Ecological assessment and geological significance of microbial communities from Cesspool Cave, Virginia, 2001, Engel As, Porter Ml, Kinkle Bk, Kane Tc,

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 [C-14]-bicarbonate incorporations and microbial heterotrophy was determined using [C-14]-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 phylum, and the identity of the remaining strains was to either the Helicobacter or Thiovulum group. Two of 10 sulfur-oxidizing, chemoautotrophic pure cultures of Thiobacillus spp. (syn. Thiomonas gen. nov.) demonstrated the ability to corrode calcium carbonate, suggesting that the colonization and metabolic activity of these bacteria may be enhancing cave enlargement

Colonization by aerobic bacteria in karst: Laboratory and in situ experiments, 2004, Personne J. C. , Poty F. , Mahler B. J. , Drogue C. ,

Experiments were carried out to investigate the potential for bacterial colonization of different substrates in karst aquifers and the nature of the colonizing bacteria. Laboratory batch experiments were performed using limestone and PVC as substrates, a natural bacterial isolate and a known laboratory strain (Escherichia coli [E. coli]) as inocula, and karst ground water and a synthetic formula as growth media. In parallel, fragments of limestone and granite were submerged in boreholes penetrating two karst aquifers for more than one year; the boreholes are periodically contaminated by enteric bacteria from waste water. Once a month, rock samples were removed and the colonizing bacteria quantified and identified. The batch experiments demonstrated that the natural isolate and E. coli both readily colonized limestone surfaces using karst ground water as the growth medium. In contrast, bacterial colonization of both the limestone and granite substrates, when submerged in the karst, was less intense. More than 300 bacterial strains were isolated over the period sampled, but no temporal pattern in colonization was seen as far as strain, and colonization by E. coli was notably absent, although strains of Salmonella and Citrobacter were each observed once. Samples suspended in boreholes penetrating, highly fractured zones were less densely colonized than those in the borehole penetrating a less fractured zone. The results suggest that contamination of karst aquifers by enteric bacteria is unlikely to be persistent. We hypothesize that this may be a result of the high flow velocities found in karst conduits, and of predation of colonizing bacteria by autochthonous zooplankton

Colonization, 2004, Stoch F.

Ecology and hydrology of a threatened groundwater-dependent ecosystem: the Jewel Cave karst system in Western Australia, PhD Thesis, 2005, Eberhard, S. M.

