Tiny pawns

Well, this has been an interesting week for cnidarians.  Do you remember the golden planulae (larvae) of the hydroid Abietinaria from a few days ago?

 

Eric is teaching a summer class right now, and he kept a few planulae around to show his students.  But when he checked on them today, this is what he saw:

 

Tiny yellow discs attached to the bowl — the planulae had undergone metamorphosis!

Below is an even closer view.  I chose these three individuals because they're in different stages of development.  Can you guess which is youngest and which is oldest?

 

The youngest juvenile is on the far left, the oldest is in the middle (lowest), and the juvenile on the far right (highest) is at an intermediate stage.  You can tell by the number of divisions in the basal disc, and by the development (height) of the stalk growing up from the center of the disc.  

Remember that these juveniles are going to become tall, extensively branched colonies (reminiscent of a fern or a miniature tree).  These are the youngest hydroids we've ever seen.  They would be too small to see in the field, so we just got lucky that they metamorphosed in the lab.  In the next image you can see the central stalk extending upward.

 

Amazingly, when I looked around, I noticed a few juveniles that had the first developing zooids!  It did not appear that these zooids had formed tentacles yet, but two developing zooids are clearly visible attached to either side of the central stalk:

 

These little hydroids have grown very quickly.  It will be interesting to see how the branching pattern proceeds, and when the first feeding tentacles appear.

A fun side note: When I first saw the these juvenile hydroids as in the last photo, one of the first things that came to my mind was that they looked like tiny chess pieces.  And then later I read an article that described a stage similar to this as the "pawn" stage!  

P.S.  To review what an Abietinaria colony looks like when it's older, see the post from 27 June 2016.

Nice spotting!

 

A beautiful White-spotted Anemone (Urticina lofotensis, formerly Tealia lofotensis) discovered nestled among mussels during a field trip to Spud Point Marina on 27 June 2016.  

Although this species can reach sizes of up to ~150-200 mm (~6-8 inches) across (including the tentacles), this tiny individual was only ~8 mm (~0.3 inches) across!

The deep red or scarlet color is distinctive, as are the white spots on the column — more easily seen when the tentacles are withdrawn (below).

 

Nice spotting, Chessie!  

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!

 

Golden -- Part 2

Okay, remember the mystery photo from last night?

 

I received some great guesses about the identity of these small organisms — and I need to congratulate Marni for submitting a correct answer! 

These are indeed planula larvae, in this case from a hydroid called Abietinaria.

Hydroids are colonial cnidarians (related to jellyfish, sea anemones, and corals) with many connected polyps.  Colonies often have a branching structure, and because of this they are often mistaken for plants.

Most of the polyps in the colony are feeding polyps — they can extend a ring of stinging tentacles to capture small animals from the water.  Other polyps are reproductive and produce the gametes that will form the next generation.

In this case, we were fortunate to have collected a female colony.  Within small capsules (gonozooids), there are attached medusoids that produce eggs which are retained and, once fertilized, develop into planula larvae.  When they're ready to disperse, the planula larvae emerge from the gonozooids and swim to a new location to begin another colony.

Here's an expanded view of the gonozooids filled with developing planula larvae:

 

And two more views so you can really see the individual larvae:

 

 

Intriguingly, I might have also found a male colony.  I'm not sure about this, but it's possible the white, flat-topped structures in the photo below contain male medusoids that will release sperm.

 

This picture is also helpful because you can see some of the tiny feeding polyps arranged along the branches.  I've circled a few in the next image, but I'm sure you'll be able to spot others:

 

So there you have it!  Planula larvae are so tiny that you don't often get to see them, so it's fun to be able to share them with you!

P.S.  On 30 January 2014, I showed a fun sequence with a planula larva (from a different hydroid species) emerging from a capsule.  To review those pictures, click here.

Golden

Well, this will be tough, but I don't have much time tonight, so I'm going to post a mystery photo for you to ponder.  

Can you guess what these are?  Each one is only ~1 mm long.  They're found in the ocean.

