Final: A Coral Reef Briefing: Visiting Someone Else's Home

This discussion topic submitted by Becky Deehr ( at 9:53 pm on 7/27/99. Additions were last made on Wednesday, May 7, 2014.

A beautiful Visit to Gaulin Reef, San Salvador, Bahamas

A Coral Reef Briefing: Visiting Someone Else's Home

First, a little mind candy: Bahamas trivia

Did you know that
· "Bahamas" comes from the Spanish "baja mar," which means shallow seas?
· Christopher Columbus landed on a Bahamian island on October 12, 1492,
which he named "The Savior" (we know and love it as San Salvador)?
· The motto of the Bahamas is "Pirates expelled, Commerce restored"?
· In the waters around the Bahamas, 5% of the world's corals can be found?
· It is illegal to collect coral or starfish in the Bahamas?
· Some of the James Bond novels are set in the Bahamas . . . Thunderball and most of the underwater scenes of the Bond movies were filmed on or near Paradise Island?
· Parts of the movie Splash (starring Tom Hanks & Darryl Hannah) were filmed in the Exumas?
(Source: 1997/1998 WebTech Designs and Education LTD website,

Ok, now down to business. This report is kind of an environmental briefing, if you will, and I encourage you to share this information with anyone you know will be visiting a coral reef! Please take this info to heart - visiting coral reefs is like being a visitor in someone else's home. I'm sure you'd be on your best behavior if you were visiting a friend's house. Treat coral reefs the same way, and we'll be sure to save/protect our valuable resource from further destruction. There's nothing on Earth like a healthy coral reef!

Especially as recreational divers and snorkellers, we must become aware of the impacts our activities can have on sensitive ecosystems. In order to preserve coral reef health and prevent further reef destruction, we all need to have a background understanding of one of the most diverse ecosystems in the world. After reading this report, I hope that you will have learned a bit about coral reefs and discovered ways that can help you minimize your individual impacts on the coral reefs you visit.

Coral Reefs

Where are they found?
1. Coral reefs are most often found between 20° N and 20° S of the equator (roughly between the Tropic of Cancer and the Tropic of Capricorn)
2. They require ample sunlight, and the best sunlight can be found in the tropics!
3. Corals require warm, clear, shallow ocean water. Most corals are found in waters between 1 and 100 meters deep, though usually less than 20m deep, with a minimum water temperature of 18° C or 64° F.
4. The best known and largest reef in the world is the Great Barrier Reef in Australia. The second largest reef occurs in Belize, and the third largest barrier reef is in the Bahamas!
(Sources:,, and

What is a coral anyway?
1. Corals are members of the animal phylum Cnidaria (also known as Coelenterata).
· The coral animal itself is a polyp, related to jellyfish and sea anemones and similar in shape.
· They are sessile and may excrete a calcareous skeleton, so they are often mistaken as plants.
· They are carnivorous, eating zooplankton and small crustaceans (Source: Goreau, T.F., Goreau, N.I., and Goreau, T.J. 1979. Corals and Coral Reefs).
· They have nematocysts, which are stinging cells, located in their tentacles.
· There are two basic types of corals, the hard corals and the soft corals.

2. Hard corals are considered reef builders.
· These corals secrete calcium carbonate (limestone) to form external skeletons. Large colonies of hard coral polyps are the architects of coral reefs. It can take upwards of 100 years for a coral to grow one inch! (Source:
· Hard corals are called stony or scleractinian corals.
· The polyps have tentacles in multiples of six. This is best seen at night when the polyps are feeding.
· There are more than 70 different species of hard corals in the Caribbean!
· Hard corals take on many different phenotypes/forms: massive and encrusting hard corals are indicative of high energy areas and are wave resistant, whereas branching forms are the most sediment-tolerant hard coral.
· Some common examples of hard corals found in the Bahamas: elkhorn and staghorn corals, boulder corals, brain corals, pillar corals, star and flower corals.

3. Soft corals don't build reefs, but they live on or near them.
· These corals are called gorgonians or octocorals (keep reading to find out more).
· The soft corals are composed of a flexible protein called gorgonin and may contain spicules of calcium carbonate.
· The polyps have tentacles in eights, hence the name octocoral.
· Soft corals have indicative shapes, often as rods or fans. Probably the most common soft corals in the Bahamas are sea whips, sea rods and sea fans.

