Cukes, worms, etc.

 I promised you critters in holes.  On the beach, at low tide. Here they are.

What was this?

Walking through the seaweedy area, I saw this little orange thing poking out from under a rock. Bright orange, warty, with tube feet and some sort of tentacly arrangement at the tip. I took a photo and moved on. There was another a few steps away, then more, all a half-finger's length, all with their tail ends down under rocks.

Another, with a darker tip.

This one was under a flat slab of rock, not too big for me. I lifted it gently. Here's what was underneath.

It's an Orange Sea Cucumber, Cucumaria miniata.

It wasn't disturbed by the absence of its shelter; it dipped its tip in the water and started to spread out the tentacles around its mouth. I very carefully replaced the stone as I found it.

Next: there were hundreds of critters in holes, these in the sandy area.

Tubeworm tubes.

There are two worms that make tubes that stick out of the sand at low tide in this area; the Red-banded Bamboo worm, Axiothella rubrocinta, and the Jointed Three-section tubeworm, Spiochaetopterus costarum. I think this is the bamboo worm; its tubes are coated with sand; the other makes transparent,  glassy tubes. The worms will be buried some 15 centimetres below the surface.

There are other residents down there in the sand. Some of them shoot water high into the air as I approach; clams (probably Piddocks). They're not attacking; they've felt the ground shake as I walked along, and are digging themselves down deeper, contracting rapidly, shooting water out of their siphons.

And along here, there are always little pink-tipped green anemones, that, once the tide has stranded them, have snuggled down into their beds, each showing only a hint of green in a circular depression in the sand.

At one point, tired from stumbling over slippery rocks, I took a break, sitting on a larger, dry rock (with a few barnacles, but no wet seaweed). In front of me was another rock, this one with holes dug into it. I took a photo, I'm not sure why. At home, looking at the photo, adding a bit of light, I realized that the holes were inhabited.

Arrows point to crabs and mystery beasties.

Not in a hole, but at the bottom of the rock,  there's a shell with a red line around the edge. I'm wondering if it could be a scallop. And what is that tiny white circle with a pink centre?

Another break. This one, on the way back to the car, but toasted and happy to get out of the sun for a bit I sat on the sand in the shade of a tall rock at the top of the intertidal zone. I  moved aside some leftover scraps of seaweed to put my bag down. And it was squirming. I turned over more; the pile was dry on top, but damp beneath, and full of tiny worms, almost too small for my eyes. The pocket camera could see better.