 

I'll reveal their identity tomorrow night!

 

Reds among the purples

Red Sea Urchins (Mesocentrotus franciscanus) among Purple Sea Urchins (Strongylocentrotus purpuratus) in tidepools along the Mendocino Coast.  The abundance of red urchins this year is notable.

Photographed in Mendocino County on 10 June 2016.

 

 

Silver stigma

 

A few days ago, Eric noticed this distinctive moth among the landscaping next to the house.  

I'm pretty sure this is a Bilobed Looper Moth (Megalographa biloba), but let me know if you have a different idea.  

Note the prominent, bilobed silver stigma in the center of each wing.

Minty

 

Coyote-mint (Monardella villosa ssp. franciscana) in bloom on Bodega Head, 22 June 2016

To learn a little more about this species, review the post from 22 July 2012. 

Feeding near shore

Nice light on the pelicans feeding near shore in Bodega Harbor tonight:

 

 

Solstice sunset

Did you notice the sunset last night?  Pretty spectacular way to start the summer.

 

 

Cool as a cucumber

Last night I shared a video of a small sea cucumber (the video is also at the end of this post) and I promised more information about it.

This sea cucumber (Cucumaria pseudocurata) is found in the rocky intertidal zone along our coast.  Recently we encountered quite a few of them nestled in shallow depressions below mats of algae.

In the field, the sea cucumbers look like little brown blobs (maximum size is ~3.5 cm, or ~1.5 inches):

 

As you probably saw in the video, when viewed under a microscope their features are easier to see, including tubefeet (for holding on), tentacles (for gathering food), and large shiny ossicles (for skeletal support):

 

Ossicles are plates made of calcium carbonate.  The shape of the ossicles helps distinguish different species of sea cucumbers.  Below is a selection of ossicles from Cucumaria pseudocurata viewed under very high magnification:

 

You can compare the real thing (above) with a book illustration (below) and look for similarities:

 

Modified from Sea Cucumbers of British Columbia, Southeast Alaska, and Puget Sound (Lambert 1997) 

And here's a wonderful close-up view of the ossicles inside the body wall and a tubefoot:

 

Perhaps you remember that the sea cucumber in last night's video was only ~3 mm long.  Cucumaria pseudocurata is a brooder and a direct developer — females lays eggs in January, males release sperm to fertilize the eggs, the female shields the developing embryos with her body for about a month, and eventually tiny juvenile sea cucumbers are visible among the adults.  

The individual in the video was probably about 3-4 months old.  Here's a still picture with a ruler to help you visualize the size (the marks on the ruler represent millimeters):

 

And in case you missed it, here's the video:

cucumaria_juvenile_sanford from Jackie Sones on Vimeo.

Little one

I haven't posted a video in a little while, so here's a nice one that Eric put together recently.  

The little sea cucumber featured in the video is only ~3 mm long.  Watch for the shiny ossicles in the body wall, tentacles, and tubefeet.  (I'll explain more tomorrow night.)
 
If you can't see the video in the e-mail, click on the title of this post to go to the website.

cucumaria_juvenile_sanford from Jackie Sones on Vimeo.


P.S.  Happy Solstice! 
 

Inspiration

 

My dad (Steve Sones) with a Striped Bass (Morone saxatilis) off Scituate, MA

 

My dad, my sister (in the yellow hoodie), and me 

 

And me sitting on a large lobster trap! 

My dad passed away recently.  It's made me think a lot about how appreciative I am that my parents spent so much time outdoors and encouraged us to explore and connect with the world around us (and to eat lots of fresh, local seafood!).

May you all have family and friends that inspire a love of nature.

Mendocino scenes

A couple of seascapes from the Mendocino coast yesterday (10 June 2016):

 

A breezy morning, with Sea Palms (Postelsia palmaeformis) in the foreground.

 

 

Sea urchins (purple), sea anemones (green), and coralline algae (pink) under water on a vertical wall along a deep surge channel.

