Introduction to the symposium

http://dx.doi.org/10.3986/ac.v42i2-3.657 From January 7 to January 11, 2013, the Karst Waters Institute (KWI) and the National Cave and Karst Research Institute (NCRKI) held an international and multidisciplinary symposium on Carbon and Boundaries in Karst at NCKRI headquarters in Carlsbad, New Mexico.There is growing interest in the dynamics of both inorganic and organic carbon in karst systems, and especially in the flux of carbon and nutrients between the surface and subsurface, and between different components (e.g. epikarst and vadose zone) in the karst subsurface. This symposium was about these and other questions connected to carbon in karst and boundaries in karst. It was especially timely both because of rapid advances in the field and the importance of carbon sequestration in global climate change The symposium highlighted recent advances in biology, geology, and hydrology that are helping us understand the dynamics of karst ecosystems, especially with respect to carbon. The talks were organized around seven main themes:• The Upper Boundary – Epikarst• The Lower Boundary – Phreatic Zone• Lateral Inputs — Insurgences• Lateral Outputs — Resurgences• CO2 — Processing and Storage• Organic Carbon — Sources and Quality• Synthesis and Large Scale ModelsSixty participants from seven countries attended the week-long meeting which included an excursion to Carlsbad Caverns National Park. For the first time at a KWI meeting, several participants, who were unable to attend in person, gave their presentations via Skype. The meeting was highlighted by two keynote presentations:• Groundwater Ecology of Alluvial River Flood Plains, Jack Stanford, Flathead Lake Biological Station, Polson, Montana• Karst – Conduit Matrix Exchange and the Karst Hyporheic Zone, John Wilson, New Mexico Institute of Mining and Technoloogy, Socorro, New Mexico.Two most distinguished karst scientists, William B. White of Pennsylvania State University and Derek Ford of McMaster University jointly summed up the meeting. The following is a list of oral and poster presentations given at the meeting. Participants were invited to submit articles that elaborated their meeting presentations to Acta Carsologica.Penny J. Boston: Chemotrophy meets heterotrophy: the inverted 'critical zone' of the subsurfaceKathleen Brannen, Annette Engel, and Ross Larson: Microbial controls on in situ production of dissolved organic matterAmy L. Brown, Jonathan B. Martin, Elizabeth Screaton, John Ezell, James Sutton and Patricia Spellman:Redox state in karst aquifers: Impacts of DOC- and DO-rich river water intrusion into Floridan aquifer springsTerri Brown, Susan M. Pfiffner, and Annette S. Engel: Component isolation and lipid profiling to characterize dissolved organic matter transformations along a groundwater flow pathSarah K. Carmichael, Mary J. Carmichael, Amanda Strom, Krissy W. Johnson, Leigh Anne Roble, Yongli Gao, Cara M. Santelli, and Suzanna L. Bräuer: Using biominerals to assess anthropogenic inpact: a case study in Carter Salt Peter Cave, CarterCounty, TNMatthew D. Covington: A simple theoretical framework to interpret spring variations and constrain mechanistic models of karst processesDavid C. Culver and Tanja Pipan: Convergence and Divergence in Caves and Shallow Subterranean HabitatsAnnette Summers Engel: Microbial activities at geochemical interfaces in cave and karst environmentsCene Fišer: Interactions between surface and subterranean amphipods in springsLee J. Florea: Preliminary carbon sequestration and denudation rates within the karst of the Cumberland Plateau, USADaniel W. Fong, Christopher Seabolt, and Kaitlin C. Esson: Determinants of macroinvertebrate diversity in karst springs of the Mid-Atlantic region, USADerek Ford: Bicarbonate water chemistry of Little Limestone Lake, a beautiful marl lake in Manitoba, CanadaFranci Gabrovšek: The relative importance of speleogenetic phases as revealed by numerical modelsChristian Griebler: Dynamics and limitations