On the move

  

 

Eric photographed this beautiful Opalescent Nudibranch (Hermissenda opalescens) wandering through a world of pastel colors on 29 January 2025. 

 

In the background: the pale pink is a crustose coralline algae, the bright pink is a Derby Hat Bryozoan (Integripelta bilabiata), and the peach is another species of bryozoan (unidentified species).

Rose-colored ribbon

  

A ribbon of rose-colored embryos!  

We were working on a few tasks in the rocky intertidal zone last night (28 January 2025) when Eric came across a Hopkins' Rose Nudibranch (Ceratodoris rosacea) that had recently laid a beautiful string of embryos.

Although we could have missed them in the past, we can't recall finding the embryos of this primarily southern species in Northern California before, so it was an interesting observation for us.

Here's a quick shot of the nudibranch with both its prey (the pink bryozoan, Integripelta bilabiata) and the ribbon of embryos:

 

 

Thanks for the great photos, Eric!

Sheaves of gills?

  

From the "Little wonder" post from ~1 week ago, I think you can tell that we've been looking closely at a couple of nudibranchs that live on the patches of bryozoan found on Giant Kelp (Macrocystis pyrifera).  Above, Eric is scanning the bryozoan colonies for signs of the nudibranchs.

We've found both Corambe pacifica and Corambe steinbergae, but these nudibranchs are small (often under 1 cm long), so it can be difficult to tell which species you're looking at. 

To make it a little easier for other folks to know what to look for when identifying these two species, Eric put together a series of video clips highlighting the differences between them (see the video below!).

In the video, first you'll see the bryozoans that the nudibranchs feed on.  The zooids emerge and extend their tentacles to feed.  When the nudibranchs appear, watch for these features:

Corambe steinbergae:
- the edge of the nudibranch is smooth around the entire perimeter
- the rhinophores are simple (no extra "decorations")
- there is a gap between the two rows of gill plumes on either side of the midline (and the gill plumes look a little more linear)

Corambe pacifica:
- the edge of nudibranch has a deep notch at the posterior end
- the rhinophores are sculptured or fluted
- instead of a gap between the two rows of gill plumes, in the center there are several gill plumes that are pinnate = with short branches aligned on either side of the main stem (they look a bit like feathers)

For reference, it also might help to see how the gills plumes of these two species were illustrated in the original descriptions:

 

Above, Corambe pacifica — the entire animal with posterior notch; a close-up of a fluted rhinophore; a close-up of the gill plumes from below (drawings by Olive Hornbrook MacFarland).

Above, Corambe steinbergae — the entire animal without a posterior notch; showing the simple rhinophores; and illustrating the gill plumes with a gap between the two rows.

One thing I didn't mention yet is that the gill position of these two species is unusual.  Many nudibranchs have gills (or other respiratory structures) on the upper surface.  In this case, the gill plumes are positioned on the underside!  But luckily Eric was able to film the nudibranchs from above and below, so this is an excellent view of the gills and the differences between the two species.

Check it out!  [And if you can't see the video player in an e-mail, just click on the title of the post to watch it on the NHBH website.]

Nicely done, Eric!  The best views of the differences between Corambe steinbergae and Corambe pacifica captured on film!

P.S.  Corambe pacifica's pinnate gill plumes have an interesting shape.  When viewing them I kept thinking about a Henri Matisse cut-out called The Sheaf (La Gerbe):

Little wonder

  

Camouflage week continues!

You might recall that back on 14 July 2024, I introduced this amazing nudibranch, Corambe pacifica.  I also mentioned that I needed to get a better photo.  Well, here you go!  And, lucky us...Eric was also able to record some beautiful video clips.

Things to look for: 

- how well the color and patterning of the nudibranch match the bryozoan in the background

- two rhinophores (sense organs) near the leading edge (viewed from above, they look like a pair of white spots)

- a small notch along the back edge of the nudibranch

- when viewed up close, sometimes you can catch a glimpse of the branched gills inside the notch (more about the gills in a future post!)

Here's the video clip (below).  [If you can't see the video player in the e-mail message, just click on the title of the post above to go directly to the NHBH web page.]

Stay tuned for more about Corambe pacifica.

And thanks to Eric for the great video!

