The Evolution of Troglomorphy

Degeneration or loss of eyes and pigment and hypertrophy of extra-optic sensory structures, a morphological syndrome termed 'troglomorphy', commonly occurs in animals which have evolved to inhabit caves. We are interested in understanding the degree to which natural selection plays a role in the evolution of cave-related morphology and how the evolution of morphology and the process of speciation are related in cave-dwelling organisms. Currently, we are using biochemical and molecular approaches to determine the genetic structure, assess gene flow and develop a phylogeny for morphologically unmodified surface dwelling and troglomorphic cave dwelling populations of the amphipod Gammarus minus. Using the techniques of quantitative genetics and multivariate statistics, the effects of natural selection on morphological features can be measured directly in the field.

Ecological Analysis of a Chemoautotrophic Groundwater Ecosystem

The Movile Cave ecosystem in southern Romania has hydrogen sulfide rich thermal waters and extensive microbial mats containing bacteria and fungi. Chemoautotrophic bacteria in these mats are capable of fixing inorganic carbon using hydrogen sulfide as an energy source. Analyses of stable carbon and nitrogen isotopes has shown that this chemoautotrophic production is the food base for 48 species of cave-adapted terrestrial and aquatic invertebrates, 33 of which are endemic to this ecosystem. This is the only cave ecosystem known to be supported by in situ autotrophic production, and it contains the only terrestrial community known to be chemoautotrophically based. Current research, using radiolabeled isotopes, is attempting to assess the amount of productivity in the system and the efficiency of trophic transfer of the chemoautotrophic production to the invertebrate consumers. We hypothesize that the high abundance and quality of this autotrophic production is responsible for the unusually high biodiversity seen in this cave ecosystem.