Super plants

by Helen M. Scott
Tuesday, December 4, 2007 2:12 PM MST

Most people have heard part of the horror story of marine biologists in June 2000 diving off the coast of San Diego to survey the native eelgrass in this coastal area.

It turns out that the biologists suddenly came face to face with an alien monster. That monster was seaweed called Caulerpa taxifolia.

As an investigation ensued, one man in France, Alexandre Meinesz, was familiar with this green monster. He had found it dozens of years earlier in the Mediterranean Sea and immediately sounded an alarm. No one listened.

Today, about 40,000 acres of Mediterranean coastline is clogged with Caulerpa, and many scientists fear the future for this sea area.

Further research into the algae found that the taxifolia spreads by a process known as vegetative reproduction, which is a form of cloning. It meant that any tiny fragment of the algae separated from the main plant contained all the genetic material necessary to grown an exact parent plant.

It’s as if a piece of human hair or a flake of skin dropped on the ground could grow into a human being. Tiny pieces of the taxi flora picked up by the anchor of one of the thousands of boats that crisscross the sea could start a colony of plants hundreds of miles away.

Scientists tracing the origins and processing and comparing dozens of samples of taxifolia from all over the world found only one strain that was a perfect match. It turned out to be not a wild plant, but a plant that had been used to decorate tropical fish tanks and one that had been bred as an artificial strain by humans.

The strain was traced back to the Monaco Oceanographic Museum, which was supposedly known to have had taxifolia in its tropical tanks and also was directly above the site of the first known infestation in the Mediterranean.

The search trail led from Monaco to an aquarium in Stuttgart, Germany. At that time, people everywhere had been trying to find a plant that could be used to decorate fish tanks, and the world’s leading aquariums imported wild specimens from the four corners of the world, but nothing could survive the environment of a tank.

However, in Stuttgard, something unexpected happened. A newly imported strain from the Pacific suddenly blossomed and thrived. It became the aquarium’s wonder plant.

Aquarium tanks use chemicals and lights to artificially recreate the natural balance of the sea. Could this manmade brew have caused the original wild strain to change and mutate into a more invasive plant than its wild cousin? To this day, no one has solved this mystery.

After Caulerpa taxifolia was found in the coastal lagoon in southern California, to avoid the disaster overtaking the Mediterranean, California officials settled on a radical campaign of eradication.

The chosen weapon was chlorine, which kills everything in its path. It is a high price, but one they are willing to pay. So far, the chlorine seems to be working, but the Mediterranean infestation has grown too large for this solution. After 15 years, the algae has won.

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