Tied in knots

The tide was high, the wind brisk, the waves bouncy. The beach near Salmon Point was just a narrow strip of stones between the water and the rocks of the breakwater. I was there to look at eelgrass and kelp, torn from their roots and holdfasts, all tangled and tossed up by the waves.

Tangle of fresh bull kelp and eelgrass.

A knot like this is full of interest; teasing out separate strands, I find mostly eelgrass, rockweed, sea lettuce, and kelp, with occasional fragments of Turkish towel or washcloth, and maybe some spaghetti-like brown algae. Living on the blades of kelp are bryozoan colonies, sometimes, if I'm lucky and sharp-eyed enough, with their tiny cryptic nudibranchs. Any holdfasts that show up house miniature worms and immature snails, possibly a baby starfish.

The eelgrass carries snails and amphipods, sometimes a stray hermit crab. And in season, there are a variety of snail and nudibranch eggs, all doomed to be tossed onto the stones to die and be sundried. Some of the eelgrass crumbles and disappears; some remains as blackish heaps, leaping with sand hoppers. 

The kelp stipes hold their shape for a long time, bleaching to a greenish yellow. Crabs and hermits love to eat this when it ends up back in the water.

Eelgrass and sea lettuce. Green blobs in the waves themselves are sea lettuce washing in.

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

La marea estaba a su máximo, la brisa algo fuerte, las olas caían en espuma sobre las piedras de la playa que ocupaban apenas unos metros entre el agua y el rompeolas de piedra. Yo estaba allí buscando hierba Zostera y quelpo, arrancados de sus raices y rizoides, hechos nudos y depositados por las olas sobre las piedras.

Primera foto: un nudo de quelpo Nereocystis luetkeana y de hierba Zostera en la playa cerca del Punto Salmón.

Un enredo como este tiene mucho de interés. Al separar cada hoja y estipe, encuentro en su mayor parte hierba Zostera, el quelpo, lechuga marina (Ulva sp.), sargaso vejigoso, con fragmentos de toalla turca, y otras algas pardas. En las hojas del quelpo viven colonias de briozoos, y a veces, si tengo suerte y los ojos no me fallan, con sus nudibranquios crípticos que comen los briozoos. Los rizoides que llegan al nudo protegen anélidos pequeñísimos y conchas marinas juveniles, y a veces una estrella de mar infantil.

La hierba Zostera marina lleva conchas marinas y anfípodos, y de vez en cuando un cangrejo ermitaño. En ciertas temporadas habrá huevos de varios nudibranquios y conchas marinas, todos destinados a morir sobre las piedras, tostarse en el sol, y o quedar como un montoncito de fibras negras donde saltan las pulgas de arena, o desmoronarse y desaparecer.

Los estipes del quelpo permanecen por largo tiempo, volviéndose suave y de un color amarillento. A los cangrejos y ermitaños les gusta comer esto, cuando por suerte cae otra vez en el agua.

Segunda foto: piedras, olas, y hierba Zostera. Las manchas oscuras dentro del agua son fragmentos de lechuga marina.

Under the dock

Hurrying from the sailboat to the inn for supper, I paused, just a moment, to look down. Everything under that dock is covered with critters.

Plumose anemones, Metridium senile, and a bright red tubeworm.

Hanging on a chain, swaying in the current, a mass of mussels, a starfish eating them, and what looks like legs of at least one crab on the far side.

At the Campbell River docks, in the last few years they have been replacing the old log pilings with metal ones. I used to find many animals down along the logs; anemones, shrimp, crabs, mussels, nudibranchs, sponges, tubeworms, scallops, barnacles, unidentified blobs. And seaweeds, green algae, kelp, red algae, yellow fuzz. On the metal ones, nothing grows. I have peered down the cracks around most of them; they're a bit fatter, and leave less space around them in the dock opening. Nothing moves, nothing attaches itself. They're clean.

On old metal found on the beach, even metal not so old, barnacles and mussels find a home. On the chain above, all metal, only the part that is usually out of the water is clean. I'm wondering: are those new metal pilings coated with some wildlife-deterrent chemical agent?

Bit of old ship, Oyster Bay, in a high current area. Seaweeds, barnacles.

