The ocean planet

  

To help celebrate Earth Day, a nice view of soft corals (Cryptophyton goddardi) from the rocky intertidal zone on Bodega Head.

P.S.  Thanks for the great photo, Eric!

Sparkling disco ball

Back in 2012, I showed a few pictures of a soft coral called Discophyton rudyi that we observed at Cape Mendocino (you can review those photos here).

In 2017, we found this species again at several locations in northern California and Oregon.  This time we also took some close-up pictures and Eric filmed a short video that we're excited to share.

Here's what Discophyton looks like up close.  Sometimes many of the polyps are extended, with tentacles spread outward:

 

Other times, most of the polyps are withdrawn, and it starts to look like a soft mound covered with little bubbles (the contracted polyps):

 

In the picture above, did you notice the granular texture surrounding each polyp?  The sparkling "grains" are sclerites, calcified structural elements that offer support and protection from predators:

 

[Note: A major predator of Discophyton is the nudibranch Tritonia festiva, which can often be found in close proximity.  Both are shown together in the photos from 10 May 2012.]

One way to recognize Discophyton in the field is to look for clusters of small disc-like mounds.  (Each mound is ~5-15 mm across.) The colonies can divide by fission, so it's likely many of the colonies in one area are clones (genetically identical).  In the photo below, can you find the splitting colony? A thin connection remains between two patches that are pulling apart from each other.

 

Yes, that's it!  The splitting colony is in the center of the picture.

The color of Discophyton can vary from white to pink to yellowish.  Note that this species is often found in shaded locations, e.g., under rock ledges.

 

And here's the video clip you've been waiting for.  Watch for subtle movements of the coral polyp tentacles.  At 10 seconds, in the upper right, look for one of the polyps to draw one tentacle down towards the center of the polyp — this motion moves prey caught on the tentacle to the mouth:

discophyton_sanford_2017 from Jackie Sones on Vimeo.

Although they're not necessarily conspicuous, it's nice to know this beautiful soft coral is a member of our local fauna.

Spreading out

Recently, Eric took some wonderful photographs of some local soft corals.  Here are a few of his best images.  This is Cryptophyton goddardi from the rocky intertidal zone:

 

Cryptophyton goddardi polyps grow in dense clusters, often on the underside of rocky ledges:

 

The coral polyps use their long, pinnate tentacles to capture zooplankton and food particles from the water:

 

P.S.  I first wrote about this species a while ago, on 25 January 2012, so for a little more information about them, click here.

P.P.S.  And if you'd like to compare Cryptophyton goddardi with another species of octocoral, Thrombophyton trachydermum, review the post called "A sparking necklace" from 28 June 2016.

A sparkling necklace

I'm very excited to share a beautiful invertebrate with you tonight.   (It's especially fun because finding it was an accident and unexpected!)

Eric was looking at a bryozoan, and he noticed this small, delicate cluster next to it:

 

He recognized it as an octocoral (or soft coral), but also realized it looked different than the species we've encountered most often in this area.  (For scale, the large polyp above is ~5 mm across, measuring from one tentacle tip across to the tip of the opposing tentacle.)

Here's a view from the side with multiple polyps extended:

 

Soft corals may be found under rocky ledges in the low intertidal zone.  In that position, the polyps hang upside down with tentacles extending downward:

 

The photo above is useful as it shows an important feature of this species.  Can you see the small, shiny pieces in the column — next to the tentacles and at the base of the polyp?  I'll zoom in so you can see them better:

 

The photo above shows the "necklace" of shiny sclerites encircling the polyp at the base of the tentacles.  

In the next photo, look for the larger, rough-looking sclerites at the base of the polyp where it is attached to the substrate (the tentacles are retracted).  There are so many sclerites embedded in the base of the polyp that it can look as if there are sand grains gathered around the colony (see second photo of this post).

 

Sclerites are small, calcareous skeletal elements.  They can be important for structural support and may also deter predators. (They are also helpful for species identification.)

 

This is the first time we've encountered Thrombophyton trachydermum.  Jeff Goddard documented it on Bodega Head years ago, but we haven't found it ourselves until now.

 

What a treat!  

P.S.  For views of two other soft corals found in northern California, see Cryptophyton goddardi on 25 January 2012 and Discophyton rudyi on 10 May 2012.

P.P.S.  Thrombophyton means "lumpy animal" and trachydermum means "rough skin" (probably in reference to the numerous sclerites).  So the scientific name of this coral basically means "a rough-skinned lump."  It seems this wonderful coral is worthy of a prettier name!

 

Hidden creature

Last week, partially as a reward for finishing field work, Eric had a goal in mind to find an animal he hadn't seen in a while.  I was impressed that he was successful — it's not easy to find!  Even its scientific name means "hidden creature."

Here's a magnified view (under a microscope):

 

Yup, it's those small orange bumps.  Each "bump" is only about 2 mm across.  And yes, this is a colonial animal (i.e., the bumps are connected to each other).

I'll zoom in for a closer view:

 

Now you might have guessed that this isn't the entire story — the animals are withdrawn.  But if you wait and watch patiently, you get to see what the rest of the animal looks like:

 

A little bit different than a bump on a rock, right?  

The next picture shows a view from above (with the mouth in the center).  The number of tentacles provides a clue to the type of animal that this is.

 

Eight tentacles helps you identify this as an octocoral, one of the soft corals found along our coast.  Because they're small and inconspicuous, many people aren't aware that soft corals occur in this area.

Another fascinating thing is that they've hardly been studied at all.  Very little is known about the biology and behavior of soft corals along the West Coast.

It's easy to be drawn to their beauty (see Eric's next photo), but it's also fun to wonder about various aspects of their lives.  What and how do they eat?  When do they reproduce?  How do they interact with their "neighbors"?  How do they protect themselves?  How long do they live?

 

Viewed up-close, the texture of their tentacles somehow reminded me of burrowing sea cucumber tentacles and amphibian feet (tree frogs, geckos) at the same time.  Increased surface area for capturing food?

 

I haven't mentioned it yet, but we believe this is Cryptophyton goddardi.  ("Crypto" = "hidden" and "phyto" = "creature" and "goddardi" from Jeff Goddard who collected the specimen in 1992 used to describe this species.)  To identify soft corals, it's important to look at their sclerites — hard spicules made of calcium carbonate embedded in their tissue.  (Sclerites may be useful for structural support or in defense against predators.)  Below are the knobby, microscopic sclerites that help identify this coral.

 

Here's one more view of this wonderful octocoral colony.  Look for two polyps with their tentacles expanded, one polyp with its tentacles withdrawn (but still visible outside of its base), and several polyps in the background (no tentacles visible).

 

Although they're small, now you can imagine these corals with their eight pinnate tentacles living under wave-swept rocky ledges.