How tiny clams play an important role in keeping ecosystems healthy

Scientists have recently identified three new genus groups and one new species of wood-boring clams. Beyond the finding that this family tree is larger and more diverse than what was previously known, the experts noted that the clams play an important role in cleaning up the wood that accumulates in the bottom of the ocean.

As tiny clams bore into waterlogged wood on the seafloor, they eat the shavings with help from special bacteria in their gills. This makes them some of the only animals on the planet that eat wood. According to the study, the creatures then live the rest of their lives with their heads down in the holes they dug, using tube-like organs called siphons to pull in water and extract oxygen from it.

Study lead author Janet Voight is an associate curator of Invertebrate Zoology at the Field Museum.

Image Credit: Image Credit: Angelo Bernardino and Paulo Sumida

“There’s not just one tree-cleaner-upper in the ocean, they’re really diverse,” said Voight. “Imagine living at the bottom of the ocean as a tiny swimming clam; you either have to find a sunken piece of wood or die. You wouldn’t think there’d be that many kinds of clams doing this. But we’ve now found that there are six different groups, called genera, and around sixty different species.”

While studying the DNA of deep-sea wood-eating clams, the researchers determined that there are at least six different genera that make up the family. Three of these genera are being described for the first time, as well as one previously unknown species. Even though the clams are tiny, they can settle in massive numbers and greatly improve the health of their deep-sea ecosystems.

“We have no idea how much wood is at the bottom of the ocean, but there’s probably a lot more than we think,” said Voight. “After big storms, we estimate that millions of tons of wood are washed out to sea. What if these clams weren’t there to help eat it? Think how long it would take the wood to rot. The clams contribute to the cycling of carbon, they play an integral part in making the wood into something that the other animals at the bottom of the ocean can get energy from. It could even affect sea level rise. It blows me away.”

The study is published in the Journal of Molluscan Studies.
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By Chrissy Sexton, Earth.com Staff Writer