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The temperate rocky intertidal is about as colorful a natural place as I’ve seen. Much of the color comes from algae, and in the spring and early summer the eye can be overwhelmed by the emerald greenness of the overall landscape due to Phyllospadix (surf grass, a true flowering plant) and Ulva (sea lettuce, an alga). However, close observation of any tidepool reveals that the animals themselves, as well as smaller algal species, are at least as colorful as the more conspicuous surf grass and sea lettuce.

Take the color pink, for example. Not one of my personal favorites, but it is very striking and sort of in-your-face in the tidepools. Maybe that’s because it contrasts so strongly with the green of the surf grass. In any case, coralline algae contribute most of the pink on a larger scale. These algae grow both as encrusting sheets and as upright branching forms. They have calcium carbonate in their cell walls, giving them a crunchy texture that is unlike that of other algae. They grow both on large stationary rocks and smaller, easily tumbled and turned over rocks.

A typical coralline “wall” looks like this:

Coralline rock with critters, 18 January 2015.  Photo credit:  Allison J. Gong
Coralline rock with critters, 18 January 2015.
© Allison J. Gong

Mind you, this “wall” is a bit larger than my outspread hand. The irregular pink blotches are the coralline algae. Near the center of the photo is a chiton of the genus Tonicella; its pink color comes from its diet, which is the same coralline alga on which it lives. The most conspicuous non-pink items on this particular bit of rock are the amorphous colonial sea squirt (shiny beige snot-like stuff) and the white barnacles on the right.

What really caught my eye today were the sea slugs Okenia rosacea, known commonly as the Hopkins’ Rose nudibranch. Now, it is very easy to love the nudibranchs because they are undeniably beautiful. The fact of the matter is that they are predators, and some of them eat my beloved hydroids, but that’s a matter for another post. Today I saw dozens of these bright pink blotches dotting the intertidal, both in and out of the water:

Okenia rosacea, the Hopkins' Rose nudibranch, emersed. 18 January 2015. Photo credit:  Allison J. Gong
Okenia rosacea, the Hopkins' Rose nudibranch, emersed. 18 January 2015.
© Allison J. Gong
Okenia rosacea, immersed. 18 January 2015. Photo credit:  Allison J. Gong
Okenia rosacea, immersed. 18 January 2015.
© Allison J. Gong

Only when the animal is immersed can you see that it is a slug and not a pink anemone such as Epiactis prolifera, which I’ve seen in the exact shade of pink. But anemones don’t crawl around quite like this:

Whenever I see O. rosacea I automatically look for its prey, the pink bryozoan Eurystomella bilabiata. Lo and behold, I found it! The bryozoan itself is also pretty.

The bryozoan Eurystomella bilabiata, preferred prey of the nudibranch Okenia rosacea. 18 January 2015.  Photo credit:  Allison J. Gong
The bryozoan Eurystomella bilabiata, preferred prey of the nudibranch Okenia rosacea. 18 January 2015.
© Allison J. Gong

Can you distinguish between the coralline algae and the pink bryozoan in the photo? Is it shape or color that gives it away? If you had to explain the difference in appearance between these two pink organisms to a blind person, how would you do it?

Every winter northern elephant seals (Mirounga angustirostris) return to their breeding rookeries in central and northern California. These animals spend the majority of their time foraging at sea, but as with all pinnipeds they must return to land to birth their pups. The breeding site in central California is Piedras Blancas, a few miles north of San Simeon. In the northern part of the state the elephant seals breed at Ano Nuevo, about 20 miles north of Santa Cruz. While elephant seals do occasionally haul out along other beaches, the best places to see them are at the rookeries during the breeding season.

The adult males typically show up first, in late November and early December. They arrive early to set up and defend territories. Adult females arrive mid-December and are herded into harems by the alpha males, who meanwhile continue to fight over territory and dominance. Since the seals' food is found at sea, all adults and subadults fast while at the rookery. They loll about in the sun, flip sand over themselves, and doze.

Elephant seals at Piedras Blancas, 3 January 2015. Photo credit:  Allison J. Gong
Elephant seals at Piedras Blancas, 3 January 2015. © Allison J. Gong

For female elephant seals, the first order of business is to give birth to their pups. The pregnant females arrive carrying a pup that was conceived during the previous year's haul-out. A given female will give birth about a week after her arrival, and pupping season lasts until around mid-January. Pups are born with very dark fur and loose, wrinkly skin, until they fill out and take on the e-seal look of fat sausages. On my visit I saw pups that still had their umbilical cords attached, as well as pups that had been nursing for a while and gotten fat.

