Protecting Microbial Habitats: Preserving the Unseen Penelope J

Part 2-Conservation, Management, Ethics: Boston,.Northup, Lavoie-Preserving the Unseen 61 Section A-Identifying and Protecting Cave Resources Protecting Microbial Habitats: Preserving the Unseen Penelope J. Boston, Diana E. Northup, and Kathleen H. Lavoie A vast, unseen world oflife covers all the surfaces that we clean and restore in caves (Lavoie and others 2000). This world encompasses the microbial realm-those organisms that youllsually can't sec because they are microscopic-that is, too small to be seen with the naked eye. lvficroor- This chapter ganisms (microbes) include bacteria (both archaeal and bacterial domains), fungi, some algae and protozoa, and viruses. Fungi, algae, and some discusses the eflects bacteria become visible to the unaided human eye when they occur in large of restoration on numbers. They often cover cave walls or other surfaces with a thin coating native microbes that (green in the case of algae, or other colors in the case of fungi and bacteria, inhabit caves as we Figures Ia, Ib, and Id). work to remove This chapter discusses the effects of restoration on native microbes that inhabit caves as we work to remove alien microbes, contemporary alien microbes, graffiti, tracked-in mud, or to remediate other human-introduced changes. contem-porary Telling the difference between resident and nonresident microorganisms graffiti, tracked-in can be difficult, and varies by situation. Algae and mosses growing near an mud, or to remediate entrance or under a skylight are native (Figure la), while the same plants other human- growing around a light in a show cave, are usually e.xotic. Fungi are introduced changes. usually not native in areas with extremely low organic content, but may be native in areas that are richer in organics. You usually will not see most of the microbes that live in caves. When you do, they will typically be visible as splashes of color (Figures Ib, Ie, 3a, and 4b). The visoal display can be either the microbial colonies themselves or their byproducts (for example, characteristic mineral deposits-some forms of manganese or iron oxides, Figure 7b). Macroscopically visible microorganisms can display a wide range of physical characteristics. Following are a few examples ofmicrohes at work in caves: Terms for Organisms Bubble-gum pink fungi Native to Caves Patches of Iluffy white mold Resident Millimeter- to centimeter-sized white colonies with pink centers Indigenous floating on pools Autochthonous Whole walls in lava tube caves glowing with silver or gold actinomycete bacteria (Figure 3a) Terms for Organisms Slimy bacterial strings (Figure 2a) Nonnative to Caves Mounds of mold covering natural organic remains like dead bats or Nonresident animal scat (Figures 4a and 4b) Exotic Patches of colorful fungi and slime on spilled food, old candle wax, or Alien vomit (Figure 4c) Introduced Allochthonous Bacteria and fungi that cavers may see in caves include forms that are common aboveground (Northup and others 1994), such as the hread molds (Rhizopus, J.\4ucor.Penicillium, and Aspergillus); Histoplasma capsulatum (the fungus that causes histoplasmosis, a lung disease often contracted in caves); and bacteria such as the filamentous actinomycetes. 62 Cave Conservation and Restoration Figure 1. Cave Microorganisms Visible to the Naked Eye Figure 1a. A moss garden grows in Four Windows Cave Figure 1b. Penny Boston collects actinomycete bacte- (lava tube), El Malpais National Monument, New ria from a wall in Ft. Stanton Cave, New Mexico. Mexico. (See page 2 of color section.) 1t o Z W ~ is Figure Ie. Unusual slime molds, fungi, yeasts, and bac- Figure Id. Ladybugs massing on an algae-covered boul- terial assemblages grow in Four Windows Cave, EI der below Carlsbad Cavern entrance, New Mexico. (See Malpais, New Mexico. (See page 2 afeolar section.) page 4 of color section.) Figure 2. Cave Organisms in a Rich Cave Food Web E ~• f ~ ~ g Figure 2a. Snottites (stalactite-shaped bacterial slime Figure 2b. Midges are visible on a snottite hanging in colonies) fonn on selenite crystals in Cueva de Villa Cueva de Villa Luz. Mexico. Luz, Mexico. E ~ ~ f f ~ ~ ~ ~ g g Figure 2e. Amblyopygid observed in Cueva de Villa Figure 2d. Fish live in a stream within Cueva de Villa Luz, Mexico. Luz. Mexico. (See page 4 of color section.) Part 2----Conservation,Management, Ethics: Boston, Northrup, Lavoie-Preserving the Unseen 63 Figure 3. Who's at Home in Cave Habitats? ~ ~ ~ g Ii; Figure 3b. Scanning electron micrograph of microorganisms on a calcite speleothem. Spider Cave, New Mexico. E J! F 1 ~ •• Figure 3a. Actinomycete bacteria shine on a lava wall Figure 3c. Scanning electron micrograph of microor- in Michael Wester's caving light. Four Windows Cave, ganisms on lava mud. Cape Verde Islands, eastern At- El Malpais National Monument, New Mexico. lantic ocean. Figure 4. Degradation of Organic Remains Figure 4a. "Marshmal- g- low cricket." A cricket ~ carcass is consumed by z: white fungi, giving it ~ the appearance of a i5 puffy marshmallow. Mammoth Cave, Kentucky. Figure 4b. Bat carcass is consumed by yellow mold on a wall near Bat Cave in Carlsbad Cavern. (See page I of color section.) Figure 4c. Human vomit covered Figure 4d. Fungi consumes a cav- Figure 4e. Scanning electron micro- with fungi was found along visitor ing rope left in La Cueva de las Bar- graph of fungi entwined in cave rope traiL Carlsbad Cavern, New Mexico. rancas, New Mexico. (See page I of fibers. Lechuguilla Cave, New (See page I of color section.) color section.) Mexico. 