Fragments of assorted seaweeds and some twigs from the shore. And squirmy worms. There was a red mite, too, but it was too fast for me.

~~~~~~~~~~~~

Les prometí animales escondidos. Aquí están.

    1. ¿Esto, qué es?

En la zona donde hay muchas algas marinas, vi esta cosita anaranjada asomándose desde debajo de una piedra. De un color anaranjado brillante, con verrugas y pies tubulares y algo que parecía tentáculos en la punta. Saqué una foto y seguí caminando. Había otra dentro de pocos metros, y luego otras, todas más o menos la mitad del tamaño de uno de mis dedos, todas con la parte trasera escondida bajo piedras.

    2. Otra, esta con una punta roja.

Esta estaba debajo de una piedra plana, de un tamaño que yo podía levantar. La moví con cuidado. Y esto es lo que encontré:

    3. Es Pepino de Mar Anaranjado, Cucumaria miniata.

No parecía estar perturbado por la falta de su protección; inclinó la boca hacia el agua y empezó a extender los tentáculos. Volví a acomodar la piedra tal como la encontré.

Luego, vi cientos de tubitos en la arena, señal de las residencias de cientos de gusanitos.

    4. Los tubos de gusanos tubícolas. Hay dos gusanos en estas partes que construyen tubos que se extienden de la arena cuando la marea está baja: los gusanos de bambú, Axiothella rubrocinta, y el gusano de Tres Secciones, Spiochaetopterus costarum. Creo que estos son los gusanos de bambú; los tubos están encrustados con arena; el otro gusano produce tubitos transparentes, como de vidrio. Los gusanos estarán escondidos unos  15 centímetros bajo la superficie.

Hay otros animales viviendo en la arena. Algunos disparan chorros de agua al aire al sentirme llegar; almejas, (probablemente Pholas sp.). No me están atacando; unicamente sintieron la vibración del suelo y se están enterrando un poco más; al contraerse, expulsan agua.

Y aquí también siempre hay esas anémonas Anthopleura elegantissima; cuando les abandona el agua, se ponen a dormir, acurrucadas en pequeñas camas circulares en la arena. Apenas se ven las depresiones y tal vez una manchita verde.

Caminar donde las rocas están cubiertas de algas resbalosas es agotador; hice una pause, sentada en una roca grande y seca, con unos pocos bálanos pero sin algas mojadas. Enfrente tenía otra roca, esta con una serie de pocitos. Les saqué una foto, no me acuerdo porque. Pero en casa, mirando la foto, aumentando la iluminación, me di cuenta que algunos de los pocitos estaban ocupados. 

    5. Las flechas apuntan cangrejos, caracoles y criaturas desconocidas. En el fondo, debajo de la roca, hay una concha con una linea roja en el borde. Me pregunto si puede ser una vieira. Y qué será ese circulito con el centro color de rosa?

Otro descanso. Este, ya iba en camino de regreso, pero bien quemada y apreciando la sombra de una roca grande donde terminaba la zona intermareal, me senté en la arena. Arrimé unos restos secos de algas marinas, para hacer espacio limpio para mi bolsa, y se movían. El alga estaba seca solamente en la superficie; abajo estaba húmeda y estaba llena de gusanitos (estos sin tubos) tan pequeños que apenas los podía distinguir. La cámara de bolsillo ve mejor.

    6. Pedacitos de varias algas marinas, con palitos desde arriba, en tierra seca. Y gusanitos inquetos. También había un ácaro rojo, pero corría muy rápido y se me escapó.

More oldies - clamshell patterns

I lined up these clamshells on the White Rock beach to look at their designs.

All these were within a few metres of each other. 2009

The designs remind me of ancient Chinese brush paintings, such as this:

Painting by Wang Hui, 1662, Metropolitan Museum of Art.

And this one's from 2012, also at White Rock.

Good excuses

Why it takes us an hour to walk one kilometre, on flat sand. It's easy going, with nothing to slow us down.

Boundary Bay, with Mount Baker, at low, low tide.

But we keep stopping to take another photo.

Clam in a tidepool, with refracted light, through a few inches of water.

Empty clamshell

Crab molt

Foot long polychaete worm, from my tank, returning to home base.

In every tidepool, hundreds of tiny, darting fish fled at our approach. These ones were "escaping" from Laurie, while I stood off to the side, without moving, except for my shutter finger.

Feather, pink and brown clam shell, worm poop, bird footprint, and a few sandy snails. As found.

Detail of feather. Worth clicking to see the tips full size.

Wave-carved sand patterns

Lugworm egg case. Most are large oval bags; this one is almost round. With worm hill and poop.

Tiny Baltic macoma shell. Most of the ones on this beach are pink. Very fragile; half the ones I bring home don't make it.