Despite the apparent laziness of the seals themselves, a rookery can be a noisy place. Pups and mothers squawk to each other, and males bellow a sort of low-pitched rumble as part of their dominance displays. Listen to the various e-seal vocalizations in this video:

In the right side of this video clip a female e-seal is being forcibly mounted by a male. I say "forcibly" because she does seem to be protesting and trying to get away. Of course, this is all just sexual selection in action--it is in the female's best interest, in terms of the quality of next year's pup, to be mated by the strongest male on the beach. Thus if she makes it difficult for him to copulate with her and he still manages to succeed, she can be reasonably certain that the father of her pup is healthy and vigorous.

However, notice that large male on the left. He doesn't like seeing "his" female being approached by another male. We kept waiting to see if a full-blown altercation would develop, but when all is said and done the animals are pretty lazy and won't waste energy on fights that aren't absolutely necessary. That big male on the left made a couple of feints towards the interloper but it didn't seem that his heart was in it.

All in all it was a fairly peaceful late afternoon at the rookery. We watched a spectacular sunset and then left the e-seals to their own devices on the beach.

Sunset at Piedras Blancas, 3 January 2015.  Photo credit:  Allison J. Gong
Sunset at Piedras Blancas, 3 January 2015. © Allison J. Gong

 

A couple of months ago I posted about the vernal equinox and the arrival of spring as heralded by the return of the swallows to the marine lab. This spring I've been keeping an eye on the mud nests that have been going up under the eaves of one of the buildings. It seemed to me that the swallows were a bit slow getting started with the nest-building, but in the past handful of weeks they've gotten more serious about it and have started raising babies.

When the birds are flying, it's pretty easy to distinguish between barn swallows and cliff swallows because barn swallows (Hirundo rustica) have a very deeply forked tail.

Barn swallow (Hirundo rustica) in flight
Barn swallow (Hirundo rustica) in flight

Cliff swallows (Petrochelidon pyrrhonota), on the other hand, have a more trapezoidal tail that is not forked:

Cliff swallow (Petrochelidon pyrrhonota) in flight
Cliff swallow (Petrochelidon pyrrhonota) in flight

This spring both species nested together under the eave of the Younger Building. When the birds' little heads are peeking out of the nest you can't see the tail (obviously) so it's harder to tell the species apart, especially when the parents are away. Turns out the species' nests have different shapes: barn swallows have nests that are described as "cup-shaped" while cliff swallows' nests are gourd-shaped. I'd read this description before but didn't really understand the distinction; this year it was pretty easy to tell the difference between the two.

In my case, the nests look like this:Swallow nests, LMLI like how the nests are just crammed in together. Most of these are cliff swallow nests, but the right-most three are barn swallow nests. That's a barn swallow flying directly towards the camera. I've seen as many as four babies peeking out of that second-from-the-right barn swallow nest. They've obviously fledged, as quite often all the nests are empty, but they will return to the nest as long as the parents keep feeding them.

Here's a closer view of the two types of nest:

Two cliff swallow nest (left) and one barn swallow nest (right)
Two cliff swallow nests (left) and one barn swallow nest (right)

As recently as this past week I saw parents sticking additional dabs of mud on the nests. Perhaps there will be a second brood once these fledglings leave for good?

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Yesterday I collected three very small Pycnopodia helianthoides stars. When I brought them back to the marine lab I decided to photograph them because with stars this small I could easily distinguish between the original five arms and the new ones:

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These guys began their post-larval life with the typical five arms you'd expect from an asteroid. At this stage they are pretty conspicuous because they are the largest arms. The other arms arise in the inter-radial regions between arms. For years now I've been wanting to watch juvenile Pycnopodia stars growing their extra arms, and it looks like I finally have my chance. I noted that these stars are all about the same size, but don't have the same number of arms. It would be interesting to see if the rate of arm appearance and growth is related to how much food the stars have. Hmmm, that sounds like a study I should do.