Three "seas"

We were doing field work on the Mendocino coast today (10 June 2016).  In between surveys, we documented a few nice invertebrates:

 

It might be tricky, but can you find three different species of echinoderms in the photo above?

There's a Purple Sea Urchin (Strongylocentrotus purpuratus).  Next to the urchin is a Six-armed Sea Star (Leptasterias sp.).  And just below the sea star, looking a bit like a brownish blob, is a sea cucumber — still to be identified...stay tuned!

Aeronautes

A few years ago, I wrote about White-throated Swifts (Aeronautes saxatilis) at AT&T Park in San Francisco — review the "Sky Sailors" post from 1 July 2012.  

We were at the park last night and I was thrilled to see several swifts actively feeding.  In 2012, I only managed blurry silhouettes, but this year I ended up with one shot showing the white throat and belly (they remind me of Orcas!).  

 

White-throated Swifts are so fast that it's hard to photograph them, especially with dim light, and between innings!  Some day I hope to have a chance in easier conditions. 

Celebrate the oceans

 

On World Oceans Day, there are so many reasons to celebrate.  Because this is a natural history blog, I'll mention two reasons related to that topic.  Tonight I'm choosing endless beauty and wonder.  

I'll always be thankful for the wonders of marine life.  I can't imagine ever visiting the ocean without being stirred to ask questions or being presented with a mystery to try to solve.   

And I couldn't be more grateful for the beauty of seascapes.  The oceans provide so many inspirations to carry with us — whether it's a seabird soaring over open ocean waves, colorful invertebrates and seaweeds in tidepools and on beaches, or storms and big surf crashing against the coast.  I'm so thankful for the oceans' gifts!

Singing redstart

A few people have expressed interest in seeing and hearing this American Redstart (Setophaga ruticilla) that appeared on Bodega Head today (7 June 2016).

This isn't a great photo, but it's the best I have under challenging conditions.  You can see the orange patches along the sides and dark gray-black splotches on the face and breast indicating a young male.

 

I managed a couple of song recordings for the record.  Below are two examples.  [If you can't see the audio files in your e-mail, click on the title of the post above to go to the web page.]

Rings around the boulders

We were on our way to do field work in the rocky intertidal zone early this morning, when we noticed this:

 

Can you see the orange coloration along the lower part of the wall and forming rings around the boulders?

Here's a closer view (below).  The boulder is about 2.5 feet across (~76 cm).  Any guess about what's causing the orange color?

 

There are orange sponges in this area that could look like this from a distance, but it didn't seem quite right, so we got down for an even closer view:

 

Spirorbid tubeworms!  Wow, neither of us had seen such dense and expansive aggregations before.  

The next photo is helpful because some of the tubeworms are underwater with their bright orange tentacles expanded, and others are out of the water with their tentacles withdrawn so it's easier to see their white tubes (with just a hint of orange at the entrance).

 

Most spirorbid tubeworms are brooders (brooding their larvae) and once released their larvae have very short planktonic durations — swimming in the water column for a very short time before they settle onto a rock (or other suitable surface).  

Perhaps the surge channel we walked by is a good setting for high retention, where many larvae are released and then settle in close proximity to each other instead of being swept away by waves and currents?

If you're interested in seeing microscope views of these fascinating tubeworms, review the post from 6 February 2012.

A greenish glow

 

It's always exciting to see an octopus.  Eric spotted this one this morning (5 June 2016).  It was in a low tidepool with lots of surfgrass (Phyllospadix sp.).  Perhaps the octopus was matching the greenish background of the surfgrass?  

The green coloration was beautiful.  Below is a closeup of the eye and surrounding skin.

 

Recently, a number of octopus like this one (Octopus rubescens) have been observed in local tidepools.  Perhaps it will be a good year for octopus?

P.S.  This is a bit of a prelude to World Oceans Day on June 8th.  How will you celebrate the oceans?

June Gloom?

 

June Gloom?  I kind of like it.  Fog photographed off Bodega Head on 3 June 2016.