Groundwater is a significant component of the world’s water balance and accounts for >90 % of usable freshwater. Around the world groundwater is an important source of water for major cities, towns, industries, agriculture and forestry. Groundwater plays a role in the ecological processes and ‘health’ of many surface ecosystems, and is the critical habitat for subterranean aquatic animals (stygofauna). Over-abstraction or contamination of groundwater resources may imperil the survival of stygofauna and other groundwater-dependent ecosystems (GDEs). In two karst areas in Western Australia (Yanchep and Leeuwin-Naturaliste Ridge), rich stygofauna communities occur in cave waters containing submerged tree roots. These aquatic root mat communities were listed as critically endangered because of declining groundwater levels, presumably caused by lower rainfall, groundwater abstraction, and/or forest plantations. Investigation of the hydrology and ecology of the cave systems was considered essential for the conservation and recovery of these threatened ecological communities (TECs). This thesis investigated the hydrology and ecology of one of the TECs, located in the Jewel Cave karst system in the Leeuwin-Naturaliste Ridge. A multi-disciplinary approach was used to explore aspects pertinent to the hydrology and ecology of the groundwater system.
Thermoluminescence dating of the limestone suggested that development of the karst system dates from the Early Pleistocene and that caves have been available for colonisation by groundwater fauna since that time. Speleogenesis of the watertable maze caves occurred in a flank margin setting during earlier periods of wetter climate and/or elevated base levels. Field mapping and leveling were used to determine hydrologic relationships between caves and the boundaries of the karst aquifer. Monitoring of groundwater levels was undertaken to characterise the conditions of recharge, storage, flow and discharge. A hydrogeologic model of the karst system was developed.
The groundwater hydrograph for the last 50 years was reconstructed from old photographs and records whilst radiometric dating and leveling of stratigraphic horizons enabled reconstruction of a history of watertable fluctuations spanning the Holocene to Late Pleistocene. The watertable fluctuations over the previous 50 years did not exceed the range of fluctuations experienced in the Quaternary history, including a period 11,000 to 13,000 years ago when the watertable was lower than the present level.
The recent groundwater decline in Jewel Cave was not reflected in the annual rainfall trend, which was above average during the period (1976 to 1988) when the major drop in water levels occurred. Groundwater abstraction and tree plantations in nearby catchments have not contributed to the groundwater decline as previously suggested. The period of major watertable decline coincided with a substantial reduction in fire frequency within the karst catchment. The resultant increase in understorey vegetation and ground litter may have contributed to a reduction in groundwater recharge, through increased evapotranspiration and interception of rainfall. To better understand the relationships between rainfall, vegetation and fire and their effects on groundwater recharge, an experiment is proposed that involves a prescribed burn of the cave catchment with before-after monitoring of rainfall, leaf-area, ground litter, soil moisture, vadose infiltration and groundwater levels.
Molecular genetic techniques (allozyme electrophoresis and mitochondrial DNA) were used to assess the species and population boundaries of two genera and species of cave dwelling Amphipoda. Populations of both species were largely panmictic which was consistent with the hydrogeologic model. The molecular data supported the conclusion that both species of amphipod have survived lower watertable levels experienced in the caves during the Late Pleistocene. A mechanism for the colonization and isolation of populations in caves is proposed.
Multi Dimensional Scaling was used to investigate patterns in groundwater biodiversity including species diversity, species assemblages, habitat associations and biogeography. Faunal patterns were related to abiotic environmental parameters. Investigation of hydrochemistry and water quality characterized the ecological water requirements (EWR) of the TEC and established a baseline against which to evaluate potential impacts such as groundwater pollution.
The conservation status of the listed TEC was significantly improved by increasing the number of known occurrences and distribution range of the community (from 10 m2 to > 2 x 106 m2), and by showing that earlier perceived threatening processes (rainfall decline, groundwater pumping, tree plantations) were either ameliorated or inoperative within this catchment. The GDE in the Jewel Cave karst system may not have been endangered by the major phase of watertable decline experienced 1975-1987, or by the relatively stable level experienced up until 2000. However, if the present trend of declining rainfall in southwest Western Australia continues, and the cave watertable declines > 0.5 m below the present level, then the GDE may become more vulnerable to extinction.
The occurrence and distribution of aquatic root mat communities and related groundwater fauna in other karst catchments in the Leeuwin-Naturaliste Ridge is substantially greater than previously thought, however some of these are predicted to be threatened by groundwater pumping and pollution associated with increasing urban and rural developments. The taxonomy of most stygofauna taxa and the distribution of root mat communities is too poorly known to enable proper assessment of their conservation requirements. A regional-scale survey of stygofauna in southwest Western Australia is required to address this problem. In the interim, conservation actions for the listed TECs need to be focused at the most appropriate spatial scale, which is the karst drainage system and catchment area. Conservation of GDEs in Western Australia will benefit from understanding and integration with abiotic groundwater system processes, especially hydrogeologic and geomorphic processes.

Ecology and hydrology of a threatened groundwater-dependent ecosystem: the Jewel Cave karst system in Western Australia [abstract], 2006, Eberhard S. M.

