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Sunday, June 30, 2013

Dreaming of ice

  
You know it's hot when I start dreaming about ice.  I'll admit I'm not a hot-weather person.  It's hard for me to even think when it's this hot.  So here's a simple picture from January 2007.  

I've always referred to the piece of ice in this image as an "ice bear."  It takes a little imagination, but can you see the bear outline, with the head on the left and tail on the right?

It's rare to get ice in tidepools here, but on 13 January 2007, it was cold enough for a thin layer of ice to form in a few of the uppermost tidepools.  I picked up a few pieces and held them against the sky for photos.

I'm working hard to concentrate on the ice bear to remember what it felt like that day...rather than sitting here sweltering!

Saturday, June 29, 2013

Too hot

It was too hot tonight to do much of anything — it was still ~76°F as of 10 p.m. — but I took a few quick shots of this pretty moth outside of our house in Sebastopol:





I'm not sure which species it is yet, but will add an addendum here later if I can figure it out.

Friday, June 28, 2013

Fortuitous

I was finishing up a survey along the rocky shore this morning and glanced down into a shallow tidepool to see a Giant Green Anemone (Anthopleura xanthogrammica) with a brownish look to its oral disc (see below).


Eggs!  This is a female anemone releasing eggs!  I turned in the other direction and saw this individual:


Sperm!  This is a male anemone releasing sperm!

I checked a few more pools and found quite a few anemones spawning today.  It's not that common to see this, so I took a few more photos.  Can you spot the female and male in the next image?

[The female is on the left; the male is on the right.]

This was a fortuitous circumstance.  I'm not sure exactly what cued the anemones to spawn (recent warm ocean temperatures? a nearshore algal bloom?).   But I happened upon them during low tide when they were in isolated pools with still water, so the eggs and sperm were concentrated on their oral discs and not yet suspended and mixed in the turbulent ocean water. 


When the tide floods these pools, eggs and sperm have the chance to be fertilized and continue development into the swimming larval stage called a planula.  Eventually the planula will attach to a hard substrate and undergo metamorphosis into a tiny anemone.

The eggs of Giant Green Anemones are relatively large for marine invertebrates (see close-up below).  Each one might be ~175-220 microns across.  (That means that you could fit about 5 eggs in one millimeter.)  For comparison, Purple Sea Urchin eggs are 80 microns and California Mussel eggs are 60 microns across.


Although Giant Green Anemones are common inhabitants of tidepools along the West Coast, you don't often encounter them spawning.


Thursday, June 27, 2013

My, what a nice lophophore you have!


How many people get to start their day with a few nice images of phoronids?  You can count yourself among the lucky ones!

Phoronids are invertebrates related to bryozoans and are in their own phylum, Phoronida.  There are fewer than 20 described species in the world.  

These pictures were taken under a microscope on 27 June 2013.  The phoronids are Phoronis vancouverensis from the rocky outer coast.  


Phoronids feed with a crown-like structure called a lophophore.  Note the U-shaped indentation on one-side.  The tentacles are ciliated and actively draw water currents down through the lophophore to trap food particles.


For the record, we also noticed a few very small phoronids (see next image).  I'm not sure how old they are, but it's helpful to document when juveniles are present.  It might indicate the timing of larval settlement from the plankton.


P.S.  See the post from 27 November 2011 for a picture of Phoronis vancouverensis in the field.

P.P.S.  In February 2012, I shared images of Phoronopsis harmeri in Bodega Harbor and a little more general information about phoronids.

Wednesday, June 26, 2013

Name that Holdfast - Part 2

Those of you who were reading the blog last spring might remember the Name that Holdfast game.  Here's a new addition.

If you haven't played before, below is the holdfast of a local marine alga — can you guess which species?  This one is from Pinnacle Gulch on 26 June 2013.  [Warning: The answer is directly below the image.]



And the answer is:  Laminaria sinclairii !


This is a wonderful kelp.  I neglected to take pictures of the entire seaweed this morning, so here are a few from the past.  The next two photos are from Bodega Head.

Laminaria sinclairii has long narrow blades in a very deep brown color:


This kelp is unusual in that it's rhizomatous, so it can grow in very dense patches.  Below it's covering the larger boulders on the left side of the image.


P.S.  Thanks to Peter for pointing out the nice holdfast arrangement this morning!

Tuesday, June 25, 2013

Not a flatworm!

When the low tides are this good, it's sometimes hard to stop looking.  On 23 June, I checked one more site and noticed something unusual.  It was relatively small (~2 cm long), oval, with an undulating edge, and a handsome dark green color.  The shape made me think of a flatworm, but I hadn't seen a local flatworm that color before.

I took a picture and then zoomed in to see more detail.  This is where digital cameras come in handy!  Here's what I saw in the field:


The distinct head and tentacles (rolled rhinophores) told me this wasn't a flatworm but rather a gastropod or sea slug.  I knew I hadn't seen this species yet, but I had a guess about what it could be.  I'd been wanting to see one for years!

