Sunday, June 29, 2008

Life on the edge

... water's edge, that is. Where the living is precarious, the environment sometimes cold, sometimes hot, now wet, now dry, now saline, now fresh. The highest intertidal zone and the splash zone.

We've been combing the rocks around the Kwomais Point headland, but recently even the afternoon low tide has been high. (Today's tide levels at White Rock: 5:12 PM - 3.7 m, 8:49 PM - 3.4 m, 1:38 AM - 4.1 m. Only the morning tide is low: 9:53 AM - 0.4.) And we've found several things I'd never seen before.

Laurie has been looking at seaweeds. I never knew there were so many types!

Rockweed. The old, familiar rockweed.

I've been comparing our photos to the ones I found on a great ID site, WSU Beach Watchers EZ-ID Guides. I've been able to identify some, but not all of the seaweeds we found. I'm still searching for the most intriguing of them all, which I'll post about in a day or two.

Green algae on the lower edge of a wet rock. And a limpet to feed on them.

And I, being in a mood for rockclimbing (of sorts), have kept more to the splash zone. And lookee here!

A tidepool, just below the highest tide line. Nothing much in it but barnacles and mussels. But while I watched, something moved.

Zooming in. See that red beastie? He was moving fast; in a couple of seconds he had scuttled out of site.

He's a Neomulgus littoralis, a red velvet mite. BeachWatchers says,
This little arachnid is only about 3 mm in diameter or about the size of a period at the end of a line of newsprint. It is found on driftwood or rocks high in the intertidal where it looks like a tiny bright red dot and may be stationary or scurrying along the surface. These little mites feed by sucking the fluids out of kelp flies.
The three I found were scurrying.

I found a great photo of these on BugGuide. "Racing", the photographer says. Except for these two. A lucky shot.

And just a bit higher on the rocks, on a bare, dry boulder, I saw what looked like a giant pillbug. Except that it was running far faster than any pillbug I had seen. I jumped up to another rock, how I don't know (Laurie had to help me down later), to get a photo. Too late; he had disappeared down a crevice. I watched that crack for about ten minutes, barely moving, in case he reappeared. Nothing doing, although I did get another distant shot at a red velvet mite on a dry rock.

I found the isopod on BeachWatchers, though. He's a Ligia pallasii, the sea slater, or rock louse.

RaceRocks has a video of these creatures, including a shot of a cute one trying to escape the weighing station.

Both these sites are copyrighted, so I can't borrow a photo; you'll have to go see for yourself.

Next: the seaweeds.

1 comment:

  1. Fascinating stuff on the beach! Thanks for the pointer to the new (for me) ID guide.


If your comment is on a post older than a week, it will be held for moderation. Sorry about that, but spammers seem to love old posts!

Also, I have word verification on, because I found out that not only do I get spam without it, but it gets passed on to anyone commenting in that thread. Not cool!