Speckled stone, with dwarf eelgrass, Zostera japonica. The stem just to the left of the stone has a row of seeds in a half sheath.

Faster than a speeding clam

Every time we go to the beach, I watch the gulls breaking clams by dropping them from a height onto the stones. And for the last year or so, I've been trying to get a photo of the actual drop.

I've been too slow, the camera has been too slow, the gulls too unpredictable, the clams too fast. But persistence pays. Persistence, and a faster camera, anyhow.

Gull following the clam down. The clam is just visible in front of the mountain.

Yay! Now to catch the two, clam and gull, just at the moment of release . . .

Failed rescue attempt

For a few days, I hosted a pair of small clams that I found abandoned high and dry on the beach, probably dropped by gulls, then left because they didn't break. The treatment had been too much for them, though; they didn't survive.

But they tried their best. Here's one, showing his teeth.

With a hermit almost small enough to enter that tunnel.

A clam has two siphons, which it extends up to the top of the sand to feed. (This clam did not burrow into the sand, a sign that it wasn't feeling all that well.) Water enters through the one towards the front, away from the hinge, (the incurrent siphon), food and oxygen are filtered out, and the waste water is pumped out through the rear siphon (excurrent).

Since the clam is a filter feeder, straining out microplankton and organic "dust" from the water, the hermit crab is in no danger; he's not going to be sucked in by the gentle current the clam generates.

Nor will he be bitten by those "teeth" around the opening of the siphon.

I couldn't find a name or a function for these tooth-like structures.

Black and white

On the beach at Boundary Bay:

Pretty cockle, about 1 inch across.

Baby sculpin, about 1/2 inch long, trying to be invisible. At full size (click) you can see the rays of the tail fin, and the fanning pectoral fins.

And a male bufflehead, on Centennial Beach duck pond:

The black head is iridescent; here it glows purplish.

Where the birds were

A couple of days ago, we were in Iona Beach park, looking for birds and finding few. Here's why:

Before we left, I photographed this sign. (Yes, that's me and my flash, reflected in the plastic cover.) I didn't get around to reading it until tonight. It explains the lonely ponds and beaches.

The second paragraph reads,

"... a rich assortment of clams, worms and other marine invertebrates attract thousands of shorebirds at low tide. ... At high tide, the shorebirds move to the nutrient-rich Iona Wastewater treatment lagoons to continue feasting."

And when we arrived, the tide was at its highest point.

Iona park and water treatment site, Google maps.

The Wastewater treatment lagoons are the four squarish ones on the right. We walked around the two lagoons on the west side. Unfortunately, the treatment ponds are surrounded by a high fence, with a weed-covered, treed dike inside it, hiding them, except for a tiny glimpse from the top of the pipeline.

The second half of the sign. Clams, worms, and ghost shrimp. What the birds eat at low tide.

In the holdfast: feathers, spines, eyes and ... mustaches?

When the tide is at its lowest, we try to be there, to walk out to the far edge and wade in the eelgrass beds or scramble over the weedy rocks. Here the shore critters thin out, giving way to those that like deeper, colder water; here the big crabs roam and the geoducks spit at us as we walk. There's a line where the starfish start, a sunfish level, a nest of kelp crabs waving pincers at the careless hand, fish and sand dollars.

I always wade in, looking out at the deeper water, where the kelp grows. I can't go there. The swaying forest with its multi-species community is always just out of reach.

But at high tide, on windy days, the tables are turned. The waves rip up boatloads of kelp and eelgrass, roll them up like carpets, and toss them on the dry shore for me to poke at. I search the eelgrass for isopods and snails, the kelp for bryozoans and flatworms, or maybe even a nudibranch or two. This week I left the blades of kelp alone and we collected small holdfasts.

Holdfast, somewhat sun-bleached.

A holdfast looks like a root mass, but it doesn't gather nutrients. It's function is to hold the kelp down. At the far end are the long fronds, and the floating bladders; without a good anchor, the kelp is at the mercy (none) of the waves. The holdfast is tough and strong; it grabs onto rocks at the bottom, where it may stay for up to seven years. It's an ideal hiding place for small creatures, an interface between sea floor and live plant, a food source and a hunting ground. I wanted to see what lived there.

