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As a native Californian, I've been living with drought my entire life. Well, maybe not so much during the El Niño of 1997-98, but even then the thought "We have water now but might not later..." was always in the back of my mind. This season we had a great few weeks of rain in late November and early December, then January was bone dry and February has been disappointing as well.

This weekend an Arctic storm is moving through the region, bringing rain and cool temperatures to coastal areas and (hopefully) snow in the Sierra Nevada. Here in Santa Cruz it hasn't rained much yet but we did get a few decent showers this morning. It just so happened that I headed down to the marine lab between showers, and the light was magnificent. The water was that magical color of aquamarine and seaglass green that I associate with the tropics. The sun was shining, casting cloud shadows on the water, which added depth to the color palette when combined with the kelp bed. So pretty!

Looking east towards Natural Bridges from Terrace Point, 28 February 2015. ©Allison J. Gong
Looking east towards Natural Bridges from Terrace Point, 28 February 2015.
© Allison J. Gong
See how translucent and green the water is? 28 February 2015. ©Allison J. Gong
See how translucent and green the water is? 28 February 2015.
© Allison J. Gong

Brown pelicans (Pelicanus occidentalis) were one of many bird species whose populations were devastated by widespread use of the pesticide DDT in the mid-20th century; in 1970 it was listed on the federal Endangered Species List. After the general use of DDT was banned in the United States in 1972 the population began to recover, and in 2009 the brown pelican was removed from the Endangered Species List (I believe the bureaucratic jargon for that is "de-listed"). It is now not unusual to see long lines of pelicans skimming the waves as they fly just above the ocean surface.

Today I didn't see any large groups of pelicans in flight, but I did catch this one flying by right in front of me.

Brown pelican (Pelecanus occidentalis) flying past Terrace Point, 28 February 2015. ©Allison J. Gong
Brown pelican (Pelecanus occidentalis) flying past Terrace Point, 28 February 2015.
© Allison J. Gong

Anyone who knows me personally knows that I'm not a big cheerleader for the marine mammals. However, seeing cetaceans in the wild is always a treat. This morning I was lucky enough to catch this pod of dolphin-type critters as they swam right off the point. There were 6-8 of them, I think. As they swam past the marine lab a couple of them indulged in some tail slapping.

Dolphins swimming past Terrace Point, 28 February 2015. ©Allison J. Gong
Small cetaeans swimming past Terrace Point, 28 February 2015.
© Allison J. Gong

I'm not enough of a cetacean expert to be able to identify the animals from photos. They did have dolphin-like dorsal fins but I couldn't see a prominent rostrum on any of them. I didn't have my binoculars with me . . . and I call myself a naturalist??

Since the animals were not traveling very quickly I decided to see if I could catch them on video. I was lucky enough to get this clip:

Can anybody help me identify what these animals are?

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Thirty-one days ago, on 20 January 2015, I spawned purple sea urchins (Strongylocentrotus purpuratus) and generated six jars of larvae. I've been examining the larvae twice a week ever since. At first they were doing great, developing on schedule with no appreciable abnormalities or warning flags. Then, at about Day 24, the cultures began crashing for no apparent reason. At first I expected to see lots of malformed, shriveled, or underdeveloped larvae, but the thing that I don't understand is that for the most part they look great. They're eating, pooping, growing, and (apparently) doing everything that they should be doing.

Case in point:

31-day-old pluteus larva of Strongylocentrotus purpuratus, 20 February 2015. © Allison J. Gong
31-day-old pluteus larva of Strongylocentrotus purpuratus, 20 February 2015.
© Allison J. Gong

This larva is PERFECT. It has all four pairs of arms now, and they are growing symmetrically. The stomach (the inverted-pear-shaped structure in the middle of the cup-shaped region) is pigmented with the red food it has been eating, and there are no skeletal rods protruding beyond the tips of the arms. This individual doesn't give me any clues as to why the culture it came from took a nosedive this past week. The other larvae that I sampled from this jar today also look good. There aren't many left in the jars from this spawning, but if they all look as promising as this one then I still have hope that some will be able to metamorphose successfully.

So what gives? I suspect that Day 24 has something to do with it. I'm working on a hypothesis and need to let it percolate inside my brain a bit more. When it's ready I want to test it, although that will have to wait until next year, as we've reached the end of this year's spawning season.

