Lechuguilla Restoration: Techniques Learned in the Southwest Focus on Microbial Preservation
article and photos by Val Hildreth-Werker &
Jim C. Werker
Pre-printed from NSS News April 1997
From February through November of 1996, cavers
gave hundreds of hours to restoration efforts in Lechuguilla. Six
restoration expeditions, led by Jim Werker and Val
Hildreth-Werker, accomplished tasks in the Southwestern Branch.
Special attention was concentrated on preserving pristine areas
of the cave and on developing restoration techniques to minimize
disturbance of biota.
Sadly, a decade of exploration has created
well-worn paths of impact through the main trails of this
world-class cave. Stray footprints have taken big bites out of
the pristine beauty once harbored by Lechuguilla Cave. Some
damage is permanent. Some areas can be repaired and restored to
near-original state. Restoration is happening, one tiny chunk of
misplaced mud at a time.
Lechuguilla's hard-earned wisdom is leading
cavers to figure out better ways to cave softly ... and leave no
trace. Cavers have always been first in finding better ways to
protect cave resources. In the spirit of that perpetual cycle to
do better, Lechuguilla is presenting us another gift ...
improvements in conservation-minded caving techniques.
The cave has received a lot of obvious impact.
Restoration seems an overwhelming task. Lechuguilla has more than
89 miles of surveyed passage abundant with breeches of pristine
areas. The obvious question jumps forth. Where do we start?
Perhaps by concentrating restoration efforts on one small
section, then moving to the next small area ... the results will
eventually add up to some degree of accomplishment. We approached
the Cave Resource Office about restoration tasks in the
Southwestern Branch of Lechuguilla.
Because microbial studies in Lechuguilla are
yielding positive and important results, it is time we take
precautions to decrease our human impact on the biota. We clearly
need to figure out methods for minimizing impact on microbial
communities while accomplishing restoration. Interest in the
microbes of Lechuguilla was originally sparked by Kiym
Cunningham's early investigations of folia and corrosion residue
in which he noted the presence of fungal and bacterial
structures. Through the study of microbial communities in
sub-surface environments on earth, such as Lechuguilla, Penny
Boston and NASA scientists are working to develop models for what
life might be like on Mars.
The weight of the responsibility to approach
restoration with respect for the microbiota is magnified by the
fact that strongly positive results are coming from Larry
Mallory's investigation of bacterial agents in Lechuguilla. He is
identifying cave bacteria which produce chemical substances that
are effective in fighting various forms of cancer. The impact of
humans on the microbial community has been investigated by Diana
Northup and Kathy Lavoie. In separate studies, they have each
tested heavily traveled routes, camps, bivy sites, and urine
dumps throughout the cave. To help cavers understand the
importance of microbial preserves in caves, Northup, Lavoie, and
Mallory have collaborated in composing a draft pamphlet
describing ways we can avoid impacting microbial communities.
Suggested guidelines in the draft are designed for Lechuguilla
and may not be applicable to other types of caves.
This is a draft version.
Comments to Diana Northup will be appreciated.
Diana E. Northup1,
Kathy Lavoie2, Larry Mallory3
In caves, we have microbes that are resident and microbes that
are transient. Transient microbes ride into caves on air
currents, in water flows, on insects, on bats, and through
humans. Anything or anyone entering a cave may carry transient
microbes. Resident microbes, on the other hand, occur as native
inhabitants of a cave. Native microbes depend solely on the
resources within the cave for survival, but transient microbes
tend to thrive where abundant organic materials are available.
Microbes that live by using organic carbon are called
chemoheterotrophs. Guano deposits, flowing water, and decaying
wood provide organic rich matter for chemoheterotrophic microbes
such as fungi. Most fungi found in caves fit this picture and are
most likely transients. Bacteria can also be brought in caves as
transients. However, current research shows that most native
microbes in caves are bacteria.
Within a typical cave, any place with sufficient moisture
might contain microbes. If there is a stream running into the
cave, you might expect to find algae washed in from the surface,
protozoa in the sediments at the bottom of the stream, and
bacteria clinging to the surface of the water and air (bacteria
like to hang out at interfaces where rock meets water and water
meets air). The banks along a stream, with their deposits of
sediment, would be home to fungal spores. These spores, the
fungal equivalent of seeds, only grow when organic matter is
encountered. Bacteria are abundant in deposits of soil or
sediment, but most bacteria are dormant unless suitable food is
present. Fungal spores and bacteria are found in the surface
water film of limestone rock and calcite speleothems. These
microbes may contribute to the formation and degradation of
speleothems.