And then one of the stars started running. And I mean running. Watch:

You might wonder how in the heck they can run so fast, and it's a valid question. We can actually examine the animal's scientific name to get an answer. "Pycnopodia" means "dense foot" and "helianthoides" means "sunflower-like." So these guys have a lot of tube feet, and they use them to run and feed. Imagine how fast we could run if we had more than two feet and could co-ordinate them this well:

So, when these guys (gals?) grow up, they'll be at least half a meter in diameter with 20-24 arms. With all those tube feet, they'll be Speedy Gonzales! In fact, they will be the terror of the intertidal--big, fast, and voracious. Anything that can't get out of their way will be eaten.

We air-breathing land mammals should be grateful that echinoderms never managed to get out of the sea. Can you imagine this monster chasing you down a dark alley, or climbing through your bedroom window?

On 11 March 2011 a magnitude 9.0 earthquake occurred off the coast of Japan. About 14 hours later, at 11:15 a.m. local time a tsunami came through the Santa Cruz Small Craft Harbor. It sank dozens of boats and significantly damaged several of the docks. People were ordered to evacuate the area before the expected arrival of the tsunami, but of course there were those who chose to stay behind and shoot videos like this one (the real action starts at about 1:00):

 

As a result of the damage to the infrastructure of the marina itself, many of the docks have been replaced since 2011, including those that are closest to the mouth of the harbor. For several years now I have been taking marine biology students to the docks to examine the organisms growing on the undersides of the docks, and this year the biological community is finally getting interesting again. These particular organisms are described as "fouling" because they are the ones that colonize the bottoms of boats and have to be scraped off periodically. They are characterized by fast growth rates and short generation times; many of them are also colonial. The first arrivals settle onto the surface of the docks, and later arrivals can take up residence either on the docks or on their predecessors. A healthy fouling community has a rich diversity of marine invertebrates, algae, and the occasional fish. This semester's trip to the harbor occurred a few weeks ago, and as usual the students were amazed at the amount and diversity of life on the docks. I remembered to bring the waterproof camera and snapped some shots.

This is what you see when you lie on the dock and hang your head over the edge:

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It's a mosaic of color and texture, really quite beautiful. You can see that mussels are the largest organisms in this community, and in turn are substrate for a variety of other animals.

Peering a bit closer to take notice of individual animals, you start to see things like this:

A perennial favorite because of its beautiful coloring. It eats my hydroids, though, so I don't like it.
Hermissenda opalescens, a perennial favorite because of its beautiful coloring. It eats my hydroids, though, so I don't like it.

 

One of the colonial hydroids, Plumularia sp. that grow at the harbor.
One of the colonial hydroids, Plumularia sp. that grow at the harbor. This species always grows in this pinnate form. Absolutely gorgeous under the microscope.
These small white anemones (Metridium senile) are about 3 cm tall.
These small white anemones (Metridium senile) are about 3 cm tall.
Feather duster worm, Eudistylia vancouveri, easily one of the most conspicuous animals on the docks.
Feather duster worm, Eudistylia vancouveri, easily one of the most conspicuous animals on the docks.
Colonial sea squirts, Botryllus sp. and Botrylloides sp.
Colonial sea squirts, Botryllus sp. and Botrylloides sp.

Colonial sea squirts, those orange-ish blobs in the last picture, are extremely common in marinas. In this photo, each distinct colored blob is an individual colony, and each colony consists of several genetically identical zooids connected by a protective covering called a tunic. Each teardrop-shaped zooid has its own incurrent siphon (the visible hole) through which it sucks in water, and the zooids in a group within a colony share a single excurrent siphon through which waste water is discharged. In Botryllus, the zooids are arranged into flower-like configurations called systems. In Botrylloides the systems are much less distinctive and wind around over the substrate. I've outlined a nice colony of Botryllus in the photo below, so you can see the easily recognized systems.

A colony of Botryllus, with zooids arranged in flower-shaped systems.
A colony of Botryllus, with zooids arranged in flower-shaped systems.

Such a wonderful world of animals and algae, right under our feet. Even people who spend a lot of time around boats don't pay attention to the stuff on the docks. To me it is a secret garden that is easily overlooked but greatly appreciated when you take a moment to get your face down where your feet are.