I brought it into the lab for a few microscope pictures for documentation.  Here's one of the first photographs under magnification:


This is a Hedgpeth's Sea Hare (Elysia hedgpethi).  Note the beautiful blue spots scattered across the lateral flaps on either side of the body.  There were tiny orange spots, too, but they're harder to see because of their smaller size.

Hedgpeth's Sea Hares are known to feed on two species of green algae: Codium fragile and Bryopsis corticulans.  The sea hare is able to retain the algal chloroplasts which continue to photosynthesize for at least 10 days after they've been ingested!

Although this individual was quite active under the microscope, I managed a few more pictures:



I wish I had more time to write about Joel Hedgpeth, for whom this sea hare was named.  I'll have to do that another night.  For now, if you'd like to read more about him, I think you can still access a short NY Times obituary here.  And there's a much more complete article in the Journal of Crustacean Biology here.  Among many (many!) other things, Joel was a marine biologist, a local Santa Rosa resident, editor of Between Pacific Tides, and well known for protesting the PG&E attempt to build a nuclear power plant on Bodega Head.


Joel also wrote an Introduction to Seashore Life of the San Francisco Bay Region and the Coast of Northern California.  I laughed when I read this passage about Hedgpeth's Sea Hare in that book: "...at first glance may be confused with a large flatworm, but the rolled structure of the head tentacles clearly separates it from flatworms..."  As mentioned in the very beginning of this post, this was my experience exactly!

Monday, June 24, 2013

Coralline mimic

Eric looked down into a shallow tidepool a few days ago and at first he had trouble figuring out what he was seeing.  The pool was filled with algae, including pink-and-white striped coralline algae, but something else was there.  His eyes adjusted and then he was very excited to realize what it was:


We've been very lucky running into octopus recently.  (I hope you're not getting tired of seeing them on the blog, but I can't resist them!  They're remarkable animals.)  And this one was demonstrating the best of its camouflage capabilities.  

We'd never seen one mimicking coralline algae before.  It was a beautiful pale pink coloration.  And it was amazing to see how it had created the narrow white lines so often found in these segmented seaweeds.  


It was a difficult setting for a photograph, with many reflections off the surface of the water, the octopus, and the algae.  But here's another attempt.


And one more image — a close-up of an arm with the delicate patterning so similar to the adjacent coralline algae.


Sunday, June 23, 2013

Complementary


Last July I showed a few pictures of Coast Onion (Allium dichlamydeum) from Dillon Beach, but here are a couple of recent images taken on Bodega Head on 21 June 2013. 

It appears to be a very good year for this species, so it's a great time to look for the brightly-colored flowers emerging among the lichen-covered rocks (beware of the Poison Oak!).  Note that the onion's leaves have mostly dried and disappeared by this time.


There's something quite complementary about the magenta of the onion and the grays of the lichens. 


Saturday, June 22, 2013

Following the birds

If you grow up fishing, with an eye on the birds to show you where the fish are, will there always be something inside of you watching out of the corner of your eye for bird activity?  

I grew up lobstering on the East Coast, but if there were a lot of birds feeding nearby, sometimes my dad would let us follow the birds and go fishing for stripers or bluefish for the day instead.

On 21 June, a flock of Western Gulls caught my eye.  And I couldn't help wondering what they were being drawn to. They were finding something on the beach.


Curiosity got the best of me and I went down to see if I could find out what they were eating.  This is what I discovered in the wrack line (next image).  Can you tell what they are?


It turns out that the gulls were after krill.  I collected a few and took some quick photos under the microscope for the record.  (The third image is a close-up of the eye.)


You may recall that I photographed ravens eating krill on the beach in March (review that post here).  It looks like this is a different species of krill.

Later in the day we went back to see if the gulls and krill were still there.  Sure enough, the gulls were still picking through the seaweed looking for krill.  The Western Gulls had now been joined by a few Heermann's Gulls (see below).  


Many of the krill that had washed ashore earlier in the day were now dried, but the gulls still seemed interested.


If you follow the birds, you never know what you'll find!

Friday, June 21, 2013

Washed with cinnamon

Remember the Northern Rough-winged Swallows I wrote about last month?  The adults successfully raised a large brood, because tonight we encountered a flock of six fledglings roosting nearby.  They must have just left the nest.

Below are views of four of the six.  Note the pinkish coloration at the gape, or base of the bill.


The very pretty rufous coloration was striking in the right light.  The Birds of North America account describes the juvenile plumage as being "washed with cinnamon" — a good description!


The next individual was sleeping in the warm summer sun, its head turned and tucked deep within its back feathers.


If you'd like to compare these juveniles with their parents, click here to see the post from 2 May 2013.

Thursday, June 20, 2013

Mystery on the Rock


Bodega Rock, off the southern end of Bodega Head, on 20 June 2013.  On the far horizon, from left to right, are the sand dunes of Dillon Beach, the entrance to Tomales Bay, and the high bluffs of Tomales Point.

