Red, green, purple

In my posts over the last week, whatever I'm talking about, the sea urchins manage to worm their way in. They're mostly green sea urchins, although a red and a purple have shown up on the beauty bush.

Time to give them the spotlight they're begging for.

Green sea urchins, Strongylocentrotus droebachiensis, are small and gregarious. They are usually mostly green, with darker lines on the test (the round shell). Sometimes they're purplish.

Purple sea urchins, Strongylocentrotus purpuratus, are larger; their spines are green as juveniles, changing to pink, red, and purple as they mature.

Red sea urchins, Strongylocentrotus franciscanus, are the largest. They may be red, purple, pinkish, or even purple-black.

A green sea urchin on beauty bush. The test is up to about 9 cm. (2 - 3.5 inches) across.The spines are short and pale green.

The green sea urchin turned over. The central part is the mouth, with the plates that serve as teeth, called "Aristotle's lantern". More on these, later.

A purple sea urchin. This specimen measures 11 cm. across, spines and all.

The purple sea urchin's test may grow to 10 cm. (4 in.), and the spines are relatively short, usually under 2.5 cm. (1 inch) long.

And a red sea urchin.

The reds grow up to 30 cm, (12 inches) across, counting the spines, which account for half the width.

Red sea urchin, upside-down, showing the mouth.

Green sea urchins have been known to live from 20 to 25 years. Reds usually live up to 30 years, but some have been found to be 200 years old. Purples commonly live up to 70 years old.

About their behaviour and quirks, tomorrow.

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En mis posts durante esta última semana, sea lo que sea el tema, los erizos de mar se han hecho evidentes. Por la mayor parte, han sido los erizos verdes, pero también aparecieron sobre las algas en la playa, un rojo y un erizo morado.

Ya es hora de hacerles caso.

Los erizos de mar verdes, Strongylocentrotus droebachiensis, son pequeños y amantes de compañía. Casi siempre son verdes, con rayas más oscuras sobre la testa (la concha que cubre el cuerpo). A veces son de color violeta.

Los erizos de mar morados, Strongylocentrotus purpuratus, son más grandes; sus espinas son verdes cuando son jóvenes, cambiando a color de rosa, rojo y luego purpúra mientras crecen.

Los erizos de mar rojos, Strongylocentrotus franciscanus, son los más grandes de todos. Sus espinas pueden ser rojos, morados, color de rosa, o hasta un morado casi negro.

Fotos:

1. Un erizo de mar verde. La testa mide aproximadamente hasta 9 cm. Las espinas son cortas y de un verde pálido.

2. El erizo verde boca arriba. La parte central es la boca, con las placas que le sirven de dientes, a las que llamamos "la linterna de Aristóteles". Más sobre estas mañana.

3. Un erizo de mar morado. Este animal mide 11 cm., contando las espinas. La testa de un erizo morado puede crecer hasta 10 cm. Las espinas generalmente son cortas, menos de 2,5 cm. de largo.

4. Un erizo de mar rojo. Los rojos llegan a 30 cm., tomando en cuenta las espinas, que bien puede formar la mitad. 

5. El erizo rojo boca arriba.

Los erizos de mar verdes viven de 20 a 25 años, los rojos hasta 30 (¡pero algunos se han encontrado que tenían 200 años!), y los erizos morados viven alrededor de 70 años.

De su comportamiento y sus caprichos lo dejo para mañana.

Recovery

This made me happy. It used to be, years back, that on any shore, from mid-tide on down, I would see mounds of purple and orange starfish. Then came the epidemic of starfish wasting disease. The purple starfish and the sunfish curled up, fell apart, and died in the millions. And then there were none.

Some days, in the last year, I've seen one or maybe even two starfish and rejoiced. This time, at the very bottom of the low intertidal zone, the starfish are back and healthy, to boot.

Purple starfish, Pisaster ochraceus

In a crack between two rocks, a lineup of starfish, with a red giant chiton.

Purple and orange. One species, two common colours. With green sea urchins.

More purples. That round spot is a hole in the sandstone with another starfish tightly coiled inside. On the far left, there's a small leather star.