of organic carbon turnover in porous aquifersJonathan S. Harding and Troy Watson: The longitudinal response of benthic invertebrate communities to caves Katrina K. Henry, Kenneth A. Salaz, and John L. Wilson: Experimental design and instrumentation to observe karst conduit hyporhiec flowJanet S. Herman, Alexandria G. Hounshell, Rima B. Franklin, and Aaron L. Mills: Biological control on acid generation at the conduit-bedrock boundary in submerged cavesBenjamin T. Hutchins*, Benjamin F. Schwartz, and Annette S. Engel: Environmental controls on organic matter production and transport across surface- subsurface and geochemical boundaries in the Edwards Aquifer, Texas, USADaniel S. Jones, Irene Schaperdoth, and Jennifer L. Macalady: Subaerial microbial life in the sulfidic Frasassi Cave System, ItalyWilliam K. Jones: Physical Structure of the epikarstJames E. Kaufmann and Jeffery Crews: Stratigraphic control on conduit development in the Ozark Karst, Missouri, USAKatherine J. Knierim, Erik Pollock, and Phillip D. Hays: Using isotopes of dissolved inorganic carbon species and water to separate sources of recharge in a cave spring, northwestern ArkansasAndrew J. Kowalczk: Quantitatively modeling source influences on cave air carbon dioxide chemistryErik B. Larson and John E. Mylroie: Quaternary glacial cycles: karst processes and the global CO2 budgetJonathan B. Martin, Mitra Khadka, Marie Kurz, John Ezell, Amy Brown: Karst in the global carbon cycleIoana N. Meleg: Spatio-temporal trends in diversity of subsurface assemblages from the vadose zone of the Carpathian karst in RomaniaAaron L. Mills, Janet S. Herman, and Terrence N. Tysall: Comparison of water quality in submerged caves with that of diffuse groundwater immediately proximal to the conduitDiana E. Northu*, Noelle G. Martínez, Lory O. Henderson and Elizabeth T. Montano: Carbon cycling in arid land caves: implications for microbial processesPedro Oromí and Heriberto D. López: Shallow Subterranean Habitats in Volcanic TerrainRandall L. Paylor* and Carol M. Wicks: Particulate inorganic carbon flux in karst and its significance to karst development and the carbon cycleTanja Pipan and David C. Culver: Patterns of organic carbon in shallow subterranean habitats (SSHs)Junbing Pu*, Daoxian Yuan, Licheng Shen and Heping Zha: Seasonal, diurnal and storm-scale PCO2 variations of cave stream in subtropical karst area, Chongqing, SW ChinaNataša Ravbar: Variability of groundwater flow and transport processes in karst under different hydrologic conditionsWhere’s the fire? Sam Rochelle, Michael N. Spilde, and Penny J. Boston: An analysis of carbon precipitates in Black and other caves of the Upper Guadalupe Mountains, New MexicoBenjamin F. Schwartz*, Susanne Schwinning, Brett Gerard, Kelly R. Kukowski, Chasity L. Stinson, and Heather C. Dammeye: Using hydrogeochemical and ecohydrologic responses to understand epikarst processes in semi-arid systems, Edwards Plateau, Texas, USAKevin S. Simon: Carbon flux in the Dorvan-Cleyzieu karst: lessons from the past to guide future researchJack A. Stanford: Groundwater ecology of alluvial river flood plainsPhilip van Beynen, Derek Ford and Henry Schwarcz: Seasonal influx of organic carbon into Marengo Cave, Indiana, USAMichael P Venarsky, Brock M Huntsman, Jonathan P Benstead, Alexander D Huryn: Testing carbon limitation of a cave stream ecosystem using a whole-reach detritus amendmentGeorge Veni:The role of karst conduit morphology, hydrology, and evolution in the transport, storage, and discharge of carbon and associated sedimentsWilliam B. White: Carbon fluxes in karst aquifers: sources, sinks, and the effect of storm flowsCarol Wicks: Hydrograph interpretation − changes in timeJohn L. Wilson: Karst conduit-matrix exchange and the karst hyporheic zoneYuan Daoxian: The role of geological processes in global carbon cycle: a reviewZhang Qjang: The stability of carbon sink effect related to carbonate rock dissolution: a case study of the Caohai Lake geological carbon sin