Two of the few places where you are likely to see colonies
made up of billions and billions of bacterial cells is on
limestone or lava tube surfaces. Those reflective white dots,
clustered together in moist areas on cave ceilings and walls are
actinomycete bacteria. Actinomycetes are responsible for the
distinctive odor that caves and soils have, unlike musty
basements whose odor is due to fungi. The air we breathe (you
won't like this part!) contains millions of fungal spores and
floating bacteria. Deep in caves, bacteria are found living in
pools and dripwater. These bacteria are specialized to grow in
very low nutrient, or oligotrophic, environments.
WHY MICROORGANISMS IN CAVES ARE IMPORTANT
Bacteria and fungi that make their home in caves are important
for several reasons. Because of their long isolation from the
surface and because of their existence in very low nutrient
environments (we're not talking about the bat guano microbes
here!), some cave microbes appear to have evolved to produce
specialized chemical compounds, or toxins, with which to fend off
neighboring microbes (their own version of assault rifles). These
microbial chemical compounds may be useful to humans in the fight
against disease or pollution. Preliminary results from Mallory's
studies suggest that microbes demonstrating this sort of
beneficial activity were collected from pristine sites that were
rarely visited by humans.
Our knowledge of the microbial world in general is really
quite limited and our knowledge of cave microbial diversity is
even more limited. Thus, the potential exists to find novel
microbes in caves. Investigation of such organisms may provide
new details about the evolutionary relationships of bacteria and
fungi.
The study of microbes in caves is also important in
elucidating how speleothems are formed. There is good, although
limited, evidence that microbes are involved in the formation of
iron and manganese oxides, sulfur compounds, saltpeter deposits,
and even calcium carbonate.
Finally, scientists are finding bacteria deep within rocks of
the earth and in association with deep-sea hydrothermal vents.
The deep subsurface environment is difficult to sample; thus,
caves provide a more accessible avenue for studying these
microbes.
HUMANS IMPACT MICROBES IN CAVES
The impact of humans on microbes in caves takes two forms. We
import foreign (surface) microbes as we explore caves. Secondly,
we bring additional organic matter into the cave in the form of
skin, hair, food, lint, urine, and possibly even feces. You are
shedding tens of thousands of skin fragments per minute! This
additional organic matter does the most harm. Native cave
microbes often live in very low nutrient environments and may not
even be able to survive in richer environments. If we add too
much organic matter, the cave habitat will cease to be a good
place for native bacteria to live; and will become, instead, a
good place for transient, surface microbes to thrive!
To decrease the number of foreign microbes you bring into the cave:
To limit the amount of human-associated organic matter entering the cave
(particularly in caves without streams):
In conserving microorganisms and the habitat in which they
exist, balance is needed. Exploration teams often inform
scientists of habitat that might contain microbes of interest. If
the care taken by explorers of Lechuguilla Cave can serve as a
model for other exploration endeavors, we can preserve microbes
that may tell us much about the world in which we live. In order
to preserve the more easily impacted microbes, we may wish to
establish a few microbial preserves in remote areas of pristine
caves and in areas with unique habitats.
If you have comments on the draft pamphlet, please contact
Diana Northup at the Biology Department, University of New
Mexico, Albuquerque, NM 87131.
1 Department of Biology, University of New Mexico, Albuquerque, NM 87131
2 Department of Biology, University of Michigan-Flint, Flint, MI 48502-2186
3 Biomes, 170 North Valley Road,
Pelham, MA 01002-9766
Lechuguilla poses a different set of challenges
for cave microorganisms. Unique microbes that require
low-nutrient environments are sheltered by Lechuguilla. Because
it is a deep cave harboring isolated pools and passages,
specialized microbial communities inside Lechuguilla survive in
the absence of surface nutrients. Many other caves receive major
inputs of surface nutrients from streams and rivers. Unlike
Lechuguilla, food is simply more plentiful where streams flow
into caves and bring an abundance of carbon-loaded, nutrient-rich
debris. In caves like Lechuguilla, where the carbon load is very
low, microorganisms are adapted to living in low-nutrient
environments. When cavers introduce skin, hair, food, mud, and
other carbon-rich materials from the surface, the amount of
nutrients in the cave environment may change.