Other than corals, what makes up a coral reef?
1. There is great biodiversity in and around a coral reef!
· Coral reefs cover less than 0.2% of the ocean floor, but about 25% of undersea species make their homes in coral reefs. (Source:
· Lots of colorful fish can be found in and on the reef. Damselfish, gobies, parrotfish, sergeant majors, black durgons, angelfish, tangs, snappers, chubs, fairy basslets, and hundreds of other beautiful fish call the reef home. These fish are often brightly colored to attract fish of the other sex for certain activities, if you know what I mean!
· Mollusks and gastropods, like the awesome flamingo tongue, sea slugs, snails and clams live around the reef. Often, those critters eat coral polyps or algae that may be growing on the corals and reef substrate.
· Octopi, squid, rays and skates, shrimps, lobsters and even a shark or two (nurse or reef) enjoy the protection and food provided by the coral reef.
· Algae of all colors and from the major groups (green, red, brown, blue-green) grow on coral reefs. This is a popular food item for many fish and other reef critters. Sometimes algae reefs are mistaken for coral reefs. However, most of the reefs in the Caribbean are coral reefs - the corals are the composers of the reefs, calcium carbonate structures built up upon hundreds of years of coral polyp life and death.

2. A coral reef community encompasses all "sides" of a coral reef.
· There are distinct differences between communities found on the hind reef, the fore reef, the top of the reef and the lower reef. (Source: Newell, N.D. 1972. The evolution of reefs. Sci. Amer. 226:54-65.)
· The hind reef is the area of the reef that is closest to the shore, and is also called the back reef. It is well protected from the ocean waves.
· The fore reef faces the open ocean and subject to strong ocean waves. Branching corals such as the elkhorn coral are indicative of a fore reef environment.
· The top of the reef is what most snorkellers see, the part of the reef that has the most surface area facing the sun.
· The bottom of the reef is inhabited by fish and reef critters that don't wish to be seen easily. These nooks and crannies near the sandy sea bottom are favorite areas for SCUBA divers to explore.

3. The surrounding areas of a coral reef are very unique.
· Sand flats allow tourists the wonderful view of the picturesque waters. With very little plankton in the water, sun can penetrate to great depth and the sandy white sea floor reflects light. The sand here may be the result of calcareous algae, such as Halimeda, or the remnants of corals and worn-down coral reefs. (Source: Hillis-Colinvaux, L. Historical perspectives on algae and reefs: have reefs been misnamed? Oceanus 29(2): 43-48.)
· Silvery fish are commonly found here, such as silversiders and barracuda, where the light slips off of their bodies and makes them difficult to see. Sand flats are often home to king helmets and queen conchs, two large mollusks that are threatened and even endangered in some areas of the world. · Sea grass beds are dominated by the flowering plants such as turtle grass, manatee grass and/or shoal grass. These gardens of underwater grasses slow water and allow for quicker deposition of sediment from turbulent water. Giant sea stars, queen conchs, and many other gastropods make their homes in the sea grass beds, which provide ample food and shelter.

What could possibly harm coral reefs?
1. Nature can be cruel.
· One of the greatest services provided by coral reefs is shoreline protection from storms and strong waves.
· Hurricanes would be even more dangerous if coral reefs didn't exist to help block some of the storm surge.
· Although tides are very natural and regularly occurring, tides can be particularly high and low at certain times during the lunar cycle. Spring tides are very high high tides, and neap tides are very low low tides, and both can have adverse effects on the coral reefs and coastal shorelines.
· No one is really sure if the El Niño phenomenon is naturally occurring or not, but it sure has an effect on coral reefs and the associated flora and fauna due to the change in ocean temperature and water level.