A little bit closer:


And even closer, so you can now see the nesting colony of Brandt's Cormorants on the upper right (west) side of the island:


I'll zoom in even a bit more for a view of the cormorants sitting on their mounded nests.  And also because there's a mystery object that I've been wondering about (see arrow in next image).  


There's a relatively obvious human-made object on the island — it's gray, somewhat rectangular, appears to made of concrete or something similar, and as you can see above, it's about as tall as a cormorant.  It seems like this is as good a place as any to ask if anyone knows the story behind this object.  Do you know what it used to be?  Who installed it and when?  Feel free to write in if you know anything about it, or can suggest any leads for me to follow. 

P.S.  And yes, those are California Sea Lions (brown) and Harbor Seals (gray) lounging on the rocks near the water line.

P.P.S.  Happy Solstice!

Wednesday, June 19, 2013

Nesting locally


Black-crowned Night-Heron (Nycticorax nycticorax), 9 June 2013

Black-crowned Night-Herons can be seen roosting in shrubs or trees along the edges of Bodega Harbor, and if you're lucky you may catch a glimpse of one feeding in shallow water at the northern end of the harbor.  The pond at the Hole-in-the-Head near Campbell Cove is also a possible place to encounter them.  

It looks like this individual is on a nest (note the placement of the horizontal sticks).  I think it's a second-year bird.  It lacks the streaking of a juvenile, but the crown is brown rather than jet black.  Darker crowns are more typical of full adults.

Can you guess how many species of herons and egrets have been observed on Bodega Head or in Bodega Harbor?  And how many of those nest locally?  [Warning: The answers follow the next image of Snowy Egrets (taken in March 2011).]


Seven species of herons and egrets have been observed on Bodega Head or in Bodega Harbor: Four nest locally (Great Blue Heron, Black-crowned Night-Heron, Great Egret, Snowy Egret) and three others have been recorded as accidentals (Little Blue Heron, Tricolored Heron, Cattle Egret).

Tuesday, June 18, 2013

Opening in the p.m.


The wonderful flowers of Wavyleaf Soap Plant (Chlorogalum pomeridianum var. divaricatum), photographed in the coastal grassland on Bodega Head on 17 June 2013.

Here's an even closer view:



I wasn't the only one interested in these flowers:


Were the ants searching for nectar?


If you'd like to learn more about Wavyleaf Soap Plant, there's a great write-up at this U.S. Forest Service website.  

One of the things I enjoyed learning about most was the species name.  I've always been curious about it so I was glad to finally learn about its origin.  The species name, "pomeridianum," derives from "post meridiem."  This is a Latin phrase for afternoon post = after and meridiem = midday.  The first two letters of this phrase led to the abbreviation p.m.  So why was this phrase attached to the plant?  The flowers tend to open late in the day or in the evening.
 

Monday, June 17, 2013

Thick-headed

So there I was, looking at this insect, thinking it might be an interesting wasp.


I had seen the narrowed abdomen or thread-waisted appearance (typical of wasps), but upon closer inspection, I noticed the single pair of wings and the "beaters" or vestigial wings immediately behind the first pair of wings.  These rudimentary structures that no longer function as wings look like small yellow teardrops on either side of the thorax.  In the photo above, look for them just in front of the last pair of legs.  The "beaters" told me that this was a fly!

I started circling around to get a closer look.  The head and eyes were very large, and check out the very long forked antennae in the next image.  And what is that skinny black thing sticking up below the antennae?


Below is another view from the side.  Now you can see the pale yellow face.  And that skinny black thing appears to be a long narrow proboscis.


The fly took off, but landed again and I took one more picture before it disappeared.


I know hardly anything about flies, but I searched around on the Internet for some clues about the identity of this intriguing species.

I think it's a type of conopid fly.  These flies are sometimes known as thick-headed flies.  There's a good chance it's in the genus Physocephala.  In 1957,
Camras and Hurd wrote The Conopid Flies of California.  Here's an illustration from that publication of a species similar to the one in my photographs:


The basic life history of conopid flies goes something like this — they're internal parasites of bees and wasps.  This means that they lay eggs inside the abdomens of adult bees or wasps.  For example, the female fly pounces on the bee while in flight, inserts her ovipositor between the abdominal segments of the bee and deposits an egg.  The fly larva develops inside the bee's abdomen.  The bee is fine and continues to be active during the early stages of the fly's larval development.  However, just before the fly larva is ready to pupate, the host bee dies, and then the adult fly emerges from the bee's abdomen.

Whew!  I'm still curious about why they mimic wasps.  Is it to avoid predators (that aren't as interested in eating wasps)?  Or is it something completely different — does this body design work better for high speed aerial maneuvers?  What do you think?


P.S.  These photos were taken at the north end of Bodega Harbor near Whaleship Road.