Blending in

  

Well, I need to take a better photo, but here's a quick one for the record.  This looks like Corambe pacifica, a nudibranch I haven't photographed yet.  It was on a bryozoan colony on a piece of drift kelp.

Along with Corambe steinbergae, this species is a bryozoan specialist. Its coloration and patterning looks just like the bryozoan prey.

For an introduction to these intriguing nudibranchs, see "Ay, Corambe!" on 20 September 2013 and "A story with a point" on 17 August 2014 (this one includes a link to a great video!).

Isopod and friends

  

We've been busy doing surveys in the field during the low tides recently, but here's an isopod photo from back in February -- a Blunt-tailed Isopod (Idotea urotoma) photographed in the low intertidal zone.  

Among other things in the photo, you can see pale pink crustose coralline algae, a small iridescent snail, Lirularia sp., and a darker pink and red bryozoan (Integripelta bilabiata, formerly Eurystomella).

Friends in the drift

Whew!  We're finishing up field work soon, but after a quick lunch along San Diego Bay today we found a large piece of Giant Kelp (Macrocystis pyrifera) washed up along the shoreline and noticed a couple of nice invertebrates on the drift kelp:

 

 

Proliferating Sea Anemone (Epiactis prolifera) — a beautiful orange individual with many juveniles visible around her column. 

 

 

 

 

The "disappearing" nudibranch Corambe sp. on a bryozoan colony (Membranipora sp.).  Look closely to spot the circular shape of the nudibranch. They're incredibly well camouflaged, with white lines and brown splotches to match the bryozoan (which is the nudibranch's prey).

I've written about Corambe before, so for more info check out the post called "Ay, Corambe!" from 20 September 2013 and "A story with a point" from 17 August 2014.  The latter post has a link to Eric's excellent Corambe video — worth watching!

Out and about

A few weeks ago, I decided to try photographing some bryozoans in the field.  It worked pretty well, and the images were interesting enough that I'll likely try again. 

Bryozoans are colonial — it's possible you've noticed them growing as low rough patches on intertidal rocks or seaweeds.  But the animals making up the colony are pretty small, and are not easy to see with the naked eye (it's much easier to appreciate them under a microscope!).  

However, I tried using the "microscope mode" on my little waterproof camera in a shallow tidepool and you could see lots of feeding bryozoans with their bell-like tentacles extended into the water.
Here's an example of Derby Hat Bryozoan (Eurystomella bilabiata) from the field:

 

I've shown some microscope images of this species before, so if you'd like to compare (or to review introductory information about bryozoans), check out these earlier posts: "Pretty in pink" from 15 February 2012 and "Pretty in pink #2" from 1 July 2013.

All together now

I had to do some intertidal field work this afternoon (18 February 2019).  When I finished, I looked around a bit.  I was starting to focus on this chiton (Lepidozona cooperi), when I noticed something intriguing next to it:

 

My first thought was that the striped object might be the arm of a brittle star.  But when I was able to see it more clearly, I realized it was a polychaete worm.  

I think we've seen this worm before — for example, see the post called "Ruler worm?" from 1 May 2013.  However, this individual appears to be broader.  When I zoomed in, I could see that it's possible she has lots of cream-colored eggs inside?

 

I'll have to ask around for some help with the identity of this intriguing worm.

P.S.  In case you're wondering, the white spiraled animal at the head end (left side) of the worm is a foram (Foraminifera).  The bright pink animal in the same location is a bryozoan (Eurystomella bilabiata).  The paler pink in the lower left corner of the second photo (and above and to the right of the chiton in the first photo) is coralline algae.

Find the Flatworm

Recently, I was trying to photograph a bryozoan (Tubulipora sp.) under a microscope...when I noticed a tiny flatworm nestled among the tubes of the bryozoan!  

I'm not which species of flatworm this, but I thought you might like to see it.  The main body color is white, but there's a nice orange color on the dorsal surface, and you can also see the two black eyes:

 

Can you find the flatworm in the next photo?  It blends in amazingly well.

 

One more "Find the Flatworm" photo.  Can you spot it?  Click on the photo for a larger version. 

 

  

What's it like to live within a bryozoan colony?

Not sure if anyone out there knows the identity of this flatworm, but if you do, let me know!

