Golden eggs and purple pores

  

Sometimes when we're doing surveys, Eric has the camera while I'm writing field notes.  So when I download the photos later, they mostly show the species we're monitoring, but every now and then Eric sneaks in a different photo (and doesn't tell me)...so it's a surprise!

Here's a fun one -- a cluster of golden fish eggs on the left side, and a pretty purple sponge with prominent excurrent pores on the right side (the excurrent pores are the large diameter holes where water is pushed out after being filtered for food).

Thanks for the colorful photo, Eric! 

Photographed in the rocky intertidal zone in northern Sonoma County on 26 May 2024.

Gold-flecked

 

 

When your eyes match your background...

 

A small sculpin in a low zone tidepool, resting on a sponge with an anemone in the background.  Photographed 6 July 2023.  [You can click on the image for a larger version.]

 

And did you notice the gold flecking on its fins?  :)

Rainbow sculpin?

  

An amazing sculpin resting on a pale purple sponge.  Photographed in the low intertidal zone on 17 June 2022.

A clean sweep

  

Such a cool view of a peanut worm (Phascolosoma agassizii) collecting food particles off the surface of a sponge.  The peanut worm in the foreground has its tentacles extended and is sweeping them backwards (to the right) as it retracts its trunk-like introvert.

We've seen this behavior so often now that we're wondering if it's mutualistic — e.g., does the sponge benefit from having its outer surface "cleaned" of large particles and does the peanut worm benefit from having a smooth surface from which to collect food?

Among the sponges

Eric recently collected some calcareous sponges (Leucilla nuttingi) in the low intertidal zone for his Invertebrate Biology course.  In the past, we had noticed some isopods living inside these tiny vase-like sponges (see post called "Sponge surprise!" from 12 January 2012).  But last week in class, two students with sharp eyes (Maddy and Michael) noticed some other interesting animals living in association with these sponges:

 

Meet the amphipod Podocerus spongicolus!  This tiny amphipod is only 3-4 mm long.  Notice its very long 2^nd antennae.  The amphipods cling tightly to the outer wall of the sponge with the pointy tips (dactyls) of their thoracic appendages.  In the photo below, you can also see the shiny calcareous skeletal elements (spicules) shining through the body wall of the sponge:

 

This amphipod can be distinguished from other Podocerus species by the fact that article 4 (A4) of the male gnathopod (feeding appendage) is extended forward (see arrow in left figure below).   The photo on the right shows this same feature in the live amphipod:

 

As its name indicates, Podocerus spongicolus is known to be associated with sponges. Otherwise, it appears that little is known about this species.  We have only been able to find a few museum records of this amphipod (from the 1930s and 1960s). 

 

It is interesting to think about its life among the sponges.  Many thanks to Maddy and Michael for spotting these amphipods, Collin for identifying them, and Eric for taking the photographs! 

Cobalt blue

I haven't posted much about sponges.  That's primarily because they can be a little more challenging to identify.  The species featured tonight, however, is quite distinctive.

Sponges are animals and have skeletons comprised of elements called spicules.  Some species have spicules made of calcium carbonate, but most have spicules made of silicon dioxide.  The spicules are wrapped in elastic fibers that together make up the wall of the sponge.

As with the ossicles of sea cucumbers (featured previously), sponge spicules come in a diversity of sizes and shapes.  The characteristics of the spicules can often be used to identify the species.

This particular sponge can basically be identified by its color alone, but we also checked the spicules to confirm the identification.

Many encrusting animals in the low intertidal zone are variations of yellow, red, orange, pink, and sometimes purple, brown, gray, or white.  This one stands out because it's brilliant cobalt blue:

 

Meet the Cobalt Sponge (Acanthancora cyanocrypta)!

We noticed this sponge under a rock overhang in the low intertidal zone in Monterey County.  It's primarily a southern species (distributed from Monterey south), but has also been reported in British Columbia.  We haven't seen it in northern California.

Note the species name — "cyanocrypta."  This sponge has symbiotic cyanobacteria (which apparently contributes to the amazing blue color).  Crypta means hidden, so I'm guessing cyanocrypta refers to the cyanobacteria living within the sponge.

Now for the spicules.  Here's an example of the types of spicules in Acanthancora cyanocrypta:

 

Figures modified from The Sponges of California: A guide and key to the marine sponges of California (Lee, Elvin, and Reiswig, 2007).

 

Note the different shapes — the long, simple tornotes; the club-like and spiky acanthostyles; and the barbell-like amphiasters.

Eric took some nice photos of the spicules so you can compare.  Remember, the spicules are microscopic.  In the images below, they are magnified 400x.  See if you can find all three types of spicules in the next three pictures:

 

 

 

There are over 250 species of marine sponges in California, so perhaps we'll be able to feature a few other species in future posts.

"Living Coral"

In-tro-du-cing...the 2019 Pantone Color of the Year..."Living Coral"!  

The first local species we thought of when we saw that Living Coral was named color of the year was this distinctive sponge found in the low rocky intertidal zone:

 

There are lots of animals in this picture, but notice the patch of pink sponge in the lower left corner. (I'm not a sponge expert, but I think this is Aplysilla glacialis.)  What do you think?  Is the color a pretty good match for Living Coral?  See more on Pantone's web site about the 2019 Color of the Year.

It'll be fun to keep an eye out for this color next year.

P.S.  Maybe some coral reef biologists will be able to add to the list of species that highlight this vibrant color!

P.P.S.  Long-time readers of the NHBH will recall past posts with Pantone colors of the year, e.g., Ultra Violet 2018,  Greenery in 2017, Rose Quartz and Serenity in 2016, and Marsala in 2015.

Spot-on

I was sorting through some pictures from last spring when I encountered this one:

 

I said to myself, "Huh...do Two-spotted Keyhole Limpets (Fissurellidea bimaculata, formerly Megatebennus bimaculatus) eat sponges?"  It certainly looks like the limpet (relatively small, dark brown shell surrounded by a bright yellow mantle) had been eating the green sponge (Halichondria sp.).  

So I read the species account in Intertidal Invertebrates of California which said this:

"This species often occurs on compound ascidians where the color pattern provides good camouflage.  In the laboratory, Megatebennus has been observed feeding on compound ascidians, and sponge spicules have been found in the gut of specimens collected in the field."

And then I laughed, because the next photo I found was this one:

 

The Two-spotted Keyhole Limpet above is in the center — with a dark brownish shell (barely visible) surrounded by a pale yellow mantle.  It's flanked by several compound ascidians, and you can see how well camouflaged it is.

The description in the species account by Don Abbott and Gene Haderlie was spot-on!

Sponge surprise!

On 8 January 2012, I photographed this beautiful sponge cluster in the low intertidal zone.  It's a calcareous sponge called Leucilla nuttingi.  Each "vase" is about 1-2 cm tall.  When reviewing the photos, I was surprised to spot an animal emerging from between the sponges -- can you find the green isopod?

Here's another photo when the green isopod emerged into the open.

To my surprise, I then noticed some interesting objects at the openings of the sponges -- some pink and white, some red, some brown and white.  I think all of them might be isopods living in the sponges!

Here's a photo showing an isopod looking out from a sponge opening (on the left, look for its eyes and antennae) and the tail end of another isopod (on the right).

 

And here's one more showing the tail end of an isopod (at the top left) and I think perhaps another head (on the right).

Fish, shrimp, and other organisms are known to live inside some sponges, but I don't know if anything is known about the relationship between Leucilla and these tiny isopods!

ADDENDUM (16 January 2012)

We took a few pictures of these intriguing isopods under the microscope: