Sunday, February 19, 2012

Between the grains of sand

With a good microscope handy, I've been able to look more closely at what's happening on the White Rock beach. Last Tuesday, I brought home a few small containers of sand and water from the contaminated area. I've been examining them to see what's alive, down there between the sand grains.

Wet sand, as my camera sees it. The little orange specks are alive.

I've been taking notes, mostly sketches of what I see, and I've scanned a few pages. I can't identify any of these things, but they give an idea of what's there. Everything I drew was alive and moving. A couple of times, a humongous (or so it seemed) copepod scooted by, at least 10 times the size of the biggest of these critters. The copepod would be about 1 to 2 mm. long.

The images may be pale; I find them easier to see by clicking to get a full-size photo.

Page 1. "Hamburger critters" like a split bun with something in between, boxes and pen-like things.

The ones labelled "1" and several similar ones don't quite match each other, but may be different stages of the same animals. # 5 is like them, but was the largest I saw. In the center, I could see something fluttering. They all swim slowly, along the length-wise axis. The "pens", # 4 and three similar ones, moved only their tips as long as I watched.

Assorted swimmers and jittery stuff.

#6 looks like a piece of threaded pipe. All the ones I saw were the same size. #8 is sort of like an amphipod, but extremely jumpy and hard to see, even though it was large. The antennae/legs/hair moved constantly.

#9 is one of the strangest animals. These are very tiny, like a balloon on a black thread. The top constantly bobs back and forth, always in the same direction.

And #10 is like a hairy flatworm, always changing shape; it has no features that I could distinguish.

Worm?

This was another of the larger animals. It lay against one of the sand grains, moving along sluggishly. Occasionally, something would startle it, and it contracted instantly into a collapsed balloon shape. A minute later, it stretched out again. I'm not sure if I saw tentacles at the forward end, or if they were a trick of the light.

Movers and shakers.

These were the weirdest of all. #13: a blob with a smaller blobby end. It turned around and around, circling about the narrow "head" end, as if it were attached. To what? It was in an empty space between widely-spaced grains.

#14 is tiny. I only saw the one. A rough pyramid, with a tentacle that I could see inside the body as well as out. It traveled with the tentacle in the lead.

#15. A tubeworm? Long and snaky, it hid behind a sand grain, extending the tip. Closed, it looked like a worm head, but it kept opening wide, showing a circular mouth. From time to time, it suddenly extended itself its full length again, as if to capture something.

#16. I can't figure this one out. A dark oval shape that spins and spins, always in the same direction, very rapidly. I could barely see the connection, but a tiny blob spun with it, sometimes close, sometimes a distance away, but always coming back as if tethered.

#17 looks like a baby sand dollar. #18, like a jellyfish. Many different animals start life as a medusa, a jellyfish shape; this could be any of them.

Besides all these and the copepods, I saw a few larger worms slithering about.

All this is good news: there's life down there. Two of the containers held sand and water from about 100 feet down the beach from the center of the dead zone; they were full of those "hamburger" critters, and others. But the two bottles from the center were basically empty; nothing but sand grains and a tiny worm.

Elva Paulson asked how big the dead zone is. I checked again, on Google maps. From where we access the beach, moving west, we went, the first time, 300 feet before I found anything alive. The next time I measured, the zone had extended and the borderline was 1700 feet down the beach; about 1/2 kilometer.

Tuesday, we began to find beach hoppers and tiny snails somewhere between those two distances. And the first bottles of sand I collected were well within the former dead zone, about 100 feet from the access.

Looking at the satellite photo, I notice that a creek comes down from the top of the hill, just there. I wonder if there's another construction project up top.

Stumble Upon Toolbar

4 comments:

Snail said...

It is a bit difficult to tell without having them here, but maybe your hamburger critters are diatoms?

#8 could be an ostracod or something similar.

A possibility for the tentacled things is hydroids.

If you can find a good guide to meiofauna, esp. one with pics, that might help you track down the IDs.

sarah said...

This post so cheers me up. Life, life, life! As usual, I don't know a blessed thing about any of this stuff, except it's obvious to me that #3 is the remote control. Keep sharing!

Snail said...

I'm almost convinced that Sarah's right about #3, but it could also be an Iced VoVo.

Susannah (Wanderin' Weeta) said...

Sarah, So that's where it got to!

Snail, thanks! I found the diatoms. They're probably Navicola sp. I found another #8 today; yes, they do look like ostracods. And I found several hydroid colonies.

I haven't had much time today, but I did find a couple of good galleries of images to search through tonight.

I'm glad I got these done; today my grandson came by, took away the microscope, and loaned me another, one that will do insects, but not diatoms.

Now I'm hooked; I'll have to buy my own asap.