Anyone who’s spent any time beachcombing in Massachusetts has likely come across a shell riddled with holes, such as the quahog (Mercenaria mercenaria) shell I found recently pictured here. These holes are evidence of the Boring Sponge, Cliona celata. It’s worth pointing out that, although many people consider sponges a lump on a rock, or in this case a lump on a shell, the name “boring” refers to its ability to make a hole in something, not its lack of interestingness.

The boring sponge is common in waters off southern New England and is known for its ability to drill holes in limestone and mollusk shells. The sponge uses acid to form tunnels in the calcium material. The only function of these holes, however, is to create a place for the sponge to live. If the sponge settles on a living mollusk, it will not consume the shellfish living inside the drilled shell, but because its protective shell has been damaged, the mollusk usually dies as a result.

With the ability to breakdown shell and limestone, boring sponges are an important bio-recycler. However, according to an article in the Smithsonian, with the effects of ocean acidification, the impact from boring sponges will be increased. According to the article, “boring sponges drilled into scallop shells twice as fast, boring twice as many holes and removing twice as much shell over the course of the 133-day study” in a lower pH environment. It’s still too early to tell what impact this positive-feedback loop will have on shellfish, or the boring sponge itself (as it destroys its habitat more quickly than it could replace itself), but to me it illustrates the wide-reaching impacts of climate change even to little known reaches of life.