Tiny orange lifers

I went down to the local aquarium this morning. And I have a few photos to process. One, though, even though it's not as clear as I would like, made my day.

One of the volunteers, knowing that I was interested in hermits (I've been in before) showed me something he'd discovered; tubeworm hermits! So tiny that they were barely visible; specks of orange among the stones and shells.

Discorsopagurus schmitti in calcareous tubeworm spirals.

These tiny hermits are among the few species whose abdomen is not coiled to fit in a snail shell. (Any rule Ma Nature makes, Ma Nature breaks.) Instead, they use tubeworm shells, which, entire, are fixed to the substrate, or broken snippets of the empty tubes.

These are females; the females live in attached tubes, and catch their food as it floats by. Males borrow bits of broken tubes, and wander about in search of females. The aquarium guy has seen one walking around, but though we searched today, he was too well hidden. Maybe next time ...

A mass of these tubeworms, alive and trolling for food.

The aquarium pumps in "live" water from just off-shore; it comes with tiny organisms, juvenile species, eggs ... They never know what's going to show up here. There are new discoveries every day.

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Visité el acuario del pueblo esta mañana, y regresé con algunas fotos. Una, aunque no salió tan bien como hubiera querido, me hizo el dia.

Uno de los voluntarios, sabiendo que me fascinan los cangrejos ermitaños (no es mi primera visita) me mostró algo que había encontrado recientemente; ¡ermitaños que viven en tubos de los gusanos tubícolos! Tan pequeños eran que apenas podíamos ver unas motitas anaranjadas entre las piedras y conchas.

Foto: Discorsopagurus schmitti

Estos ermitañitos son unos de los pocos cuyo abdomen no forma un círculo para poder acomodarse dentro de una concha de caracol marino. Usan, en cambio, los tubos hechos por gusanos tubícolos; frescos, se encuentran adheridos al sustrato; también se pueden usar tramos de los tubos rotos.

Estos en la foto son hembras; viven en tubos fijos, y pescan su comida cuando pasa en la corriente. Los machos se visten con pedazos de tubos rotos, y así libres, andan en busca de hembras. El voluntario había visto uno de estos, pero aunque lo buscamos hoy, se quedaba escondido. Tal vez otro dia ...

Foto: Un grupo de gusanos tubícolos, algunos con sus tentáculos extendidos.

El acuario obtiene su agua "viva" directamente de la corriente cercana. Llega con organismos pequeños; primeras etapas de especies locales, huevos, y más .... Nunca saben que es lo que va a aparecer mañana.

Just worms. Beautiful worms.

They hide their bright, flowery faces in the deep shadows underneath rocks. When the tide abandons them, they flee. When the water comes back, it pays to kneel in seaweed and peer into their hideaways, cautiously; the slightest disturbance will cause them to retreat into their tubes and slam the doors.

Red trumpet calcareous tubeworms, Serpula columbiana. Taken with flash: it's dark down there.

The worms live in white tubes attached to the rock, curved outward at the head to spread their feeding tentacles. The central circle is a funnel-shaped door, or operculum. It seals the tube when the tide goes out, hiding the brilliant head.

Zooming in. I like the rayed funnel on the one on the right.

The spaghetti worms cannot retract their tentacles, as most tentacled worms do. And they really do look like wet spaghetti dumped in the sand, with a sculpted carrot for a body.

Spaghetti worm, Terrebelid sp.

The white "spaghetti" are feeding tentacles. Just beneath them, some of the red gills are visible here. The worms build themselves a soft mud tube, but are not always protected by it. In this photo, only the tail of the worm remains in the tube.

The polychaete worm is not as spectacular as its cousins, but viewed closely, has lovely, shimmery colours, blue, green, pink, and sometimes red.

Zooming in to display the iridescence.

Blowing his own trumpet

I had promised to try to get a photo of the tiny tubeworm's "trumpet", so this afternoon, I propped the camera an inch away from the worm, and got him to sit for his portrait.

Red trumpet calcareous tubeworm, Serpula columbiana, back view of the mouth.

The worm ("Red, for short) wasn't the least bit shy; I kept taking a few photos, picking him up and repositioning him, trying again, moving him again ... "Red" would hide in the tube while I moved things around (wouldn't you, too, if a monster the size of a skyscraper picked you up?) but by the time I'd got back to the camera, there he was, waving his tentacles around enthusiastically.

