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Saturday, April 29, 2017

Sprinkled with pollen

This morning Eric and I were watching a Red-backed Jumping Spider (Phidippus johnsoni) when it started tracking something above it.  Then all of a sudden, it jumped and caught something!

I could see yellow, and here's what I saw when I zoomed in:



The spider caught a small bee!


Here's one more photo of the spider taking away its prey (presumably to a safe spot for eating):


I wondered what the spider thought about the pollen.  We couldn't stay to watch, but it would have been interesting to see if the spider ate the pollen-covered legs or left them behind.


P.S.  I first wrote about Red-backed Jumping Spiders in a post called "Zip line" on 30 January 2013.

Thursday, April 27, 2017

Water views


Looking east across Bodega Harbor. The lighting this afternoon highlighted the different zones mudflats (brown), eelgrass beds (dark blue), and the boat channel (light blue).



Looking northwest from Salmon Creek Beach.  Winds were blowing ~25 knots (~30 mph) in the early evening.  [Water temperatures reached ~10°C (~50°F) this morning.]

Wednesday, April 26, 2017

April showers


Approaching showers, 24 April 2017
 

Tuesday, April 25, 2017

A long tail?

Remember all of the Purple Sea Snails (Janthina umbilicata) we found last year?  For example, review the posts from 20 January 2016 and 6 March 2016 (or scroll down to the bottom of this page and enter "janthina" in the search field to see all of the previous posts).

You might also recall that we found six Janthina on 24 January 2017.

And I haven't mentioned it on the blog, but I also found one individual on 13 March 2017.

We're continuing our surveys to document the "tail" of the distribution of observations associated with the 2015-2016 El Niño.  That is, how long do species likely associated with the El Niño continue to appear in northern California, even after El Niño conditions have ended?

Well, we found one Purple Sea Snail today (25 April 2017)...so the tail continues to lengthen:


Let me know if you encounter any of these little purple pelagic snails.  We'd love to hear about any other sightings this year.

Monday, April 24, 2017

Crossed cups around the Pacific Rim

Okay, remember the mystery photo from last night?  Here's a reminder, with a slightly different view:



I'll zoom out a bit so you can see a little more.  And yes, for those of you who were wondering, the sand grains on the tentacles are a clue:


Any guesses yet?  When we first found this animal, we didn't know what it was.  We had to step through various options and rule out different groups.

Did you notice that the skin adjacent to the tentacles looks shiny?  Here's an extreme close-up so that you can see what I'm referring to:


Those shiny pieces are ossiclestiny calcified plates.  To help identify this organism, we looked at a few of the ossicles under high magnification (400x):


Do you have a guess yet?  Think about a soft-bodied animal with a cluster of branched tentacles at one end and microscopic ossicles embedded in the body wall. 

It'll probably help if I tell you that although this animal doesn't have them, most of this animal's relatives have tube feet. 

Here's another look at those digitate (finger-like) tentacles:


Yes!  It's a sea cucumber!  We hadn't seen this species before.  It's a Sand Sea Cucumber (Paracaudina chilensis).  Amazingly, it's distribution includes the entire Pacific Rim (coastal South America, Central America, North America, China, Japan, Australia, and New Zealand).

As you might guess from the common name, and the pictures, this sea cucumber burrows in the sand.  It ingests large volumes of sand to capture organic material from the sand grains for food (hence the "sticky fingers").

This is what the entire sea cucumber looks like (photo below note there was debris sticking to the cucumber, but that's likely a result of being in the drift line).  We found it washed up on the beach, and puzzled over it for a while.  With my hand lens I could see the tentacles — that helped because the tentacles didn't look right for a peanut worm or a sea anemone.  

Note the very long posterior end.  This sea cucumber lives upside down in the sand (up to 50 cm deep) — tentacles down, and posterior end up near the surface.



The shape of the ossicles helped clinch the identification as Paracaudina chilensis.  Many of them are beautiful three-dimensional "crossed cups."  Compare the ossicle images above with this published figure from a specimen in Australia:

Modified from O'Loughlin, P.M., S. Barmos, and D. VandenSpiegel. 2011. The paracaudinid sea cucumbers of Australia and New Zealand (Echinodermata: Holothuroidea: Molpadida: Caudinidae). Memoirs of Museum Victoria 68: 37-65.
 

P.S.  Are you wondering about the extra credit (i.e., the source of the brilliant red coloration in the tentacles)?  Paracaudina chilensis has hemoglobin-filled blood cells (in the body cavity and in the tentacles)!  The hemoglobin is likely an adaptation to living buried down in a low-oxygen environment.
 

Sunday, April 23, 2017

Like little jesters' caps?

A close-up mystery photo, taken with a microscope.  Do you have any ideas about what type of organism this is?


I'll reveal the answer to this mystery tomorrow night.

P.S.  Extra credit if you can guess why the structures are red!

Saturday, April 22, 2017

Resting on the beach


A beautiful Harbor Seal (Phoca vitulina) pup, 22 April 2017

Remember the mother/pup photos from several years ago?  You can review that post from 14 May 2013 here.