This thesis investigates the hydrology and ecology of a threatened aquatic root mat community in the Jewel Cave karst system in the Leeuwin-Naturaliste Ridge, Western Australia. Development of the karst system dates from the Early Pleistocene and the caves have been available for colonisation by groundwater fauna since that time. Speleogenesis of the watertable maze caves occurred in a flank margin setting during earlier periods of wetter climate and/or elevated base levels. Watertable fluctuations over the last 50 years did not exceed the range experienced in the Quaternary history. The recent groundwater decline in Jewel Cave was not related to rainfall, nor groundwater abstraction nor nearby tree plantations. However, it did coincide with a reduction in fire frequency within the karst catchment. The resultant increase in understorey vegetation and ground litter may have reduced groundwater recharge through increased evapotranspiration and interception of rainfall. The populations of two genera and species of cave dwelling Amphipoda are largely panmictic. Both species have survived lower watertable levels during the Late Pleistocene. A mechanism for the colonization and isolation of populations in caves is proposed. Faunal patterns (including species diversity, species assemblages, habitat associations and biogeography) were related to abiotic environmental parameters. The ecological water requirements of the community were determined as a baseline for evaluation of impacts such as groundwater pollution. If rainfall continues to decline, and the cave watertable declines > 0.5 m below the present level, then the groundwater ecosystem may become more vulnerable to extinction. The taxonomy and distribution of root mat communities is poorly known and a regional-scale survey is required to properly assess their conservation requirements. Meanwhile, conservation actions for the communities need to be focused at the scale of the karst drainage system and catchment area.

Extended Abstract: Ecology and hydrology of a threatened groundwater-dependent ecosystem: the Jewel Cave karst system in Western Australia, 2006, Eberhard, Stefan M.

This thesis investigates the hydrology and ecology of a threatened aquatic root mat community in the Jewel Cave karst system in the Leeuwin-Naturaliste Ridge, Western Australia. Development of the karst system dates from the Early Pleistocene and the caves have been available for colonisation by groundwater fauna since that time. Speleogenesis of the watertable maze caves occurred in a flank margin setting during earlier periods of wetter climate and/or elevated base levels. Watertable fluctuations over the last 50 years did not exceed the range experienced in the Quaternary history. The recent groundwater decline in Jewel Cave was not related to rainfall, nor groundwater abstraction nor nearby tree plantations. However, it did coincide with a reduction in fire frequency within the karst catchment. The resultant increase in understorey vegetation and ground litter may have reduced groundwater recharge through increased evapotranspiration and interception of rainfall. The populations of two genera and species of cave dwelling Amphipoda are largely panmictic. Both species have survived lower watertable levels during the Late Pleistocene. A mechanism for the colonization and isolation of populations in caves is proposed. Faunal patterns (including species diversity, species assemblages, habitat associations and biogeography) were related to abiotic environmental parameters. The ecological water requirements of the community were determined as a baseline for evaluation of impacts such as groundwater pollution. If rainfall continues to decline, and the cave watertable declines > 0.5 m below the present level, then the groundwater ecosystem may become more vulnerable to extinction. The taxonomy and distribution of root mat communities is poorly known and a regional-scale survey is required to properly assess their conservation requirements. Meanwhile, conservation actions for the communities need to be focused at the scale of the karst drainage system and catchment area.

Subterranean biogeography: what have we learned from molecular techniques?, 2007, Porter Megan L.

Subterranean faunas have unique distributional attributes, including relatively small ranges and high levels of endemism. Two general models have been proposed to account for these distributional patterns–vicariance, the isolation of populations due to geographic barriers, and dispersal, an organism’s ability to move to and colonize new habitats. The debate over the relative importance of each of these models in subterranean systems is ongoing. More recently, biogeographical studies of subterranean fauna using molecular methods have provided new perspectives into the distributional patterns of hypogean fauna, reinvigorating the vicariance versus dispersal debate. This review focuses on the application of molecular techniques to the study of subterranean biogeography, and particularly the contribution of molecular methods in estimating dispersal ability and divergence times. So far, molecular studies of subterranean biogeography have found evidence for the common occurrence of multiple independent colonizations of the subterranean habitat in cave-adapted species, have emphasized the importance of the genetic structure of the ancestral surface populations in determining the genetic structure of subsequent hypogean forms, and have stressed the importance of vicariance or a mixed model including both vicariant and dispersal events.

A Taxonomic Survey of Lamp Flora (Algae and Cyanobacteria) in Electrically Lit Passages within Mammoth Cave National Park, Kentucky., 2007, Smith Thomas, Olson Rick

A taxonomic survey of the lamp flora from electrically lit passages in Mammoth Cave, Mammoth Cave National Park, identified 28 species. Overall, cyanobacteria were dominant represented by 14 species (50% of the total), green algae had eight species (29%), and six diatoms species (21%) were present. There was not a correlation between species diversity and temperature, but there is a general trend of increasing diversity with warmer temperatures. There were two algal or cyanobacterial species identified in this study that overlapped with previous studies. There is a lack of continuity between previous studies only having one species identified in more than one study. This suggests a high algal turnover and possible colonization rates.