 

Beauty and intrigue

A few miscellaneous images from our trip to Oregon in late May:

 

A purple encrusting bryozoan, Disporella separata

 

Peanut worm, Themiste pyroides, with coralline algae

 

The nudibranch Aeolidia loui (formerly Aeolidia papillosa) 

The beauty and intrigue of coastal marine invertebrates!

Little ship at sea

 

A little ship at sea...recently discovered on a fishing float washed up on a local beach.

Perhaps some of you have found similar floats?

 

It's always interesting to wonder about the origins and journeys of objects that wash up on the beach.  

In this case, the Chinese characters reveal some clues.  Thanks to Evelyne, here's a translation of the characters surrounding the ship:

➤ The top two characters (on either side of the ship's sail):

 

浙 江 = Zhejiang Province, a province on the central eastern coast of China, south of the Yangtze River  

➤ The bottom two characters on the left:

溫 州 = Wenzhou City

 

➤ And the bottom two characters on the right:

蟠 凤 = Pan Feng Village  (separately these two characters also mean "coiled phoenix" and are part of an idiom used in a poem by one of the most famous Chinese poets, Li Bai)

It's likely that this float was made in this Chinese village.  But where did the float begin its journey in the ocean?  We're not sure, but there is another clue.  Did you notice the white, lacy animal growing in patches on the float?

See photos above, and here's an extreme close-up:

 

This is the skeleton of a bryozoan, and thanks to Jim we know that it's Jellyella eburnea, a species associated with warmer water.  So although we don't know the entire route of the float and the little ship, it likely spent some time in warmer water (possibly to our south).

P.S.  Many thanks to Evelyne, Jim, Megan, and Miho for their assistance with this story!

Frost in the intertidal zone?

A few nights ago while doing work in the rocky intertidal zone, we spotted quite a few patches that at first looked like frost:

 

Here's another view of a branched alga showing a similar effect:

 

We knew it couldn't be frost, and when we took a closer look, we were impressed:

 

These are extensive bryozoan colonies covering the algae.  In the photo above, the bryozoan Membranipora has grown around the branches of Neorhodomela larix (a common intertidal seaweed).

I've posted about bryozoans a few times, but to see what these beautiful marine invertebrate colonies look like when submerged and viewed under a microscope, check out the post from 27 January 2015, especially the 5th and 6th pictures.

I'm not sure why the bryozoans are so extensive this year, but my guess is that they've done very well with the warm ocean temperatures during the last two years.

Any bright ideas?

 

Yesterday, 7 March 2016, I encountered this very large light bulb washed up on the beach. 

Here's a picture with my foot for scale:

 

I don't know anything about vintage (?) light bulbs, so if anyone can provide more information about this bulb, I'd be very interested.  Can you tell how old it is?  What was this type of bulb used for?  Are they still in use today?

You might have noticed that one side of the bulb (the side that was floating downward below the ocean surface) supported a few different pelagic animals.

Here's a closer view of that side:

 

And I zoomed in even in more so that you can see the pelagic gooseneck barnacles (Lepas sp.) and the bryozoans (off-white, rough patches):

 

I'd love to hear any ideas you might have about the type of bulb this is.

 

Spiky -- Part 2

Apologies for the delay.  A couple of nights ago, I posted a mystery photo and asked if you recognized the type of animal it was:

 

This is a tough one!

But isn't it intriguing?

I can give you a small hint, and tell you that the picture shows the animal viewed from above.

And here's another clue: This is the larval stage of a marine invertebrate.  So it's quite small (microscopic).

What makes it look so "spiky" are very long cilia used for swimming.

As an adult, it's colonial — and the feeding members of the colony extend beautiful, bell-like lophophores to capture food particles from the water (see pictures at the end of this post).

Here's a view of the same animal from the side:

 

Note the triangular shape.  You can see that the lower edge is fringed by cilia, and that there's an apical tuft at the top. 

This is a cyphonautes larva — the swimming stage of some species of bryozoans (the most common example in this area would be Membranipora).

In the image above, perhaps you noticed the long, narrow "bar" in the middle of the cyphonautes larva (it looks like a straw)?  It's one of the ciliated ridges that the larva uses to feed.  

The diagram below illustrates the basic feeding process.  There are different types of cilia on the ridges.  They draw water into an incurrent chamber, sieve particles from that water, move the particles to the mouth, then the water exits through the excurrent chamber:

 

Diagram modified from Strathmann and McEdward.  1986.  Cyphonautes' ciliary sieve breaks a biological rule of inference.  Biol. Bull. 171: 694-700.