And I finally got a clear shot at that tiny "trumpet".

It still looks like a badminton birdie to me. On a stem.

This is the door of the tube. When Red goes back into his tube, he pulls the feeding tentacles in, then the "trumpet", which he spreads across the opening, locking it down.

I noticed, in my photos, many even tinier plants or critters, like those white pinheads to the left above, or little green shrubs, too small for my eyes alone to see. I wonder if I can zoom closer in, to get a good look at them, too. It's turtles, or at least critters, all the way down!

Pink and white tentacles

Tonight, as I was putting my critters to bed, (checking their water quality and temperature, tidying crab construction zones, preparing to turn off the light) I noticed a new resident: an inch-long, white, twisty tubeworm.

It was glued to the remains of the warty tunicate's kelp holdfast, where it certainly hadn't been evident before. And the whole contraption, tunicate, holdfast, and tubeworm, had rolled up against the glass where I could see that it was alive and feeding.

Red-trumpet calcareous tubeworm, Serpula columbiana

These tubeworms secrete a mucus which precipitates calcium carbonate from seawater, which forms a hard tube, growing from the mouth end. (The calcium carbonate comes from dissolved shells of dead snails and other shelled creatures. Everything is used, reused, recycled.)

They settle on any hard surface. Seaweeds such as kelp aren't solid enough, but the holdfasts are as tough as wood, even when they're old and eroded, such as this one.

Delicate colours. These tubeworms come in colours from pink and white to brilliant red.

Each tubeworm has a lid, or operculum, which it pulls in after itself to plug the tube when it retreats. Open, it takes the shape of a funnel, or trumpet, which gives the tubeworm its name. In these photos, it can be seen, fuzzily, at the back, looking sort of like a pinkish badminton birdie.

Backing off to see the whole tube in context.

I'll have to take another batch of photos, to see if I can manage to focus on that operculum.

White on blue

All that remains of a calcareous tubeworm colony on a plastic float, left high and dry on a wharf:

Spirals, curves, angles

These are the tubes made by three species of tubeworms, The tiny spirals, about 1/8 of an inch across, protected the dwarf calcareous tubeworms, Spirorbis spp. The curvy, fat tubes are probably by a relative, Serpula vermicularis, and the rough, oddly-shaped, thinner ones belonged to a different Serpulid. Alive, they would each house a worm with a brilliant, feathery top,

HItchhiking worms

I made a quick trip to the beach to collect seaweeds for my critters. I chose the upper end of Boundary Bay, where the sand is muddier and wormier; as I waded along in an inch of water as the tide receded, worms kept spitting at me just before my shadow touched their holes. I think they are more sensitive to the vibration my footsteps made than to the change in light. (Barnacles notice the shadow first.)

In an hour of wading, I found only eelgrass, and not much of that, on this end of the Bay at mid-tide. But each blade of eelgrass had at least one limpet crawling on it. And the limpets were carrying their own burdens:

One tiny limpet, 7 busy spiral tubeworms, Spirorbis spirorbis

Another limpet, with 10 tubeworms.

The limpets don't seem to be bothered by the excess weight of tubeworms, probably more than the weight of the limpet itself. In a way, they may actually benefit the limpet, protecting it from attack by hungry crabs that content themselves with picking the worms out of the tubes instead of trying to crush the limpet. After a day in my tank, most of the worms are gone; the hermit crabs have harvested them.

What else I found in the muddy sand, tomorrow.

Tentacles with tentacles

Spiral tubeworms ride another small limpet.

There are two tubeworms here. The limpet is feeding on the glass wall of the tank.

Commensal worms tomorrow.

Beast of burden

Since I found a worm inside the shell of one of my limpets last month, I've been keeping a close eye on the whole limpet community, hoping to find another worm, maybe even to identify it.

I've seen a few, fleetingly. I'm working on getting photos.

Meanwhile, here's a badly overworked young limpet.

7 calcareous tubeworms on one poor limpet.

The limpet is about 2/3 the width of the blade of eelgrass, itself only 4 mm wide, making the limpet under 3 mm across, and the tubeworms under 1 mm. each. The worms themselves are pink or red; the white spiral tubes, are made of calcium carbonate. If the light is right, the colour of the live worm shows through.