The pilings at the Heriot Bay wharf are logs. And they're home to thriving communities. I hope they don't decide to "improve" them.

Worm caves and oyster grins

I bought an old abalone shell in a garage sale for a buck, 11 years ago. It sat on a shelf until I decided to use it in the aquarium as a hermit crab gym set. It has been very popular. The plumose anemone has chosen it as her permanent base, worms have built their tubes on the back, limpets sleep on the shiny floor, and the hermits still climb to the top to look at the world.

Over these ten years, much of the shell has dissolved into the water, and assorted algae have coated the rough outer side, creating interesting patterns. And colonies of tiny worms have made their homes in the pores, by now eroded into deep caves.

Outer rim of abalone shell, with algae and worms

Abalone shell, before being tanked, 2007. The outer shell is porous. The barnacle and tubeworm remains dissolved long ago.

The oyster, picked up on the beach after a storm, has been here only a few months. The shell was scrubbed white by wind and waves, but tank algae are at work here, too. And the oyster, not in the least fazed, is grinning.

Toothy grins

The oyster is a filter feeder, and pumps large volumes of water in, over the gills, where edibles are caught in mucus and moved down to the mouth.  What looks like teeth in those smiles are tiny tentacles. The gills are just behind them, sometimes visible when the oyster opens a bit wider.

Infinitely complex

I was inspired by a scientist on Twitter a few days ago. Allison studies species interactions, and her experience has been in the intertidal zone. As she says, she has had"my face down in the seaweeds for 5 years" looking at communities composed of hundreds of species.

To illustrate her Twitter series, she has been searching through her old intertidal photos looking for examples of interactions between species. "What a good idea!" I thought, and dug out my oldest photos, looking for the extras, the critters that weren't the feature of the photo, but were living alongside them. What have I missed?

Worms, barnacles, mussels, miniature sea urchins, sponges, anemones, tiny fish, more worms, more worms, eggs. Seaweeds of all kinds and colours. Most of these are in the unfocused areas of the photos, but they're there.

Purple starfish. With barnacles, stubby isopods, sponge, a worm, and a half-dozen hairy hermit crabs, walking on the star, or nestled between two of its arms.

Another starfish, with at least 5 species of seaweeds. Blowing the photo up, I discovered many tiny snails, one large blue-shelled snail, a crab, a limpet and, of course, barnacles. No telling how many beasties are sheltering under the seaweeds.

I still have oodles of photos to examine. I wonder what else I'll find.

Miniature water garden

No matter how often I scrub the inside walls of my aquarium, it usually has a haze of green and red algae growing back. And a school of copepods browsing among the plants.

I usually scrub it all off, just before I take photos. This time, I left things as they were.

Yellow-green and red algae start off with circular spots, becoming splotches. Green-green algae start off as blobs, become bigger blobs. Sand grains (regular fine beach sand) show the comparative sizes.

The copepods have one eye each. The ones carrying a round trailer are females; look closely at the one on the left: you can see the egg cases.

In the sand below, miniature polychaete worms scoot up and down their tunnels, waving twin tentacles to capture today's lunch, bits of detritus, scraps of the algae.

Here, the tentacles extend up into the water column. Food particles travel down a groove to the hungry mouth below.

My flash disturbed the worm and he shrunk back into his tunnel. But he soon forgot about it, and pushed back up to the surface to keep on fishing.

Today, I also saw a two-inch long green ribbon worm, out looking for prey. He's an active predator who likes barnacles. He hid in the sand before I collected the camera.

Blooming meadows

A couple of days ago, I posted a photo of a tiny beastie I'd just discovered in my aquarium.

Here it is again. A couple or three millimetres long.

Yesterday, I took dozens of photos of the general area, mostly on two oyster shells and the sand around them. I found several of the same animals.

There are two here. The colour is lighter, but the characteristic stripes are the same. And the size. I think they're baby snails, born in the tank. The little green things may be copepods, taking a break from their constant racing about.

Zooming in close like that, ignoring the parade of hermits and crabs and focusing instead on the background, I noticed how alive this "bare" surface really is.

Fertile fields. Algaes and diatoms, protozoa, and who knows what else. Pinks and purples and greens and blue-blacks. Good grazing for a tiny snail.