Until recently I hadn't closely observed what it looks like when a leather star (Dermasterias imbricata) succumbs to wasting syndrome. When I had the outbreak of plague in my table almost 18 months ago now, my only leather star was fine one day and decomposing the next, so I didn't get to see what actually happened as it was dying.

(Un)fortunately, one of the leather stars at the marine lab started wasting a bit more than two weeks ago, and this time I was able to catch it at the beginning. This animal wasn't in my care so I didn't check on it as frequently as I would if it had been living in one of my tables, but one of the aquarists pointed it out to me when it began getting sick.

The first symptom was a lesion on the aboral surface. I say "lesion" but it's more of an open wound.

Dermasterias imbricata with aboral lesion, 2 February 2015. ©Allison J. Gong
Dermasterias imbricata with aboral lesion, 2 February 2015.
© Allison J. Gong

You can see that the animal's insides are exposed to the external environment. In the photo above the whitish milky-looking stuff is gonad (I'm pretty sure this animal was a male) and the beige ribbon bits are pyloric caeca, essentially branches of the stomach that extend into the arms. What typically happens along with the development of lesions like this is an overall deflating of the star as the water vascular system and other coelomic systems become increasingly compromised, and the tendency for the animal to start tearing off its arms.

Which results in this, a week later:

Wasting Dermasterias imbricata, autotomizing its arm, 9 February 2015. ©Allison J. Gong
Wasting Dermasterias imbricata, autotomizing its arm, 9 February 2015.
© Allison J. Gong

This poor animal had torn its arm off, and continued to live for a while. I find it fascinating that the lack of a centralized nervous system means that this animal literally didn't know it was dead. It was finally declared officially dead two days later. Compared to how quickly wasting syndrome kills the forcipulates that I've seen (Pisaster, Pycnopodia, and Orthasterias), the leather stars take a long time to die--several days from start to finish, opposed to a matter of hours as I saw with my stars. The leathers didn't seem to be hit as hard by the first wave of the disease outbreak, either. Is Dermasterias somehow able to fight off the infection a bit longer? It would be interesting to know, wouldn't it?

This afternoon I was enjoying the sunshine and watching the small finchy birds flitting about in the big coffeeberry bush off our back deck. I call this bush the "conference bush" because every spring the birds congregate in it and chatter to each other like conventioneers. When the bush blooms it becomes populated with foraging honeybees, which add their own buzz to the cacaphony. I had identified lesser goldfinches, juncos, chestnut-backed chickadees, and the impossible-to-distinguish purple/house finches and was watching a male Anna's hummingbird making his diving displays. I was looking for the female he was displaying to when out of the corner of my eye I saw a brown bird, about the size of a scrub jay, crash into the bush.

All of the little finchy birds fled the bush instantly and the bush became silent. Training my binocs on the locus of the commotion I saw a sharp-shinned hawk perching in the tree.

Juvenile sharp-shinned hawk (Accipiter striatus).
Juvenile sharp-shinned hawk (Accipiter striatus). © John Rowe, October 2010

It was a very handsome bird. It perched and looked around for a few seconds then did a bit of preening. Directly above the hawk's right shoulder I saw a female finch, perched desperately frozen to her twig. I don't know why she hadn't escaped with the others. She was obviously trying her hardest not to be seen, but the writing was on the wall. While I was watching through the binocs the sharpie exploded up and grabbed the finch, then busted out of the bush, carrying its prey out of view. I heard the poor finch squawking for about half a minute before she finally died.

This is definitely the most amazing thing I've seen so far this week. Nature, in all her glory, is every bit as unsentimental as she is spectacular. Wow!

Yesterday I drove up the coast to Pigeon Point to do a little poking around. I had originally planned to search for little stars, survivors that had made it through the most recent outbreak of wasting syndrome. But I got distracted by other things and gave up on the stars, for now. I need to do some thinking about the best way to find tiny animals in a very complex 3-dimensional habitat.

I did spend quite a bit of time turning over rocks in tidepools. The most common critters I found were the usual suspects--porcelain crabs, limpets, snails, the odd sculpin or two, and chitons. One rock yielded a gold mine: five chitons of a species I didn't recognize (which doesn't mean I haven't seen it before, just that I didn't immediately know its name) that demonstrated a most interesting behavior.