2. However, there are many unnatural disturbances wreaking havoc on the world's coral reefs.
· Humans play a bigger role in disturbing coral reef ecosystems than you may expect: 8% of the world's population (1/2 billion people) live within 100km of coral reefs! (Source: Report to the U.S. Coral Reef Task Force (May 5, 1999) delivered by Rafe Pomerance, Deputy Assistant Secretary of State for the Environment and Development.)
· Sewage, agricultural runoff, deforestation, sedimentation and all forms of water pollution are extremely harmful to the sensitive coral reef flora and fauna. Small changes in water temperature, salinity and aquatic nutrients are extremely dangerous!
· Over-fishing and the use of destructive fishing practices, such as cyanide poisoning, blasting and explosives, threaten native fish populations to near extinction and endanger overall coral reef health.
· Boating, for recreation, tourism or subsistence or commercial fishing, is also very threatening to coral reef ecosystems. Careless anchoring and the discharge of wastes, trash, oil and gasoline can be detrimental to coral reefs for countless years. Remember the Exxon Valdez accident? That occurred ten years ago, and the effects are still surfacing!
· Global warming is now more fact than fiction. The raising of water temperature and water level worldwide will affect more than just coastal human communities; coral reefs have spent hundreds of years forming and building to just the right heights in just the right temperature and depth of water. People are unknowingly controlling the health and destruction of coral reefs with their greenhouse gasses!
· Just a final note: Scientists say that humans and human activities have killed 10% of the world's coral reefs. It is estimated that 70% of all corals on the planet could be destroyed in the next 20-40 years if we don't change our destructive habits! (Source:

Etiquette for Visitors of Coral Reefs

So, now you're wondering, "Just what in the world can I do to minimize my impacts on coral reefs?" Since changing your lifestyle may be difficult (minimizing wastes, riding a bike more often than driving your car, reusing items rather than landfilling them or recycling them, etc.), the following is a list of things you can do to help protect coral reefs while on your tropical vacations. Keep in mind that you are a visitor in someone (something) else's home, so mind your manners and be respectful. Remember the Golden Rule: Do unto others as you would have them do unto you. And above all, try to leave the place better than you found it. This may often require picking up after others, but I am confident that you can undertake the additional burden (if any).

Things You Can Do When Visiting Coral Reef Ecosystems:
1. You'll be in the tropics, so you'll need to wear sunblock. Apply your sunblock early in the morning, allowing the sunblock to soak into your skin rather than immediately rub off in the water. This will increase the effectiveness of your sunblock and prevent damage to coral reefs. Sunblocks and suntan lotions are oily, so do your part to reduce the amount of oil that gets introduced into the coral reef ecosystem. The same can be said for insect repellants and other types of lotions.

2. Don't collect samples of corals and coral reef critters while visiting coral reefs! It is illegal to collect corals in the Bahamas anyway, so don't risk getting caught! Take only pictures and memories. Also, be a smart consumer and don't buy souvenirs made of coral reef materials. Don't patronize vendors that sell such items, and avoid buying "live rock" items for your fish tanks if you suspect that they have been harvested using harmful or illegal measures.

3. You know you do it . . . yes, I'm talking about urinating somewhere other than a restroom. I know it's hard to find a restroom when you're swimming around in the ocean, but make sure you know where you're depositing your bodily wastes. If it's bad for you to keep those wastes inside your body, know now that it is bad for coral reef flora and fauna to be exposed to those wastes, too! If you can't get to a restroom, be sure to make your deposit away from coral reefs and other sensitive flora and fauna. Either go somewhere up on the beach, close to the shore (a small threat to humans, I know), or out in the open ocean, where the risk of your nitrates and ammonia reaching a reef is small.

4. Snorkelling is a great way to see the reef. Remember that when you are snorkelling to avoid standing on coral reefs and in sandy areas near the reefs. Coral reef critters are very sensitive to sediment being kicked up - coral polyps can be suffocated by sand in the water! Standing on the reefs will harm and even kill many organisms with just one step, so try not to make contact with the reefs in that manner. Snorkelling involves swimming around and above the reef, not sampling or resting on the reef!

5. I'm just as guilty as the next person of this next coral reef visitor's sin: accidentally kicking the reef with your fins. We all know it's an accident, but the corals and reefs suffer for the accident nonetheless. Be aware of your body at all times when swimming around the reefs; there are no "reef police" out there, so you have to patrol yourselves.

6. Be sure you know the depth of the water you are swimming in. Often, swimmers, snorkellers and SCUBA divers accidentally bump into reefs because the water they are in is shallow. Be careful not to grab onto a coral to help you maneuver around a reef! This is extremely harmful to the reef! Also, avoid swimming over reefs in shallow water. Just one wave could leave you sitting, standing or otherwise inhabiting a reef!

7. SCUBA divers: Take Note! When you've got all that gear on, it's difficult to have control of yourself and your gear. Practice operating your equipment in open water before threatening the reef environment. Work on your buoyancy, fin kicks and keeping your instruments near your body at all times! Equipment brush-ups occur more often than you are aware, so it is best to remind yourself often to keep your equipment from scraping a coral reef.

