Do they get overtime pay?

 Anemones at low tide. When the water recedes, they shrink into themselves, becoming greenish circles in the sand or soft lumps on the side of a rock. But between the rocks, where the sand dips and a few inches of water still cover them, they stay open and feeding. Do they grow bigger in these spots, or reproduce more enthusiastically? I wonder.

Pink-tipped green anemone, Anthopleura elegantissima, very pale, with bubbles.

Burrowing anemone, Anthopleura artemisia. With red feathery seaweed, with bleached tips.

This burrowing anemone has been eating mussels.

A small family grouping. "Colonies of clones actually war against each other." (Marine Life PNW)

Next: colonies on dry rock, waiting out the low tide.

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Unas anémonas, vistas durante la marea baja. Normalmente, cuando el agua desaparece, las anémonas se encogen, haciéndose apenas unos circulitos entre la arena, o cojines suaves en los lados protegidos de las rocas. Pero entre las rocas, en los espacios donde las corrientes hacen pocitos en la arena, y el agua sigue cubriéndolas, se quedan abiertas, comiendo. ¿Será que aquí crecen más, o se reproducen más rapidamente?

Fotos: 

1. Una anémona verde con las puntas color de rosa; ésta es muy pálida. Anthopleura elegantissima.
2. Una anémona verde, Anthopleura artemisia. Con un alga marina roja, pero con las ramitas blanqueadas por el sol.
3. Otra anémona verde; este ha estado comiendo mejillones.
4. Un grupo familiar. "Las colonias compuestas de clones hasta llegan a hacer guerra contra otras." (De la enciclopedia Marine Life PNW)

Mañana; otras colonias situadas en roca donde la marea baja las deja en seco.

Biodiverse, very biodiverse

 We have some beautiful low tides coming up, but they're going to arrive here after dark. (Sunset these days falls around 7::30 PM.) I followed the tide as it started out in the late afternoon, and found anemones, feeding happily, then closing down as the water disappeared.

Window into a tide pool.

The surface of the water in the tide pool reflected the sky, but the shadow of my head revealed a pink-tipped green anemone, Anthopleura elegantissima, fully open. With it in this little tide pool are several rockweeds, and three red algae; a feathery, delicate one, a narrow-bladed species, and a broad blade; the white algae is a red that has been sun-bleached. On the right are strands of the brown Sargassum. And there are several fragments of the green sea lettuce, Ulva spp. Also present: periwinkle snails, limpets, and something orange, probably a sponge. And unseen, but always there in great numbers: the worms. And a clam on the sand nearby was spitting at me.

 

Still underwater, still waving those tentacles.

The colours of this anemone vary; the tips go from barely pink to red. The columns and the oral disc are sometimes bright green, in others they may be more of a yellowish cream. The green colour is usually due to the presence of single-celled green algae, but the anemone may also produce its own colour. The green algae are photosynthetic and provide a large part of the anemone's energy needs.

"Although the green colour present in some specimens is produced by the animals themselves, this process can only occur when the unicellular symbiotic alga Chorella is residing in their tissues." (Marine Life of the Pacific Northwest)

The lichens aren't the only composite species.

Very pink. The column is always covered by rows of tubercules, seen here as pale green bumps.

As the water recedes, the anemones start to shut down.

Edge zone; open tentacles on the right, closing, closed out of water.

And when the water is gone, they turn into yellowish donuts with cherry filling.

These anemones grow on rock. The sand has collected around them. As the sand dries, they will all shrink back to their base, and disappear from the surface, leaving only slight depressions. Until the tide comes in.

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En esta temporada, nos llegan unas buenas mareas bajísimas, pero (mala suerte) por este rumbo, la bajamar toca ya bien puesto el sol (que desaparece a las siete y media). A media tarde llegué a la playa y seguí el agua mientras se retiraba, encontrando unas anémonas, contentas con los tentáculos abiertos mientras había agua, y luego encogiéndose cuando se iba.

Foto #1: Una vista en un pocito mareal. La luz se reflejaba en la superficie del agua, pero mi sombra abrió una ventanilla, mostrando una anémona clonal, Anthopleura elegantissima, y varias algas. Se ven aquí, primero Fucus gardneri, luego tres algas rojas: una delicada, una de una hoja larga, y otra de hoja ancha. Las algas blancas son algas rojas quemadas por el sol. A la derecha hay varios hilos de Sargassum muticum, un alga marrón, invasiva. Y luego pedazos del alga verde que llamamos lechuga marina, Ulva spp. ¡Hay más! Varios caracolillos, unas lapas, y unas masas anaranjadas, probablemente esponjas. Y no se ven, pero los hay en gran número; los gusanos de varias especies. Y al lado del pocito mareal, una almeja me estaba escupiendo.

