Stranded on shore

 

 

It's been a while since we've seen pyrosomes washing up on local beaches, but Eric photographed this one today, 12 October 2023.  It was ~5 cm long.

 

For an introduction to pyrosomes, see the post called "Fire bodies" on 8 December 2014.

 

P.S. If you happen to see any other pyrosomes washing up, I'd be interested in hearing about your observations!

 

In the drift line

  

During a short walk along Bastendorff Beach (near Charleston, OR) today (28 October 2022), I noticed a few of these small salps in the drift line.  I think this is Thalia democratica.  I know it's hard to see the entire animal — the gelatinous portion is transparent — but I don't know how often this species is seen washing up in Oregon, so I thought I'd post it for the record.

P.S.  For more photos and information about Thalia democratica, see the post called "Diamonds in the drift" from 26 August 2014.

Icicles on the beach?

  

Hmmm...they look a little bit like icicles, don't they?  

Pyrosomes (Pyrosoma atlanticum) have been washing up on local beaches recently.  These were photographed on Bodega Head on 23 December 2021.

For more photos and information about pyrosomes, check out the post called "Fire bodies" from 8 December 2014.

Storm strandings

  

Just a quick photo of several pyrosomes washed up on Salmon Creek Beach tonight (28 October 2021).  

 

It's been a while since we've seen pyrosomes locally, but the storm must have pushed some closer to shore as there were hundreds (or even thousands) of pyrosomes on the beach tonight.  Most were relatively small — ranging from ~1-3 cm long.

 

There was an impressive diversity of offshore gelatinous zooplankton washed up tonight — including the pyrosomes, two types of pteropod, one species of heteropod, two kinds of salps, and one siphonophore.  I'll try to show examples of them during the next day or two.

 

To review an introduction to pyrosomes, check out the post called "Fire bodies" from 8 December 2014.

Tubes and slippers on the beach

I've heard from several people that pyrosomes have been washing ashore on beaches — in Monterey and Bodega Bay, California and in Seaside, Oregon.  We saw some pyrosomes ourselves last night (22 February 2017) on Salmon Creek Beach:

 

We estimated there were over 1,000 pyrosomes washed up along about a 1-km stretch of beach.

Below is a closer view.  You might recall that pyrosomes are a type of pelagic tunicate, related to sea squirts.  [For an introduction to pyrosomes, review the "Fire bodies" post from 8 December 2014.]

 

We encountered a variety of sizes (most of them were on the larger end of this size range):

 

I've received a few questions about how to tell pyrosomes from Corolla spectabilis pseudoconchs.  So for anyone who's been puzzling over either one, here's a side-by-side comparison.  Note the overall shape (oval vs. elongate) and color (clear and transparent vs. pinkish and opaque) and structural differences (slipper-shaped vs. tubular).

 

And if you haven't seen it yet, there's an introduction to Corolla on the "Gelatinous thimble" post on 11 August 2012.

Washed ashore

 

Just a quick note that with this recent storm, many interesting pelagic animals have washed ashore.

Do you remember the pyrosomes from 2014?  Quite a few are appearing on the beaches now.

For a description and more information about pyrosomes, review the post from 8 December 2014.

And stay tuned for more interesting discoveries!

Serena's wish

This morning Serena submitted a comment on last night's "Fire bodies" post saying that she had seen pyrosomes in the Channel Islands this summer.  At the time, she also observed a small crustacean living inside the pyrosomes.  I replied that I, too, had noticed a small crustacean inside a few of the pyrosomes washed up on Salmon Creek Beach yesterday.  Serena wrote back that she'd like to see a picture of one...so...here it is!

 

I don't know if this is the same animal that Serena saw, but it does have very large eyes, a feature that she remembered. 

At first I thought this might be an isopod because it looked fairly flattened from top-to-bottom.  However, with more attention, and some research, I'm now thinking this is probably an amphipod.  Although amphipods are often flattened side-to-side, some of the hyperiid amphipods can have a more rounded appearance. 

