AND EDUCATION FOR THE NEXT GENERATION
MAGICAL POWERS OF THE ESTUARIES
BY BOB BERGEN
PROFESSOR OF SCIENCE,
AND TEEN ANGLER MENTOR
Now that we have looked at some of the magic of estuaries, it's time to
look at one final piece of magic.
Recall that the "Magical Power of Estuaries" revolves around
at least three, maybe four, different communities of producers: emergent,
submerged and floating plants, and that the floaters come in two basic
sizes: the microscopic plant plankton and the macroscopic (that is,
visible to the naked eye) algae the drift in and out of seagrass beds.
Remember also that estuaries have two completely different sources of
power, and that estuaries also receive nutrients from two different
sources: runoff from the land and incoming tides from the ocean.
Now for the last bit of magic. But first, a little history.
Until very recently, say the past several hundred years, we lived on
and around estuaries without causing any lasting damage. The shoreline of
Florida is littered with the mounds of native American peoples who lived
here as much as 12,000 years ago -- yet these folks did no damage to the
life of an estuary that we can see. And they lived along those estuaries
for nearly all that 12,000 years.
Then the invasion began, starting in the early 1500s. By the 1800s,
most of the major coastal cities of the USA were already teeming with
people, and with industry. After all, if you wanted to move cattle, or
lumber, or tea, or anything else measured in tons, the easy way was by
water. By the mid-1800s, Boston, New York, Philadelphia, Baltimore,
Washington, Charleston, Savannah, Jacksonville, Mobile, New Orleans were
all thriving port cities. On the west coast at the same time, San
Francisco was leading the way.
And all were built on estuaries.
Where did the trash from all these millions of people and thousands of
ships go? Overboard, into the estuary. And where did all the sewage go?
Into the estuary. At that time, and even today in much of the world,
estuaries were and still are considered buggy, bad-smelling swamps that
made great places to dump garbage.
Many, perhaps most, of the world's estuaries have been degraded by
poisons, landfills, loss of habitat, overfishing and other of man's
activities to the point that most if not all their magical productivity
has been lost.
In 1974 I wrote a series of articles for the Palm Beach Post about the
importance of mangroves (our estuarine emergents) and seagrass beds. One
of my interviewees was a former commercial fisherman who now owned a large
seafood house. As we talked about the roles of mangroves and seagrasses in
the productivity of estuaries, he suddenly leaned forward in his chair,
took the cigar out of his month, and looked at me wide-eyed. "Do you
know," he said, "my condo is built right on top of the grassbed
where I used to catch all my bait shrimp!" That's called "loss
Now that I come to think of it, our president, Al Bernetti, and
wife/webmaster Suzanne live in a condo on the water -- which was built on
top of a grassflat I used to wade-fish 50+ years ago!
Let's look more closely at some of the insults we humans heap on
estuaries. We'll start with pollution.
We can break pollutants down into two big categories: poisons and
The poisons can be further broken down into two big categories:
pesticides and metals. Pesticides are used on lawns, farms, golf courses
and lots of other places. We generally use more pesticides than necessary,
and the excess then runs off into canals or rivers which feed estuaries.
A moment ago I picked on our president. Well, he is definitely not
alone. I am for sure an environmental criminal. And some of the stuff I
did back in the early '60s will be around to haunt you-all throughout your
lives. At that time, I worked in mosquito control for our county. And I
put out probably 100 pounds of a pesticide called DDT; we used it to kill
mosquito larvae in ponds, ditches, canals - wherever. Now DDT has a
half-life in the environment of 20 years; that means that every 20 years,
half of it is gone, but the other half is still out there killing all
kinds of things. So if I put out 100 pounds by 1965, 50 pounds was still
killing things in 1985. And in 2005, 25 pounds was still out there
killing. And in 2025, 12 1/2 pounds will still be killing stuff. And in
2045? 2065? We biologists figure ten half-lives must pass before the stuff
is diluted enough not to matter. For DDT, that's 200 years!
