Coolest thing ever?! I think so!

So we're encouraged to have pets in class, and I chose to take care of some Owenia sp. because I thought their development was cool. Today I was changing their water and giving the more food, when I thought I'd check them out under the scope. Some of them were really close to settlement, and even started settling on the slide. Luckily, there are tons of video cameras around and I was able to capture the process.

Here it is, Owenia settlement, speed up, in all its glory.

More cute worms!

In addition to Owenia there were lots of other larvae in our plankton tows. These are just two of my favorites, although everything looks cute when it's a baby! The top is some sort of polychaete, and the bottom is not technically a worm although it is worm-like.


It is a phoronid, and is most closely related to bryozoans and brachiopods. Their bodies are shaped like worms, although they have a great feathery lophophore which they use to filter water for food, and their anus loops out near their mouth. They also live in tubes, and they can brood their young in it. There are only 20 species of phoronids world wide.

Revenge of the epitokes

Another night light at FHL. This time we got the large epitokes, about as long as my forearm. You can see a shrimp trying to break the worm open to get the gametes inside later in the movie.

Friday Harbor

So, I have just gone up to Friday Harbor Laboratories and have been enjoying my immersion in science after quite a long spell without. I am learning all about larval biology, so have been going on field trips to many different sites, like this mudflat pictured above, to look at egg masses and collect larvae.

One of my favorites is this Owenia sp., which is a type of worm that builds tubes out of small sandy particles. This creature has an interesting development, as the juvenile worm develops around the intestine of the larval body. When it is ready to settle, it drops out of the sac where it was developing and eats its old larval body.

Life Photo Meme: Hairy

Kingdom: Animalia

Phylum: Annelida

Class: Polychaeta

Order: Aciculata

Family: Aphroditidae

This is my favorite annelid. It is called a sea mouse, and from the top it is very difficult to distinguish as a worm as it is covered in seate (or chaete, depending on who you ask). It is not until you take a look at its underside, that you can see the segmentation common to worms, and the parapodia special to polychaetes.

The sea mouse can reach 6 to 8 inches (15-20 cm), and lives on the sea floor in from subtidal areas to moderately deep waters. (This particular sea mouse was caught in a benthic trawl at ~150 ft (50 m). They are active hunters and feed on other polychaete worms.

There is some interest in the optical properties of their seate. The seate projecting from the parapodia are often a copper color, but can turn a bluish-green when see from the right angle (and when not covered in mud). The crystalline formation of the seate is far more efficient in handling light than current man-made optical fibers [1].

Life Photo Meme: Procreation

Kingdom: Animalia

Phylum: Annelida

Class: Polychaeta

Order: Aciculata

Family: Nereididae

This was a bit of a tough choice for me, as I have an oddly large assortment of animal mating pictures (although I always kick myself for not having the camera on me the day I saw barnacles mating). I decided to go with this 'morning after' picture, as I find this type of procreation to be very bizarre.

These are Nereis sp. worms. They normally live on the benthos, but when these particular worms get ready to mate, their bodies undergo a startling transformation. Their internal organs degenerate, and their body cavity fills with gametes. They develop stronger podia (paddle-like feet) for swimming and better sensory organs. Then, when the moon is right, they swim up into the water column. Males will find a female and swim in circles around her... then they both explode.

So above you can see chunks of worm, white strands of sperm, and reddish-yellow eggs (both of which are released from the body cavity by the explosion).

Photohunter: Strings

When I think of strings, I think of the spaghetti worm. This worm lives in mucus tubes surrounded by rocks or sand generally in the intertidal areas and uses its thin white tentacles to gather food. The tentacles for a worm this small would probably be a little under a foot in length, while a worm with a body length of a foot will have tentacles about 3 feet in length. The tentacles themselves have a little groove filled with cilia (hair-like structures), that are used to move food particle from the sea floor to the mouth.

As an added bonus, you can also see a string of nudibranch eggs (the thick white wavy line to the right of the worm).

Animalpedia: Christmas tree worm

Kingdom: Animalia

Phylum: Annelida

Class: Polychaeta

Order: Canalipalpata

Family: Serpulidae

This is some species of christmas tree worm, Spirobranchus sp., found in a coral head in Australia. These worms have a hard calcareous tube, which they can retract into to escape from predators. They can see light and dark, and may retract if a shadow passes over them. The two christmas tree-like plumes are made up of ciliated tentacles which they use to filter out plankton. The cilia sort them by size and the worms only ingest plankton of the correct size. The larvae of these worms preferentially settles on certain species of coral. There are different coral preferences for different Spirobranchus species. A really good online article on them can be found here.