Identifying strange creatures can be tricky. Identifying strange creatures with virtually no recognisable features ... now that's a real challenge.  
Image: Nick Nickerson
This blob of gelatinous goo popped up on the shores of a lake in Canada last week – and it sent us on quite the sleuthing mission. Because the organism is so transparent, some suggested it was an ascidian (or tunicate), a sac-like marine invertebrate. But after a couple of days spent poking around – and a hand from our friends at London's Natural History Museum – we finally settled on a different ID. What you're looking at is a colony of another filter-feeding aquatic invertebrate: the bryozoan Pectinatella magnifica.

Nova Scotia local Nick Nickerson encountered the living "Jello" on Doctor's Lake, a freshwater body connected to the North Atlantic by a system of estuaries, rivers and other lakes. Despite living in the area for 14 years, he and his wife had never seen anything like it.

"[It was] quite firm, transparent ... It seemed to have, I don’t know, an intestinal tract or a line right through it. Very, very strange," he told the local Kings County News.

In fact, the "intestines" that Nickerson describes are likely something else: a part of a plant. Each member of a bryozoan colony is a clone of the first. These filter-feeding copies, called zooids, work together to survive, so they secrete a special protein that binds them. As it forms, that soft "exoskeleton" (the slimy mass you see in Nickerson's photo) has a similar consistency to egg white, so the clones tend to use roots, plant stems and sticks for added structural support.
Individual zooids. Image: Carolina Biological Supply Company
Wright State University biologist Dr Tim Wood, who has studied the organisms in detail, explains that the group found at Doctor's Lake looks like it's seen better days. Healthy Pectinatella colonies tend to be greenish-brown in colour, as seen in the "alien blobs" that washed up recently in California (and the header image to this article). 

"We have
passed the photo around and there is a lot of head scratching," he says. "But finally the consensus among all of us is that this is indeed Pectinatella. It looks a bit battered, with most of the outer living layer sloughed off – it does not look like a normal, healthy colony."

Under the right conditions, a single healthy colony of the floating sieves can span some two square meters – but don't panic if you find one. Bryozoans are not dangerous to humans, even though their jelly has been known to enter piping systems. "The slimy surface with its distinctive odour is [also] thought to repel potential predators," adds Wood. "Although very little is actually known about that aspect." In fact, these creatures can even be quite helpful: because they suck up a lot of silt and algae, bryozoans can greatly contribute to water clarity!  


Top header image: