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Coastal Watershed Factsheets
Coral Reefs and Your Coastal Watershed
United States
Environmental Protection
Agency
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Office of Water
(4504F) |
EPA 842-F-98-008
July 1998 |
oral reefs are among
the world's richest ecosystems, second only to tropical rain forests in
plant and animal diversity. However, they are extremely sensitive environments
that have special temperature, salinity, light, oxygen, and nutrient
requirements. If environmental conditions fall outside the acceptable range of
these requirements, the health and dynamics of a coral reef community can be
severely disrupted. That's why coral communities are sensitive indicators
of water quality and the ecological health of the coastal watershed. They
respond to alterations within the entire coastal watershed, such as changes in
freshwater flows and nutrient inputs. Consequently, pollution from the
destruction and alteration of surrounding coastal watersheds can directly
affect the health and productivity of a coral reef.
What Are Coral Reefs and What Do They Do?
Coral reef ecosystems are unique, biologically diverse systems recognized as
valuable economic and environmental resources. Many people think coral reefs
are made of plants or rocks, but they are actually made of animals! A coral
polyp is a delicate, limestone-secreting animal. The limestone serves as a
skeleton that either is embedded within the living tissue of the coral or
encloses the animal. A coral reef is made up of colonies of these coral polyps.
There are several benefits of coral reefs.
- Coral reefs are an important recreational and aesthetic resource for people
visiting or living in coastal areas. People use coral reefs for fishing,
underwater photography, scuba diving, and snorkeling.
- Coral reefs provide protection for harbors and beaches, which are often
found behind reefs because the reefs provide natural protection from heavy wave
action caused by coastal storms.
- Coral reefs are home to a number of species of fish and other marine
species, including many that we rely on for food and economic purposes.
- Coral reefs also serve as a laboratory for students and scientists to study
and learn about complex ecological and biological processes. In addition, the
reefs yield many biological treasures that are increasingly being recognized as
natural sources of biomedical chemicals.
Some Impacts on Coral Reefs
Coral reef habitats are extremely sensitive to disturbances, such as various
forms of pollution and physical contact. Pollution of coastal watersheds poses
a threat to the existence of coral reefs. Impacts can result from activities
occurring near the reef itself or from areas within the coastal watershed that
drain to the reef. Disturbances and pollution can lead to diseases in coral
such as bleaching (when the algae that give corals their color die). Natural
occurrences, such as hurricanes, can adversely impact coral reefs through
high-energy storm surges and the resulting resuspension of sediment. However,
reefs are usually able to recover from natural disturbances.
People using the reef can have an adverse impact on reef resources.
Portions of a coral reef can be broken by the impact of boat anchors and boat
groundings. Divers and snorkelers can harm the reef by simply touching it or by
removing the corals. Suntan oil from swimmers and snorkelers can harm or even
kill sensitive corals. Dragging hooks, fishing line, and nets across the coral
reef, as well as placing and recovering lobster traps on reefs, can be
damaging. Overfishing also harms coral reefs by removing important species that
eat the algae growing on corals. When these fish species are removed, the algae
overgrow the corals, smothering them.
Marine debris, trash floating on the ocean or resting on the ocean
floor, comes from many sources, including boaters, divers, improper disposal of
trash on land, storm water runoff to rivers and streams, ships and other
vessels, and offshore oil platforms. Marine debris can harm fish species and
other aquatic organisms that use the reef. Trash that lands on the reef can
kill corals by continually rubbing against it or smothering it.
An excessive amount of nutrients from improperly treated sewage,
atmospheric deposition, agricultural and urban runoff, and cleaning products
high in phosphates can harm coral reef habitats. In excess levels, nutrients
overstimulate the growth of aquatic plants and algae. When nutrient levels
increase, the delicate balance that exists between corals and algae is
destroyed and the algae can overgrow the corals. When this situation is
prolonged, the corals are smothered and die beneath the algal carpet. This, in
turn, affects the fish and other aquatic organisms using the area, leading to a
decrease in animal and plant diversity and affecting use of the water for
fishing and swimming.
Some of the leading causes of nearshore coral decline can be related to
land development and nearshore construction that are not environmentally
sensitive. Sediment, silt, and other suspended solids wash off plowed fields,
construction and logging sites, urban areas, strip-mined land, and eroded
stream banks when it rains. Increases in coastal sediment are also caused by
construction of seawalls, docks, and marinas; land-clearing; boats running
through shallow waters, disturbing and suspending silts with their propellers;
and snorkelers and divers kicking up sediment. Sediment can block sunlight that
is essential for the survival of some corals, which live in a very close
relationship with microscopic plants (algae) that require sunlight to survive.
In addition, heavy sedimentation can bury corals, inhibiting their growth or
killing them.
Pathogens are disease-causing microorganisms such as viruses,
bacteria, and parasites. Pathogens are harmful to corals, causing disease and
scarring in many species. These microorganisms enter water bodies from sources
such as: inadequately treated sewage, storm water drains, septic systems,
runoff from livestock pens, and boats that discharge sewage.
Coral reefs are vulnerable to the introduction of a wide variety of toxic
substances, including metals (such as mercury and lead), toxic organic
chemicals (such as PCBs and dioxin), pesticides, and herbicides found in
sources like industrial discharges, urban and agricultural runoff, mining
activities, and runoff from landfills. Some toxic substances bind to sediment
and are transported to coastal waters through sedimentation. These toxic
substances can cause scarring, death, or reproductive failure in fish,
shellfish, and other marine organisms. In addition, they can accumulate in fish
tissue, leading to fish consumption advisories. The sensitivity of corals makes
them especially vulnerable to the introduction of toxic substances.
What Is EPA Doing to Protect Coral Reefs?
International Coral Reef Initiative
-- In 1994, EPA, along with the State Department, the National Oceanic and
Atmospheric Administration, and the Department of the Interior, formed an
international coalition to coordinate information and bring higher visibility
to the need for coral reef ecosystem preservation. The coalition became the
International Coral Reef Initiative (ICRI), which now includes a
membership of more than 90 countries.
EPA's Watershed Approach-- EPA has joined with others to
promote the Watershed Approach nationally as a means to further restore and
maintain the physical, chemical, and biological quality of our nation's
waters, including coral reefs. By addressing issues on a watershed scale, those
areas that pose the greatest risk to human and ecological health can be
targeted, several pollutants can be addressed at one time, the public can be
involved in cleaning up the environment and protecting coral habitats, and
integrated solutions for environmental protection can be considered. This is
particularly important given the contribution of activities and
sources of pollution within the larger watershed to the decline of coral reefs.
Through the Watershed Approach, integrated coastal zone management tools and
watershed concepts can be applied in the development of comprehensive
management and conservation plans. The Watershed Approach aims to determine
protective approaches for controlling identified stressors to coral reef
ecosystems. EPA's Coastal Watershed Protection Strategy
specifically provides technical assistance and support to priority coastal
watersheds, such as National Estuary Programs (NEPs) and other coastal
waters identified by states.
Other EPA Programs-- In assisting coastal states with the
development of their Coastal Nonpoint Pollution Control Programs, EPA
and other federal agencies developed guidance specifying management measures
for sources of nonpoint pollution (diffuse runoff of pollutants) in coastal
waters. In its program, a state or territory describes how it will implement
nonpoint source pollution controls. EPA also works with other federal agencies
to protect human health and coral reefs by reducing marine debris. The efforts
include the establishment of the National Marine Debris Monitoring
Program, which looks at the origins and amounts of marine debris deposited
along U.S. coasts. EPA and the Coast Guard work together to regulate the
transportation of municipal and commercial waste on vessels and to issue
regulations for the manufacture, maintenance, and efficiency of marine
sanitation devices (boat toilets), as well as the establishment of “no
discharge zones” for vessel sewage. EPA also regulates the discharge of
pollutants from facilities into sensitive marine waters. EPA assists states in
the development of water quality standards designed to protect human
health and aquatic life. This assistance includes the development of criteria
for water quality that accurately reflects the most up-to-date scientific
knowledge about the effects of pollutants on aquatic life, such as corals, and
human health.
What Can You Do to Help Protect Coral Reefs?
You can do several things to help protect coral reefs and your coastal
watershed:
- Be informed and involved. Learn about coral reefs and their
importance to your coastal watershed. Participate in training or educational
programs that focus on reef ecology. Be an informed consumer; ask the store
owner or manager from what country the coral was taken and whether that country
has a management plan to ensure that the harvest was legal and sustainable over
time. Support the creation and maintenance of marine parks and reserves. Become
a citizen volunteer. As a volunteer you might be involved in taking water
quality measurements, tracking the progress of protection and restoration
projects, or reporting special events like fish kills and storm damage.
Volunteer for a reef cleanup or a beach cleanup. If you don't live near a
coast, get involved in your local watershed program. Report dumping or other
illegal activities.
- Take responsibility for your own backyard. Determine whether
additional nutrients or pesticides are needed before you apply them, and look
for alternatives to fertilizers and pesticides where the chance of runoff into
surface waters might occur. Even if you live far from a coral reef ecosystem,
these products might ultimately affect the waters that support coral. Consider
selecting plants and grasses with low maintenance requirements. Water your lawn
conservatively; the less water you use, the less runoff will eventually find
its way into the oceans.
- Practice good housekeeping. Learn about procedures for
disposing of harmful household wastes so they do not end up in sewage treatment
plants that can't treat them or in landfills not designed to receive
hazardous materials. Around the house, keep litter, pet waste, leaves, and
grass clippings out of street gutters and storm drains to prevent their
entrance into streams that might flow to reefs. Use the minimum amount of water
needed when you wash your car to prevent waste and runoff. Never dump any
household, automotive, or gardening wastes into a storm drain. They might end
up on the reef. Take used motor oil, paints, and other hazardous household
materials to proper collection sites such as approved service stations or
designated landfills. Always follow label directions for the use and disposal
of household chemicals. Keep your septic tank in good working order. The
improper disposal of wastes and hazardous materials can lead to water quality
problems and harm to the sensitive coral reef habitats.
- Respect the reef. Help keep the reef healthy by following
local guidelines, recommendations, regulations, and customs. If you dive,
don't touch the coral. Keep your fins, gear, and hands away from the
coral since this contact can hurt you and will damage the delicate coral
animals. Stay off the bottom because stirred-up sediment can settle on corals
and smother them. Avoid entering sensitive habitat areas with your boat or
other motorized watercraft. Maintain your boat engine to prevent oil and gas
leaks. Keep all waste produced during your excursions in a safe place to be
disposed of properly when you're back on land. If you go boating near a
coral reef, don't anchor your boat on the reef. Use mooring buoy systems
if they are available. Maintain and use your marine sanitation devices
properly. Conserve energy and keep your auto in good running condition. By
conserving energy, harmful air emissions leading to air deposition are
minimized.
For additional information...
Call EPA's Oceans and Coastal Protection Division at (202)
566-1200.
Also visit the following EPA web sites:
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