A Taxonomic Survey of Lamp Flora (Algae and Cyanobacteria) in Electrically Lit Passages within Mammoth Cave National Park, Kentucky, 2007, Smith Thomas, Olson Rick

A taxonomic survey of the lamp flora from electrically lit passages in Mammoth Cave, Mammoth Cave National Park, identified 28 species. Overall, cyanobacteria were dominant represented by 14 species (50% of the total), green algae had eight species (29%), and six diatoms species (21%) were present. There was not a correlation between species diversity and temperature, but there is a general trend of increasing diversity with warmer temperatures. There were two algal or cyanobacterial species identified in this study that overlapped with previous studies. There is a lack of continuity between previous studies only having one species identified in more than one study. This suggests a high algal turnover and possible colonization rates.

Historical biogeography of subterranean beetles – “Plato’s cave” or scientific evidence?, 2007, Moldovan O. T. , Rajka G.

The last two decades were particularly prolific in historical biogeography because of new information introduced from other sciences, such as paleogeography, by the development of quantitative methods and by molecular phylogeny. Subterranean beetles represent an excellent object of study for historical biogeography because they are the group with the best representation in the subterranean domain. In addition, species have reduced mobility, display different degrees of adaptations to life in caves and many specialists work on this group. Three processes have shaped the present distribution of the tribe Leptodirini (Coleoptera Cholevinae) in the world: dispersal, vicariance, and extinction. Therefore, three successive stages can be established in the space-time evolution of Leptodirini: (1) dispersal from a center of origin in the present area(s); (2) dispersal, extinction and vicariance among the present area(s); and (3) colonization and speciation in the subterranean domain. The Romanian Leptodirini, especially those from Western Carpathians is examined with respect to these processes. Their pattern of distribution in different massifs and at different altitudes is discussed, with possible explanations from a historical biogeographic point of view.

How long does evolution of the troglomorphic form take? Estimating divergence times in Astyanax mexicanus, 2007, Porter M. L. , Dittmar K. , Pé, Rezlosada M.

Features including colonization routes (stream capture) and the existence of both epigean and cave-adapted hypogean popula­tions make Astyanax mexicanus an attractive system for investi­gating the subterranean evolutionary time necessary for acqui­sition of the troglomorphic form. Using published sequences, we have estimated divergence times for A. mexicanus using: 1) two different population-level mitochondrial datasets (cyto­chrome b and NADH dehydrogenase 2) with both strict and relaxed molecular clock methods, and 2) broad phylogenetic approaches combining fossil calibrations and with four nuclear (recombination activating gene, seven in absentia, forkhead, and α-tropomyosin) and two mitochondrial (16S rDNA and cytochrome b) genes. Using these datasets, we have estimated divergence times for three events in the evolutionary history of troglomorphic A. mexicanus populations. First, divergence among cave haplotypes occurred in the Pleistocene, possibly correlating with fluctuating water levels allowing the coloni­zation and subsequent isolation of new subterranean habitats. Second, in one lineage, A. mexicanus cave populations expe­rienced introgressive hybridization events with recent surface populations (0.26-2.0 Ma), possibly also correlated with Pleis­tocene events. Finally, using divergence times from surface populations in the lineage without evidence of introgression as an estimate, the acquisition of the troglomorphic form in A. mexicanus is younger than 2.2 (fossil calibration estimates) – 5.2 (cytb estimate) Ma (Pliocene).

Pattern and process: Evolution of troglomorphy in the cave-planthoppers of Australia and Hawai’i ‒ Preliminary observations (Insecta: Hemiptera: Fulgoromorpha: Cixiidae), 2007, Wessel A. , Erbe P. , Hoch H.

