Back to the Ediacaran
in a pool of Ophrydium blobs
Sacred Site of the Epic of Evolution
visited by Connie Barlow, 14 October 2013
Lookout Mountain, Alabama
On 14 October 2013, Michael Dowd and I closed off a day of writing and other work by visiting a favorite stretch of The Little River, on Lookout Mountain (in DeSoto State Park). It hadn't rained in awhile, so the river was running clear and gentle. The photos below show both the gentle river and the slickrock stream bed that is overwhelmed by a torrent of water after impressive rainstorms.
On this warm autumn afternoon, I wandered with my camera along the streamside vegetation and peered into the clear pools that had been isolated from the main river for perhaps a month, after the last floods subsided. I found two such pools at the canyon wall directly left of the foreground slickrock in the above left photo. Each had a few small fish darting for cover. I was surprised by how clear they were, even though "stagnant."
Suddenly, I noticed a half-dozen gelatinous, emerald green blobs, about the size of my hand, resting on the gravel bottom of the shallow pool.
Their structure resembled a gelatinous mass of salamander eggs, similar to what I had encountered in early spring in an ephemeral forest pool a few miles from this spot.
I used my walking stick to move two of the blobs toward me, for close examination. . .
There was no evidence of eggs or larvae within the mass, though I could see the shell of a small landsnail that was embedded near the base. (See photo below right.)
Indeed, it would have been shocking to see any eggs, given that this was mid October. So what was it?
A vague memory began to form.
A paleontologist friend, Mark McMenamin, had told me long ago about a field trip to a bog in Massachusetts with biologist Lynn Margulis, best known for her theory of the endosymbiotic origins of eukaryotic cells.
In that freshwater bog they had found a mysterious colonial protoctist.
I emailed Mark (photo above left), at his office in the Geology Department of Mt. Holyoke College (Massachusetts), and attached two photos for him to identify. His response:
"What you have found here appears to be colonies of the protist Ophrydium, the same creature that Lynn and I encountered in Hawley Bog, MA. With their torus shapes, yours look even more like Ediacarans than ours did! Nice discovery, and thanks for sharing these photos."OPHYRIDIUM! Now that I had a name, I could google the details. Sure enough, Lynn Margulis and Brian Duval co-authored a paper in 1995 on the blobs of colonial Ophrydium at Hawley Bog: "The microbial community of Ophrydium versatile colonies: endosymbionts, residents, and tenants.
The final sentence in their paper's abstract: "The growth habit in the photic zone and loose level of individuation of macroscopic Ophrydium masses are interpretable as extant analogs of certain Ediacaran biota: colonial protists in the Vendian fossil record."
EDIACARANS! So, experiencing Ophrydium blobs in a pool in Alabama was a way to venture back in my imagination to the Ediacaran time of Earth's geological past just before the first trilobites and shelly creatures would appear in the fossil record!
So I used google scholar to look inside his first book, and lo! There was an entire chapter titled "Ophrydium".
Here is an excellent webpage to learn more about Ophridium colonies and the symbiotic algae within them that produce the bright green color.
Golly! I have just scoured the web and, truly, my photos do seem to be the best pictures of Ophridium colonies.
I look forward to returning to my friends and my favorite forested areas on Lookout Mountain Alabama and taking them on a little hike "back to the Ediacaran."
First on my list will be the "Riverkeeper" of The Little River: Billy Shugart.