Sunday, June 19, 2016

Ephemeral jellies

If they appear at all, look for freshwater jellyfish during the hottest part of late summer in local stillwater quarries and lakes.

In the Tennessee Valley there’s a small gelatinous creature that is virtually transparent with only a slight hint of white or maybe green to give it any sort of hue. Its body is 99 percent water and has no skeleton or head or brain or organs for respiration or excretion. The creature does have a mouth, long tubular stomach and reproductive organs, but little else. So it can eat and make babies, or clones of itself. You might think that such a small biological oddity would live their life unnoticed. Most of the time they do. Yet one week last summer they garnered serious media attention.

What can be so newsworthy?

Freshwater jellyfish are indeed odd, ethereal aquatic animals that live a double life. For most of their existence, they’re underwater polyps, so small and well camouflaged they are virtually invisible. Studying them, or even finding them is a difficult undertaking. At times however, on hot summer days, these polyps go through a transformation. They produce umbrella-shaped adults called medusae that look like the beached jellyfish that most of us know from trips to the seashore; except the medusae of freshwater jellyfish remain small, coin sized. These milky-clear jellies swim towards the overhead sunlight and drift back down into the depths hunting for food, creating a shimmering effect just below the surface. Often the medusae are seen floating or swimming in clusters of dozens, hundreds or even thousands. These clusters are called “blooms.” It’s during these medusa outbursts that they become see-able, but predicting when and where they’ll appear borders on the impossible...

For the rest of the story, read my article in the May/June 2016 issue of The Tennessee Conservationist.

And for more about freshwater jellyfish in Tennessee watch for my next book, Ephemeral by Nature, to be published in 2017. 


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