Each worm is capped by a round lid, or operculum, visible on the one at the top in this photo. It hides the worm in case of danger or exposure, and also serves as a brood chamber for the young. It flips back for the worm to extend its feeding tentacles.

As I watched the limpet, it moved along the eelgrass blade, eating algae, seemingly undisturbed by the load on its back, probably weighing more than the limpet itself.

More limpet photos tomorrow.

Green, fading to black

One of the pleasures of summer along our shores is to wade at the low, low tides, knee-deep in the eelgrass beds, watching the swirl of the deep green blades reaching up to the surface and floating there. We watch our step carefully; among the stalks, good-sized, maybe toe-pinching crabs scuttle. On the long leaves, if we look closely, we can see large green isopods and small snails. Sculpins and other small fish dart away at our approach, no matter how stealthily we tiptoe.

Most of what lives in these green forests, though, we don't see. Kozloff, in his chapter on sandy beaches, lists, among the inhabitants:

• On the leaves: the tinies; diatoms and other microscopic plants, invisible alone, but in mass, forming a brownish "fur" or long threads; bacteria, protozoa, algae, microscopic worms, crustaceans, copepods.
• The small critters: amphipods, including skeleton shrimp, hydroids, flatworms, ribbon worms, jellyfish, anemones, chink snails, sea slugs, including Melibe leonina, two species of isopods.
• On the mud, sand, roots: bubble shell snail, clams, sea stars, sea cucumbers, five crabs; Dungeness, red, two spider crabs, and helmet crabs.

Another list adds sponges, bryozoans, spiral tube worms. I would add the limpets and their cargo. There are many more, and we must not forget the fish.

So important is Zostera's role in this food cycle that estimates reveal that more than 20 species of commercially valuable fish species feed in these eelgrass meadows at some point in their lives. (R.I. Sea Grant Fact Sheet)

 That's the summer.

Summer eelgrass, waiting for the return of the tide.

In the fall, the eelgrass begins to die back. Stormy seas rip up the plants by their roots, and propel them toward the shore. The waves, coming and going, roll them up in dense masses, metre-long tough leaves wound and knotted around each other, and push them onto the beaches. There, they gradually die and blacken, always pushed further up the beach by the next tide's eelgrass roll-up, until they form great mounds of black, sharp-smelling gunk.

Drying eelgrass, caught on driftwood log. Boundary Bay.

But their useful life isn't over yet! First, while they are drifting ashore, Canada geese congregate to eat the green stems that they usually can't reach.

Geese and gulls, watching the eelgrass come in. White Rock.

I collect handfuls for my aquarium critters from the fresh rolls, disentangling the greenest, the ones with bits of root still attached. In the winter, the low tides usually fall well after dark; I can't wade out to what's left of the eel-grass beds. I'm glad it comes to me, instead.

In summer, any eelgrass I harvest is well checked over for other life. I always find limpets, usually quite a few snails, occasionally an eel-grass isopod or two. There may be amphipods along the leaves, often polychaete worms in the roots, and always the fuzzy diatom communities.

In the fall and winter, the eelgrass looks bare until I run a finger down a leaf; then I notice the hard, raspy bryozoan communities, the thickening where a cryptic limpet is attached, and maybe an isopod will transfer his clingy feet to my finger. All of these go into the aquarium where I plant the eelgrass.

I don't bring home the black stuff. Some people do; I have seen gardeners with wheelbarrows and big barrels on the shores of Crescent Beach and Boundary Bay, filling their containers (once a pickup truck bed!) with nutritious mulch for the winter garden.

But I do roll it over, to watch hundreds of beach-hoppers leap every which way. (I remember, back when Laurie didn't know me quite so well, I called him over to see. "Look!" I said, and turned over a heap of dead eelgrass. He wasn't prepared; the hoppers ended up on his legs, and he jumped back, annoyed. He got over it, and now is as enthusiastic as I am. Sometimes more.)

Inside that rotting mass, worms, fungi and bacteria work at reducing it to fine dust, which will sift slowly out to sea, returning the nutrients to their source for another round. In the meantime, tiny black flies swarm over the surface, feeding and breeding in the relative warmth from the decomposing grass. Nothing ever gets wasted.

