May 27, 2005 ::No. 224

Most marine animals begin their lives with a mysterious odyssey — mysterious, at least, to humans in the scientific community.

Life for such animals as mussels, sea stars, urchins, rockfish and snails starts as microscopic larvae floating in ocean currents that potentially carry them far from where they originated.

Where do they come from? Where do they end up? Or do they simply disappear?

“We know where the adults are, and we know they produce buckets of larvae, but we don’t have any idea where the larvae end up,” said Danielle Zacherl, assistant professor of biological science at Cal State Fullerton. She is studying a representative snail species called Kellet’s whelk.

Zacherl is in the midst of a three-year study supported with $232,778 in grant funding from the National Science Foundation. Data from her research tracking whelk larvae may point to how and where other species, including those that are good fishery resources, disperse and ultimately settle.

“Marine reserves are also a hot topic in California right now,” she said, adding that knowing how various sea creatures disperse and establish themselves could help set up effective reserve networks, where neighboring marine reserves supply each other with larvae that produce the next generation.

Invisible to the naked eye, the young whelk’s miniscule calcium carbonate larvae shells “act like tiny flight recorders” by absorbing chemicals from the ocean during their journeys.

“We’ve been validating that larvae produced in different populations actually have a chemically unique tag,” she said. “A lot of the work we do here involves how metals, such as barium or strontium, might tell where the shell was created.”

One of the mysteries with many marine species, including Kellet’s whelk, is that while there are visible adult populations, little evidence exists of immature generations. “We only see pulses of juveniles every once in a while. There’s a huge swath of coastline where, effectively, there’s no juveniles recruiting into the population for years at a time,” said Zacherl, who is working with four CSUF students, as well as UC Santa Barbara colleagues Robert Warner and Steve Gaines on the study.

So how do these populations continue to persist if the young are unaccounted for? “That’s the question we’re working on,” said the researcher. “There’s some concern that there are some populations that might die out.”
Zacherl, who joined the Cal State Fullerton faculty in 2003, earned her doctorate from UC Santa Barbara.

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