Starring Pseudemys species
With co-star Basicladia chelonum (Arnoldiella chelonum)
Holidays make for idle hands—a an extra opportunity for swampy play. Thus the off-schedule post. Happy 4th!
Ever notice how cooters on logs have a shag carpet on their backs? Today I snitched a pinch of turtle turf and enjoyed it microscopically. The turtle was not even inconvenienced.
Teachers like to cite the turtle toupee as an example of the ecological relationship called commensalism where one party gains while it’s all the same to the other: a “win—I don’t care” relationship. In such Kindergarden accounts the algae gains a happy home with no consequence to Yertle.
But it is richer than that. First of all, although multiple algae and some cyanobacteria ride turtles, the alga Basicladia chelonum rules—it lives exclusively on turtles, and is abundant on them. The alga has evolved 100 percent dependence.
The piggyback alga is unknown to harm its host. And perhaps it’s a friend with benefits. Biologists in the 1950s kicked the question around inconclusively, speculating that the algae perhaps give camouflage. But what hungry beast worries an armored turtle? If the alga is camo, it hypothetically helps the lurking turtle hide from its prey, until snap! Personally strikes me as far-fetched, but then again so do helicopters.
Another old hypothesis is that the algae are turtle food. Can you imagine one trying to reach around and grab salad from its back? Nobody thinks that, of course, but do turtles eat algae off of each other? (Hours sitting in canoe with binoculars and note pad.) Also possible, maybe the algae are a big green evaporative cooler. Like any of these ideas? Nobody has done enough research to know.
There is another possibility. In 2005 engineering student Colleen Bennett studied the antibiotic effects of Basicladia algae. A sanitary turtle is a happy turtle.
The algal fuzz is creeping with life, an inhabited little planet. The creatures on the shell wonder if they are alone in the turtleverse, or if there are other turtles out there with alien life. What can you find in the wet green carpet? Answer…more than I can list. More than I know. Probably some “new species.” Let’s see: tiny tagalong algae of many sorts, microcrustaceans, and my personal favorites, a menagerie of weird Protists resembling creatures from another galaxy.
Today I found Rotifers, peppy little “wheel animals” spinnin’ and popping. Here is one fresh from the turtle.
CLICK TO SEE FOR YOURSELF.
They were loitering with Suctorians. Now, Suctorians are about as odd as critters can be, and yes they suck. Suctorians have tentacles, usually in paired tufts and with swollen tips. When a small creature touches, the tentacles stick, sting, and suck. I mean it…they suck the vital juices right out of the prey. Suctorians are not nice, and they have poor table manners. CLICK HERE to see a Suctorian from the catch of the day brandishing its right to bear arms. Spoiler alert: its movements are subtle.
The takehome lesson is the topside of a turtle is a squarefoot ecosystem. It’s hopping and happening. And severely under-studied so far as I know. What else is lurking in that little green jungle? and is the turtle really so oblivious?