So many starfish! Almost like old times! It got so that I was walking past piles of starfish without stopping to take their photos.

A rare pinkish-brown coloured star, with another of the purples.

Leather star, Demasterius imbricata.

The pale yellow circle on the top of this leather star is the madreporite; all starfish and other echinoderms, like the sea urchins and the sea cucumbers, have one, although not always so visible. The madreporite is a plate of porous calcium carbonate which funtions as a sieve regulating the water pressure in the starfish's vascular system.

Two leather stars and green sea urchins in another rock hole.

And not one sign of a rotting arm! So good!

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Esto me hizo feliz. Hace años, acostumbraba ver montones de estrellas de mar, de color azul púrpura o anaranjada, en todas las playas mientras se bajaba la marea. Y luego, por el año 2013, surgió la epidemia de desgaste de estrellas de mar, en la que se torcían y se desbarataban los brazos de las estrellas y los soles de mar, resultando siempre con la muerte del animal. Millones perecieron. Y luego, no se encontraban estrellas sanas en nuestras costas.

Algunas veces durante el año pasado, encontraba una o tal vez hasta dos estrellas cuando la marea bajaba, y me regocijaba. Ahora, en la parte más baja de la zona inferior de la intramareal, han regresado las estrellas, y todas parecen estar sanas. ¡Tantas eran, que por fin, pasaba a su lado sin pararme a sacar fotos! ¡Casi como los tiempos antiguos!

Fotos: estrellas de mar Pisaster ochraceus, anaranjadas y violetas, y estrellas "de cuero" Demasterius imbricatus, con su diseño de manchas anaranjadas. Y algunos erizos de mar verdes.

En la primera de las estrellas "de cuero", se ve claramente un círculo de un color más pálido. Esta es la madreporita, un órgano común a todos los equinodermos, tales como las estrellas de mar, los erizos y el pepino de mar, aunque en algunos apenas se puede ver. Es una placa porosa de carbonato de calcio, que sirve de coladera, y ayuda a mantener la presión del agua en el sistema vascular del animal.

Wooly brown carpet

The beach I chose for the low tide exploration this year is an an old glacier plain; an almost flat expanse of sandstone, interspersed with groups of large rocks, usually lined up as if shoved to the side by a sliding glacier, with a few large erratics near the low tide mark. The sandstone is scored in straight lines, some parallel to the shore, others heading straight out to the channel. Glacier tracks.

I've been here before, at mid-tide levels. Not often; the beach has not been easily accessible. The access point is at the end of a dead-end road with three houses on it, which in turn is an off-shoot of a slightly longer dead-end road. To reach the beach, I had to climb a parking barrier, then scramble down a rocky drop-off. Until now; now someone has made a short path skirting the fence and dropping down the side on easy steps. Nice!

Looking northish. Showing eroded slab of sandstone, long scratch mark. Note the green sea urchins at the base of the slab. More on these later.

Glacier tracks. With purple sea urchin.

Seaweed-covered  beaches can be tricky. It's hard to tell what's underneath, whether rolling rocks or sudden holes or slimy mud; I have fallen several times. luckily without too much damage. This flat sandstone beach is safer; there are few rocks, and the holes are shallow.

But there's always slippery seaweed. Even on this shore, my feet slip on the green and yellow seaweeds. But here, there's a carpet of a brown, scratchy, wiry seaweed. The patches are interspersed with areas where sea lettuce, rockweed, and bag algae grow, all very slippery underfoot. Mostly, I skirted these areas, walking confidently on the slip-proof carpet.

Looking south. With red sea urchin. The erratic at the left was just at the edge of the water when the tide turned.

The seaweed is called "beauty bush". I'm not sure why. It's brown, lumpy, shapeless except at a close view.

Beauty bush, Callithamnion pikeanum. With rockweed and big barnacles.

This is one of the coarser members of this family of red algae, and it is usually purplish brown to reddish brown in color. It is perennial and so extremely densely branched that it appears woolly. (E-Flora BC)

I broke off one branch to get a better look.

The little round branchlets almost look like evergreen cones.

My guide book, Marine Life of the Pacific Northwest, comments that it is "reminiscent of a miniature fir tree lying on its side."

