The photograph above shows two branches of elkhorn coral growing in the water near Key West, Florida. The brown and bumpy parts of the coral branches are alive and healthy. The white spot on the left branch is infected with the bacteria.
Click on image for full size
Courtesy of University of Georgia

Coral killer on the loose: Are coral reefs dying because of our waste?
News story originally written on June 28, 2002

New research has found that bacteria are responsible for killing 85% of the corals in reefs near the Florida Keys. The bacteria is a fecal coliform bacteria called Serratia marcescens and it is commonly found in the intestines of humans as well as other animals. That means that when you flush the toilet, you have flushed some Serratia marcescens down the drain with the rest. These bacteria doesn’t hurt people; it lives within our intestines without bothering us. Coral, however, can be killed by it.

The bacteria affect only one species of coral, elkhorn coral. A few years ago in the Florida Keys, elkhorn coral was the most common species, but now it is difficult to find living elkhorn coral, and it has been recommended for the endangered species list.

Scientists have been observing the deteriorating health of the corals near Florida for many years, calling the white spots that develop on elkhorn corals white pox disease. They saw that once the disease first appeared on the corals of a reef, it would spread to the entire reef within a year. They could see how the disease was affecting the corals, but they didn’t know what caused it until Kathryn Patterson, a scientist on the research team, found the bacteria in the bodies of diseased corals.

Researchers still don’t know exactly how the bacteria get into the corals, but they suspect that sewage pollution is the cause. If water flushed down toilets in southern Florida does not receive proper treatment before it winds up in the ocean, it may contain bacteria that kill corals. “We must maintain the highest possible water quality standards in the Florida Keys,” said James Porter, head of the research team.

Reef corals, like elkhorn coral, build large stony skeletons on the shallow ocean floor in warm tropical places. They provide shelter and food for many other reef creatures. “These coral reefs are so beautiful and so important,” said James Porter, “We must do out best to protect them.”


Last modified August 6, 2002 by Lisa Gardiner.

You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Hope for the World’s Coral Reefs?

After many years of damage, scientists report that coral reefs in several parts of the world have started to recover during 2002! Each year a team of scientists who study coral reefs gives their assessment...more

Peeking at Coral Reefs from Space

On May 20, 2003, the crew of the International Space Station took a photo of the Earth below them that shows more than a dozen coral reefs sitting in the shallow waters of the Red Sea. The light blue...more

The Tragedy of the Commons

The term "Tragedy of the Commons" was coined by Garrett Hardin in a 1968 article in Science magazine. The concept, however, dates back to the days of Aristotle. Briefly, it states that a shared resource...more

1999--A Year in Review...

It was another exciting and frustrating year for the space science program. It seemed that every step forward led to one backwards. Either way, NASA led the way to a great century of discovery. Unfortunately,...more

STS-95 Launch: "Let the wings of Discovery lift us on to the future."

The Space Shuttle Discovery lifted off from Kennedy Space Center at 2:19 p.m. EST, October 29th. The sky was clear and the weather was great as Discovery took 8 1/2 minutes to reach orbit for the Unitied...more

Moon Found Orbiting Asteroid

A moon was discovered orbiting the asteroid, Eugenia. This is only the second time in history that a satellite has been seen circling an asteroid. A special mirror allowed scientists to find the moon...more

U.S. is Fed Up with Russia

Will Russia ever put the service module for the International Space Station in space? NASA officials are demanding an answer from the Russian government. The necessary service module is currently waiting...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA