Microbes, Vultures and Conches

Microbes, Vultures and Conches

I just returned from my usual morning 4-6 mile walk on the

beach at Marco Island in Florida and picked up my latest issue of

the American Chemical Society”s publication “Chemistry.”

After my walk, I was caught up in the influence of microbes on

the environment and an item in Chemistry dealing with

beneficial microbes which live in lake and stream bottoms.

These microbes apparently love to dine on methyl tertiary butyl

ether (MTBE) and just plain tertiary butyl alcohol (TBA). I

don”t expect you to be familiar with either MTBE or TBA and I

certainly would not be myself, except for the recent furor in the

media over MTBE in particular. For the past few years, MTBE

has been mandated as an additive to gasoline which lessens

pollution and results in cleaner air. TBA is another gasoline

additive. Now it seems that MTBE is a potential human

carcinogen that is making its way into our ground water supplies.

The MTBE, according to the article, evaporates into the air when

you fill your gas tank. It then dissolves in rain and ends up in the

lakes and streams. Gasoline spills may permit MTBE to take a

more direct route into our water supplies. At least in the lakes

and streams, however, these “good” microbes degrade the MTBE

and TBA into nontoxic products. The whole affair of the

legislated addition to and now removal of MTBE from our

gasoline illustrates again the complex interactions that can result

from fiddling with our environment.

But back to my walk this morning. I”ve been walking the beach

here on Marco Island for over 4 years now and today saw

something I”d never seen before. Lined up on two areas of the

beach were hundreds, maybe thousands of Florida conch shells.

I hadn”t seen more than maybe tens of these shells before and

they were typically scattered over a wide portion of the beach.

Furthermore, today”s shells were not dead but were moving,

propelled by the very much alive conches inside. Virtually all

the conches were associated with circular holes in the sand about

1-2 inches deep, out of which they must have emerged. One

fellow beach-walker said he had been coming to Marco for 20

years and had never seen anything like this. I was so taken with

the conches that I forgot I was walking on a sandbar without a

dry path to the main beach. As a result, I had to retrace my steps,

adding an extra one-half to three-quarters miles to my walk.

Today, my wife and I also hosted some relatives from

Pennsylvania and we took them on a tour of the island, which has

some very upscale houses in beautifully landscaped

neighborhoods. At one point we were all shocked by another

sight which I had never seen before in my 72 years. In this one

neighborhood, there were hundreds of large black birds flying

around and roosting on the roofs of these fancy homes. At first,

we all thought they were very large crows but when some flew

near our car we realized that they had rather evil-looking faces.

Well, what should appear in the local paper today but an article

about homeowners in the Marco area under siege by hordes of

vultures! The residents found it impossible to go outside and

enjoy any outdoor activities. Apparently, vulture droppings are

considerably more of a problem than those of the passing

seagulls. Why all the vultures? They have come to feast on the

piles of dead fish washed up on the banks of the river and inland

waterways so plentiful in this region bordering the Everglades.

Why the dead fish? Microbes, in the form of the “red tide,” are a

likely answer, according to the newspaper article. I have to rely

on my feeble memory (no computer or Web access down here),

but I believe that the red tide is caused by proliferation of some

kind of algae or other organism(s) that periodically foul the

warm waters off the Florida coast. My own hypothesis is that the

red tide is also responsible for the conch-beaching I observed this

morning.

So, here we have an example of “bad” microbes resulting in

profound local environmental effects. Obviously, the red tide

effects are restricted to this relatively limited geographical area.

The MTBE-eating “good” organisms, if they can be widely

deployed, may have a much wider and beneficial impact if

MTBE contamination is as widespread as some media reports

indicate.

This environmental stuff is really tricky. Some day I may get up

enough courage to try to write about global warming!

Allen F. Bortrum