In the upper intertidal zone, I find mainly tiny periwinkle snails, hermit crabs in periwinkle shells, the occasional whelk, and barnacles. And seaweed: mostly sea lettuce and sea hair, all very slippery underfoot.

The lower intertidal zone is another story. So much to see! Even a couple of lifers! Tomorrow, an ambitious chiton.

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La playa que escogí este año para el dia de la marea baja es una antigua llanura glacial: un campo casi completamente plano hecho de arenisca, entrelazada con grupos de piedras grandes, casi todos alineados, como si hubieran sido empujado a un lado por una montaña de hielo ambulante. Hay unos bloques erráticos cerca del nivel más bajo de la zona intramareal. Se ha cortado la arenisca en lineas rectas, a lo largo de la costa, o dirigiéndose directamente al mar. Huellas glaciales.

He visitado antes, al nivel mediano intramareal. No tan frecuentemente, porque la playa no ha sido de fácil acceso; se llega por un callejón sin salida, donde solamente hay tres casas; este callejón se deriva de otro callejón sin salida un tantito más largo. Para llegar a la playa había que trepar sobre una barda del estacionamiento, y luego hacerse camino entre rocas al nivel de la arena. Hasta ahora: esta vez descubrí que alguien ha hecho un senderito que evita la barda y baja por escalones a la playa. ¡Qué bien!

Primera foto: mirando al norte, mostrando el borde de la plancha de arenisca, y una grieta glaciar. Se ve un grupo de erizos de mar verdes al lado de la plancha. De estos, veremos más adelante. 

Segunda foto: una grieta glacial. Y un erizo de mar morado.

Las playas con muchas algas pueden ser peligrosas. No se puede ver lo que hay abajo, sea piedras rodantes u hoyos inesperados o lodo resbaloso; me he caído varias veces, por suerte sin mayores daños. Esta playa de arenisca, plana y sólida, es más segura. Hay pocas piedras y los hoyos son de poca profundidad.

Pero siempre hay algas marinas resbalosas. Aun en esta playa, mis pies se me van caminando sobre las algas verdes y amarillas. Pero aquí también hay un tapete de alga café, rasposa, como si fuera de alambre. Hay grandes areas donde crece la lechuga de mar, sargaso vejigoso, y alga de bolsita, pero les dí la vuelta, caminando con confianza sobre ese tapete anti-resbalante.

Tercera foto: mirando hacia el sur. Con un erizo de mar rojo. El bloque errático en el agua, estaba casi fuera por completo cuando la marea llegó a su punto más bajo.

La alga marina café se llama en inglés "arbusto de belleza", no me imagino porque.

Cuarta foto: "arbusto de belleza" con sargaso vejigoso, y unos bálanos grandes.

"Este es uno de los miembros más ásperos de esta familia de algas rojas, y casi siempre es de un color café morado a café rojizo. Es perenne y tan densamente ramificada que parece de lana." (De E-Flora BC)

Quinta foto: rompí una ramita para verla mejor. Las ramitas parecen conos de pino.

Mi libro guía, Marine Life of the Pacific Northwest, hace el comentario que "trae a la memoria un abeto caído."

En la zona superior intramareal de esta playa, encuentro caracoles de mar "bígaro", ermitaños en concha de bígaro, una que otra bocina, y bálanos. Y algas marinas de las resbalosas.

Aquí en la zona baja, la situación cambia. ¡Tantas cosa que hay! ¡Incluso algo que nunca había visto antes! Mañana, empiezo con un quiton muy valiente.

Holding on

 How do sea urchins hang on upside-down on the bottom of floats?

Green sea urchins, Strongylocentrotus droebachiensis, on the underside of a float.

It always looks impossible; those spines don't stick to anything. But I've watched them in my aquarium; on the mouth side, which is the uppermost side in this photo, in among the spines, they have thin tube feet. The tubes, with a suction cup on the end, can extend beyond the spines; with them, they can walk about, just as a starfish does.

They use the feet to attach themselves to underwater structures, and also to capture food particles and move them towards the mouth.