With all the organic stuff we bring into caves,
it is easy to understand that human presence might build up the
nutrient base. Surface microbes have a better chance of surviving
in caves when we introduce carbon-rich nutrients. When the food
supply changes, the microbial community is likely to change. The
surface organisms, enabled by the introduced food supply, may
take over the environment. Native low-nutrient organisms may not
be able to survive. Adding to or changing the nutrient base may
favor the survival of surface microbes over the survival of
native microbes. Microbial communities requiring low-nutrient
environments could easily be destroyed by human impact.
Cavers doing restoration now have to be acutely
aware of contamination issues! How do we work in areas and
minimize our human impact? Preserving the microbiota is the major
concern for restoration projects in Lechuguilla. How do we adapt
common restoration practices for use in a giant microbial
preserve? Following are descriptions of techniques used in
Lechuguilla. More questions, answers, and better ideas will
arise, but for 1996, here are examples of how we approached
restoration with respect to the amazing diversity of sub-surface
microbes.
First, we are using latex gloves for nearly
every restoration task, especially in pristine or little traveled
areas. Powder-free latex, vinyl, or rubber gloves are worn. Some
people may be allergic to latex, though teams have not
experienced ill-effects. Watch for rashes on the hands.
Occasional severe reactions have been reported in medical
literature. Holes and tears can be a problem. Some cavers rarely
rip their gloves while others go through several pairs a day.
Surgical gloves are reasonably comfortable, work well, fit right,
and last longer than other choices.
Many restoration projects require water. In
Lechuguilla, water is not carried into the cave for restoration
tasks. It is carefully and conservatively taken from designated
pools. Striving to take care in not cross-contaminating pools,
water is used only in the area near the pool from which it came.
Turkey basters are used to put pool water into spray bottles.
Bottles, sprayers, basters, sponges, buckets, brushes, etc. are
new or disinfected for each area of the cave. Because scientists
have found differing microbial communities in pools only a few
feet apart, we try to always identify and avoid possibilities for
contamination.
To conserve water, simple filters are put to
work. Restoration water and debris collected in sponges is
squeezed into buckets and allowed time for the larger particles
to settle. If the water does not clear, it is strained through a
simple sponge filter. Foam or sponge material is compressed into
a clean water bottle with the bottom cut off. Debris is caught
around the edges of the sponge. Treated foam products are avoided
since we do not know what chemicals they may add to the cave.
Restoration water is filtered through this makeshift funnel and
recycled for another dose of restoration work in the same area.
Mud sometimes collects on the bottoms of pools
near trails due to foot travel. Hand pumps are used
to collect the silt while water is filtered directly back into
the pool. The makeshift funnel described above is held at the
water outflow, allowing debris to be caught in the filter. For
some pools, a rubber hose is attached to the pump. Two cavers can
operate the device, one pumping and filtering, one directing the
hose. The pump is disinfected before using it in a different
pool.
We are investigating methods to disinfect
equipment between uses. The following information has been
provided by James Cokendolpher. Currently, chlorine bleach and
hydrogen peroxide look like the disinfectants of choice. Both
need a contact time of about 10 minutes; you can not just wipe
them on and off and expect to kill much. Hydrogen peroxide
rapidly breaks down into water and oxygen. There are two types of
chlorine bleach: one is calcium hypochlorite and the other is
sodium hypochlorite. They break down into sodium or calcium
chloride (sodium chloride is table salt) and water. Both are
highly corrosive and special care should be taken to keep them
away from caving gear. Because of the toxicity of these compounds
to microbes, they should be carried and stored in the cave in
small containers. In that way, any spills will not wipe-out large
numbers of desirable microbes. One tablespoon of bleach per
gallon of water will kill many microbes! More research is needed
to determine what residue is left by various disinfecting agents,
what percentage is effective, what organisms are addressed, how
long the agents continue to work, and how the cave is effected.
FLAGGING TRAILS IN LECHUGUILLA
Trail maintenance is an important aspect of
restoration. When Lechuguilla trails were originally designated,
flagging tape was laid in one foot lengths and a dotted line of
trail was created. Often, only one side of trail was marked.
Problems persisted with lost flagging, hard to find pathways, and
too many misplaced footsteps. Based on years of observation,
Carlsbad Caverns National Park made the decision that double
flagged trails have positive and beneficial influence on the
preservation of cave resources. Trails are now being double
flagged throughout Lechuguilla. Double flagging--continuous lines
of orange surveyors tape defining both sides of the trail--helps
guide footsteps to stay on impacted areas. Double flagged trails
may be visually more obtrusive. However, for the National Park
Service, protection of the cave comes first, and experience has
defined that double trails do help to conserve Lechuguilla's
fragile, irreplaceable resources.