8. If you are diving or snorkelling with a dive outfitter/tourist boat, ask for an environmental briefing. Request that your dive master tell you about the area you'll be visiting before you hit the water. Ask about dangerous currents, the type of reef you'll be visiting, typical fauna and flora found at the reef, etc. The more you know, the less harmful you're likely to be!

9. If you notice a lot of damage to the reef, report it to someone! Tell several people if you must, but make sure someone knows. Boat anchors scar reefs, trampling across reefs kills everything, and coral bleaching indicates unhealthy corals and is not normal. Worldwide bleaching events have been known to occur (an especially deadly episode occurred between 1986 and 1989), so the sooner you report a problem, the sooner the problem can be addressed.
You don't have to be an expert to recognize damage to a coral reef - trust your instincts!

You shouldn't have to memorize this list. Most of the information is common sense and can be found at just about any website concerning coral reefs. However, not everyone knows and understands coral reefs. Please be sure to pass this information along to your friends and family before you go on your next coral reef vacation!
If you would like more information on coral reefs or coral reef etiquette, please be sure to visit any of the following websites. My list is in no particular order and certainly not all-inclusive; there are thousands of websites about coral reefs. Any search engine will give you hundreds of thousands of hits! Check them out for yourself.
· This site is hosted by the Missouri Botanical Gardens.
· This is a good place to find information about marine environmental education. It has links to many other similar organizations.
· Wow! What a great place to visit in person if you're ever in Key Largo, Florida. This website can tell you more about this park if you can't get there for yourself.
· Here you can access information about Team OCEAN (Ocean Conservation Education Action Network), which is a group that provides on-water education for Florida Keys visitors.
· Any website hosted by NOAA is awesome! This one is a link to the May 1995 State of the Reefs Regional and Global Perspectives report.
· At this website you can access a fact sheet released by the Bureau of Oceans and International Environmental and Scientific Affairs. The U.S. Department of State on October 19, 1998 put it out.
· This is an interesting website that can give you more information about corals and coral reefs.
· This is a joint website sponsored by the International Marinelife Alliance and the Coral Reef Education for Students and Teachers (CREST).
· This is the website of the Reef Environmental Education Foundation (REEF).
· The Mother Jones website is filled with information on so many different subjects! The sites I've listed are merely three links within the website.
· This website is hosted by The Coral Reef Alliance. Lots of good stuff here!
If you are looking for a bit of scientific reading, I can suggest some articles for you. I have identified several articles relating to SCUBA diving, coral reef health and the prevention of further loss of marine biodiversity. If you are interested in any of those topics, I encourage you to read on!

Carlton, J.T., and Butman, C.A. 1995. Understanding marine biodiversity: a research agenda for the nation. Oceanus Fall/Winter, pp4-10.

Gibson, J., McField, M., and Wells, S. 1998. Coral reef management in Belize: an approach through integrated coastal zone management. Ocean & Coastal Management 39, pp229-244.

Hawkins, J.P., and Roberts, C.M. 1993. Effects of recreational SCUBA diving on coral reefs: trampling reef-flat communities. J. Applied Ecol. 30, pp25-30.

Hegarty, A. 1997. Start with what the people know: a community based approach to integrated coastal zone management. Ocean & Coastal Management 36:1-3, pp167-203.

Hierta, E. 1994. Rescuing the reef. National Parks Nov./Dec., pp32-37.

Hinrichsen, D. 1996. Coasts in crisis. Issues in Science and Technology. Summer, pp39-47.

Hinrichsen, D. 1997. Coral reefs in crisis. BioScience 47:9, pp554-558.

Medio, D., Ormond, R.F., and Pearson, M. 1997. Effect of briefings on rates of damage to corals by SCUBA divers. Biol. Conserv. 79:1, pp91-95.

National Oceanic and Atmospheric Administration. 1998 (on-line). "The extent and condition of U.S. coral reefs" by Steven L. Miller and Michael P. Crosby. NOAA's State of the Coast Report. Silver Springs, MD: NOAA.

Pendleton, L.H. 1995. Valuing coral reef protection. Ocean & Coastal Management 26:2, pp119-131.

Rouphael, A.B., and Inglis, G.L. 1997. Impacts of recreational SCUBA diving at sites with different reef topographies. Biol. Conserv. 82:3, pp329-336.

Tuxill, J. and Bright, C. 1998. Protecting nature's biodiversity: mending strands in the web of life. Futurist June/July, pp46-51.

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