Small sea urchin, in my tank, showing off its tube feet. Oct. 2019

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Los erizos de mar; ¿cómo es que se adhieren a la cara inferior de objetos en el agua? Las espinas que los cubren son redondeadas; no pueden agarrar nada.

Alrededor de la boca, tienen muchos "pies" en forma de tubo, llamados pies ambulacrales. Estos pueden extenderse fuera del alzanze de las espinas. En el extremo, tienen una ventosa que les permite caminar o adherirse, a la manera de las estrellas de mar. También pueden usar los pies para agarrar pequeños objetos flotantes y llevarlos hacia la boca.

Underwater bouquet

Off the docks at Brown's Bay the other day, the wind was brisk and the water surface choppy, but in a few sheltered spots I could see the communities living on the underside of the floats.

Giant plumose anemone, Metridium farcimen.

The floats are blue plastic. And we're lookiing through the reflections of the structures overhead.

Anemones, seaweeds, worms, and jellies. Click to view full size.

And here's the same photo, annotated. The gunk may be sponges.  But I missed a limpet. Do you see it?

Kelp, anemones, mussels, limpets, and a glowing red worm. The greenish spikes are on sea urchins.

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En el muelle en Brown's Bay el otro dia, había viento haciendo olas, pero en algunos lugares se podía vislumbrar las comunidades que viven en la parte inferior de los flotadores. (Que son de un plástico azul.)

Primero: una anémona "emplumada gigante".

La segunda foto tiene toda una comunidad. En la siguiente, los habitantes tienen nombres. Hay anémonas, lombrices "plumero" (son rojos), otros lombrices en tubos, un par de medusas, varias especies de alga marina, y una masa que probablemente consiste en diátomos o si no, de esponjas. Y se me olvidó una lapa. ¿La ves?

En la última foto, aparte de todo lo anterior, hay un grupo de erizos de mar; son los que tienen las espinas verdes.

Toothy lantern

What can you eat with only five teeth?

Sea urchin mouth, with its five teeth.

If you're a sea urchin, you can even chew into rock with them.

Small green sea urchin, Strongylocentrotus droebachiensis, with its spiky shadow.

The teeth are the bottom (because the mouth faces down) part of the mouth structure called Aristotle's Lantern, supposedly because when Aristotle drew one, he thought it looked like a lamp. They are made, like the test and mollusc shells, of calcium carbonate, CaCO3. We see CaCO3 every morning as we make breakfast; egg shells are made of calcium carbonate. So is chalk. And the antacid we take after too big a meal.

So how does a sea urchin bore a hole in rock with chalk?

A 2016 study by the Pacific Northwest National Laboratory shows how it's done, although they don't mention sea urchins specifically.

Calcium carbonate is one of the most important materials on earth, crystallizing into chalk, shells, and rocks. Animals from mollusks to people use calcium carbonate to make biominerals such as pearls, seashells, exoskeletons, or the tiny organs in ears that maintain balance. These biominerals include proteins or other organic matter in the crystalline matrix to convert the weak calcium carbonate to hard, durable materials.

If a tooth does chip, it repairs itself, filling in the gap with a freshly built CaCO3 and protein structure. No need for dentists!

The sea urchin's main diet is a lot softer than rock, of course; it eats mostly algae. A swarm of urchins can demolish a kelp forest. Chewing rock is construction work, making safe holes to sleep in.

Under the wharf, it's spring.

The tide was low, the sun was shining, and there was no wind; the perfect time to visit the docks and peer underneath the floats again. The water was smooth and clear, exposing the communities clustered along pipes and logs.

This year, or maybe this time of year, the sea urchins were out in full force. I hadn't seen them here before.

Under a floating office. Green sea urchins, about a couple of inches across.

More urchins, several scallops encrusted with weeds and worms, barnacles and a feather-duster worm, on a plastic pipe under the ramp.

A rusty pipe and a rope underneath the ramp. Sea urchins again, purple and beige feather duster worms, a red sponge (on the whitish pipe on the left) and a larger, greyish sponge. On the far left, a mass of tubeworms. At the top right, a brilliant red feather duster.