The hermit's shell is populated, too. Look at the edge, where the light shows up the tiny pink and green growing things.

It's turtles flowers all the way down.

Pink hair

Occasionally, wading in the eelgrass beds, I see what looks like a swirl of delicate pink lace floating by; finery that, bought in a store, would have a label saying, "Handwash only, with care."

They're remarkably resilient; I caught a double handful, tossed it in my bag, threw a couple of heavy clamshells and a tangle of eelgrass on top, and hauled it from pillar to post around the beach. It made the trip home intact, with not a shred torn off.

Filamentous red algae, with mussels, snail, and at least one skeleton shrimp. Can you find it?

Collected fresh like this, before they've been tossed up on the beach and sun-dried, they're home to hundreds of small critters. Skeleton shrimp are usually the first I see, mostly because they keep dancing. Then there are tiny black dots that under the microscope turn out to be baby snails and mussels. And each thread of the lace is surrounded with fine hairs, and a swarm of zippy copepods, and in season, jiggling crab or hermit zoea, trying to dodge the skeleton shrimp.

And then there's the seaweed itself:

Dotted-line branches. With passengers.

Zooming in.

My Encyclopedia tells me that there are maybe 60 or more species of these filamentous red algae along our coast, usually under 6 inches long.

Most are difficult to identify without the aid of a microscope.

Filamentous algae are made up of rows of single cells, in some species forming long threads, in others, branching. Each cell has a double wall; the outer ring contains the pigment that gives it the red colouring, phycoerithrin, masking the clorophyll that converts sunlight to sugars.

These are large cells; think of those snails crawling up and down the threads; multi-celled critters, with a complex anatomy, each total smaller than one cell of the algae.

Serendipitous goop

Ok. I've been told to stop dawdling and get on with it.

Remember the white stuff that showed up in my aquarium leavings? Maybe not. Here's what I wrote then, September 30th:

Last week I emptied the tank, washed the sand, and replaced everything. As usual, I kept out the dirty water I'd washed the sand with, and let it sit overnight, just in case any tiny snails were hidden in the gunk. Normally, the dirt settles, and the snails climb to the top, where I catch them and return them to the tank, then dump the goopy mess. 

But this time, there was a white network of fibers just on top of the settled gunk, below the inch or two of clear water. I stirred the water again, and let it sit. Two hours later, there was the net again. Three times I stirred it; every time, white lines made a road map along the top two hours later.

And here are a couple of photos:

The white stuff is all tiny, almost straight fibers, growing at both ends.

Growing and spreading across the bowl. This is a patch about 3 inches across, IIRC.

I asked for help. People made suggestions in the comments: marine slime molds, mineral precipitation, salts. Nothing worked out.

Then, reading the article about sea star wasting syndrome by Ron Shimek, I found photos, a description and a reason that matched what I had found. They're bacteria; Beggiatoa sp.

The Reef2Rainforest photo:

Bacterial mat, in the wild.

"The black surface and white bacterial mat is exactly what would be predicted after a major mortality event in the sediment. The black sediment is made in anaerobic environments by sulfide loving bacteria. It is the result of significant decomposition in the sediments proper- where animals died and are now decomposing and releasing a lot of nutrients from their rotting bodies. ..." (From the photo text.)

The white is a characteristic bacterial genus named Beggiatoa. It has several species that metabolize hydrogen sulfide and decomposing critters. (From the caption of another photo.)

The mat in my bowl was on the gunk that I'd collected from washing the sand and the filter in my aquarium. It would have decomposing critter food, mostly shrimp pellets, and rotting eelgrass and sea lettuce. I could smell the shrimp, faintly. I had poured off the clean water as the muck settled, so there was only an inch or two of water over the black stuff; a concentrated mess of rotting animals and plants. It would be more acidic than the clean water I replaced in the tank; Beggiatoa likes acidity.

Beggiatoa lives in freshwater and marine environments. It is present in all the world's oceans, from shallow intertidal waters to the bottom of the deeps. It would be found in the stuff I bring back from the beach, but not in a concentration sufficient to form this sort of mat until I isolated it. I have tried to see if I could recreate the conditions and grow another batch, but not so far.