I didn't have a lot of time, but I also found one reference that listed a few known associates of pyrosomes which mentioned hyperiid amphipods.

For now I'll call it an amphipod, but I'd be very interested in feedback from anyone with more experience.

 

And now for some more imaginative thoughts: 

What is it like for an amphipod to live inside of a pyrosome?  When I saw one, it was positioned such that it appeared to have a view looking out at the world through the transparent tunic of the pyrosome.  It must be quite something to be drifting along inside of a long, jet-propelled cylinder.  Do they see other animals swimming by?  Can they move to different places within the pyrosome, e.g., from side to side or front to back?  What is it like for the amphipod when the pyrosome starts to bioluminesce?  Pyrosome bioluminescence can be triggered by motion.  Can the movement of an amphipod start a bioluminescent wave?

Above I mentioned that Serena remembered the amphipod's large eyes.  While observing them, I tried to come up with a name for their color.  I'll let you look, and then I'll tell you what I came up with below.

 

You're going to laugh at me, but eventually I decided on "marsala"— the 2015 Pantone Color of the Year!

What?  You hadn't heard about the color of the year yet?  Well then, you'll have to check it out here at the Pantone web site and see if you think it's a match for this amphipod's trendy eye color.

"Fire bodies"

This morning Alex asked us about a mystery animal he had observed on Salmon Creek Beach.  He described it as gelatinous, long and finger-like, and covered with short spikes.  I've spent many years listening to people describe different types of animals and trying to assist with identifications.  I like this game.  My mind immediately starts working on the puzzle.  This time, as I listened to Alex, I wasn't coming up with an answer.

He told me where he had found them and it wasn't far away.  When I got there, it was easy to spot them.  This is what I saw:

 

They varied in size from about 1 cm to 11 cm long.  The one below was about 4 cm (1.5 inches) long:

 

Here's one of the larger individuals in my hand:

 

We had to look at them under the microscope to confirm the identification.

This is a pyrosome, probably Pyrosoma atlanticum.

So now you might be asking, what is a pyrosome?

A pyrosome is a pelagic tunicate, somewhat like a salp.  It's a colony of individual units or zooids embedded in a common gelatinous tunic.  You're seeing the entire animal in these pictures.  It's a rigid cylinder, closed at one end (the rounded end) and open at the other (the "squared" end).

This diagram may help.  It shows the entire colony, how the zooids are positioned along the periphery, and then there's a close-up of an individual zooid:

 

Modified from Invertebrate Zoology, Sixth Edition (Ruppert and Barnes, 1994)

Note that each zooid has two siphons.  The buccal siphon faces out and pulls water in.  The atrial siphon leads to the central cavity.  Once water flows into the large central cavity, it exits via the single large opening at the back end and slowly propels the colony forward.

The gill basket is used for both respiration and filter-feeding.  Below is a view of several zooids under the microscope.  You can see the buccal siphon at the top, the large gill basket, and the endostyle (on the right).  The endostyle produces mucus that lines the gill basket for feeding — and is thought to be the precursor for the vertebrate thyroid gland.  (The red spot is the brain.)

 

Here's another view that allows you to see how the zooids are embedded in the tunic, and it's really just their siphons that extend above the surface:

 

I don't know how often pyrosomes are seen in this area.  This is the first time I've seen them since moving here (10 years ago).  If you've observed them before, I'd love to hear about it.

Here's another interesting fact about pyrosomes.  Pyrosome comes from "pyro" for "fire" and "soma" for body = "fire body."  The name derives from their amazing bioluminescence.  

After we read about this, we took a quick look at them later in the evening.  Sometimes there would be scattered bright flashes, but when Eric picked one up it was so bright and sustained that it looked like a glow stick!

I'm so thankful that Alex noticed these mystery animals on the beach and pursued his curiosity to ask us about their identity.  I had no idea when I woke up this morning that I'd be documenting a pelagic invertebrate that I'd never seen before!