Aquatic
cave environments are important resources.
To
scientists, they represent unique study sites. Biologists have collected
many new and important species of animals from caves such as remipedes
(an new class), amphipods (related to shrimp), and sclerosponges (a
"cross" between sponges and corals). Geologists have utilized
speleothems for paleoclimatic studies. Archaeologists have found pivotal
cultural remains in submerged caves. And hydrologists have used caves
for studying the role groundwater plays in cave development. Some caves
are important as they are the only known sites in which threatened or
endangered species live. It is imperative that these locations be maintained
in a stable manner to avert driving the species into extinction.
To
ranchers and locals, they represent swimming holes or watering locations
for livestock.
To
divers, caves provide sites for both recreational and training purposes.
The attractive attributes of caves include unique formations, visual
appeal, clear visibility, and unusual or new environments.
Cave
environments are fragile. Most caves exist in delicate equilibrium.
Any changes to this equilibrium, even minor changes, can have tremendous
impact. The geologic formations in caves may take thousands, or even
millions of years to form. Some animals that live in caves can survive
only in very special environments, and cannot tolerate many disturbances.
Water quality changes in caves may affect both the biology and factors
such as visibility. The aesthetic appeal as well as overall environmental
quality of caves can suffer as a result of many factors.
The
number of cave divers being trained in the United States has increased
dramatically in the last ten years. However, the number of caves available
to these divers has remained relatively constant. Thus, all of these
caves suffer more diving activity. This elevated level of activity increases
the environmental stress and has resulted in perceptible changes in
many caves. If degradation in cave sites is to be minimized, we must
recognize what impacts our activities have, and how to mitigate or reduce
these impacts.
SURFACE ZONE:
Conditions
in caves are affected by surface conditions. Water, nutrients, and sediment
all enter caves through surface openings. Our actions may alter the
amount. Common problems include trampling or removing plants, walking
down paths or banks comprised of soft or unstable earth, and building
or wearing gullies or ramps.
Altering
material input into caves can adversely affect cave fauna by increasing
turbidity and sedimentation rates or by changing nutrient supply. Our
activity on the surface may decrease visibility, or increase silt in
the cave. Increased sedimentation rates have lead to obstruction of
entrances and cave passages. We need to evaluate our surface activity
for its impact on water flow into openings.
Landowners,
unaware of the detrimental effects of their actions, may damage or alter
surface features. Education often corrects this. In many cases informed
landowners have permitted the construction of retaining walls or concrete
walkways, decreasing the amount of material flowing into caves. The
manner in which owners are approached is critical, however, as they
ultimately control our access.
Direct
actions we can take to enhance conservation are varied. Leave natural
vegetation undisturbed. Avoid interfering with indigenous animals. Collect
and remove trash. Protect sites from erosion. Cave sites have been opened
and closed based on we act. Any time you visit a site, you represent
the entire diving community. Exhibiting proper respect for the environment
and the landowner's authority is critical if sites are to be left available.
DRY CAVE ZONE:
Some
cave diving sites require travel through sections of dry cave before
reaching the water. This section of the cave also needs preservation.
Constructing
paths may alter flow characteristics into the cave. Trash is especially
detrimental, as it will not biodegrade or otherwise disappear. Special
care must be taken to carry out all refuse, including biowaste such
as food scraps and fecal matter. Leaving biowaste may adversely affect
endemic populations of animals by disturbing the natural food cycle,
either by providing too many nutrients, or by enticing other animals
from outside the normally closed system.
Animals
that live in caves have special adaptations that enable them to survive.
Many forage at night, and seek refuge in caves during the daylight hours.
Travel through cave systems that have colonies of organisms, especially
bats, may adversely disturb those creatures. Cave passages harboring
endangered species of bats should be avoided. Bats may be seasonal residents.
Caves that contain seasonal populations should be avoided during those
months when bats are present. This is particularly true of colonies
hibernating in winter, and during breeding season.