And they're fascinating bacteria! They are one of the largest prokaryotes (bacteria and similar organisms); up to 200 microns in diameter. That's 2 millimetres, the length of a small carpet beetle. And each filament may grow up to 1 centimetre. No wonder I could see them with the naked eye!

The metabolism of prokaryotes is far more varied than that of eukaryotes (That's everybody else, including us. -Me), leading to many highly distinct prokaryotic types. For example, in addition to using photosynthesis or organic compounds for energy, as eukaryotes do, prokaryotes may obtain energy from inorganic compounds such as hydrogen sulfide. This enables prokaryotes to thrive in harsh environments as cold as the snow surface of Antarctica, studied in cryobiology or as hot as undersea hydrothermal vents and land-based hot springs. (From Wikipedia)

Most Beggiatoa don't need organic food, nor sunlight, to grow.

They are one of the few members of the chemosynthesizers, meaning that they can synthesize carbohydrates from carbon dioxide and water using energy from inorganic compounds. Beggiatoa are found in polluted marine environments, and can be seen by the naked eye as a white filamentous mat on top of the water as a sign of environmental deterioration. (From MicrobeWiki.)

Not all Beggiatoa are white; some are yellow or orange; the white comes from granules of sulfur stored in the filaments.

As I saw, the filaments move about, both spreading, gliding along, and moving vertically. (How they do this, I couldn't discover.) "They respond to oxygen, light, and presumably sulfides."

They prefer the interface between a solid sulfide-containing base and oxygenated water, and use elements from both. In some situations, the surface sediment is oxygenated during the day, due to the the activity of algae in the sunlight. Then when the sun goes down, the oxygen is depleted and the sediment becomes anoxic. Beggiatoa pick up sulfides in the anoxic zone at night, then combine their sulfur with oxygen from the water in the daylight. A short video on YouTube shows this process.

They grow where there is an abundance of rotting organic matter, where the decomposition processes have resulted in an acidic, anoxic, sulfide-rich environment. This means that they may be a marker for pollution, such as sewer outfalls, or die-offs. But they do not contribute to the pollution; rather they help to return the area to a condition usable by more "normal" life forms.

So, while they showed up where the sea stars are dying, they are not the cause. Scientists are still looking. (Maybe it's a virus.)

More info.
The Genera Beggiatoa and Thioploca
And the original article, again.

No end to mysteries

I do routine maintenance on the aquarium, daily, and half the time, it seems that I have to say, "What on earth is that?"

Last week I emptied the tank, washed the sand, and replaced everything. As usual, I kept out the dirty water I'd washed the sand with, and let it sit overnight, just in case any tiny snails were hidden in the gunk. Normally, the dirt settles, and the snails climb to the top, where I catch them and return them to the tank, then dump the goopy mess.

But this time, there was a white network of fibers just on top of the settled gunk, below the inch or two of clear water. I stirred the water again, and let it sit. Two hours later, there was the net again. Three times I stirred it; every time, white lines made a road map along the top two hours later.

Monday evening

I looked at the clumps under the microscope: all I could see were tiny, straight threads. Watching one for a while, I could see it grow, lengthening at both ends. When I stirred the mix, I could still see shreds of threads, unconnected. But two hours later, there was the network again.

Monday evening, overview. The bowl is 6 inches across. This is about a 3 inch section.

I was gone for a day, and came back Wednesday afternoon. Part of the bowl was covered with a papery coat; the rest was still clumps of threads, some still making a road map.

Wednesday afternoon

Zooming in, Wednesday afternoon.

The filled-in areas looked like papier-mache pulp; all short, white fibers, arranged every which way.

Thursday afternoon. The "roads" are gone, replaced by individual clumps.

I looked at several of these clean clumps under the microscope. There was nothing to see but the white fibers, still short and straight, sticking out in all directions.

Zooming in. Nothing but white fibers on the dark background.

Over the weekend, the threads covered the whole area, without any organization into clumps or roads. When I shook the bowl Sunday night and again this morning, they disappeared, and returned in a couple of hours to the final, uniform covering. No roads, no clumps.

I don't even know where to start to find out what this was.