At home, I dumped my holdfasts into a bowl of fresh sea water, and gently pried and cut them apart. (Even the thinner stems are as tough as green wood.) Quite a few dead amphipods and skeleton shrimp floated off; it had been a rough trip, from sea floor to rollers to dry shore and sunlight, then to a plastic bag in the trunk of a car.  And the centre area, inside the teepee of "roots" was full of broken barnacle shells, the barnacles eaten away.

But then the worms came wriggling out. First, the polychaetes:

Small polychaete with an almost-human face. Love the moustaches!* And a live amphipod.

There were quite a few of these, mostly small; under a couple of inches long. And another few scale worms, which I had not seen before.

15-scaled worm, Harmothoe imbricata. I counted the scales, 15 per side.

Another 15-scaler, about an inch long.

Look at the upper end: each scale is like a sequin, circular. In these, one arc of the circle is black, which makes the pattern down the back. It is the same species as the one above, though.

And look at that little tentacly thing. That's what held me up; I couldn't identify it.

A better view. Notice the black dots on the central stalks of the "feathers".

I looked for others in the holdfasts, and thought I saw a tiny one like this, but with a stalk. I missed it, trying to fish it out, and never found it again. But there was something similar, fixed on the holdfast:

Hmmm ... Cnidarian, said my granddaughter.  Tubeworm? said I. Not in my book, whatever it is. About 1/4 inch high.

What else? There were a half-dozen mussels jammed in between the "roots", umpteen sand-grain-sized, black snails, many little brown isopods, several clams:

It looks like a geoduck, but it's barely a centimeter long, siphons and all. And it was the largest.

And loads of tiny green sea urchins:

Green sea urchin, Strongylocentrotus droecachiensis. With three black snails.

Sea urchins thrive on kelp, in such numbers that they are capable of killing an entire kelp forest if not kept down by other predators, such as sea otters.

Both sea otters (Enhydra lutris) and sea urchins (Strongylocentrotus spp.) play critical roles in the stable equilibrium ecosystem. Sea urchins graze kelp and may reach population densities large enough to destroy kelp forests at the rate of 30 feet per month. Urchins move in "herds," and enough urchins may remain in the "barrens" of a former kelp forest to negate any attempt at regrowth. Sea otters, playing a critical role in containing the urchin populations, prey on urchins and thus control the numbers of kelp grazers.

From NOAA.

The ones that came home with me are too tiny, as yet, to have done much damage. Now they're in my aquarium, in the remains of one of the holdfasts; they can eat that, for now.

Tiny, unusual shell. No snail inside. Checkered hairysnail, Trichotropsis cancellata. Eats leftovers from calcareous tubeworms.

And I was still wondering about that spiral of tentacles. I couldn't find it anywhere on the web or in my books. I decided, last night, to search again; I washed the bits of holdfast that hadn't gone into my tank thoroughly, again, shaking and prying at the stuff stuck in cracks. And I found these:

Feather duster worm. I don't know what species.

Same worm, different angle. This was about an inch and a half long.

I found several more, smaller and much smaller. The tiniest, I picked up in an eye-dropper:

Very much alive, and waving about.

So I'm thinking that the mystery "flower" (as Laurie calls it) is probably the plume of a feather-duster worm, broken off. I couldn't find its match in the Encyclopedia, but reading every description, I discovered another clue: some of these feather-duster worms have small eyes on the spine of the branches (radioles). The twin-eyed feather-duster, Bispira sp., for an extreme example, may have as many as 1,000 pairs!

Here's that photo again:

Are those eyes?

I almost forgot: there were also at least three flatworms, so tiny they were just pale brown specks that wandered around when I put them in a plastic cup with a few teaspoons of water. They're in the tank, now; competition for the two big ones that were already there.

*Reminds me of Yosemite Sam.

When is a worm not a worm?

Answer #1: When it's a clam.

I grew up hearing about shipworms, the dreaded teredo worms that ate the logs that supported our wharves and float houses, and made our boats leaky. I'd seen their long holes in driftwood, and their white tubes cemented into the holes; long, snaking tubes for a tubeworm. Not until tonight did I learn that I had been completely mistaken about them all these years.

