Why it's needed.
An article reprinted from FISHING FACTS (The magazine for today's fresh-water fisherman.)
How it works.
What it does for lakes, farm ponds, reservoirs, flowages and factory and feedlot run-off and effluent lagoons.
Sure, many of our fishing waters have become polluted, and others are getting there. Yes, it will cost billions to clean it up. Nothing new about that, is there? Well, we wouldn't waste your time and our space simply to write another "sick lake" story. We all know that it will take years - and billions - to hunt down every source of water pollution and correct it. (It will be a long, hard struggle, and we may not even win.)
BUT, a relatively inexpensive piece of equipment has come along which is available to anyone with the desire to do something about their "sick waters." One unit will handle a lake or pond up to 5 acres. Resort owners can use two or three units in front of their places to help eliminate fouled swimming beaches and provide better fishing right out in front of the place. Individual lake home owners can install their own unit out in front of their place, and if a number of adjoining property owners do likewise, a whole section of the lake can be improved.
The piece of equipment that can do all this is the Lake Bed Aerator, which acts to add natural dissolved oxygen to water to replace the dissolved oxygen which pollution and eutrophication has stolen from it. Fishing waters with sufficient dissolved oxygen means more and better fish who multiply better, fight better and taste better.
Our interest in the Lake Bed Aerator lies in the fact that it is relatively inexpensive and represents something that YOU can use to help your own fishing waters, if they are "sick." It is not a "cure-all," and it won't clean up an entire reservoir that's 90 miles long...but it may work real "magic" for you wherever you install it.
An article in Fishing Facts of March 1974 ("Hope For Troubled Waters"), resulted in inquires from and installations of lake bed aerators in all parts of the country. Every report that has reached us about their performance has been positive, most of them glowing. Those who installed Lake Bed Aerators are excited about them, so are we. It's a simple, practical piece of equipment for the do-it-your-selfer, for a business establishment, or for a town or municipality.
This article, coming 13 months after the "Hope For Troubled Waters" story, was written at our request.
We think there are many of our readers - and their friends - who might wish to give careful CONSIDERATION to the purchase and usage of such equipment. (We don't try to tell you what to think or what to buy, but we do try to give you information that will assist you in arriving at your own decision.)
The author of this article, Dr. Mervin F. Browne (known as "Doc" Browne by his fishing friends), graduated from the University of Illinois in Chemistry and received his Ph.D. in Organic Chemistry at the State University of Iowa in 1951. "Doc" had directed the research and development activities associated with pollution abatement and waste disposal for several large corporations. These include LOF Glass Co., Owens-Corning Fiberglass, National Distillers and Chemical Corp., and Phillip Morris.
Being a do'er, "Doc" decided to do something about pollution of our lakes, both man-made and natural. Seeing the need for providing the do-it-yourselfer with proper dependable, yet inexpensive equipment to save this valuable resource and sport, "Doc" developed the Venturi principle of aeration and thermal destratification known as the gen-AIR-ator.
"Doc's" local friends know him as a German band clarinet player, private pilot and Civil War buff.
(gen-AIR-ator is the Trademark of Grovhac, Incorporated, 4310 N. 126th St., Brookfield, Wisconsin 53005.)
WHO NEEDS HELP?
Lake restoration is now a big item of interest and controversy in America. Pending legislation to grant Federal Funds for the installation of systems to restore the nation's lakes to some condition other than the ones they are in now, seems certain. To those who own lake property and to those many people who use lake property, such a program brings up many questions.
First, we must assume that there is something wrong with the lakes that make some sort of "restoration" necessary. Secondly, we must also assume that if we were given enough money by our government, we could change our sick or dying lakes into something else that we would like better, perhaps lakes like the Indians had when the white man first came. Or maybe like the lakes were when they were first formed 10,000 years ago as the last glacier faded away.
In any event, some lakes are "bad" and we want them to be made "good" and Uncle Sam or somebody else with a lot of tax money is going to fix them for us "free."(?)
