Killer Seaweed Invades United States

A killer alga has invaded the waters off California. In June 2004, biologists identified a Caulerpa taxifolia mutant as an alien invader in the San Diego area. This alga normally grows in the warm waters of the Caribbean Sea, but it can survive the colder waters of the Pacific Coast, and if not controlled, could spread from California south to Peru.

Where did this killer come from? As innocent as it seems, it was bred for home aquariums, and then was probably dumped into the water system, where it began to reproduce prolifically. The alga is so adaptive that it can overtake the normal flora of an area, outstripping and outcompeting all other living plants. Currently, 10 patches of the killer alga have been sighted off the California coast, and they are being watched closely by the Southern California Caulerpa Action Team.

The U.S. government has placed this strain of C. taxifolia on the noxious weed list, which means that any possible source of contamination of the weed will be highly restricted. Shipments that contain any type of C. taxifolia and pass through an area where the variety is established, or thought to be established, will be refused entry.

Questions

Describe another instance in which an introduced species has become a problem for the existing ecosystem.
How could one alga compete with another in an area? What measures could the Caulerpa Action Team take to decrease the spread of the introduced alga?
Why do you think commercial shippers might be concerned about restrictions on C. taxifolia?
List the types of biological impact the introduced species could have in Pacific Coast waters.

Assignments

Review the characteristics of an alga, and find out what C. taxifolia in particular looks like.
Research another species of weed invader, and report to the class on what you found.