Northwest Dive Club

I've always swam past a patch of "dead stalks" but on my first dive with the new camera and a 60mm lens I took a pic anyways...



I noticed the "dead stalks" have Phoronid-like white shapes growing from it. These are not visible to the eye. This patch of "dead stalks" is about 1 meter in diameter on the side of a jetty rock at around 20 ft depth. These are much smaller than White Colonial Phoronids. I would estimate these small white shapes to be maybe 1/2 or less of a mm. The thick stalks the white shapes are growing out of are maybe 3 - 5 cm long.

Here is a closer view of an in-focus stalk...



Any ideas? Not all that exciting, but finding out the boring dead stuff is actually some kind of colony peaked my interest.

Great photos, and thank you for sharing!

One of the biggest insights I've had diving is that very little of what we see is dead. Mostly, we just don't recognize the life that's there.

Hi John,

I think your animal is a sedentary polychaete. At the Feiro Center we have some critters, that look very much like yours, growing on some empty rock scallop shells. From a distance (for me that means a foot or more) it looks like the shell in question is moldy; a closer look reveals individual animals very similar to your photo. Closer yet they look like this: Please pardon the depth of field; the photo was taken with an 8x macro lens from a distance of a couple of inches and I'm afaid that I didn't get the settings quite right.
I posted this picture to Ron Shimek's Marine Depot forum at http://forum.marinedepot.com/Forum11-1.aspx about two years ago and both Dr. Shimek and marine worm expert Leslie Harris of the Natural History Museum of Los Angeles County said that they were probably some sort of sabellid but I suspect, based on where they were living, that they could be serpulids instead.
Of course, I could be misinterpreting your photo! A "horseshoe" shaped tentacle crown called a lopophore is diagnostic of the phoronids and your images didn't seem (to me at least) to show that feature.

Tentacularly yours,

Alex

It looks like your sedentary polychaete photo shows the lopophore coming out the end of the stalk. In my pic it looks like very tiny lopophores are coming out of the sides of the stalk. It could look like mold, but they do seem shaped like lopophores. I don't see anything coming out the end of these stalks, although that could very well happen some other time such as at night.

I found a more in-focus view of the side of one of the stalks. Now these stalks are about 3mm thick, so these lopophores are just a small fraction of a millimeter. They appear to be evenly distributed along each stalk. If they were colonizing on a dead stalk of (say the stalk from a monterey stalked tunicate) something then I'd expect they wouldn't tend to have such an even distribution.

I think the problem is my post is a bit confusing. Sorry about that.

Tidepool Geek, I'm starting to see what you are talking about. I was locked onto the fuzz on the larger stalks. When I looked at the other stuff, at original resolution http://johne.smugmug.com/Underwater/Yaq ... 7&lb=1&s=O I was amazed. I was so locked onto those thick stalks that I didn't bother looking elsewhere.

I see the tubes I think you are looking at. These are in clear-ish tubes amid all the small clutter I assumed was hydroids.

In fact, now that I look at the original resolution I see a zoo of stuff. There is a lot going on in this picture, more than I saw before.

The fuzz on the stalks, I'm starting to think it is an encrusting bryozoan. It could even be "Tubeworm Fuzz". Very tiny lopophores.

Also in this pic are some solitary hydroids that look a lot like the Solitary Pink Mouthed Hydroid. I took a pic of one that was separate from all this mess: http://johne.smugmug.com/Underwater/Yaq ... 7&lb=1&s=O

Some of the hydroid-like stuff is branched and often have lopophores irregularly. A bryozoan?

I think I need to come back to this patch and take more care, better photos, better notes. At the time I took this pic I just thought it was a patch of dead stalks and hydroids.

John has some sort of bryozoan with uncalcified zooids. Look up Flustrellidra corniculata - probably not the right species but similar. http://www.wallawalla.edu/academics/dep ... ulata.html

Alex's photo is indeed a sabellid, probably one of the small Chone species.