Sultry summer days practically beg to be enjoyed near the shady edge of a lake. The shade keeps it cool and makes it possible to enjoy birds, dragonflies, butterflies and fish.
One organism that’s noticeable in July is a mysterious floating mass of jelly. It looks like a football-sized blob. It’s usually attached to a log or stump in a shallow area, and it seems to have a textured fuzzy coating.
The first time I encountered one of these gelatinous masses many years ago I was perplexed. It reminded me of nothing I had ever seen in an invertebrate zoology class.
So it was back to the books.
First, though, I had to get a better look. I used a paddle to hoist it into the canoe. It seemed to be simply a gelatinous mass. The exterior was covered in what appeared to be irregularly shaped textured plates. It was just slightly rough to the touch.
When I sliced it open, the interior was indeed pure jelly. If this thing was alive, it had to be the exterior covering.
Back in my office, I scoured textbooks and field guides until I finally recognized the mysterious creature. It was a bryozoan, a member of an obscure group of invertebrates. Its scientific name is Pectinatella magnifica.
It turns out these gelatinous masses are colonies of thousands of individuals called zoids. Each of the textured plates I had originally noticed consisted of several zoids. Under a powerful hand lens, each zoid resembled a flower. The “petals” were actually tiny tentacles that capture organic food particles suspended in the water. It was the tentacles that gave the blob its fuzzy underwater appearance, and each zoid helped clear the water of organic debris.
The blob itself was a gelatinous mass produced by the zoids so they would have something to which to attach themselves. The jelly is more than 99 percent water.
By late summer, the zoids produce statoblasts, tiny burr-like offspring analogous to plant seeds. The statoblasts stick to the fur of mammals such as muskrats and mink and to the feathers of ducks and other waterfowl. That’s how Pectinatella gets dispersed to other bodies of water, both near and far.
Pectinatella cannot survive winter temperatures, so it overwinters in the statoblast stage, which remains dormant until spring. Then they “germinate” into individual zoids. The zoids then grow and reproduce rapidly…