A teredo is a clam. An odd clam, to be sure; it's long (up to 2 feet) and snaky, like a worm, and the body's only protection is the calcareous tube it coats the tunnel with. But it does have the clam shell. On it's "head", or at least, the leading end. And it uses the double shell as teeth, to chew its way through the wood.

Its two shells, enclosing only the front end of the body, function as a tool, rather than a protective covering; their ridged and roughened surfaces are used for boring. (From bruceruiz.net)

Like other clams, it has two siphons. They are at the "tail" end. And the leading end is the foot. (It's a bivalve monopod.)

Drawing from bruceruiz.net

I was looking teredos up because Laurie took an interesting photo of shipworm-eaten wood today. I wanted to check my spelling, and ended up wandering around shipworm pages. Fascinating!

Like other clams, the teredo is a filter feeder, straining plankton from the water. But it also eats some of the wood it burrows in, with the aid of the bacteria it houses in special structures called "bacteriocytes". These bacteria produce enzymes that digest the cellulose of the wood. (Nobanis) They also "fix" nitrogen, and produce necessary amino acids.

(In this way, they are similar to termites, which also rely on protozoans and bacteria to digest the cellulose in wood. And similar, also, to us humans, whose intestines are home to many bacteria that work with us to digest our food. Not wood, though. Our bacteria can't handle cellulose.)

Laurie's photo. A rain- and wave-worn section of shipwormy log. Our local teredo is Bankia setacea.

Or there is Answer #2: When it's a crustacean.

The gribble, or gribble worm, as it is often called, also drills through wood found underwater,  like pilings, float logs, and boats. It is not a worm, but a crustacean, a marine isopod.

Limnoriidae are second only to theTeredinidae in the amount of destruction caused to marine timber structures such as jetties and piers. ... Gribbles bore the surface layers of wood, unlike the Teredinidae which attack more deeply. Their burrows are 1–2 mm diameter, may be several centimetres long, and have the burrow’s roof punctured with a series of smaller ventilation holes. Attacked wood can become spongy and friable. (From Wikipedia)

These critters seem to make their own enzymes to digest cellulose, but at least one species does find a use for symbionts:

L. tripunctata is unusually tolerant ofcreosote, a preservative often used to protect timber piles, due to symbiosis with creosote-degrading bacteria. 

Log showing gribble damage, and a teredo tube. Oyster Bay.

Come to think of it; I've never seen a live gribble or teredo; just their holes. I must remedy that.

Getting muddy. Or not.

Along the highway leading into the Boundary Bay beach area, a sign warns of extreme high tides.  (Checking the tide tables, I see what they mean; across the bay from us, high tide was 13 feet. On the other side of the peninsula, it was just under 16 feet. That means the water comes right up to the walls that protect the community's back yards.)

We were lucky, though; we stopped at the inner end, the Mud Bay end, but we got there as the tide was going out.

Looks good. But it's slippery, soggy, mushy, sticky mud. Goopy mud.

Logs, mud, and watery mud.

Did I mention that we were on the Mud Bay end? Until it's been dry for a while, you can't walk there without good boots. Unless you're a horse with big, floppy feet:

Splash, splosh, plop.

Hope they like being groomed. They're going to need it.

My boots are in the bathtub, getting dry enough to clean. At least they're waterproof up to the zipper at the ankle. Laurie's shoes were not.

But the view was worth it.

Mount Baker, from a back yard. Not ours, unfortunately.

North Shore mountains, with a flight of sandpipers.

We brought home a few pale pink macoma clam shells* that had been tossed up alongside the walls. In one of them, I found a tiny flatworm (1/4 inch long), the palest, cleanest, almost transparent green; its miniature ruffled pharynx gleams whitely from its middle. How it stays that clean in sticky mud is a mystery.

*I didn't know this about macomas:

"Macomas are mud-dwelling clams which differ from most other bivalves in their mode of feeding. Most clams are filter-feeders. They draw water into a siphon, filter out nutrients and exhale the filtered water through another siphon. Macomas are deposit feeders. The inhalent siphon is very long and and sweeps over the mud, acting like a vacuum cleaner." From MBL (Woods Hole)