The Blob

Last night I sat down with “Amphibians of Oregon, Washington and British Columbia” by Corkran and Thoms …. Looking forward to looking up the great big egg mass we found attached to some submerged wood at Ben Irving Resevoir. Wow! It was a duzy. It was a gelantous mass about a foot across and sunk even deeper into the water than that. But what was it? My best guess was maybe several amphibians laid their eggs together, the eggs hatched, and now a big slithery mass of firm goo floats just beneath the water surface. Either that or some science fiction movie dude has been at work.

My book has a nice ‘egg key,’ i.e. it asks questions and based on the answer you go to another question until the find which amphibian is involved. Sounds easy, doesn’t it. The first question was easy: are the eggs laid in a string or in a mass of jelly. Jelly! But the farther I got, the more confused I became. Nothing seemed to fit. Finally I went back to the beginning and found a hint I shouldn’t have overlooked: Not all jelly masses are egg masses; some are certain types of algae.

Nest step, the computer. I Googled ‘jelly mass + algae’ and then clicked on the University of Maine’s website, “ What’s that stuff in water?” Now we’re cooking! Maybe I’ll solve this mystery yet. I soon learned my big blob wasn’t algae either.

“What’s that stuff in water?” did have a photograph that looked somewhat like my blob ; and it was big -- “Bryozoan” or “moss animal.” I never heard of that! But I had to admit this blob isn’t exactly what I expect to stumble across when peering down into Ben Irving Reservoir. Now my curiosity was really piqued. I spent the next hour gleaning information. I am amazed to find there is a basketball sized animal living twenty-five miles from me and I never heard of it.

Bryozoan colonies are made up of tiny animals called ‘zooids.’ They live in colonies rather like sponges, but sponges are different in that their colony of animals builds a firm structure, the sponge. Bryozoan zooids also build a communial structure but it is gelantous and basically leaves no trace when the colony dies. We had found a bryozoan colony, in fact we found we found several when we started looking for more. Each colony was attached to a piece of submerged wood, an old root or a stick. It is likely this colony is made up of Pectinatella magnifica, one of the several fresh water bryozoans. Most bryozoans are marine.

Each colony started from one statoblast, the tiny disk-shaped ‘seed’ that the mature zooids put out in great quantities. Remember, this is a plant and not an animal, but ‘seed’ is the best word I could come up with. I think the dark spots on this closeup photo are statoblasts and golden spots haven’t matured yet.

This photo is of a fairly young colony on the nearest stem. The original statoblast has already grown into fifty or more lumps. Each lump will eventually look like rosettes on the larger ball, and each one contains 12 to 18 zooids.

Here is the bryozoans colony that started all this fuss … the one that is about a foot across and sinks even deeper into the murky water. If you poke it, it is quite firm.

These big slimy balls of goo may sound creepy, but further reading tells me they tend to live in water that can use some cleaning up. Each zooids has a filter system by which it eats, improving water quality in the process. This food gathering organ was too small for us to see with our naked eye, but apparently is extended during feeding or can be withdrawn into the interior of the colony. Until fairly recently bryozoan colonies were only known to be found east of the Mississippi River. So far it is a mystery how they got to the West Coast, but the statoblasts are extremely durable. They can freeze, dry out, and stay dormant for long periods of time. Man or even a bird could have brought them West.