make up the snottites shown in Figure 1 (image by M.Spilde and D.Northup). Gypsum and elemental sulfur crystals are produced in situ by the organisms and incorporated into the biofilm. Upper right: “nests” of bacteria and microfungal hyphae are visible on the calcite fibers found in “Crisco” moonmilk from Spider Cave shown in Figure 1 (image by M.Spilde and P. Boston). Lower left: cut edge through a thick (1.5 cm) biofilm mat from Cueva de Villa Luz showing the dense packing of organisms, filaments, minerals, particles, and slime (image by D. Soroka). Lower right: fossil biofilm from paleo pool fingers, Hidden Cave, New Mexico, United States. Acid etched preparation, image by L.Melim, M.Spilde, and D.Northup.

doi:10.4324/9780203483855-67

Chapter

make up the snottites shown in Figure 1 (image by M.Spilde and D.Northup). Gypsum and elemental sulfur crystals are produced in situ by the organisms and incorporated into the biofilm. Upper right: “nests” of bacteria and microfungal hyphae are visible on the calcite fibers found in “Crisco” moonmilk from Spider Cave shown in Figure 1 (image by M.Spilde and P. Boston). Lower left: cut edge through a thick (1.5 cm) biofilm mat from Cueva de Villa Luz showing the dense packing of organisms, filaments, minerals, particles, and slime (image by D. Soroka). Lower right: fossil biofilm from paleo pool fingers, Hidden Cave, New Mexico, United States. Acid etched preparation, image by L.Melim, M.Spilde, and D.Northup.

Chapter

make up the snottites shown in Figure 1 (image by M.Spilde and D.Northup). Gypsum and elemental sulfur crystals are produced in situ by the organisms and incorporated into the biofilm. Upper right: “nests” of bacteria and microfungal hyphae are visible on the calcite fibers found in “Crisco” moonmilk from Spider Cave shown in Figure 1 (image by M.Spilde and P. Boston). Lower left: cut edge through a thick (1.5 cm) biofilm mat from Cueva de Villa Luz showing the dense packing of organisms, filaments, minerals, particles, and slime (image by D. Soroka). Lower right: fossil biofilm from paleo pool fingers, Hidden Cave, New Mexico, United States. Acid etched preparation, image by L.Melim, M.Spilde, and D.Northup.

ABSTRACT

Biofilms can form in water under rapidly running conditions and on the humid surfaces in caves with no running water (Northup et al., 2000). This plasticity in the ability to exploit many different habitat types, fundamental cave geochemistries, and hydrological conditions make biofilms and mats a highly significant feature of subterranean ecosystems. Furthermore, because calcium ions seem to play an important role in adhesion of cells to surfaces, carbonate caves are in a unique position to chemically encourage biofilm formation. Unusual properties of calcium ions encourage interactions with protein and polysaccharide adhesin molecules at the cell surface. Calcium helps to neutralize the electrically active double layer between cell and substrate, thus promoting adhesion.