Friday, December 18, 2009

Veggie shopping. On the beach.

I wanted some sea lettuce. Or, in its absence, a bit of rotting kelp. Not for me, of course, but the crabs and hermits in my aquarium love the stuff. And the barnacles were wanting some fresh sea water, swarming with plankton. So when it stopped raining, we headed down to Boundary Bay again, plastic bags and bottle in hand.

Centennial Beach was almost empty; the sensible people were staying inside, in the warmth.  The pond was iced over.

"Thin Ice," a sign warned. I tested it, following Hugh's example, throwing rocks onto it. It didn't even chip. Not so thin.

There was no ice on the bay; the water was too bouncy to freeze.

A colourless day, grey and chill. The tide was high, just starting down. A few seagulls bobbed up and down offshore. The only sound was the incessant "Swish, swish, swish" of the waves.

We walked along the edge, poking in the eelgrass for goodies. Laurie found a small clam, and a ring of limpet shell, just the rim. I found an empty snail shell. Nothing else; the waves were tying everything loose up in tight knots of eelgrass. There was no sea lettuce, not surprising in mid-winter, of course. I did pick up a few pieces of kelp with holdfasts; the crabs swarm over those, poking into all the crevices for choice edibles.

Water for the barnacles, good stuff, full of stirred-up nutrition; I uncapped my bottle and dipped it in a spot where the shore slopes down steeply. An extra-large wave caught me unprepared, soaked my jacket sleeve and threatened my ankles. I gave up, with barely a cup of water. We were half-frozen anyhow.

A hint of colour and form on the way back across the dunes.

Sculpture. Needs a name.

At home, I decorated the aquarium with kelp and eelgrass, poured the cup of water over the barnacles. My offerings were enthusiastically received with waving cirri and snatching pincers. I rinsed out the plastic bag, and checked the bit of detritus for amphipods or miniature snails. A micro-dot of a critter was dancing along the bottom of the bowl. Even with the hand lens, it was still a speck; I got out the microscope.

Critter. 0.75 mm nose to tail. That's 750 micrometres (┬Ám), or 1/30 inch.

I don't know what it is. Some sort of larva, maybe? Or an animal too small for my books to notice? Does anybody know?

I also found this little shrimpy thing.

I would say it's an amphipod, since they are plentiful in this water, except that the tail doesn't curve under. Help!

All in all, a productive afternoon, even though there was no sea lettuce.


  1. I pulled out my handy Guide to Microlife book that I purchased shortly after obtaining a microscope and numerous peanut butter jar ecosystems. I think it is very nice they didn't name the book "morons with microscopes," as that is certainly how I feel sometimes. But it certainly is enjoyable for me when I'm trying to identify creatures.

    On first glance of your second shot, I certainly would have said amphipod as well (I easily have thousands living upstairs). But given the odd tail, maybe it is some sort of (order) eucopepoda. A pic in my book of a (genius) canthocamptus is very similar, although it has a longer tail. Did you observe it swimming? Was it a side-swimmer like an amphipod? Maybe the tail is straight because of what is inside it.

    The first one has me seriously stumped. It looks pretty complicated; I'd be excited to hear if you learned more about it.

  2. Bill, Thanks! I Googled your order and genus names, and looked at photos. From what I could see, the two are copepods. I found photos similar to the "shrimpy" one, with the straight tail and all.

    The other one seems to be some species of Cyclops. In my photo, you can see the one eye, center front. I didn't find any exact matches, though.

    I'll keep looking.

  3. It doesn't help when half of the sites I find are in Japanese or Dutch. At least I can stumble through the Dutch, but the Japanese is far beyond me.

  4. Neat. I tried Google Translate with Japanese (and other Asian languages) with moderate success. It is a cumbersome task, but when in a pickle, it does the job.

    The book I use for such micro searches is Guide to Microlife by Kenneth Rainis and Bruce Russell. It is a little pricey for a fairly tiny paperback ($35 US, $49 Canadian), but full of pretty good info (although I didn't get an exact hit on your guys, it did give some options to continue searching). I bought my copy off Amazon which probably had a decent discount.

  5. Thanks, Bill. I'll look that one up.


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