There were several masses of jelly, probably egg masses. This one was on a piling partly exposed by the low tide. I touched it; it was soft, but firm, not sticky.

This was down on the bottom, underneath a float. It's about a hand's width across. An anemone, but not one I recognize.

I have visited the docks several times during the winter, peering down the gaps between pilings, squinting between logs. All I have seen in the water were fish, maybe because of the lack of light, or possibly some of the summer residents have retreated to more sheltered locations. I'm glad to see the crowds coming back.

Shifting shapes

The many shapes of intertidal beasties.

Long and twisty:

Long-armed brittle star, Amphiodia occidentalis. Aka snaky-armed brittle star. Disturbed in sand or mud, they stretch out and twist out of sight, gone in seconds. In my hand, they curl and twist into a knot. This one hadn't decided whether to go left or right.

Tubeworms, hiding from the light.

Saddleback gunnel. Accompanied by another of those kelp crabs with a sea lettuce hat.

Round and spiky:

Green sea urchin, Strongylocentrotus droebachiensis. (That name's a bit of a tongue-twister, isn't it?) Topside. Those spines are in constant motion.

When I was a kid, someone told me that sea urchins were good to eat. You just broke one in half, and ate it, raw, on the half-test. With a spoon.

I had to try it. I brought home a green sea urchin from the beach, cracked it down the middle, and tasted it. Not bad. I took another bite, and another. And while I spooned out that first half, the second half walked itself across the counter and dropped to the floor.

That did it. I apologized to the urchin and returned it to the beach. I never ate another.

Sea urchin underside, showing the mouth.

Mouth open, showing off his five teeth.

Blobby shape-shifters:

Pink-tipped green anemone, Anthopleura elegantissima, half-way between the ball form and the flower shape.

Compact and round:

Probably a stubby isopod, Gnorimosphaeroma oregonensis. Also a shape-shifter; they curl up into a ball and roll away when I touch them.

All of these were in the mid-tidal zone, 50th parallel north.

Shoulda, coulda, didn't

It's a mistake to be too easily satisfied, too quickly beguiled by the obvious. Flipping rocks at low tide, there's a tendency to say, "Look, a clingfish! Look, a pretty anemone, an angry crab!", to take a few photos and go on to the next rock without stopping to really pay attention.

And so doing, I miss out.

At least in some of my photos, taken with a wide enough view, and with a minimum of hand shake, zooming in back at home, I can discover many of the beauties I should have seen in situ.

This was supposed to be a photo of the rose anemone.

Busy scene.

Once I zoomed in, look at what I found:

You may want to click on this and enlarge it.

There's a juvenile wolf eel in there. And I had never seen one before; I wish I had noticed it while I was on the beach.

Another one; this was supposed to be a photo of the clingfish. But there's a complete brittle star, out in the open; I missed it live.

Two starfish, orange and purple, two large snails, several tiny ones, a kelp crab, two grainy hand hermits, pieces of gorgonian, pink and purple encrusting stuff, a long calcareous tubeworm, baby sea urchins, an adult sea urchin, spiral tubeworms, assorted polychaete worms, and the brittle star. Oh, and the clingfish.

About those baby sea urchins; really tiny sea urchins, barely visible in this photo, even at full zoom.

There are at least 5 sea urchin babies here, besides the medium-sized juvenile. I've saturated the red stuff, so as to highlight the pale pinhead urchins.

A purple sea urchin may live up to 70 years. The green sea urchin, a bit smaller than the purple, and more short-lived, grows about 1/2 inch per year. I found both of these, green and purple urchins, on this visit to the beach. A scuba diver told me he's seen thelarger red sea urchins here in the subtidal zone; they grow to about a foot across, counting the spines, and may live up to 200 years. I don't know what species the babies are, but they must be only a few months old.

One more photo; worms that I didn't notice, in a photo of an unco-operative gunnel.

A purple ribbon worm, three different polychaetes (one is striped, upper left), and a spaghetti worm (upper left, orange and yellow). And a four-armed green starfish, a hermit, two purple crabs, an urchin, and a brittle star.

Next visit to the lower intertidal zone, I think I'll sit me down in one spot and look at everything. Easier on my back, too.