Metals are generally poisonous at some concentration. Living things
must have tiny amounts of some metals; iron, for example, is at the heart
of the hemoglobin molecule, and if you, like me, don't process iron well
or get enough, you are anemic. Magnesium, of all things, is at the heart
of the chlorophyll molecule. But metals in overdose are highly poisonous,
and some of the amounts involved are so tiny they are hard to believe.
Some of the common metals seen in waterways include copper, zinc, lead and
others. These metals get into our waters from the wearing of tires on
pavement, the gases coming from the tailpipe on your car, burning coal to
generate electricity, and multiple other sources.
Now to excess nutrients. They come from two main sources: agriculture
and sewage. The nutrients we worry about mostly are nitrogen and
phosphorus, in the form of nitrates (or ammonia) and phosphates. Sewage is
the easy one to control, but we don't do a super job of it. Yeah, we treat
our sewage to remove bad bacteria and viruses - but most treatment plants
don't touch nutrients in the effluent from the plant. A few, known as
advanced wastewater treatment plants, do remove excess nitrates and
phosphates from sewage effluent, usually by allowing the effluent to sit
for a while in a marsh or pond, where plants grow and take up those excess
Agriculture - and suburban lawns and golf courses - are harder to work
with. A sewage treatment plant is known as a "point source
discharge," which means the nutrient-laden effluent leaves the plant
through a pipe (a "point source"). Agriculture and suburbia are
harder to work with; their excess nutrients and poisons just run off the
land all over the place. But always downhill, and usually into a ditch,
canal, river, lake, pond - or estuary.
A town I lived in a few years ago (Jupiter, FL) is actually collecting
that overland runoff and treating it as sewage. It ends up going through
an advanced wastewater treatment plant - and it costs money to do it.
Agricultural runoff can also be collected and treated (usually by giving
it time in a marsh or pond) to allow plants to remove excess nutrients
from the fertilizer used on the farm.
Question: where does your milk come from? Cows, of course. And cows
give more milk if they feed on rich grasses, made rich in nutrients by
artificial fertilizers. Question: how many cow splats does a cow produce
in a day? These are loaded with the nutrients the cow didn't utilize - and
the average cow produces 80 pounds per day! So a pasture with 100 head of
dairy cattle produces 4 tons of sewage a day. Where does it all go?
Worse still, how about pigs? We raise lots of pigs, and their feces are
especially noxious - and loaded with nutrients. Talk to the folks who live
in North Carolina about the effects of a hurricane which flooded pig
sewage ponds; the rivers carried the "stuff" into Pamlico Sound,
and created two dead zones in the Sound. Or talk to commercial fishermen
in Louisiana, where the Mississippi River has created a dead zone of
thousands of square miles in the Gulf of Mexico - from excess nutrients
carried downstream from the farms of the midwest.
So we have horror stories. What can we do about them?
We've already done the easy stuff. Point sources of pollution, easy to
identify and act on, are by and large under decent control. Nonpoint
sources are the hard part. And that's where the effort is going today.
What can you, as an individual, do? You've already started, by joining
Teen Anglers. A next step, if you wish, is to do volunteer work. Talk to
your state and local parks people, see if there are any stream or pond
rehabilitation projects you can work on, find out about your local
government to see if they have any projects that might use you as a
volunteer -- things like planting trees, water quality sampling and so on.
Another direction where you can make a difference is to join an
organization which promotes conservation. Ducks Unlimited, Trout
Unlimited, Audubon, the Coastal Conservation Association -- there are many
organizations looking for members to help on their projects. Maybe even
get a group of you together to do something. One person CAN make a
Good fishing, tight lines, and may the wind always be at your back.
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Bob Bergen, Professor of Science, Retired. Teen Angler Mentor
2008[National Teen Anglers]. All rights reserved.
Revised: February 10, 2010