Bryozoan colony on dying eelgrass.

In my aquarium, fall eelgrass only lasts a couple of weeks before it dies and turns black. I doesn't look good, and eventually will disintegrate and clog the filters, so I remove it. But first, I make sure I'm not removing live animals. Most of the limpets have moved on to greener pastures; so have the isopods and amphipods. But there are still patches of bryozoans and hydroids.

I wondered, the other day, whether the bryozoan colonies were still alive, so I brought them out to a tray of shallow water and examined them under a microscope. All the tiny, glassy barrel shells were empty; the makers were gone.

Each little tube was the home of one zooid.

If you were seeing these photos live, you would also see tiny specks of light moving between the shells, barely visible transparent threads weaving back and forth, white dots that seem to have legs scuttling across the green spaces. The bryozoans have died, but the colony is still very much alive. And the spiral tube worms are still busy catching the specks and threads for supper.

Bryozoan colony with feeding tubeworm.

I replaced the eelgrass in the aquarium. These industrious hunters and gatherers deserve their full life span.

Obelia and the Very Messy Limpet

When we go to the beach, I pick up a bag of veggies for the animals in my aquarium. The crabs love green sea lettuce; I often see them grab a floating leaf, tear it into chunks and gobble it down. They're fond of a side salad of red Turkish towel, too. The big brown anemone seems to do better when there is a bit of rotting kelp nearby. Hermit crabs like the red stuff; thin red algae and Turkish towel. Some hang out on the sea lettuce, picking at the surface.

Snails and limpets feed on fresh eelgrass, but the hermits like it best a bit aged, covered with weedy growths. They browse knee-deep in the "pasture", whether eating the weeds or searching for bits of detritus, I don't know.

Eelgrass blade, with fuzz and a couple of limpets.

The last batch of fuzzy eelgrass brought along a small limpet, as fuzzy as the grass itself.

Limpet, bubbles, and a city on a hill.

The limpet is about 1/2 cm. lengthwise, less than 1/4 inch. I looked at it through a magnifying glass, to see if the tiny spiral worms were alive, and found a thriving community, more diverse than I had expected. I've been trying to get photos ever since, difficult since I needed it to stay underwater so that the waving, feeding critters would be out. There was so much activity that, even in still water, the eelgrass blade floated to and fro.

Side view.

In the peak of the limpet shell, a new eelgrass plant is growing. Under its shade, there's a circular patch of bryozoans. The red blob above this, and red lines in other spots, are feeding tubeworms. At the rim, two tiny (less than a millimetre long) mussels are hanging on.

Empty worm cases (Spirorbis) on the top of the shell.

The feeding tentacles of many tubeworms, in the crevices between stalks and spiral worm shells, are only visible under a microscope; among them tiny crawling and swimming things wander about.

A mussel on the eelgrass. Maybe a millimetre long. And on its tip (look closely) there's another shell, possibly a limpet.

It would be much easier to examine this limpet shell without all the weeds cluttering up the view. Or so I thought, until I came to my senses and paid attention to them, too.

One branch, covered with buds.

More than buds.

The "weeds" are animals: hydroids, one of the Obelia* species. They are cnidarians, related to the jellyfish; the adults form stalked colonies, but the young start out as medusas, miniature jellies. The "buds" are polyps, some feeding, some reproductive. In the photo above, just above the centre, you can see one open polyp, feeding. The tentacles are tipped with stinging capsules that explode when a prey animal touches them, incapacitating it so that the tentacles can bring it down to the mouth.

When a polyp is disturbed, it shuts down quickly. Most of the ones I saw were closed. I guess I was scaring them.

A closed polyp, with the tentacles pulled inside a thin case.

Life cycle of an Obelia. Image from Kent Simmons, U of Winnipeg.

The reproductive polyp has no tentacles. Inside it, baby medusas form and are set free as they mature.

Empty reproductive polyp.

I saw one tiny stalk with the open tentacles at the top, hiding at the base of the eelgrass blade, either a new branch on the old colony or a young polyp, recently settled. It was too small, too transparent for my camera.

*Obelia. Sounds like a woman's name. Would you name a kid Obelia?