Mussel Bound

One of the tiniest residents of the Schaible Science Center is a thumbnail-sized bivalve called a scorched mussel. Its natural habitat is along Florida’s Atlantic Coast, but it has found temporary quarters in a cabinet inside Kyle Bennett’s crowded lab.

Bennett, an assistant professor of biology at Elmhurst, has spent much of the last decade getting to know the scorched mussel and its close relatives in the genus Brachidontes. In his research, Bennett uses molecular tools and DNA analysis to draw sharper distinctions between species of Brachidontes that appear virtually identical in form and structure. In the process, he hopes to better understand how, when and why species developed and branched off from common ancestors.

In his lab recently, Bennett held up a small vial containing a Brachidontes specimen. “I’m obsessed with these little creatures,” he acknowledged with a rueful smile. Brachidontes figures prominently in Bennett’s plans for the summer break. As his students filed in to drop off final papers or say an end-of-semester goodbye, Bennett talked about his upcoming 10-day field expedition to Florida. Bennett will be collecting specimens from two species—one found along Florida’s Atlantic Coast, one on the Gulf Coast. By harvesting and analyzing genetic material from each population, he hopes to produce new insights into how the species evolved. Did the development of distinct species, for example, coincide with falling sea levels brought on by an Ice Age?

Bennett’s research depends on the high-tech gene-sequencing tools that have become widely available to scientists only in the last decade or so. They have made operations that were once prohibitively costly and time consuming vastly more affordable and accessible. In the process, they have changed the way ecologists like Bennett work.

“Only now are we getting the tools we need to understand how genomes change over time,” Bennett said. “These tools are changing the way we see evolutionary processes.”

For all his current reliance on the new generation of high-tech approaches, Bennett said he was drawn to his field by his love of what he called “bucket-and-stick ecology,” with its emphasis on field work and specimen collection.

“Who doesn’t love field work? I mean, it’s tromping around knee-deep in tropical waters,” Bennett said. “But there are some questions you can’t answer with bucket-and-stick.”

It was nearly 10 years ago, during a research trip to the Florida Keys, that another scientist posed to Bennett just such a question: How can we be sure that two populations of Brachidontes, with all their apparent similarities, are really two different species?

Bennett has been investigating the tiny mussels ever since, looking to fill in blank spaces on their family tree. He hopes to identify previously unrecognized species of Brachidontes. And while his work now involves more data-crunching and statistical analysis than he ever imagined, there is still a need to get out in the field—or in Bennett’s case, knee-deep in seawater. Take his upcoming trip to Florida.

To harvest the genetic material he needs for his study, Bennett will have to nurture each population of mussels to create the optimum conditions for sperm production. That will mean shuttling between Florida’s Gulf and Atlantic coasts over a period of 10 days, feeding each group a specially prepared algae meal every other day.

“Basically, I’m going to be baby-sitting mollusks,” Bennett said.

Sounds like a job for an erstwhile bucket-and-stick ecologist.


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