The Use of Multi-beam Sonars to Image Bubbly Ship Wakes

During the past five years, researchers at Penn State University (PSU) have used upward-looking multi-beam (MB) sonar to image the bubbly wakes of surface ships. In 2000, a 19-beam, 5° beam width, 120° sector, 250 kHz MB sonar integrated into an autonomous vehicle was used to obtain a first-of-a-kind look at the three-dimensional variability of bubbles in a large ship wake. In 2001 we acquired a Reson 8101 MB sonar, which operates at 240 kHz and features 101-1.5º beams spanning a 150º sector. In July 2002, the Reson sonar was deployed looking upward from a 1.4 m diameter buoy moored at 29.5 m depth in 550 m of water using three anchor lines. A fiber optic cable connected the sonar to a support ship 500 m away. Images of the wake of a small research vessel provided new information about the persistence of bubble clouds in the ocean. An important goal is to use the MB sonar to estimate wake bubble distributions, as has been done with single beam sonar. Here we show that multipath interference and strong, specular reflections from the sea surface adversely affect the use of MB sonars to unambiguously estimate wake bubble distributio

Organic Carbon in Shallow Subterranean Habitats

subterranean habitatsOrganic carbon is likely to be a limiting factor in shallow subterranean habitats (SSHs). Data on dissolved organic carbon (DOC) in three SSHs are reviewed: (1) hypotelminorheic and associated seepage springs (Nanos Mountain, Slovenia), (2) hyporheic zones (Rhône River, France and seepage streams on Nanos Mountain, Slovenia), and (3) epikarst (China, Slovenia, and USA). Hypotelminorheic habitats are superficial groundwater sites less than 1 m below the surface that exit from seepage springs. Hyporheic habitats are the underflow of streams and rivers. Epikarst is the uppermost zone of karst with extensive small cavities and channels. Nanos hypotelminorheic sites that harbored stygobiotic species had organic carbon values averaging 3.4 mg C L−1, and temporal variability was high. For hypoheic sites in the Rhône River basin and on Nanos Mountain, mean values ranged from 1.4 to 3.5 mg C L−1. In the more extensively studied Rhône River basin sites, temporal variability was low. Epikarst DOC ranged from 0.70 to 1.10 mg C L−1 in three caves in China (Shihua Cave), Slovenia (Postojna Planina Cave System) and United States (Organ Cave, West Virginia). These results suggest that organic carbon in aquatic SSHs is lowest in epikarst.Keywords: dissolved organic carbon, epikarst, hyporheic, hypotelminorheic, seepage spring.DOI: 10.3986/ac.v42i2.60

Biological Monitoring in Caves

Leta 1999 sva opisala 20 jam in kraških vodnjakov, v katerih živi po 20 ali več na podzemlje vezanih vrst živali. Pet izmed teh jam je ali pa je bilo urejenih za turistično izrabo: Postojnsko-planinski jamski sistem (Slovenija), Sistem Baget - Sainte Catherine (Francija), Shelta Cave (Alabama, ZDA), Mammoth Cave (Kentucky, ZDA) in Vjetrenica (Bosna in Hercegovina). Prav dejstvo, da imajo lahko močno preurejene jame z visokim številom obiskovalcev tudi pestro favno, kaže, da se oboje ne izključuje. Številne standardne tehnike za vzorčevanje, so uporabne le v maloštevilnih jamah. Te metode so le omejeno uporabne. Onesnaženje je lahko za jamske živali neposredno pogubno ali pa omogoča površinskim živalim, da tudi v podzemlju izpodrivajo. Zato moramo zasledovati tako gostoto favne, kot tudi spremembe v njeni taksonomski sestavi. Ob načrtovanju novih posegov je treba pred kakršnim koli urejanjem raziskati krajevno favno, tako površinsko kot podzemeljsko. Za biološko zasledovanje stanja priporočava naslednje: 1. vzorčenje skozi daljše obdobje; 2. nastavljanje vab v kopenskih in v vodnih habitatih; 3. nastavljanje lončastih pasti v kopenskih habitatih.In 1999, we described the twenty caves and karst wells that have 20 or more species of obligate cave organisms living in them. Among these caves five are developed as tourist caves — Postojna-Planina Cave System (Slovenia), Baget - Sainte Catherine System (France), Shelta Cave (Alabama, USA), Mammoth Cave (Kentucky, USA), and Vjetrenica Cave (Bosnia & Herzegovina). For these and other tourist caves, there is a special responsibility to protect this fauna. The very fact that caves with large numbers of visitors and with modifications to the cave can have high species diversity shows that the two are not incompatible. Many of the standard sampling techniques, may work in some caves only; they are of restricted use. Pollution may be either directly detrimental to the cave fauna or may enable surface species to outcompete the endemic cave fauna. Therefore, changes in the quantity of fauna have to be monitored as well as changes in its taxonomic composition. In the case of new tourist installations, the local cave and surface fauna has to be investigated prior to any modifications. For biological monitoring, we recommend one of the following: 1. minimum-time census, rather than minimum-area census; 2. baiting in both terrestrial and aquatic habitats; 3. pitfall traps (baited or unbaited) in terrestrial habitats

