Biological Sampling Through Wells as Windows into the Edwards Aquifer

Presented on Wednesday, May 1, 2013
Krista McDermid, Zara Environmental LLC, Manchaca, TX

The first step in understanding the condition of the aquifer through the use of biological indicators is to survey and understand those indicators.  From blind leeches to eyeless sucker-mouthed catfishes, the biodiversity of the Edwards Aquifer is world-renowned.  These species are primarily known from the fresh water/saline water interface in this karst aquifer that is the sole source of drinking  water for almost two million people, and they are essential components of that ecosystem. Performing biological surveys in a system where deep water wells act as the only windows into the aquifer presents a unique set of challenges and opportunities. In an effort to improve our understanding of species' ranges and obtain new material from the deep portions of the Edwards Aquifer, we began a sampling effort equal to or greater than any previously undertaken in this system.  Biologists visited and contacted over 75 landowners in five counties, obtained permission to sample for biology, and then sampled 43 wells between 2008 and 2010 for aquifer organisms.  New locality records and genetic sequences were added for two species of blind catfishes (the widemouth blindcat Satan eurystomus and the toothless blindcat Trogloglanis pattersoni) which had been undocumented since 1978.  These were the last two species of ictalurid catfish in North America for which genetic sequencing had not been performed.  Twenty new locality records were identified for various aquifer crustaceans, an entire order of fauna (Bathynellacea) was added to the biological inventory of the aquifer, and an undescribed species of Diacyclops copepod was collected.  So many new discoveries in such a short time clearly indicate that the deep aquifer system is one of the last frontiers we have to explore and understand, an understanding that is vital for the continued monitoring and guardianship of aquifer health.

Krista McDermid
Zara Environmental LLC, Manchaca, TX
Krista McDermid is an ecologist with Zara Environmental. She holds a master’s degree in Wildlife Ecology from Texas State University in San Marcos, and a bachelor’s degree in Evolution, Ecology, and Behavior from the University of Texas at Austin. McDermid has been a part of the Zara team since 2007, and during that time has focused on central Texas salamanders, bats, karst invertebrates, and aquifer biota.
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