Certain tubeworms now thriving deep in the Gulf of Mexico live to be over 250 years
When a creature turns out to be 250 years old, it seems that a little historical context is in order. So consider: When certain tubeworms now thriving deep in the Gulf of Mexico started their lives, Louisiana belonged to France, and the city of New Orleans was just coming into its own. That´s the recent finding of Penn State University researchers who study tubeworms nourished by hydrocarbons that leak from the Earth´s crust at cold-water openings called seeps. The tubeworms are the longest-lived known invertebrates--with the exception of colonial animals such as coral in which pieces may die but the colony lives on.
To measure their subjects´ ages, the scientists stained the creatures´ white casings blue and then came back later to measure how much new white growth extended beyond the blue sections. One conclusion: A tubeworm at a hydrocarbon seep takes between 170 and 250 years to grow 6.5 feet long.
This slow growth particularly surprised scientists because tubeworms that live at hot hydrothermal ocean-floor vents--which spew out material as hot as 750 degrees F.--are among the fastest-growing invertebrates on Earth. They can easily grow more than 3 feet in a year. "The hot hydrothermal vents are a much more vigorous, variable and ephemeral environment than the cold hydrocarbon seeps," says Penn State biologist Charles Fisher.
In other words, the cold seeps provide stable, long-term habitat. But scientists are concerned that offshore oil drilling may change conditions for the worms. "Technology now is making drilling possible at deeper and deeper sites, so these deep-water communities may no longer be safe from human activity," says Penn State biologist Derk Bergquist.