Climate, abiotic factors, and the evolution of subterranean life

Climate, and more generally the physical conditions in caves and other subterranean habitats have a profound influence on the biota. At longer time scale (centuries), climate change can force and/or isolate species in subterranean habitats. Not only Pleistocene climate changes, but earlier ones as well, suchas the Messinian salinity crisis were important in this regard. While many speleobiologists assume that caves are nearly constant environmentally and withscarce organic carbon, this is not the case, especially in non-cave subterranean habitats. Many shal­low subterranean habitats, suchas epikarst, seepage springs, and talus harbor highly modified organisms, ones without eyes and pigment and withelongated appendages. Yet these habi­tats are highly variable withrespect to temperature and other environmental factors, and often have highlevels of organic carbon. Overall, the role of these shallow subterranean habitats in the evolution and biogeography of subterranean species may be crucial. On smaller spatial scales, environmental differences, suchas differences in chemistry of epikarst water, may be im­portant in allowing large numbers of species to coexist

What Does the Distribution of Stygobiotic Copepoda (Crustacea) Tell Us About Their Age?

Geographic distribution of stygobionts is often used to estimate age of a group by assuming vicariant speciation with little or no subsequent dispersal. We investigated the utility of using distributional data for Slovenian stygobiotic copepods by assuming that dispersal is a way to measure age of a species. We list some species of Copepoda that, on the basis of their range and frequency of occupancy within their range, should be older. Body size is not predictor either of range or frequency of occupancy

Morphological variation in Gammarus minus Say (Amphiopoda, Gammeridae), with emphasis on subterranean forms

Gammarus minus Say is a common amphipod species in springs and caves of limestone areas of the eastern and middle-eastern United States. Samples of populations from the central Appalachians were examined closely and morphological variation between spring and cave populations was analyzed. This species occurs in three morphological forms: a spring form, an intermediate cave form and an extreme cave form. The latter form was termed variety tenuipes by some earlier workers but has no nomenclatural validity. In contrast to the spring form, the cave forms show a reduction in eye structure, a change in pigmentation of the integument and a proportionate increase in the length of some of the appendages. It is concluded that G. minus is an extremely vagile and highly variable species that can occupy a variety of habitats, ranging from surface springs to small or large cave systems in certain karst areas

Fifty Years of the Hypotelminorheic: What Have We Learned?

Originally described by Meštrov in 1962, hypotelminorheic habitats are superficial subterranean drainages, typically less than a meter or so in depth, that emerge at small seepage springs. These are persistent wet spots, typically with blackened leaves in small depressions. There may be no flow during dry periods, but the underlying clay retains water above. They share the landscape with other small bodies of water (močila in Slovenian), not necessarily connected with groundwater. Hypotelminorheic habitats (mezišča in Slovenian) usually harbor a fauna dominated by species adapted to subterranean life, characteristically without eyes or pigment. The basic chemistry and hydrology of the habitat is described as are the basic faunal elements. The habitat is placed in a more general context by reviewing how species invade the habitat, their morphology, and their possible connection to deeper subterranean habitats

Morphological Differences Among Eyeless Amphipods in the Genus Stygobromus Dwelling in Different Subterranean Habitats

The amphipod genus Stygobromus occurs in a variety of subterranean habitats in North America, including caves, phreatic (groundwater) lakes, and superficial subterranean habitats (seeps and epikarst). The habitats share the absence of light but differ in other features, such as pore size of the habitat, available food, and degree of seasonality. Measurements of body size, antennal size, and antennal segment number of type specimens were compared for 56 species occurring in the eastern United States. Except for differences in body size, differences among species in the four different habitats were not significant. Body size was related to relative pore size of the habitat, e.g., epikarst, with the smallest spaces, had the smallest species. However, in all habitats, there was one very large species (\u3e 15mm); these enigmatic species apparently occupy a distinct ecological niche, perhaps being more predatory. Differences in relative antennal size showed no significant differences among habitats, and differences in number of antennal segments were marginally significant (P = 0.06) among habitat types and not in the predicted pattern. Differences among habitats in seasonality and available food seemed to be a minor part of the selective environment; absence of light seemed to be a major part of the selective environment