Tag Archives: Worms

‘Mermaid bracelets’ ashore a curious find Down Under

Published July 9, 2016 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2016 Susan Scott

wormsOne of the joys of snorkeling or beach walking in Australia is finding marine animals new to me. It’s also frustrating because being on my sailboat, I often don’t have internet access or the right books on board to look up what I’ve found.

The creature that stumped me on my recent trip appeared on Whitehaven Beach during an extremely low tide. At first glance the thing looked like a line of white seashells tangled up in brown and green seaweed. But when a small wave rolled over the clump, it stayed in place, fixed to the spot.

Down the beach, a longer string of shells and seaweed appeared, then another and another, all streaming behind the receding water like glistening ornaments. Mermaid bracelets, I named them, because a few of the shells in the strands were the forams I wrote about called mermaid pennies (May 28).

I gently scooped sand from around one of the shell ropes and found it anchored a few inches down in the sand. I laid my strand above the break to examine it, and out from the end popped a pair of rust-colored antennae and behind them several fuzzy legs. I had found a bristle worm that collects shells. I’m home now, and, as usual, Google found my mystery worm first try, even with the lame search words “polychete (bristle worms’ scientific name) that makes tubes from shells.” My worm’s name is Diopatra (rhymes with Cleopatra). Members of this group live in self-made tubes of thin, paperlike material onto which they glue small shells, bits of algae and pieces of coral. The worm lives with the lower part of its tube body buried vertically in the sand and the top part drooping head-down over the seafloor, like a candy cane.

Diopatra shell jackets look decorative to us, but for these ambush predators they’re camouflage. When a small invertebrate wanders close to the worm-in-shell-clothing, the worm darts partially from its tube and grabs its prey with sharp jaws. When fresh meat is scarce, the worms eat dead plant and animal tissue.

Hawaii hosts at least two species of Diopatra. These little cross-species-dressers extend a third or more of their length from their tubes to feed in an arc around their anchored base. In some areas the worms’ dense presence between reef and beach stabilizes sand, preventing beach erosion.

These shell-dressed worms are exposed at very low tides, during which times the worms are in danger of drying out and/or getting eaten. I’ve not seen them before, but I’ll now be on the lookout.

I like the rather regal name Diopatra, and found it means “divine habitat” in Greek. For those of us who love walking beaches during low tide at first light, these worms are well named.

Tuamotos’ marine life vies for attention, but worms win

Published May 27, 2013 in the “Ocean Watch” column, Honolulu Star-Advertiser ©2013 Susan Scott

Blue Christmas Tree Worm by Tim Sheerman-Chase used under Creative Commons License.

What’s this? A big orange cushion star with its own pair of shrimp! I must write about them.

But oh, the fish! I have to describe humbug damselfish. Shrimp gobies. Lemonpeel angelfish.

Then again, the giant clams glow so brilliantly in the noontime sun they practically hurt my eyes. They must be my first subject.

But how can I skip the multiple sharks that are almost begging to be better understood?

To clear my mind of its saltwater delirium, back on my sailboat, Honu, I rinsed off with some precious fresh water, opened my books and made a commitment to share the joy of worms.

During an early snorkeling excursion, I found a stand of coral as splotched with color as the brightest aloha shirt. So full of tropical flowers was the coral head that I could barely make out its lime green base.

As I swam nearer I saw the creatures responsible for the lovely garden: a dense colony of Christmas tree worms.

These tropical marine creatures look more like plants from a Dr. Seuss book than worms. Their tentacles’ shape is similar to that of stubby pine trees except the branches spiral around a center trunk and come in a stunning array of colors. Some are solid reds, yellows, blues and greens; some wind around in stripes and others are almost plaid.

Mature Christmas tree worms’ tentacles are as big around at the base as they are tall, from 1 to 2 inches here in the South Pacific. Hawaii’s Christmas tree worms grow to only about a half-inch high and across.

The worm begins life as a tiny top-shaped larva that swims, drifts and eats other plankton. After a few weeks of wandering, the maturing worm settles down on a living coral head. There it secretes a calcium carbonate tube around its body. This kills the coral polyps below.

The worm keeps up with new coral growing around it by secreting, in rings, new “floors” to its home base.

These worms never leave their dwellings. To get food and oxygen, the worm holds its pair of treelike tentacles into the current, snaring tiny organisms that drift past.

These gorgeous appendages are supersensitive to light and nearby water pressure. Get close enough, as I do when taking pictures, and the worm withdraws its branches in a flash, slamming its door shut. (Sorry, the satellite phone I use to send my stories from sea can’t do photos.) The door is a round hard shell similar to that of a snail’s operculum, commonly called a cat’s eye.

Seconds later the worm peeks out. If the coast is clear, the two tentacle trees emerge like a fast-frame film of a flower blooming.

The sight is so inspiring it makes me want to design my own Christmas tree worm aloha shirt — including, of course, cushion stars, shrimp, gobies, angelfish, clams and sharks.

Christmas Tree Worm. By Nhobgood Nick Hobgood (Own work)
[CC-BY-SA-3.0 or GFDL], via Wikimedia Commons

Marine biologist Susan Scott writes the newspaper column, “Ocean
Watch”, for the Honolulu Star-Advertiser, www.staradvertiser.com

©2013 Susan Scott