ECOSYSTEM DYNAMICS AND POLLUTION EFFECTS IN AN OZARK CAVE STREAM¹

Abstract

Subterranean ecosystems harbor globally rare fauna and important water resources, but ecological processes are poorly understood and are threatened by anthropogenic stresses. Ecosystem analyses were conducted from 1997 to 2000 in Cave Springs Cave, Arkansas, situated in a region of intensive land use, to determine the degree of habitat degradation and viability of endangered fauna. Organic matter budgeting quantified energy flux and documented the dominant input as dissolved organic matter and not gray bat guano (Myotis grisescens). Carbon/nitrogen stable isotope analyses described a trophic web of Ozark cavefish (Amblyopsis rosae) that primarily consumed cave isopods (Caecidotea stiladactyla), which in turn appeared to consume benthic matter originating from a complex mixture of soil, leaf litter, and anthropogenic wastes. Septic leachate, sewage sludge, and cow manure were suspected to augment the food web and were implicated in environmental degradation. Water, sediment, and animal tissue analyses detected excess nutrients, fecal bacteria, and toxic concentrations of metals. Community assemblage may have been altered: sensitive species‐grotto salamanders (Typhlotriton spelaeus) and stygobro‐mid amphipods—were not detected, while more resilient isopods flourished. Reduction of septic and agricultural waste inputs may be necessary to restore ecosystem dynamics in this cave ecosystem to its former undisturbed condition.

Terrestrial filamentous fungi from Gruta do Catão (São Desidério, Bahia, Northeastern Brazil) show high levels of cellulose degradation

“…The largest amount of total organic carbon was observed in the epigean area, as expected, because this location had a greater richness of carbon sources. The input of organic carbon into the subterranean environment occurs through two main pathways: small openings, cracks, and sinks that allow the entry of leaves, wood, and debris from streams and epikarstic environments (Simon et al, 2007), or carbon (Graening and Brown, 2003) or visiting sightseers. The epigean area also had higher microbial biomass values compared to the internal sites in the cave.…”

“…Some studies that assessed organic matter decomposition in aquatic and marine sediments in caves showed high microbial activity in the early stages of decomposition that correlated with increased microbial respiration (Fishez, 1991;Galas et al, 1996). Other researchers emphasized the importance of the microbial community as key organisms at the base of the subterranean environment food web and in decomposition processes (Pohlman et al, 1997;Graening and Brown, 2003). However, few researchers have studied the involvement of cellulolytic microorganisms in the decomposition process in cave environments (Semikolennykh et al, 1975;KoilRaj et al, 2012).…”

Trophic Dynamics in a Neotropical Limestone Cave

“…However, studies that relate the balance between the availability and processing of food resources in caves are still scarce (Gibert 1986, Jasinska et al 1996, Graening and Brown 2003, Simon and Benfield 2002, Simon et al 2007, Souza-Silva et al 2007). Such studies, however, are crucial for the understanding of the trophic dynamics and their influence on the maintenance of the underground diversity.…”

Using Stable Isotopes of Carbon to Investigate the Seasonal Variation of Carbon Transfer in a North-western Arkansas Cave

“…Karst hydrogeology dominates northwestern Arkansas, and intense agricultural activities and rapid population growth in the region have led to degraded water quality (Davis et al, 2000;Graening and Brown, 2000). Nationally, Arkansas is ranked second in broiler-chicken production and fourth in turkey production, and three of the top five counties in Arkansas for agricultural sales are in the northwestern region of the state (U.S. Department of Agriculture, 2002; U.S. Department of Agriculture, 2007).…”

“…Stable-isotope analysis is a useful tool for understanding the exchange of carbon between reservoirs, because biogeochemical reactions change isotopic compositions in predictable ways (Kendall, 1998). Carbon isotopes (d 13 C) are particularly useful in karst settings, where characterizing biogeochemical cycling along groundwater flow paths is critical for understanding and protecting sensitive cave and karst water resources (Doctor et al, 2006;Graening and Brown, 2000;Katz et al, 1997;Lee and Krothe, 2001).…”