Have you ever seen a pocket of
frogspawn in a pond? It looks like a lumpy, slimy blob, right? Now imagine that
a blob you thought was frogspawn turned out to be something else entirely!
Workers at Stanley Park, in
Vancouver, were surprised when exactly that happened to them. They discovered
that one of the park’s ponds was full of brain-like blobs – blobs that turned
out to be animals! The slimy balls are known scientifically as bryozoa
(pronounced bry‑uh‑ZO‑uh), but they’re also known as moss animals, or even
dragon boogers. Gross!
So what are bryozoa, then?
They’re a kind of water-dwelling invertebrate. Individually,
they’re microscopic – a blob like the one shown here is actually made up of
thousands of little organisms called zooids. These zooids feed by
using their miniature crown-like tentacles to scoop food particles towards
their mouths.
Lot of species of bryozoa –
including the one they found in Vancouver – use asexual reproduction (which
means that they reproduce offspring without the need for a partner) to produce
lots of identical zooids. These zooids are easy prey for fish and insects, so
they all bind themselves to one another with sticky mucus. The result is a firm
but slightly squidgy blob, up to a metre wide. Their chances of being eaten
become much lower if they stick together, so they stay connected to each other
in what’s known as a colony.
This type of bryozoan is
normally found in western parts of the United States, so it was a bit of a
surprise to come across them in Canada. Some scientists think that rising
temperatures across the world have allowed them to migrate into water that was
previously too cold for them.
Although this is the first time
that anyone has seen these moss animals in Stanley Park, that doesn’t
necessarily mean that they’re actually new to this place. Their greenish-brown
colour means they are easily camouflaged in muddy, murky water, so it’s very
possible that they’ve been there for years, unnoticed. In fact, bryozoa often
only come to people’s attention when they grow inside water pipes, eventually
blocking them!
So now you know – if you’re out
and about near some water and you see a patch of frogspawn, take a closer look.
You might be looking at a bryozoan!
Watch Oceans: Coral Seas to find out more about other types of small animals that live in colonies.