Some
caves contain speleothems; cave formations such as stalactites, stalagmites,
calcite flowstone, draperies, and helectites. These take centuries to
form. Take care not to break them. Speleothems should not be collected
and removed as souvenirs. Walking over formations may soil or otherwise
mar them. Routes should be selected to avoid traversing such geologic
formations.
Graffiti
is a problem in many caves, especially those with easy access. Divers
should not add to the problem by contributing their "work."
Such admonishment applies to submerged cave areas as well.
WET CAVE ZONE:
Flooded
caves have many of the same attributes as dry caves: unusual and rare
animals, novel geologic formations, and unexplored territory. Many cave
systems are filled with clean, clear waters of virtually unlimited visibility.
Because of the technical difficulty in accessing water filled caves,
they tend to be less despoiled than dry caves. However, once disturbed,
they heal much more slowly, if at all.
Physical
features of submerged caves suffer the most obvious damage. Speleothems
form only in dry caves. Any speleothems in submerged caves formed when
water levels were lower. If these speleothems are broken they will remain
broken forever. They will not grow back, nor can they be successfully
repaired. Damage to formations in Mermaid's Lair in the Bahamas prompted
local cave divers to unsuccessfully attempt their repair using contact
cement. In some cases, it takes only the slightest touch to send large
formations toppling. In one instance, a slight brush of a fin caused
a ten-foot high column to collapse on its side, breaking into three
major pieces as it did so. Even exhaust bubbles can decimate some frail
features like helectites. Extreme care is needed to preserve submerged
formations.
Although
they appear dull and useless to the novice cave diver, silt formations
are of value. Silt deposits in a cave may be flat and virtually featureless,
or may contain layering which formed as the sediments were laid down.
Disturbing the silt, especially localized disturbances like hand marks
or fin prints, are visual indications that divers have traversed the
location. Such blemishes are more than visual intrusions. Such actions
may destroy valuable scientific evidence that could yield significant
information about cave formation, paleobiology, or archaeology. In most
caves these disturbances are permanent.
Honing
of diving skills will minimize your impact. Under-developed buoyancy
control skills rank highest in causing damage. Hitting ceilings and
banging onto floors causes irrevocable damage. In the Room of Tears,
a large chamber in Carwash Cenote in Mexico, divers striking the ceiling
razed a forest of stalactites. The importance of practicing precise
buoyancy control cannot be over-emphasized.
Poor
trim closely follows poor buoyancy control as a cause of damage. Proper
trim for involves maintaining the body in a horizontal position. Most
ocean divers have a feet down, head up body position when submerged.
In caves this results in fins damaging formations on the floor, and
gouging holes in soft sediment bottoms. You can modify your trim by
changing the location of weights to make the center of gravity match
the center of buoyancy. When in proper trim, you can maintain a horizontal
attitude while in an unmoving, resting position.
Fin
techniques contribute to damage. Use specialized kicks, like the modified
flutter, to minimize fin contact with the walls, ceilings, and floors.
As cave passages change characteristics, vary your propulsion style
to avoid damage that would result if only one finning technique was
used.
Kinesthetic
awareness (awareness of oneself in relation to one's surroundings) is
a sense that is developed through practice and experience. By knowing
where your body is at all times, you can limit contact with the cave.
Avoid traversing restricted passages containing delicate features until
you develop this sense.
Equipment
may contribute to damage as well. Dangling lights, dragging submersible
pressure gauges, loose alternate second stages, scooters that are used
with the propellers pointing downwards, or cameras set down on the bottom
can all cause damage, as well as be safety hazards. Modify your equipment
configuration to prevent damaging the cave.
Some
caves are more tolerant of damage than others. Caves with high flow,
little silt, and no speleothems are much less likely to be permanently
disfigured than those with little flow and an abundance of "soda
straws" or other easily damaged speleothems. Experience plays an
important role in preventing damage. Until a proper level of skill is
developed, constrain your diving activities to more robust caves.
Occasionally
caves may appear hardy, but are actually quite friable. Touching seemingly
solid walls to pull yourself through a cave may result in a lump of
rock being detached from a soft limestone wall. Other walls may have
a thin patina of oxides. The Devil's Ear/Eye system in Florida originally
had completely black walls from this type of veneer. Gradually this
coating was eroded away by divers grasping the walls, leaving many areas
completely white.