64 Cave Conservation and Restoration Figure 5. On a Speck of Mud ~ ~ ~ Figure Sa. Actinomycetes grow on gypsum paste (pH Figure Sb. Collecting moonmilk paste that has the con- " 1.0) in Cueva de Villa Luz, Mexico. (See page 2 of color sistency ofCrisco~ Spider Cave, New Mexico. (See page section.) 2 of color section.) z ~ ~ Figure Sc. Scanning electron micrograph of gypsum Figure 5d. Scanning electron micrograph of Crisco-like paste. Cueva de Villa Luz, Mexico. moonmilk. Spider Cave, New Mexico. Figure 6. Examples of Biofilms in Caves E J! j f .,; ~ ~• ~ I Figure 63. Biovermiculations (microbial mud mats) on " Figure 6b. Microbial mats (known as "phlegm-ball walls in Cueva de Villa Luz. Mexico. (See page 2 afeolor mats") in hydrogen sulfide springs in Cueva de Villa section.) Luz, Mexico. E .E J! f I ~ ;;- ~ j o Figure 6c. U-Ioops discovered in Lechuguilla Cave, Figure 6d. Pool fingers in Lower Cave. Carlsbad Cav- New Mexico. ern, New Mexico. (See page 2 of color section.) Part 2-Conservation, Management, Ethics: Boston, Northrup, Lavoie-Preserving the Unseen 65 Figure 7. More Examples of Biofilms in Caves Figure 7a. Colorful surface microbial mats found in Figure 7b. Conspicuous biofilms like this black iron hydrothermal springs at Yellowstone National Park, mat may contain significant microbial populations, ex- Wyoming. (See page 3 of eo lor section.) tracellular materials like polysaccharide slimes and en- zymes, and precipitated minerals like iron oxides. Coldwater Cave, Iowa. (Sec page 3 ofeolar section.) ~~ '" ,';I,~\;'". "~1"l'." 'I'..~ -<l,> (. ~.-~{~,~ ".',~~ "~ , .1 ~ ~ , " Figure 7d. Invisible bio-films ~ ~ on flowstone and other moist ~ " Figure 7c. Wearing protective gear, Penny cave surfaces are enough to Figure 7c. Mike Spilde collects a Boston collects a sample from conspicuous support cave-adapted inverte- sample from colorful encrusta- dangling biofilms in Cueva de Villa Luz, brates. La Cueva. de las Bar- lions of manganese and iron ox- Mexico. (See page 3 of color section.) rancas, New MeXICO.(Seepage ides that can contain rich micro- 3 of color section.) bial diversity. Lcchuguilla Cave, New Mexico. (See page 3 of color section.) Actinomycetes give caves their musty odor and can provide spectacular displays in lava tubes and some other caves (Figures Ib, 3a, and Sa). Walls covered with actinomycetes gleam as if they have been coated in silver when a caver's head lamp reflects ofT thousands of beads of water on the It's ditlicult to care colonies (Figure 3a). Some of the fungi and bacteria are contaminants from humans or human artifacts and should be removed (Figures 4c and 4d), about something while others are native to caves and deserve the protection afforded to you can't sec, but other wildlife. Knowing the difference can be difficult, even for experts. microbes in caves play many important roles in nature Why Should Cavers Care About Microbes? and may produce It's dimcult to care about something you can't see, but microbes in caves compounds of play many important roles in nature and may produce compounds of untold value to untold value to humans. Study of microorganisms is critical to our under- humans, standing of fundamental biology, the way biogeochemical cycles work on Earth, and the way rocks and minerals on our small rocky planet are precipitated and weathered. 66 Cave Conservation and Restoration Organisms That Decompose and Recycle Microbes, especially bacteria and fungi, play crucial roles as decomposers in all ecosystems on Earth. The familiar food chain production system (sunlight energy trapped by plants, plants eaten by herbivores, herbivores eaten by carnivores) often neglects to mention the important decomposition subsystem of food chains. As dead organic materials (withered vegetation, animal wastes, and carcasses) accumulate in the environment, decomposer organisms recycle it back into CO, (carbon dioxide), H,o (water), and nutrients that enter biogeochemical cycles and return to the production system. All life on Earth would cease without the action of decomposer microbes. Many ecosystems on Earth have food chains based on the decomposition of organic material (Schaechter 1997; Needham and others 2000; Wackett and others 200 I). Examples include soil, large rivers, the deep ocean, some lakes, and most caves. Food Chains Based on Sulfur Compounds Microbes that use organic matter provide tbe base of the simplified food chain found in most caves.

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