The evolution of troglobites comprises three distinct problems: cave colonization by an epigean ancestor, the evolution of tro­glomorphies, and intra-cave speciation. The study of cave-dwell­ing planthoppers has contributed much to our understanding of troglobite evolution and provides useful model systems to test various aspects of the theoretic framework developed in re­cent years. Most promising in this respect are taxa with several closely related but independently evolved troglobiontic lineag­es, such as on the Canary Islands, in Queensland/Australia and on the Hawaiian Archipelago. Closely related species often oc­cur in caves with comparable ecological parameters yet differ in their age. Here we use comparative age estimates for Australian and Hawaiian cave cixiids to assess the dynamics of reductive evolutionary trends (evolution of troglomorphy) in these taxa and cave planthoppers in general. We show that the degree of troglomorphy is not correlated with the age of cave lineages. Morphological alteration may not be used to draw conclusions about the phylogenetic age of cave organisms, and hypotheses based on such assumptions should be tested in light of these findings.

A Taxonomic Survey of Lamp Flora (Algae and Cyanobacteria) in Electrically Lit Passages within Mammoth Cave National Park, Kentucky, 2007, Smith T. , Olson R.

A taxonomic survey of the lamp flora from electrically lit passages in Mammoth Cave, Mammoth Cave National Park, identified 28 species. Overall, cyanobacteria were dominant represented by 14 species (50% of the total), green algae had eight species (29%), and six diatoms species (21%) were present. There was not a correlation between species diversity and temperature, but there is a general trend of increasing diversity with warmer temperatures. There were two algal or cyanobacterial species identified in this study that overlapped with previous studies. There is a lack of continuity between previous studies only having one species identified in more than one study. This suggests a high algal turnover and possible colonization rates

Observations on the Cave-Associated Beetles (Coleoptera) of Nova Scotia, Canada, 2009, Moseley M.

The cave-associated invertebrates of Nova Scotia constitute a fauna at a very early stage of post-glacial recolonization. The Coleoptera are characterized by low species diversity. A staphylinid Quedius spelaeus spelaeus, a predator, is the only regularly encountered beetle. Ten other terrestrial species registered from cave environments in the province are collected infrequently. They include three other rove-beetles: Brathinus nitidus, Gennadota canadensis and Atheta annexa. The latter two together with Catops gratiosus (Leiodidae) constitute a small group of cave-associated beetles found in decompositional situations. Quedius s. spelaeus and a small suite of other guanophiles live in accumulations of porcupine dung: Agolinus leopardus (Scarabaeidae), Corticaria serrata (Latrididae), and Acrotrichis castanea (Ptilidae). Two adventive weevils Otiorhynchus ligneus and Barypeithes pellucidus (Curculionidae) collected in shallow cave passages are seasonal transients; Dermestes lardarius (Dermestidae), recorded from one cave, was probably an accidental (stray). Five of the terrestrial beetles are adventive Palaearctic species. Aquatic beetles are collected infrequently. Four taxa have been recorded: Agabus larsoni (Dytiscidae) may be habitual in regional caves; another Agabus sp. (probably semivittatus), Dytiscus sp. (Dytiscidae), and Crenitis digesta (Hydrophilidae) are accidentals. The distribution and ecology of recorded species are discussed, and attention is drawn to the association of beetles found in a Nova Scotia “ice cave”.

Microbial Communities and Associated Mineral Fabrics in Altamira Cave, Spain., 2009, Cuezva S. , Sanchezmoral S. , Saizjimenez C. And Cañaveras J. C.

Evidences of microbial colonizations were observed in Altamira Cave, Spain. These consisted of distinct small coloured colonies, both on walls and ceiling, mainly located in the area near the cave entrance, which progressed until reaching the Polychromes Hall. The colonizations were characterized by a high morphological and microstructural variability and related to biomineralization processes. Two main types of CaCO3 deposits were related to the colonies: rosette- or nest-like aggregates of rhombohedral calcite crystals, and spheroid to hemispheroid CaCO3 elements. Colonies distribution seems to be controlled by microenvironmental conditions inside the cavity. The areas of the cave showing higher temperature, relative humidity, and CO2 concentration fluctuations presented a minor biomineralization capability.