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The astronomical onset of spring is the vernal equinox, which this year occurred on Thursday 20 March 2014. The date is determined by the movements of the Earth and the sun, and occurs regardless of weather conditions anywhere on the planet. Some people look to plants for an indication of spring: the first day that a crocus pops up through the snow, or the first blossoms on a cherry tree. For me, I know that spring has sprung when certain birds show up in my world.

The first red-winged blackbirds make themselves heard in January, which is too early to be thinking about spring but at that point in the year it's nice to be reminded that the days are getting longer. The red-wingeds' calls are heard throughout February and March; it always makes me smile to hear them lekking. Some time in March I see the first barn swallows at the marine lab, and once they start plastering mud under the eaves I know that spring is here.

A few years ago the swallows chose a site sort of under a stairway to build their nest. They started plastering mud in a corner of the wall and constructed a neat little home in which to raise their young. That year they raised four babies successfully.

At this point they're the same size as their parents.
At this point they're the same size as their parents.

The parents were still feeding them, but the babies almost didn't fit into the nest anymore. It was so cute. I'd walk under them to get to the door and they'd all pivot their heads down to look at me.

The parents were pretty blase about people walking under their nest all day:

The parentsIt was up to us to make sure we didn't get pooped on. Sometimes you'd have to dodge the splat.

Once the babies fledge and start feeding themselves, we get barn swallows swooping around the courtyard. They seem to be more active in the afternoons, when the wind picks up. They look like they're having so much fun, zooming around like miniature 737s.

I bet it's fun to be a swallow in the springtime.

 

This past Tuesday and Wednesday afternoon I took my marine biology students to the rocky intertidal at Natural Bridges State Beach. We completely lucked out with the weather; the storm system that brought some of the rain that we desperately need had cleared out, leaving calm, clear seas and little wind. Perfect weather for taking students out in the field, in fact.

First of all, we didn't see any stars. Not that I was looking for them, particularly, but I was keeping an eye out for them and at this time last year I would have seen many Pisaster ochraceus hanging out in the pools and on the rocks. Here are a couple of pictures I took at Natural Bridges in years past:

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The stars, when present, are prominent residents of the mid-intertidal zone, where they feed on mussels. But now, alas, there don't seem to be any. They WILL come back, and it will be interesting to monitor their population recovery.

I enjoy taking students in the field because many of them have never been there before, and it's always fun looking at a familiar scene with fresh eyes. When everything is new, it is very easy to be excited and enthusiastic, which these students are.

We saw, among other things:

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Fish! The fish on the right was about 15 cm long. I think it's a woolly sculpin (Clinocottus analis), but IDing sculpins in the field is pretty tricky.
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This fish was much smaller, only about 10 cm long. It could be a fluffy sculpin (Oligocottus snyderi), or it could be a smaller woolly.
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This is an encrusting sponge, Haliclona sp. I've seen it in shades of rosy pink, too. The large holes are oscula, the sponge's excurrent openings. And that's a big gooseneck barnacle (Pollicipes polymerus) hanging down from the top of the picture.
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An assortment of intertidal critters sharing space on a rock. How many chitons can you spot?  How many barnacles?  How many limpets?
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This is one of my favorite intertidal animals, the owl limpet (Lottia gigantea). These large limpets are farmers. They keep an area clear of settlers by grazing at high tide. You can see the marks left by this individual's radula. The limpets also manage their farms, letting the algal film grow on one section while feeding on another.
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I love macro shots like this! The green tufty stuff is Cladophora columbiana, a filamentous green alga. Isn't it a vibrant green color? To give you an idea of how fine the Cladophora filaments are, that snail in the background is about the size of a quarter.
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And last, a gratuitous anemone shot. Ahhh, Anthopleura xanthogrammica, what a photogenic creature!

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Over the Memorial Day weekend I took my students out on the early morning low tides at Natural Bridges State Beach.  While they were ooh-ing and ahh-ing and filling out their assignment worksheet, I was playing around with my new camera, taking pictures in the water.  Because I am not a photographer and sea anemones just sit there, they quickly became my favorite subjects.  Not to mention the fact that they are simply  beautiful and photogenic creatures.

At Natural Bridges we have four species of anemones in the genus Anthopleura:

  • A. xanthogrammica - giant green anemone
  • A. sola - sunburst anemone
  • A. elegantissima - aggregating anemone
  • A. artemisia - moonglow anemone

Of these species, the first two are notable for their large size.  At Natural Bridges they can get to be the size of a dinner plate.  They live side-by-side in tidepools, and since there are many deep-ish pools at Natural Bridges they are among the most conspicuous animals in the intertidal along the northern California coast.