 Foto #2: Varias anémonas, todavía bajo agua, todavía agitando sus tentáculos.

Los colores de estas anémonas son variables; las puntas de los tentáculos van desde color de rosa hasta rojo fuerte. Las columnas y el disco oral son verdes, a veces brillante, a veces pálido. El color verde se debe a la presencia de algas unicelulares verdes, aunque a veces la anémona puede producir su propio color. Las algas verdes son fotosintéticos y proveen gran parte de los requisitos de energía de la anémona.

"Aunque el color verde presente en algunos de estos animales es producidos por los mismos, este proceso solo puede operar cuando la alga simbiótica unicelular reside en sus tejidos." (Marine Life of the Pacific Northwest)

Los líquenes no son los únicos que viven unidos con algas.

Foto #3: Una anémona con tentáculos de un color más vívido. La columna está siempre cubierta de estos tubérculos verdes.

Mientras desaparece el agua, las anémonas empiezan a cerrarse.

Foto #4: Mitad en agua,  mitad en seco. 

Foto #5: Y cuando el agua se ha ido completamente, las anémonas más bien parecen donas rellenas de jalea de fresa.

Estas anémonas crecen en la roca. La arena se acumula alrededor. Cuando esta arena ya se secó, las anémonas se habrán encogido aún más, dejando apenas una leve depresión en la superficie de la arena.

Hasta que suba la marea de nuevo.

Underwater flowers

And anemones. Like yesterday's starfish, brightly coloured, some underwater, some out in the open, waiting for the tide to come back in.

The white lines on the tentacles and the location, half-buried in sand, mark these as Burrowing Anemones, Anthopleura artemisia. The one in the shade may be as brilliant as the other, when the sunlight reaches it.

Dark green, neon green. Again, it depends on the light. When the water recedes, they draw the tentacles in, sometimes hiding completely under the sand.

Very few markings on this one, among rocks. The same species, or another?

A bright green one, swept by the waves.

Pink-tipped green anemones, Anthopleura elegantissima, on the side of a long line of rocks. Thousands of them, clones all crammed together.

A closer look. The columns are green, covered with "goosebumps", and the tentacles have pink tips, here retracted until the water comes back.

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Y unas anémonas de mar. Como las estrellas de mar que subí ayer, algunas están bajo el agua, otras en las rocas expuestas al aire y al sol, esperando a que regrese la marea.

Fotos:

1. Las lineas blancas en los tentáculos y el sitio donde se encuentran las marcan como la anémona excavadora, Anthopleura artemisia. La que se halla en sombra puede ser tan brillante como la otra, una vez que le lleguen los rayos del sol.
2. Dos tonos de verde. Depende de si la luz le ilumine. Cuando la marea baja dejándolas fuera del agua, retraen los tentáculos y a veces desaparecen completamente bajo la arena.
3. No se ven lineas blancas en esta, situada entre rocas. ¿Es una de la misma especie, u otra?
4. Otra anémona muy verde, bailando bajo las olas.
5. Estas son las anémonas verdes con puntos color de rosa, Anthopleura elegantissima. Cubren casi por completo un lado de una hilera larga de piedras. Miles y miles de anémonas, todas clones.
6. Acercándonos un poco. Las columnas son verdes y llevan "piel de gallina", y los tentáculos tienen las puntas color de rosa. Aquí los han retraído hasta que vuelva el agua.

Shy sand dwellers

 When I arrived at Stories Beach, the tide was on its way down. I followed it as it went, walking along the edge of the water, peering under and behind rocks, staring into tide pools to watch tiny fish, counting whelks and starfish...

A girl asked me about the circles she saw in the sand; squishy circles, just sand, but it sunk away from her finger when she touched them. Anemones. There are two common species on this shore that do this, hiding away when the water drops.

Pink-tipped green anemone, Anthopleura elegantissima.

I often see these, crowds of them, in sandstone, where they dig themselves a hole. At low tide, they look like pock marks on the stone; as soon as the water covers them again, they spread out their pink tentacles.

In the photo there are also a couple of hairy hermit crabs in periwinkle shells. And a limpet: there are always limpets.

Burrowing anemone, Anthopleura artemisia.

The other anemone that retreats under the sand on this beach is the burrowing anemone. This one lives in sand, especially near rocks. Sometimes they hide themselves completely; sometimes they still wave the tentacles about as long as they're wet. It depends. On their mood, maybe?

The burrowing anemones come in a variety of colours. There are at least 7 in this photo.

Also in the photo, look for the tube worm's tube with a drop of water on the tip. The other pinkish projections from the sand could be algae; I should have dug one up to see.

