Sandblasting Cannonballs

In a coastal morphology course at UWF, taught by a geologist named J.P. Morgan, I formally learned something that growing up on the beach had already taught me. (now THAT is a sentence.) If I remember correctly, Professor Morgan had taught at LSU before coming to UWF.

On a chilly November morning, J.P. had us on Pensacola beach pointing out the scarp where powerful winter waves had cut into the slope. His message, "Summer beaches are depositional, winter beaches are erosional." In general, the energy of winter storms and nor'easters removed sand from the beach slope, while the gentler waves of summer pushed sand back on to the slope.

(Summer hurricane strikes are special events that cause both dramatic erosion and depositional changes, but they are the exception rather than the rule.)

JP would have loved the beach I was on yesterday. It was demonstrating everything he had said about the winter beach. Everywhere along that beach, a sharp escarpment, a miniature sand cliff, separated the upper beach from the intertidal zone.

The dunes closest to the sea were carved in half by an earlier storm, exposing their loess layers for all to see.

An offshore wind was blowing hardwon summer sand out to sea, biting my bare ankles and sugar coating all the flotsam.


This upside down Cannonball Jellyfish was frosted with sand crystals.


The whispy, white mist is actually swirls of sand blowing from the dune line to the Atlantic.

The waves and the wind were going head to head. The waves won, but the wind turned the spray around and sent it packing.

Here is a cannonball jelly plucked fresh from the water. Any jellyfish is essentially, (even more than us) a bit of living seawater. Some jellyfish are as much as 98% water. Cannonballs are the body builders of the jellyfish world, with a firm rubbery body that is high in collagen.

They are fished commercially for the (mostly) Asian market. Growing up, I would have laughed in your face if you said people actually eat jellyfish. That was my ignorance of course, turns out millions of people munch jellies.

I am not one of them.

So ...

...do cannonballs sting?

Depends.

I have handled a bazillion of them with no sting.

My assumption has always been that their nematocysts are too weak to penetrate tough ol'human skin.

If you research them on the internet, the articles speak of a stinging toxin and effects on the cardiac system.

Huh?

I do have this one bit of direct evidence of their sting.

Years ago, when Junior was a tadpole of about 8, I found a cannonball jelly in the shallows. Junior and his sisters were frisking in the surf like a pod of dolphins who just found a school of mullet. I called the kids over and held the jelly upside down, giving them a brief lesson on Cnidaria. They were good sports and listened even though they wanted to be back splashing in the waves and flexing their inner dorsal fins.

They asked a few questions, touched the jellyfish, and giggled at the rubbery feel of it.

The upside down cannonball was essentially a bowl and was holding about a pint of seawater. At the conclusion of my lesson, I dumped the water on Junior's belly. That was their cue to run laughing back into the waves.

Junior came back within two minutes, complaining of a burning, itching belly ... classic jellysting symptoms.

Severe parental guilt ensued. It seems that young human bellyskin is more sensitive than tough old hand skin. The jelly water probably contained detached nematocysts (stinging cells) which activated against his 8 year old skin.

We fixed the sting with a trip to Dairy Queen, but it changed my opinion of cannonball stingnicity.

Not for me of course, I still handle them, but I no longer dump them on small children.

If we peek under the cannonball jelly's skirt, we can see the inner workings. Cannonballs actively swim by pumping water and they congregate in vast schools. As they work through the water column, they are constantly slurping up the planktonic larvae of all manner of fish, molluscs, and crustaceans.

In turn, they are preyed upon by seaturtles ... especially leatherbacks. As I mentioned earlier, they are also preyed upon by us, mostly for the Asian market.

You can find them, packaged and dried, in your local Asian grocery store.

If you find them, enjoy! Along with beche de mer, urchin gonads, and cauliflower, it's a gustatory experience that I don't care to have.