In
some caves, even the most careful diver cannot avoid damaging the system.
This especially true when exploration is occurring. The processes that
shape caves occur slowly, and are often precariously balanced. Minor
water displacements, exhaust bubbles, or even slight brushes against
a wall or ceiling by the guideline frequently cause rock to come tumbling
down. Exhaust bubbles in unexplored cave passages commonly bring down
a veritable rain of debris, ranging in size from small pebbles to diver-sized
blocks.
Change
affects the biological components of caves as well as their physical
aspects. Casual recreational cave divers should not access caves that
contain threatened or endangered species. Unless there is a valid scientific
purpose for visiting such caves, they should be avoided.
Animal
life should not be molested or collected. The most common abuse of this
is the collection of lobsters from marine caves. Often the lobster in
a marine cave may be the only important breeding population in the area
due to over-harvesting where the crustaceans are less protected.
Some
animal species are dependent upon special water characteristics. These
animals often live in anchialine caves. Anchialine caves are found near
shorelines, and contain two or more different water layers that are
in part tidally controlled. In some caves, these water layers are separated
by sharp density interfaces of different salinities, called haloclines.
It is not unusual to have fresh water resting directly above marine
water, separated by a boundary layer that is imperceptibly thin. Other
chemical aspects may also differ. For example, dissolved oxygen in one
water mass may be high, while inches away it is nearly zero. Different
animal communities may inhabit each water mass.
Caves
have been in undisturbed equilibrium for thousands of years. As divers
pass through the halocline boundaries, they mix water masses. If they
remain below the halocline, exhaust bubbles rise and mechanically agitate
and mix the waters. While the effect of a few divers probably have no
long-term harmful consequences, the effects of many divers repeatedly
visiting a site may significantly alter water composition. Observations
in the Bahamas show that the salinity of a fresh water lens that was
repeatedly toured by local dive store groups had measurably risen. In
some cases such a disturbance could have a negative effect on indigenous
life.
Below
the halocline, equally invisible changes can occur. Dissolved oxygen
levels below haloclines can be exceptionally low, allowing very primitive
crustaceans to survive. Yet, divers' exhaust bubbles contain about 32
million times more oxygen. Some of this oxygen dissolves into the water,
raising overall concentration. Theoretically a site could be rendered
uninhabitable to indigenous life if it experienced sufficient diver
pressure.
Factors
unrelated to diving also impact water quality. Regional pollution caused
by the widespread use of fertilizers, for example, can impact quality.
Local pollution sources, like chemical dumping or subsurface sewage
emplacement, can contaminate groundwater found in caves. Groundwater
pumping for fresh water can draw down the water lens, allowing saltwater
intrusion. In some regions these factors are monitored by governmental
agencies. You can help curb such abuses by informing appropriate officials
when observed. If you can, take personal action to have potentially
harmful activities ceased.
CONSERVATION
EFFORTS:
Education
is the key to conservation. Educating divers who access, or who are
likely to access caves in the future, is critical if cave environments
are to be preserved. Education should occur in two phases, general problem
awareness, and specific conservation oriented diving skills.
Cave(rn)
diving courses and briefings for supervised diving activities of all
sorts should reinforce environmental preservation philosophies. Bolstering
an awareness of potential problems is especially important when divers
are visiting from other locales, and are unaware of how they may cause
trauma. Equally important is that dive instructors set an example that
others can follow. Students learn by example. If diving educators pay
only lip service to conservation, then efforts to establish a strong
conservation ethic will ultimately prove ineffective. Besides the philosophical
aspects of conservation, specific skills must be taught which will enable
divers to minimize their impact upon the places they dive.
