My last missive (April 6) included a lot of whining about “the winter that wasn’t.” Well Mother Nature, not content to allow humans, certainly not this human, to get any sort of grip on her, served up a splendid spring, I must say, if a bit dry.
Instead of the dreaded flipping of the switch from April’s 40s and 50s to a May 1 90 degrees and 90% humidity, we were treated to a late spring of cool, dry days in the 70s and low 80s. Nineteen out of the 31 days of May were below the normal average, as were 15 out of the 20 spring days of June. But before I go extolling the benevolence of Kahèsëna Hàki (the Lenni Lenape Mother Earth), the normal 4.27 inches of rain we normally get in May was this year a bone-dry .31 inches, while June followed on with a very slightly moister .51 inches for the month, as compared to the average 4.24 inches.
Which probably goes a long way to explaining the outbreak of toxic algae blooms in so many of the lakes in our area recently. These cyanobacteria (blue-green algae) are always in attendance and, in fact, are probably the oldest living organisms on Earth. Most pose no threat to humans and other animals, while others that are toxic normally are few enough not to be a problem. But when it gets warm, and more importantly, when levels of nutrients in the water, that is, lawn and agricultural fertilizer runoff, as well as sewage and storm water, increase, the wee beasties have raucous parties and billions of newborn cyanobacteria are the result. Most are harmless. Some are not, and emit some of the most powerful toxins in nature, with ominous names like Microcystin, Cylindrospermopsin, Anatoxin and Lyngbyatoxin. They can be more toxic than cobra venom, and can cause everything from annoying stomach pains and headaches, to liver damage and neurological symptoms like muscle weakness and dizziness.
As if the smoke from the fires in Quebec wasn’t enough.
What all this reminded me of was a trip several years ago to my wife’s family’s place in New Smyrna Beach, on the east coast of Florida. Florida’s been suffering through the saltwater version of cyanobacteria blooms: the dreaded red tide.
I remember these when we lived on the Chesapeake. You couldn’t really see or smell anything, but when the red tide would ooze into the Patuxent and Potomac Rivers, a massive, frantic, free-for-all took place along the shoreline, as crabs and fish and every living creature scrambled to escape the oxygen-deprived waters where the invading algae settled. It was quite a sight, with everybody and their uncle scooping up crabs and fish.
But back to Florida. My wife’s nephew and I went inland to Blue Springs State Park, where manatees congregate around a great underwater spring both in times of cold and when the red tide chases them up the St. John’s River from the coast. We kayaked among these huge, calm vegetarians, the only completely herbaceous marine mammal. It would surface next to our kayaks, and, like a giant dog, enjoyed our scratching their mottled, smooth hide.
Then, right before they would disappear beneath the water’s surface, the out-of-place, but unmistakable sound of flatulence caused us to look at each other.
Then we saw the bubbles where the sea cow had been.
A little investigation showed that this is how manatees control their buoyancy. They hold their gas in to create buoyancy, then let it out to dive.
Unlike fish, manatees lack a specially designed organ known as a swim bladder that uses gas to regulate their buoyancy.
A study published in the peer-reviewed journal The Anatomical Record in April 2000 described observations showing that when manatees submerge, they are able to do so with minimal movement, indicating that there may be another force at play. Constipated manatees have also been recorded as lacking the ability to dive.
Putting two and two together, Sentiel Rommel, John E. Reynolds III, authors of the Anatomical Record paper, state:
“We also hypothesize that such contractions, in concert with contractions of the thick abdominal muscles (obliques, transversus, and rectus...), may compress gas in the massive large intestine, thereby contributing to buoyancy control. Additionally, because of compartmentalization of gas into discrete ‘chambers’ or folds in the large intestine, fore and aft distribution of gas within ‘a boney intrathoracic channel’ may be manipulated thereby contributing to pitch control.”
So there you have it — the likely manner in which the manatee dives and rises.
Michael Lynch lives in Upper Black Eddy.
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