Ecophysiology and Food Web Dynamics of Spring Ecotone Communities in the Edwards Aquifer, USA

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dc.contributor.advisorNowlin, Weston H.
dc.contributor.authorNair, Parvathi
dc.contributor.committeeMemberSchwartz, Benjamin F.
dc.contributor.committeeMemberHutchins, Benjamin T.
dc.contributor.committeeMemberTomasso, Joseph R.
dc.contributor.committeeMemberHardy, Thom B.
dc.date.accessioned2019-07-23T17:44:44Z
dc.date.available2019-07-23T17:44:44Z
dc.date.issued2019-08
dc.description.abstractSpring orifices serve as ecotones between groundwater and surface water habitats. It is thought that organisms living in physicochemically stable spring ecotones should exhibit small tolerance ranges; however, previous experiments examining this prediction are equivocal. I examined this hypothesis by investigating effects of elevated temperature and decreased dissolved oxygen on several riffle beetle species (Coleoptera: Elmidae), including two ecotone specialists. Results indicate that ecotone-associated species exhibit stenothermal tolerance profiles when compared to surface species. I also examined resource use in invertebrate communities at two spring ecotones using stable isotopes of carbon (δ13C) and nitrogen (δ15N) and amino acid-specific stable isotopes (δ13CAA). Results indicate that spring ecotones contain trophically complex communities with substantial niche partitioning among species. I finally examined the hypothesis that subterranean organisms in systems with ample energy resources (such as guano caves or spring ecotones) may not exhibit reduced metabolic rates. I assessed metabolic and biochemical responses of a subterranean amphipod (Stygobromus pecki) that inhabits spring ecotones and compared these responses to their epigean relative. Results indicate that S. pecki, despite its occupation of relatively resource rich spring opening ecotones, still exhibit lower metabolic rates relative to their epigean relative. Cumulatively, this body of research provides new and critical information on the ecology and evolution of spring ecotone communities, which are among the least studied and poorly understood aquatic ecosystems.
dc.description.departmentBiology
dc.formatText
dc.format.extent127 pages
dc.format.medium1 file (.pdf)
dc.identifier.citationNair, P. (2019). Ecophysiology and food web dynamics of spring ecotone communities in the Edwards Aquifer, USA (Unpublished dissertation). Texas State University, San Marcos, Texas.
dc.identifier.urihttps://hdl.handle.net/10877/8386
dc.language.isoen
dc.subjectKarst
dc.subjectstenothermal
dc.subjectresource partitioning
dc.subjectcrenobionts
dc.subjectBayesian mixing models
dc.subjectterrestrial organic matter
dc.titleEcophysiology and Food Web Dynamics of Spring Ecotone Communities in the Edwards Aquifer, USA
dc.typeDissertation
thesis.degree.departmentBiology
thesis.degree.disciplineAquatic Resources
thesis.degree.grantorTexas State University
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy

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