Anthopleura sola (left) and A. xanthogrammica (right) in a shallow pool at Franklin Point.
Anthopleura sola (left) and A. xanthogrammica (right) in a shallow pool at Franklin Point.

It's easy to identify these animals when they're sitting right next to each other.  The difficulty comes when you see only one in a pool by itself with nothing to compare it to.  In a nutshell, here are some things you can use as clues to determine which species you have in front of you.

Let's start with Anthopleura xanthogrammica, the giant green anemone.  This animal's oral surface and tentacles are a solid color, varying from bright green to golden brown.  There are no conspicuous stripes on the central disc and the tentacles are relatively short and stubby, without any white patches.

Anthopleura xanthogrammica, photographed at Natural Bridges State Beach
Anthopleura xanthogrammica, photographed at Natural Bridges State Beach

Anthopleura sola, on the other hand, usually has distinctive radiating lines on the oral disc.  Hence the common name of Sunburst Anemone.  Its tentacles are generally longer and more slender than those of A. xanthogrammica, and often have sharp-edged white patches.  Sometimes the tips of the tentacles are tinged a pale purple.  Anthopleura sola are usually brownish-green in color, and I haven't seen any that are as bright green as the A. xanthogrammica anemones.

Anthopleura sola, photographed at Natural Bridges State Beach
Anthopleura sola, photographed at Natural Bridges State Beach

That's all well and good, but sometimes you come across an individual that doesn't completely follow the rules.  Or rather, it looks like it could belong to both species. Such as this fellow (fella?):

Hmmm...sola or xanthogrammica?
Hmmm. . . sola or xanthogrammica?

The animals obviously don't read the descriptions.  This one has xanthogrammica shape and overall color, but those lines on the disc read as sola-ish.  I would call this one a xanthogrammica.  What do you think?

As I suspected, the little Dendronotus veligers didn't last very long.  On Wednesday the very last survivors had kicked the proverbial bucket.  All that was left in the jar was some debris and scum from leftover food.  They lasted nine days post-hatching, which is about the norm for me when I've tried to raise nudibranch larvae.  Something just happens (or doesn't happen) around Day 10 and they all crash after a week or so of apparently vigorous life.  Someday I may figure out what's going on.  In the meantime, RIP, little guys.

On the more fun side of marine biology, there's a new exhibit at the Seymour Center that is extremely cool.  Someone brought in a buoy that had been out in the ocean for a long time.  It's a perfect example of a fouling community.

People who have boats or just spend time in marinas know about fouling communities.  They're all the stuff that gets scraped off the bottoms of boats.  It's also the same stuff that grows on pilings and the underside of floating docks.  In this case the term "fouling" refers to early recruiting animals and algae that grow quickly to monopolize space.  Many of the fouling species seen in harbors are invasive non-natives.

A few years ago I hung a box of slides off one of the docks at the Santa Cruz Yacht Harbor and left them there for several months to see what would grow.  Here's what recruited and grew on a single slide measuring about 5x7.5 cm:

Fouling community of invertebrates and algae on a glass slide.
© Allison J. Gong

As you can see, it's a very colorful world down there!  The brightest red curly stuff is an introduced species of bryozoan called Watersipora.  It is a fast grower and can overtake the other stuff and form large clumps.  It grows as an encrusting sheet over surfaces, but when two sheets make contact they grow up each other and form those curly upright bits.  To model how this works, hold your hands in front of you, palms down, with the fingers facing each other.  Push your hands together until your fingertips meet, then continue to move them towards each other.  What happens is that your hands flex and your finger tips get moved upwards until your palms come together in a praying position.  If your hands were encrusting sheets of bryozoan colonies, that's how you'd get those curly pieces.

Anyway, the buoy on display at the Seymour Center has a lot of large barnacles.  The barnacles have been actively feeding and molting since they arrived last week.  They are definitely the most animated critters growing on the buoy, as shown here:

 

Barnacles are crustaceans that lie on their backs entirely encased in hard shells glued to other surfaces.  They feed by extending their thoracic appendages and sweeping them through the water to capture detritus and plankton.  It's a strange way to make a living, but it does work.

 

 

 

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