Thomas C. Kane

A Chemoautotrophically Based Cave Ecosystem

Microbial mats discovered in a ground-water ecosystem in southern Romania contain chemoautotrophic bacteria that fix inorganic carbon, using hydrogen sulfide as an energy source. Analysis of stable carbon and nitrogen isotopes showed 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.

Ecological Assessment and Geological Significance of Microbial Communities from Cesspool Cave, Virginia

Microbial mats from hydrogen sulfide-rich waters and cave-wall biofilms were investigated from Cesspool Cave, Virginia, to determine community composition and potential geomicrobiological functioning of acid-producing bacteria. Rates of microbial mat chemoautotrophic productivity were estimated using [ 14 C]-bicarbonate incorporations and microbial heterotrophy was determined using [ 14 C]-leucine incubations. Chemoautotrophic fixation was measured at 30.4 - 12.0 ng C mg dry wt -1 h -1 , whereas heterotrophic productivity was significantly less at 0.17 - 0.02 ng C mg dry wt -1 h -1 . The carbon to nitrogen ratios of the microbial mats averaged 13.5, indicating that the mats are not a high quality food source for higher trophic levels. Ribosomal RNA-based methods were used to examine bacterial diversity in the microbial mats, revealing the presence of at least five strains of bacteria. The identity of some of the strains could be resolved to the genus Thiothrix and the Flexibacter - Cytophaga - Bacteriodes...

Productivity-Diversity Relationships from Chemolithoautotrophically Based Sulfidic Karst Systems

INTRODUCTION Microorganisms in most natural systems have typically been considered ecologically important in the cycling of carbon through the ‘microbial loop’ and decomposer niches (e.g., Azam et al., 1993; Bachofen et al., 1998). The discovery of diverse communities at deep-sea hydrothermal vents and cold seeps brought to light the importance of microorganisms as significant contributors to ecosystem autotrophic processes (e.g., Deming & Baross, 1993; Sassen et al., 1993). Indeed, chemolithoautotrophy (e.g., metabolic pathways where energy is gained from inorganic compounds

Microbiological characterization of a sulfide‐rich groundwater ecosystem

Movile Cave, recently discovered in southern Romania, contains sulfide‐rich thermal waters in submerged passages, as well as isolated air pockets. The water surfaces within the air pockets are covered by substantial microbial biofilms, while the air bells contain an abundant and diverse community of terrestrial and aquatic animal species. Based on the results of dehydrogenase activity, fecal streptococci counts, and stable carbon isotope ratios, we propose that the cave community is biologically isolated and receives little, if any, organic carbon inputs from the surface environment. Several sulfide‐oxidizing chemoautotrophic bacteria were isolated from the cave waters. One putative Thiosphaera sp. strain, LV‐43, was further characterized. The presence and high level activity of RuBisCO was clearly demonstrated in this strain.

Genetic structure of morphologically differentiated populations of the amphipod Gammarus minus

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Genetic differentiation ofNiphargus rhenorhodanensis (Amphipoda) from interstitial and karst environments

Electrophoretic variation in proteins encoded by seven presumptive gene loci was analyzed in four populations of the stygobiont amphipodNiphargus rhenorhodanensis. The four populations occur in different habitats, including one in drainage canals, another from sediments of the Ain River, a tributary of the Rhône River, and the remaining two occur in a karstic massif (Dorvan, Ain, France) in the epikarstic and at the base level of the massif, respectively. Six of the seven loci were polymorphic within or among populations, with as many as three electromorphs segregating at the most variable loci. Significant deficiencies in the frequency of heterozygotes were common. Genetic divergence between the two populations of the Dorvan Massif and between the two of the Ain River (forest and sediment habitats) was large. This was highly unexpected, particularly in the case of the two hydrologically connected populations of the Dorvan Massif. It is suggested that either low migration rates or the presence of ecological barriers to gene flow may result in strong genetic differention among local populations ofNiphargus.

Genetic Structure and Morphological Differentiation: Gammarus minus (Amphipoda: Gammaridae) in Virginia

-In two large karst areas, one in West Virginia and the other in Virginia, populations of Gammarus minus (Amphipoda) in caves have significantly larger body size, longer antennae and significantly reduced eye size compared with populations occurring in springs. We examined genetic structure (allozyme variation) and morphological differentiation (ommatidia number) of caveand spring-dwelling populations of G. minus in the Wards Cove karst drainage in Virginia. We found that: (1) there is significant genetic and morphological differentiation between the hydrologically connected cave and spring populations, but (2) there is little genetic or morphologic differentiation between the two hydrologically connected cave populations. These patterns are essentially identical, both qualitatively and quantitatively, to those reported for the geographically disjunct West Virginia populations. These data support the hypothesis that the similar morphologies of cavedwelling G. minus in West Virginia and Virginia are driven by similar selection pressures. These results also suggest that the taxonomic status of cave and spring populations, currently considered to be conspecific, should be re-evaluated.

Environmental and Genetic Influences on the Social Grouping Tendency of a Communal Spider

Within the study of animal social behavior, attention has been focused primarily on vertebrates or eusocial insects, and most models generated to explain the genetics of social grouping or the evolution of social behavior in general apply to those systems (Wilson 1971, 1975, Brown 1975, Oster and Wilson 1978, Wittenberger 1981, Hermann 1982).

Microbial mats in a thermomineral sulfurous cave

The thermomineral sulfurous waters at Mangalia in southeastern Dobrogea, Romania, have been known and used as spa facilities for well over 2,000 years (Feru and Capota 1991). Hydrogeologieal studies performed during the last 60 years (Macovei 1912; Ciocirdel and Protopopescu-Pache 1955; Moissiu 1968; Feru and Capota 1991) identified a deep captive sulfurous aquifer located in Barremian-Jurassic limestones, extending 15 km to the North and 50 km to the South of Mangalia. In the Mangalia region, a system of geological faults allows the deep water to ascend toward the surface and mix with the Sarmatian oxygenated waters (Lascu et al. 1993). The biological investigation of the subsurface ecosystems associated with the sulfurous waters at Mangalia commenced in the late eighties, after the discovery of Movile Cave and its unique subterranean chemoautotrophically based ecosystem (Sarbu, 1990).