At
both a national and international level, specific cave conservation
measures are being mandated. Some national and state parks have been
established which protect submerged cave systems. Chankanaab Park, Cozumel,
Mexico has one of the world's longest explored submerged caves within
its boundaries. Manatee Springs and Peacock Springs State Parks in north
Florida both contain extensive submerged cave systems. Procedures have
been established to protect the resources within these caves, including
the necessity for proper credentials before being allowed access.
On
Grand Bahama Island, Lucayan Caverns National Park was established solely
for the purpose of protecting what was then the world's longest explored
submerged cave system. Closed for four and a half years while a management
plan was being drafted, it is now open to diving on a limited basis,
subject to strict controls.
Other
cave systems have been closed to preserve threatened species of animals.
Examples in the United States include Logan Cave, Missouri, Key Cave,
Alabama, and Devil's Hole, Nevada. Efforts such as these should be respected
and promoted.
CONCLUSION:
Submerged
cave systems are unique resources for scientific, recreational, and
other public purposes. As a diver, you can either help protect them,
or cause irreparable damage. The choice is yours. If you are a dive
instructor, encourage your students to gain the requisite knowledge
and skills before accessing these potentially fragile locations. If
we all strive to protect these sensitive environments now, future generations
of divers will be able to enjoy them.
The
unique sensitivity of submerged cave environments forewarns of lessons
for all diving environments. All divers should be schooled in the need
to preserve the environment they are visiting; freshwater lakes and
rivers, oceans, reefs, wrecks, kelp forests, caverns and caves, or anywhere
else. It is incumbent upon us all to instill a strong conservation ethic
in divers from the novice level on up.
SIDEBAR:
Several
non-profit organizations in the United States promote cave conservation
efforts. The National Speleological Society (NSS) and the American Cave
Conservation Association (ACCA) deal with the preservation and conservation
of all caves. The NSS and the ACCA have sponsored research in caves,
promoted and lobbied for legislation to protect caves, and have assisted
governmental agencies in drafting management plans to protect specific
caves. The NSS has also conducted programs to train cavers to "cave
softly," minimizing impact.
The
National Speleological Society Cave Diving Section (NSS-CDS) and the
National Association for Cave Diving (NACD) specifically are involved
with the conservation of caves that are partially or wholly submerged.
The NSS-CDS and NACD also conduct training programs in proper cave diving
techniques. These courses include information specifically designed
to reduce man's effect on the cave environment.
Membership
in the NSS, ACCA, NSS-CDS, and NACD is open to interested and concerned
members of the public, and helps support the activities of those corporations.
Further information on the activities and training programs of these
organizations is available by contacting them directly. Addresses are
as follows:
National Speleological
Society American Cave Conservation Association
Cave Avenue P.O. Box 409
Huntsville, AL 35810 Horse Cave, KY 42749
NSS Cave Diving
Section National Association for Cave Diving
P.O. Box 950 P.O. Box 14492
Branford, FL 32008-0950 Gainesville, FL 32604
About the Author:
Jeffrey Bozanic
P.O. Box 3448
Huntington Beach, CA 92605-3448
E-mail: JBozanic@JeffBozanic.com
Jeff
serves as the Executive Director of Island Caves Research Center, a
non-profit organization formed for the purpose of conducting scientific
investigations in submerged cave systems. His research diving activities
have taken him to the Bahamas, Palau, Guam, Mexico, Canary Islands,
Antarctica, and other worldwide locations. Jeff was certified as a NAUI
Instructor in 1978, and as a cave diving instructor in 1983. He is certified
to teach cave diving for the NSS-CDS, NACD, IANTD, and NAUI. He is active
in teaching rebreather, nitrox, technical nitrox, and trimix diving
courses. He has published extensively on diving education topics, with
heavy emphasis on cave diving safety techniques. He has edited/reviewed
many diving textbooks, and is the author of Mastering Rebreathers. He
has served on several Boards of Directors in the diving community, including
as Chairman of the NSS-CDS and as Vice Chairman of NAUI, and as Treasurer
on the AAUS Board. He has received the NAUI Outstanding and Continuing
Service Awards; the Silver Wakulla and Abe Davis Awards for safe cave
diving; and the SSI Platinum Pro 5000 Award.
