Publication Date
5-2020
Abstract
Karst aquifer spring habitats around the world support a diversity of specially-adapted, unusual, or rare aquatic flora and fauna. Temperature is one of the most appealing attributes of spring habitats because the consistent groundwater flow associated with springs maintains more constant temperatures than surface flows susceptible to seasonal and diurnal fluxes. Karst aquifers commonly have specific point-source discharge resulting from fractures causing more abrupt changes in local water conditions compared to discharge from granular sand aquifers. Mapping the temperature distribution associated with karst spring discharge can help delineate the most important habitat areas associated with spring-dependent organisms. The downtown spring complex in the Northern Segment of the Edwards Balcones Fault Zone aquifer in central Texas is home to several spring-dependent organisms including an endemic salamander, Eurycea chisolmensis, that is federally listed as “threatened”. Temperatures were measured with a Solinst TLC meter and with a hand-held infrared camera. The Solinst TLC meter was able to measure temperature rapidly and the FLIR infrared camera provided dramatic visual images while documenting dynamics associated with spring discharge temperatures. The temperature data were comparable to specific conductance data indicating that temperature could be used to map areas of basic water chemistry changes in local systems. Aquatic plant assemblages correlated well with the areas delineated by temperature gradients. Overall, temperatures in Salado Creek and the associated spring orifices of the downtown spring complex showed a relationship between temperature and preferred habitat for spring organisms. The results indicated that temperature was an effective parameter to use in spring habitat studies due to its high importance to spring dependent organisms, low cost, and ease of collection.
DOI
https://doi.org/10.5038/9781733375313.1036
Temperature: an easy, inexpensive, but useful tool for mapping karst spring habitats.
Karst aquifer spring habitats around the world support a diversity of specially-adapted, unusual, or rare aquatic flora and fauna. Temperature is one of the most appealing attributes of spring habitats because the consistent groundwater flow associated with springs maintains more constant temperatures than surface flows susceptible to seasonal and diurnal fluxes. Karst aquifers commonly have specific point-source discharge resulting from fractures causing more abrupt changes in local water conditions compared to discharge from granular sand aquifers. Mapping the temperature distribution associated with karst spring discharge can help delineate the most important habitat areas associated with spring-dependent organisms. The downtown spring complex in the Northern Segment of the Edwards Balcones Fault Zone aquifer in central Texas is home to several spring-dependent organisms including an endemic salamander, Eurycea chisolmensis, that is federally listed as “threatened”. Temperatures were measured with a Solinst TLC meter and with a hand-held infrared camera. The Solinst TLC meter was able to measure temperature rapidly and the FLIR infrared camera provided dramatic visual images while documenting dynamics associated with spring discharge temperatures. The temperature data were comparable to specific conductance data indicating that temperature could be used to map areas of basic water chemistry changes in local systems. Aquatic plant assemblages correlated well with the areas delineated by temperature gradients. Overall, temperatures in Salado Creek and the associated spring orifices of the downtown spring complex showed a relationship between temperature and preferred habitat for spring organisms. The results indicated that temperature was an effective parameter to use in spring habitat studies due to its high importance to spring dependent organisms, low cost, and ease of collection.