Stenoplax heathiana, on underside of rock, 31 January 2015. Photo credit:  Allison J. Gong
Stenoplax heathiana, on underside of rock, 31 January 2015.
© Allison J. Gong

I turned the rock over and watched as the chitons ran away from the exposed surface onto the other side. Yes, RAN. I've never seen a chiton do anything this fast. Chitons, for the most part, lead apparently inactive lives. When we do get to see them in their natural setting, at low tide, they are usually scrunched down hard on the rock waiting for the water to come back. Obviously they are much more active when covered with water, but we don't get to see them then. In the lab, where they can be immersed all the time unless they crawl up the walls, they do wander around a bit; however, to see a chiton do much of anything requires time-lapse photography.

Don't believe that a chiton can run? Well, get a load of this:

This is in real-time, not sped up. Watch the chiton push a limpet and the snail out of the way. Okay, I'll grant that a limpet and a snail are not the strongest obstacles one could face when trying to flee from the light. But you can't deny that this chiton seems to be feeling a sense of urgency.

This species, Stenoplax heathiana, spends its days buried in sand on the underside of rocks. It comes out to feed at night, not on algal scums as most chitons do, but on bits of algae that drift by and get caught between rocks. Apparently the chiton can be found exposed in the very early morning. I'm going to have to try finding some this spring when we get our morning low tides back.  Anybody want to come with me?

 

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On another glorious afternoon low tide the other day, with the help of a former student I collected six purple urchins, Strongylocentrotus purpuratus. Given that we're in about the middle of this species' spawning season, I reasoned that collecting six gave me a decent chance of ending up with at least one male and one female that hadn't spawned yet.

Yesterday, after the urchins had been in the lab for somewhat less than a whole day, I shot them up and waited. Three females began spawning almost immediately (yes!) and one male started a few minutes later. When all was said and done I ended up with four females and two males. It turns out that the largest individual, with a test diameter of almost 10 cm, was a male but didn't spawn very much at all. I infer from this that he had already spawned in the field before I collected him.

Female (left) and male (right) spawning purple sea urchins (Strongylocentrotus purpuratus). 20 January 2015. Photo credit:  Allison J. Gong
Female (left) and male (right) spawning purple sea urchins (Strongylocentrotus purpuratus), 20 January 2015.
© Allison J. Gong

At the current ambient sea water temperature of 14°C, hatching begins around 24 hours post-fertilization. Early this afternoon I checked on the beakers and they had indeed begun hatching. Sea urchins hatch at the blastula stage of development, when they are essentially a ciliated hollow ball of cells. The cilia allow the larvae to swim, but at this size they are at the mercy of even the weakest current. Thus, for the most part they act as particles, getting carried wherever the current takes them.

1-day-old embryos of S. purpuratus. The empty space inside each embryo is called the blastocoel. 20 January 2015. Photo credit:  Allison J. Gong
1-day-old embryos of S. purpuratus. The empty space inside each embryo is called the blastocoel. 20 January 2015.
© Allison J. Gong

As the embryos hatch, they swim up to the top of the beaker, then move down towards the bottom. I call this "streaming." At this point in our artificial culturing system the embryos are living in still water without any current, so this behavior is due primarily to their ability to swim. There is probably some interesting physics involved, but I'm not enough of a physicist to figure out what's going on at that level. But whatever it is, it's a really cool behavior to watch:

Rather mesmerizing, isn't it? Each of those tiny orange dots is an individual embryo. Once the embryos hit the water column I pour them off into larger jars and begin stirring them. Right now they're small enough to swim on their own, but once they start feeding and growing they get heavier and would sink to the bottom without some current to keep them suspended. The contraption we use to stir jars of larvae is a manifold of paddles connected to a motor that moves the paddles back and forth, creating the right amount of current to keep the larvae from settling on the bottom without getting beat up by the turbulence.

Here's the paddle table in action. It's a noisy SOB.

For now the embryos just hang out in the jars and get stirred. Their first gut, the archenteron, will be visible tomorrow and the larvae will be able to eat on Friday. Stay tuned!

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

 

At last, a publication on the causative agent for sea star wasting syndrome! Several co-authors have written a paper that was published in the Proceedings of the National Academy of Sciences (PNAS), in which the culprit was identified as a densovirus.

The Smithsonian wrote up a nice article summarizing the findings here.

While it remains to be seen why the virus caused such widespread disease this time, at least now researchers have something to focus their work on.

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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