Laying flagging tape for trails takes a bit of
skill development. There tends to be more to the process than
expected. It is good to define techniques before entering the
cave, and then work in small groups, each with an experienced
flagging person directing the process.
Flagging is always "tied down" to
prevent inadvertent movement of the tape. Long lengths are used
... convenient lengths vary for different types of trail. Each
end of flagging is secured to a rock or natural protrusion.
Pretty or unusual speleothems are avoided. Flagging is laid in
the trail, not on the fragile edges, not on pretties, and not on
pristine speleothems. Trails tend to grow out to and sometimes
beyond the flagging if given the opportunity. Rocks and
protrusions are used as necessary with a wrap and twist of the
flagging.
Trails for heavy traffic are laid with about an
18 inch width for walking. This distance allows for easy foot
placement when carrying weighty packs; however, more narrow
trails work okay to avoid formations on the floor or to encourage
slow, deliberate movement through decorated areas. When a
stalagmite is obviously used as a handhold, part of it is
included inside the flagged trail. Anything inside the flagging
eventually is discolored, trampled, or flattened.
Crawl-ways are given two to four feet of trail width, depending on how low the ceiling is and how wide cavers need to spread hands and knees to avoid scraping the ceiling with packs.
On climbs, the flagged trail should be wide
enough to accommodate handholds and footholds for cavers with
different climbing styles. Cavers move through passages with
varying levels of skill and footwork. It helps to try out the
trails laid on slopes and climbs, going both up and down, before
deciding where to put flagging. The goal is to keep hands and
feet inside of flagged routes.
On steep slopes where travel tends to create
erosion, zigzagging the path helps preserve the trail and sets
the stage for easier travel as the trail becomes worn. On
unavoidable steep slopes, safety requires that we remove and set
outside the trail any loose rocks that may slide.
Cavers are wearing surgical gloves when
flagging trails. Diana Northup has advised that our bare hands or
caving gloves may introduce nutrients down lengths of trail that
are defining pristine, untouched areas of the cave. On the
restoration trips into Lechuguilla, we try to establish practices
that are in tune with updated knowledge and that minimize impact
on microbial communities. Another consideration is the flagging
tape itself. Some flagging tapes are rich in carbon. Are we safe
to assume all plastics are inert to cave bacteria? Because some
bacteria live on hydrocarbons, more research is needed to better
define trail marking materials.
Stray footsteps and trails leading to nowhere
are being carefully fluffed. To avoid disturbing surrounding
pristine surfaces, each footstep is "fluffed" or lifted
only in the impacted area. Small plastic or nylon bristled whisk
brooms work well. Occasionally, a fresh plastic spoon is used in
unusually delicate areas.
Small laminated paper signs have been used
along the trails of Lechuguilla for several years. The Park
Service has decided to use additional laminated signs throughout
the cave. Part of our restoration task includes listing
suggestions for the placement of simple, easy-to-read signs,
especially along the trade routes. Examples of signage include: stay
inside flagged trails; brush off helmet and clothes before
entering this area; boots off here; flowstone shoes only.
On white gypsum surfaces, stainless steel
brushes are carefully used with light sweeping motions to peel
off layers of grime. A heavy hand will produce unsightly grooves,
so special care and a light touch are both pertinent. Stainless
steel bristles are necessary because we want to avoid introducing
rust and organic materials. Stray bristles that come loose are
carried out of the cave. Gypsum debris is caught in plastic bags
to avoid contaminating pools or speleothems.
Campsites are fluffed with nylon or plastic
bristled whisk brooms before exiting the cave. Care is taken to
not stir up dust. By gently brushing the surfaces of the impacted
campsite, buried debris and trash is found and carried out. This
helps reduce the spreading of campsite edges into pristine
surfaces.
