes and depressions can be
delineated accurately using semi-automated methods operating on
high-resolution Digital Elevation Models (DEM). This will be done by
using standard Geospatial Information System (GIS) hydrologic tools to
fill depressions within the DEM. The initial DEM will then be
subtracted from the filled DEM resulting in detected depressions or
sinkholes. These results will then be compared to the state
inventories. Results will be used to test proposed scaling
relationships for the size and distribution of sinkholes and
depressions. The resulting catalog of sinkholes and depressions can
then be used for hazard and risk assessment, cultural resource
management and ecological habitat identification.
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last updated or validated on January 24, 2019