One of the things I love about living on the island is that I find something new all the time. We were on the beach today, and saw a long, tube-like pile of sand castings. Upon closer review, it looked like someone was squeezing a tube of sand toothpaste from up under the sand. Carey Sullivan had a phone with some battery life on it, so we taped the process.
Here’s a photo:


There were a few squeals of fascination/disgust, hence the musical soundtrack. The movie is best if you watch it in HD.

I wasn’t sure what it was, so I emailed the movie and photo to Keith McCullough, my instructor for the SC Master Naturalist class and guru of all nature questions. Keith responded pretty quickly with the fact that it was a lugworm, probably Arenicola marina, known for u-shaped burrows and sandy fecal castings.

This exhibit at the aquarium shows it like this: (lugworm on the right)

I did a little more research in Seashore Animals of the Southeast and found out that “it is an important tiller of marine soils, much like earthworms in garden soils”, p.214. They are divided into three segments, with the back one closest to the surface. In the process of creating the castings we were watching, the worm is in greatest danger of something on the surface bothering it, so the entire rear end can be cast off and regenerated. Some species even have a pigment that stains human skin! The front end of the lugworm is buried under the sand, but there can be a shallow depression in the sand above its head where it has ingested a bunch of sand. According to marinebio.org, they reoxygenate the sand around them, and constitute 30% of the biomass on an average sandy beach! In early spring, they produce long (up to a yard) gelatinous egg masses. I remember finding these at 6 pipes one spring and wondering what on earth caused them:

The tidepools on the island are fabulous right now: they are beautiful in the early sunlight, and always provide something new to research and learn about!