Restoration tools that have served the light
and packable needs of expedition caving are listed: collapsible
or folding buckets with handles; industrial sprayers that come
with plastic screens on the end of the sprayer tube, cut off to
screw into skinny lightweight plastic water bottles; blue
tight-celled car washing sponges designed to stay soft and
absorbent (blue pieces are easier to pick up when the sponge
begins to deteriorate and they have to be replaced for each
trip); hand-sized upholstery brushes found in auto supplies;
fresh toothbrushes; whisk brooms with plastic or nylon bristles;
powder-free surgical gloves; flagging tape for trails and for
special areas; variety of syringes, tweezers, and hard plastic
picks; fresh turkey basters; and plastic zip-closure freezer
bags, especially the 2 gallon size.
Continually trying to identify ways to lessen
caver impact on Lechuguilla and other caves, we have become aware
of some simple actions that can reduce impact. We consciously
work at keeping hands off walls, ceilings, and handy leaning
places. Obviously, sometimes a handhold is needed for balance; so
we try to use small points of contact, knuckles, fingertips,
etc., rather than big muddy palm prints. Lots of convenient
protrusions and features are along cave trails, but we do not
have to use them as rest stations. We can sit within the trails.
Why continue to destroy something outside the trail just because
somebody sat there first? The old ethic of placing our feet in
someone else's footsteps has propagated too much unnecessary
impact.
When we see a set of footprints across a cave
floor, we try to remove, fluff, or erase the evidence. If we are
going to do more damage by trying to restore a footstep, we leave
it alone, perhaps place a sign, and hope people will learn that
one footprint should not invite more.
Cave softly ... and leave no trace. Move
gently. Spot each other through delicate areas. Make it okay to
remind each other when we forget and perform some old habit.
Think about eliminating the need for restoration. Realize that
different types of caves deserve different attitudes. Figure out
what the caves in your area need, talk among yourselves, and make
it okay to change your behavior.
With respect for the fragile, non-renewable
resources of Lechuguilla, we have worked with scientists, cavers,
and the National Park Service in composing a set of guidelines
for travel in Lechuguilla. Both novice and experienced cavers
participate in these trips; thus, some points may seem obvious to
the seasoned expedition caver. The following guidelines would not
be appropriate for all expedition caves. However, the ideas might
provide beneficial protocol for some newly discovered caves
around the globe.
MINIMUM IMPACT CAVING IN LECHUGUILLA
The overall goal of Carlsbad Caverns National
Park and the Cave Resource Office is to allow limited access to
Lechuguilla Cave while minimizing all impacts to the cave. Every
person entering the cave is responsible for his/her own actions
and for the actions of team members. Expedition Leaders and Team
Leaders have tremendous responsibility for the safety and ethics
of their personnel and for impacts to the cave. If problems
persist, the Leader must abort the trip and the team will leave
the cave.
As we learn more about the cave environment, we
are in a continuing process of evaluating and redefining caver
ethics. The following statement of conduct for Lechuguilla comes
from the experiences and thoughtful contributions of many cavers.
In any cave, think safety, take care of yourself and your team.
Move with stewardship, avoid biological as well as microbial
impacts, and take care of the cave resources.
In summary, we all participate in a continuing
cycle of learning better ways to protect fragile cave resources.
Microbial studies and restoration trips have helped in evaluating
the behaviors and ethics that are beneficial in protecting and
conserving some types of caves. When developing guidelines for
specific caves, or when doing restoration in any cave, it is
extremely important to consult with the scientists and managing
agencies. In choosing our actions, the cave comes first.
Restoration projects require dedication, time, expense, and a variety of skills contributed from many cavers. Some give volunteer effort. Some give professional committment. All give a heartfelt sensibility for protecting, conserving, and preserving irreplaceable cave resources. The list will continue to grow, but for 1996, on behalf of Lechuguilla and the National Park Service, we thank the following cavers who participated or consulted in the Southwest restoration expeditions. We also thank LEARN cavers for coordinating two weeks of restoration expeditions to the West and the Near East with more than 20 volunteer participants from around the nation. Names include Frank Deckert, Dale Pate, Jason Richards, Harry Burgess, Diana Northup, James Cokendolpher, Rane Curl, Harvey DuChene, Larry Mallory, Jim Werker, Val Hildreth-Werker, Tom Mayer, Joe Miracle, Billy Hoffman, June Hoffman, Barbe Barker, Paula Bauer, Lois Bergthold, Dan Dennison, Mark Esco, Jeff Greving, Carol Holsey, David Kelton, Barry Loucks, Rita Loucks, John Lyles, Bobby Mack, Madina Mansur, Mike Mansur, Andy Mayer, Dan Orr, Roland Vinyard, Dale Webb, Buddy Welker.