Reefs in peril
spacer Reefs in peril
Proximal causes of decline in health of coral reefs hot buttons for peril part of BIOLOGY OF CARIBBEAN CORAL REEFS overfishing/reef collecting on Caribbean coral reefs disease on Caribbean coral reefs SCUBA/snorkeling recreation on Caribbean coral reefs future of Caribbean coral reefs pollution on Caribbean coral reefs eutrophication of Caribbean coral reefs hot button for bleaching part of Biology of Caribbean Coral Reefs
There are several major proximal causes for reef decline. The topic of pollution is dealt with here, while other topics are accessible via the "hot" buttons.
subtitle button for "pollution" section of BIOLOGY OF CARIBBEAN CORAL REEFS website Pollution

Pollution of coral reefs comes from many sources, including release of sewage into reef areas directly or via rivers, seepage from septic fields or discharge of septic tanks from tourist hotels, and industrial wastes. Once they are outside of the 12-mile limit from Caribbean islands, cruise boats release "black", "brown", and "gray" water without restriction into the ocean. Sedimentation from excessive land clearing could also be considered a kind of pollution, although its main effect would likely be smothering.

Chronic effects of gasoline and oil spills around marinas, and throughout heavily trafficked recreation areas tend to create sterile areas.  

NOTE black water is bilge water, often with oil contamination; brown water is toilet sewage; and gray water is anything with soap in it, such as laundry, kitchen, bath, and sink water

seahorse cartoon for "reefs in peril" section of BIOLOGY OF CARIBBEAN CORAL REEFS photograph of an old cannon taken from a video

"This old cannon may be just be a plant for the tourist SCUBA divers in the Cayman Islands, but many genuine ones exist throughout Caribbean reefs. It’s ironic to think that reef contamination and destruction started, no matter how innocuously, with its first visitors." - Little Cayman Island 2002


Coral reefs are especially susceptible to oil contamination, both acute, from wrecks, and chronic, from natural oil seeps and offshore dumping of ballast waters from ships. various forms of oil pollution on reefs



photograph of octopus with tin can around its denAlthough junk such as old bottles, tin cans, and other debris deposited around Caribbean reefs is mostly biologically harmless, its presence may be associated photograph of beer bottle with fire coral growing on itwith a more insidious lack of environmental awareness and an ignorance of what are the serious threats to survival of coral reefs.

Fire coral Millepora sp. grows on a beer
bottle in St. Kitts


An octopus Octopus sp. has collected some shiny stuff for its
den in the Bahamas
. Photo courtesy Anne Dupont, Florida

  photograph of running shoe with attached goose barnacles Lepas anatifera
Floating shoe with attached goose barnacles Lepas anatifera in Aruba
photograph of beach debris in Little Cayman Island
Beach debris on Little Cayman Island

photograph of surfer within a cresting wave of garbageIf you've ever felt angry standing on the deck of a dive boat and seeing endless numbers of plastic bags passing by, think of how you would feel about surfing or diving in this debris-laden water off the coast of Java. Millions of tons of plastics are dumped into the world's oceans every year. The big stuff is bad enough when eaten by sea turtles, birds, fishes, and other organisms, but the worst and most insidious is the fine particulate matter that plastic becomes when it degrades through exposure to UV light and wave action. These particles are microscopic in size and permeate all ocean waters. Their debilitating effect on fishes and suspension-feeding invertebrates is to clog gill filaments and feeding structures, affecting gas exchange and food intake, sometimes fatally. Photograph courtesy Zac Noyle and
National Geographic Magazine


A surfer in Java has a close view of ocean "garbage" as it passes by overhead.