Below is a short video clip of a cyphonautes larva swimming — viewed from the side and from above.  After watching the video, be sure to scroll down to see photos of the adults, too.

 

cyphonautes from Jackie Sones on Vimeo.

The larva will swim in the open ocean for several weeks before finding a place to settle down.  You'll recognize adult bryozoan colonies as white, lacy crusts on kelps or other seaweeds.  Here's what they look like under a microscope:

 

The adult bryozoan colony and the cyphonautes larva look so different that it was a long time before the connection was made between the two stages.  It's easy to see why!

 

October colors

 

A couple of weeks ago, Jason and Matt mentioned they'd been seeing these nudibranchs at the Spud Point Marina docks.  I've been saving the pictures because they seemed perfect for Halloween!

This is Polycera atra.  I've seen it called a Black Dorid, or an Orange-spike Polycera.  (Halloween Nudibranch wouldn't be such a bad name either!)

Although there is a consistent color theme, individuals are variable.  In contrast to the first individual, others are quite dark — see below:

 

The combination of black and white longitudinal stripes with yellow-orange spots is quite striking.  The next image is a close-up of one individual's head, showing the frontal veil with spiky processes and two spiraled rhinophores (sensory organs) extending upward.

 

 

Polycera atra feeds on Bugula, a common bryozoan growing on the docks.  Although the nudibranchs can blend in with their dark bryozoan prey, their eggs ribbons are bright white.  The easiest way to find the nudibranchs was to look for the egg ribbons and then to search for a nudibranch nearby.  [These nudibranchs were about 2 cm (3/4 inch) long.]

 

Happy Halloween!

A story with a point

Last September I wrote about a fascinating predator-prey interaction that involved an inducible defense.  The bryozoan responds to being preyed upon by a nudibranch by growing significant spines.  I showed the nudibranch and the bryozoan, but I didn't have pictures of the spines.  Are you ready to see them now?  

To review, here's the nudibranch, Corambe steinbergae, and the bryozoan, Membranipora sp.  The nudibranch is so well camouflaged that you'll need to look carefully along the left side of the image to find it.  The darker zooids (members of the bryozoan colony) just behind the nudibranch have probably been eaten.

 

Below is a close-up of the nudibranch, showing its head that was exposed while it was probing the bryozoan colony:

 

And now for the spines.  First, here's an illustration to help you know what to look for.  The inset shows a close-up of a single zooid with elongated spines at the corners and numerous smaller spines along the edges.

 

Modified from Harvell, C.D.  1990.  The ecology and evolution of inducible defenses.  The Quarterly Review of Biology 65: 323-340.

Now here's the real thing, from two different angles:

 

Would those spines deter you from eating this bryozoan?

Eric is so impressed with this nudibranch-bryozoan interaction that he filmed some video and set it to music.  This has to be one of his best invertebrate music videos.  Follow the link below to watch it on YouTube — you don't want to miss it!

"Nudibranch predator (Corambe steinbergae) and bryozoans"

P.S.  For the record, these bryozoans and nudibranchs were found on kelp blades washed up on Salmon Creek Beach on 8 August 2014.

Fireworks

 

Seemed a closeup of a bryozoan colony would be an appropriate image for the 4th of July weekend — the open lophophores, or feeding tentacles, remind me of fireworks.

The lophophores can be completely withdrawn. The next two pictures are the exact same portion of the colony — the first shows the lophophores pulled in, the second shows most of the lophophores extended.  You can compare the positions of the spines to orient yourself within the colony.  

 

 

Speaking of spines, here's a little fact for you.  The units that support the lophophores are called autozoids.  But the units that produce the brown, chitinous spines are called kenozoids.  Below is a zoomed out picture showing more of the colony and more of the spines among the lophophores.

 

Above, you might have noticed that this bryozoan colony is growing on a piece of pink coralline algae.  This bryozoan species is also found growing on kelp.  When the waves are big, large Flustrellida spinifera colonies frequently wash ashore on local beaches and are often mistaken for algae.  You might have seen them before (next image), but perhaps you haven't had a chance to view their beautiful lophophores and intriguing spines under a microscope!