A small burrowing anemone, in a vivid lime-green.

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Cuando llegué a la playa, la marea ya bajaba. La seguí, caminando al borde del agua mientras se alejaba, mirando debajo y alrededor de las rocas, deteniéndome para observar las peces en las pozas de marea, contando caracoles marinos y estrellas de mar...

Una muchacha me preguntó acerca de los pocitos de arena que encontraba; círculos de arena que respondían cuando los tocaba, retrayéndose aun más en la arena. Anémonas, le dije. Hay dos especies de anémona en esta playa que se esconden cuando el agua huye.

Primera foto: Una anémona agregante, Anthopleura elegantissima.

Veo estas frecuentemente; multitudes, colonias enteras. Se excavan hoyos en la arenisca, una piedra muy suave. Cuando la marea está baja, estos hoyos parecen cráteres miniaturas llenas de arena; cuando regresa el agua, vuelven a extender sus tentáculos color de rosa.

En esta foto también hay dos cangrejos ermitaños "peludos", Pagurus hirsutiusculus. Y una lapa. Siempre hay lapas.

Fotos 2 a 4: Anémonas excavadoras, Anthopleura artemisia.

La segunda anémona que se esconde bajo la arena es la anémona excavadora. Esta vive en la arena, generalmente cerca de las rocas. A veces se esconden completamente cuando la marea baja; a veces mantienen los tentáculos al descubierto, mientras todavía permanecen húmedos. Todo depende. De su idea al momento, parece.

Vienen en una variedad de colores, desde un gris algo roseáceo hasta verde o anaranjado. La anémona chica en la última foto es lo más verde que he visto.

En la tercera foto también se ve un gusano de tubo, alzado sobre la arena, con una gota de agua encima. Hay por lo menos 7 anémonas en la foto. Las otras cosas que sobresalen de la arena pueden ser algas; no se me ocurrió desenterrar una para ver si así era.

Caught in the act

I happened to glance at the aquarium at just the right moment to see an anemone spawning.

Pink-tipped green anemone, releasing sperm!

I've checked several videos, all showing fogs of sperm floating out in a slow, continuous stream. This little guy spit out three (that I saw) quick bursts of cloudy material, with a few seconds interval between. I had time to run for the camera and catch the third. There was no fourth. (Hooray for autofocus!)

Anemones in aquaria usually reproduce by splitting in half, creating two separate animals that each go in their own way. This is generally the case in my tank; there are two pink-tipped greens half-way through a split today and another couple of new pairs starting to move apart.

Sexual reproduction is rarer, at least in tanks. The anemones, although they were "born" by cloning, still manage to become either male or female, not necessarily the gender of their parent individual. This one is male.

A study on Anthopleura elegantissima in north San Francisco Bay, California shows that gonads build in size through spring and summer, and spawning occurs in late summer/early autumn.  Gonad indices peak coincidentally with high surface seawater temperatures. ... Eggs are released in brown mucousy masses, while spermatozoa are released in milky-white masses. (From A Snail's Odyssey)

Note: the schedule may be different because my tank didn't suffer the more extreme winter that outside waters would.

There is some evidence that males begin spawning earlier than females, and perhaps this stimulates the females to spawn. (Same site, Research study 2)

I'll be monitoring the anemones more frequently in the next few days. I have no idea which are female; I hope some are.

There's not much chance of this producing more anemones here; the fertilized eggs swim in the current for a while, and will probably be caught in the filter. The critters are smart to use the splitting strategy in captivity.

Spring fever already

I turned over an oyster in my tank and crashed an amphipod party.

It's orgy season!

The amphipods scattered, but most of them were moving slowly because they were travelling in pairs. The male chooses a female and holds onto her until she's ready to mate, sometimes for a week. In this photo, I caught 4 couples and one lonely singleton.

Spring is on its way; even in my tank, inside, away from the tides and disrupted by on-again-off-again lighting, the critters know it. Several of the male hermit crabs are dragging around their chosen mates, too. And the anemones are multiplying like rabbits.

Pink-tipped green anemone, "Stretch", splitting in two.

Most of these anemones elongate to about twice their width, and then separate, but this one is ambitious and has spent several days stretching out to start the clone at a good distance from the parent. I just went to measure it; from one end to the other, it's 7 cm. And now the bridge between is shredding. By this afternoon, the youngster will set off on his own path.

This species of anemone is capable of reproducing both sexually and asexually. As adults, A. elegantissima release gametes into the water that join to form genetically unique individuals that settle on intertidal rock. This genetically distinct individual can then proliferate through binary fission. (Wikipedia, Aggregating anemone)

"Stretch" may be slightly confused as to the time of year; sexual reproduction starts in February, but the resulting gametes are usually released in summer. However, two weeks ago, before starting the stretching exercises, this anemone released a whitish cloud from its mouth. There's a YouTube video showing a spawning anemone here; this is what "Stretch" was doing.

