Human Flower Project

Orrington, MAINE USA

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Princeton, MAINE USA

Friday, August 19, 2005

Weeding an Underwater Garden

Invasives? Non-native coral may pose a threat to the Gulf of Mexico’s deep and beautiful garden.

While landlubbing gardeners battle knapweed in Colorado, goldenrod in China, even some species of the national flower proteas in South Africa, marine biologists have discerned an invasive threat to an undersea garden.


Madracis coral “landscape” of the Flower Garden Banks.

Photo: Flower Garden Banks National Marine Sanctuary

The Houston Chronicle reports today that a non-native coral growing on oil and gas platforms in the Gulf of Mexico poses a new threat to the Flower Garden Banks reef.

Located 105 miles south of the Texas/Louisiana border, the Flower Garden Banks is an underwater city, one of only two actively growing coral reefs in the Gulf of Mexico and home to many species of fish and sponges. The colony is “perched atop two salt domes rising above the sea floor,” and began growing there some 10,000 to 15,000 years ago. The combination of “a hard surface for attachment, clear sunlit water, warm water temperatures, and a steady food supply” made an ideal environment for young corals (planulae) washing in from the west to catch hold and thrive. The reef now extends over 385 acres. Snapper fisherman spotted it about 1900 and, seeing its glorious spectrum of colors, named it “Flower Garden.” In 1992, it was designated a national marine sancturary.

The Houston story, based on a federal report released yesterday, says that orange-cup coral, native to the Pacific Ocean, is growing on oil and gas platforms in the area. Emma Hickerson, Flower Garden’s research coordinator, is concerned that orange-cup may be aggressive and overtake the native coral. “We don’t want it on the reef,” she said.  “We don’t know what the impact might be.” (Flower Garden has other problems, too: fertilizer-heavy fresh water coming from the Mississippi River, a bacteria called “white plague,” and climate change.)

“Last year, 46 colonies of orange cup coral were removed from Geyer Bank, a coral mass about 12 miles east of the East Flowers.” Dina Cappiello’s interesting article describes how gulf oil and gas drilling stations also attract marine life; after they’re retired, some become, in effect, artificial reefs, popular with divers even though, in some cases, perilous to other coral communities. Scientists said that eventually the platforms covered with orange-cup might be moved to another undersea spot, away from the Flower Garden.

A timely note: We learned from the Flower Garden’s website that “Ten days after the full moon in August, many of the corals on the bank spawn on one night… some divers say it looks like the ocean is snowing in the wrong direction!” Today’s the August full moon. Mermaids, get ready. Do you have dates for the prom?


Coral spawn   Photo: Flower Garden Banks National Marine Sanctuary

Posted by Julie on 08/19 at 10:10 AM