There are countless species of marine worms living in environments all over the world. Some of the most spectacular are Christmas Tree Worms. Like something from a Dr. Seuss story, and looking almost like they’re from a strange and faraway planet, these little worms are fun to photograph and fascinating to watch. Let’s take a closer peek.
Christmas Tree Worm Basics
When you think of a worm, you might be imagining something fairly flat, elongated, and drab-looking. Christmas Tree Worms fall into none of these categories. Instead, they appear elaborate, as their colorful respiratory and feeding appendages, or “crowns” wave lightly in the current.
Like many other tubeworms, they never leave the shelter of their homes to swim or crawl freely in the water. Instead, they simply anchor themselves to a convenient point, then they put on an almost never-ending show.
Each of the two crowns every Christmas Tree Worm possesses is composed of delicate structures called radioles, which, upon closer inspection, have a feather-like look. These “feathers” are actually cilia that carry prey down into the worm’s mouth. Sometimes you’ll hear these structures referred to as “gills”, and that is also true since these prostomial palps have been modified to function as a means of respiration as well as a method for capturing nourishment. Not at all picky about what they eat, Christmas Tree worms are filter feeders, consuming everything from zooplankton to bits of detritus dropped by messy eaters hovering above them.
Widely distributed throughout the planet’s tropical seas and oceans, Christmas Tree Worms are most often encountered in reef environments throughout the Indo-Pacific, as well as in the Caribbean. Colonies of these animals can often be found embedded in heads of stony corals, preferring brain corals and porites to other coral species. To anchor themselves to the coral, tiny developing Christmas Tree Worms bore a hole through the living outer layer of coral polyps into the stony skeletal structure below. They then begin to secrete a calciferous substance that later becomes a tube, serving as both protection and shelter. While some other tubeworm species are capable of shutting off their tubes, these worms do not have that ability.
You’ll find Christmas Tree worms in all kinds of exciting color combinations. Some are shades of yellow or orange, while others live up to their name by displaying red and white candy cane stripes. Some are blue or purple, and some are a lovely iridescent shade of white, pale pink, or periwinkle. It is not uncommon to find an entire colony displaying a rainbow of shades all within just a few square feet of space.
With no natural predators, these fantastic little creatures are what is known as a sedentary part of the living reef system. When the reef suffers damage, so do they. They are susceptible to death from pollution and can be killed by careless divers. Never touch a Christmas Tree Worm. Instead, capture it on film. While these animals are very small, they do play an important role in keeping reefs clean and healthy; respecting them and their environment will help to ensure their survival.