These anemones, Anthopleura elegantissima, are either male or female (many others are hermaphrodites) and groups that have reproduced by splitting are clones, all the same sex. So spawning in my tank may be a wasted effort; the whole colony may be all males. Or females. (The only way I could know for sure would be to break the anemone off its site and look for sex organs; the female's are brownish pink, and the male's are yellowish white.)

Fading to yellow

Pink-tipped green anemone in winter colours.

Anthopleura elegantissima

Out on the shore, these anemones are green, with pink or very pink tips. In the tank, and especially over winter, they gradually lose the green algae that give them their colour. These algae need sunlight to grow. Indoors, there are only a few hours of filtered sunlight; in winter, in my apartment, they get only artificial light.

Most are olive to bright green (depending on the species of algal symbionts present) with tentacles tipped in pink. Individuals that live in microhabitats that are deficient in photosynthetically active radiation (PAR), such as under docks or in caves, lack symbionts and are pale yellow to white in color. (Wikipedia)

The anemones on our shores are a very bright green, unless they're hiding under deep rock overhangs.

Anemones, Edgewater beach, 2009

From a paper referenced in this Wikipedia post: " ... anemones display phototactic behavior and may  move to regions of the cave that produce the best physiological fit between host and symbiont species." (David Secord, 2005)

This may possibly hint at the reason all of the pink-tipped green anemones in my tank congregate along the front wall, where the light is stronger.

The internal algae, busily converting sunlight and carbon to carbohydrates, provide oxygen to the anemone hosts as a by-product. Without this, the anemones survive, but do not reproduce as quickly. However, in my tank, a year ago, there were 5 of these anemones. I counted this afternoon; now there are 19, and one is busy splitting in two, to make it 20.

Morning sunlight should be arriving at their window sometime in April. If it's strong enough (I may re-direct it with a mirror to be sure), some of the green colour may return.

Looking again at the first photo, I am reminded that a powdery green algae grows everywhere in the tank, on walls, shells, even on hermit crab carapaces. But not inside the anemones; it's obviously not the correct species. And it likes artificial light.

Mystery # 1

This is an trio of pink-tipped green anemones. They're a dime a dozen in the intertidal zone. But look again.

Anthopleura elegantissima, with whelks and Wosnesenski's isopod.

First, what has it been eating? It looks like a black snail shell, and, separate from that, two pieces of very white flesh. Is the anemone in the act of expelling the snail shell and simultaneously swallowing the meat?

Second, and this really leaves me wondering; look closely at the right bottom of the anemone. Look through the translucent flesh. See the circle of what looks like snail eggs inside?

Zooming in.

How did they get there? Did a snail crawl in, avoid being digested, exit the stomach, and lay her eggs? How is that possible?

Or are these part of the usual anemone anatomy that I have never seen, and can't find in any cross-section diagram?

Or did the anemone just crawl along the rock and station itself on top of eggs?

And no, they can't be seen from the opposite side; I'm not looking through the entire animal.

What do you think?

Comparing anemones

One basic capture and swallow system, three different styles.

A head full of hair. Metridium senile.

M. senile adheres to rocks, boulders, man-made structures, pebbles and shells. It favours places where the current is strong. (Wikipedia)

No matter where I put "Metty's" shell, she moves back under the pump again. She likes that current. But she is extremely sensitive to touch and shrinks back into a lump if anything too big brushes her tentacles.

Pink fringe. Pink-tipped green anemone, Anthopleura elegantissima. 

There are four of these in my tank. They spend most of their time on the oyster shells, near the sand and out of the strongest current. They get walked on all the time, and don't like it much, but never move to a "safe" place.

Long, fleshy tentacles, very sensitive, sticky. Doesn't bother hermit crabs, but gives shore crabs a nasty sting. "Val", the burrowing anemone, Anthopleura artemisia.

"Val" seems to like being jammed into a corner. She sticks to the glass underneath the sand, so has to put up with the weekly tank scrub, instead of being moved to a safe place. She doesn't seem to mind all kinds of action around her, even being mounded with sand; she keeps on feeding throughout the procedure.

Side by side

Here's one of the new pink-tipped anemones, feeding and growing, standing tall.

Anthopleura elegantissima

And, right next to it, one of the Leafy Hornmouth snails:

Ceratostoma foliatum, with the Warty tunicate behind it.

I love the contrasting textures, the rough, craggy shell of the snail, and the creamy greens, pinks, reds, and yellows of the soft tissues.