Some interdependencies in a lake ecosystem. The aquatic ecosystem is complex and its components are interrelated. The various life forms depend upon one another for their existence. Courtesy of Upper Great Lakes Regional Commission
Some general characteristics of lakes - Lakes are more than standing bodies of water. Their physical and chemical characteristics make them ideal homes of an immense variety of organisms and communities of plants and animals. A lake ECOSYSTEM is composed of a community of interacting animals, plants and bacteria, and the physical and chemical environment in which they live. All parts of the ecosystem is composed of a community of interacting animals, plants and bacteria, and the physical and chemical environment in which they live. All parts of the ecosystem mesh in an intricate scheme of interdependence. This drawing indicates the complexity of lakes, and shows that it is not possible to disturb one part of aquatic ecosystem without affecting numerous other parts.
Nothing is "free." As property owners, if you do get a government project on your lake, you'll lose a great many of your property rights. You don't want that. Tax money spent here will only make inflation worse. What is wrong with the lake anyway? Why the fuss?
WHAT'S "GOOD" AND WHAT'S "BAD?"
Let's see what makes a lake "bad" that we once found to be "good." Shallow water is the biggest complaint I hear these days. It is the cause of such problems as excessive weed growth in many cases where the lake property owners do not recognize this cause, and where fish freeze out or winter-kill. Such lakes cannot support a population of game fish, because in the winter when the water is covered with ice and snow, there is oxygen depletion and the fish smother to death.
Streams and local rain run-off bringing in mud and silt fill up some lakes. Only dredging will restore such a lake. The soil, sand, gravel, or clay will not go away by itself. One such lake is Lake Kadija in the Medinah Country Club, Medinah, Illinois. Once twelve feet deep, the erosion of Illinois top soil has filled in the lake to the point where one can wade through 90% of this 60 acre manmade impoundment. Such is the fate of thousands of lakes. What happened to Kadija happened to Lake Decature at Decature, Illinois, Lake Vermillion at Danville, Illinois, and Little Muskego Lake near Milwaukee.
If there is some bottom over 40 feet deep, as in the case of Little Muskego Lake, a good game fishery can be maintained with a little help from the Department of Natural Resources. They drained down the lake and poisoned the trash fish. Upon refilling, they stocked desirable species so that today this should be a great fishing lake, one that we would term "good." Right? Wrong! Now this brings us to the second big complaint - pollution.
IT'S THEIR FAULT!
There are two kinds of pollution. The first, manmade pollution, had received so much attention from activists that we've lost sight of the second kind, natural pollution or eutrophication. Again, many lake property owners, teachers, and students overlook the natural production of vegetable matter from sunlight, air, and water by photosynthesis in green plants and algae as the primary cause of a lake going "bad." If you fish there, you don't like too many weeds growing and rotting on the lake bottom, crowding out the sport fishing, and stinking up the water so badly that often the fish you do catch taste stale and muddy.
|"Water contains a variety of dissolved minerals such as carbon, nitrogen, phosphorus, potassium, sodium, iron and calcium…essential to tissue building by living things. Of particular interest are nitrogen and phosphorus…important nutrients for plant growth.
"When present in excess, such nutrients can stimulate the rampant spread of aquatic vegetation in lakes." Courtesy of Upper Great Lakes Regional Commission
As plants die and sink to the bottom, they serve as additional plant food, hastening growth of more aquatic vegetation. With an increasingly heavy load of oxygen-robbing waste on the bottom, the filter feeders, plant eaters, fungi and aerobic bacteria can no longer survive. The lake dies from the bottom up.
Of course, man can speed up the normal death of a lake by pollution of his own making. Anything that fertilizes the algae and weeds speeds up their work of turning the lake into a meadow. Here again, the excessive growth of weeds and algae cause a build-up of decaying organic matter and the stagnant lake is called "bad." This is apart from the dumping of mine wastes, chemicals, fuel oil, and who knows what into a stream or lake that results in a fishkill. Occasionally, there are toxic substances that kill the fish, but mostly it's oxygen depletion that does them in.
WHAT IS LAKE BED AERATION?
"Aeration" is the term we use to mean adding air to the water. Because air contains 22% oxygen, aeration adds oxygen to the water.
Several forms of aeration have been used in the past. Most of these older units are what we call "surface splashers." Various designs of post-mounted or float-mounted electric motor driven pumps or propellers cause fountains of water to splash into the air. These are fine in shallow water such as a fish hatchery. Unfortunately, these various units expose just surface water to the atmosphere. As we shall see later, where the oxygen is really needed in a lake, is at the bottom.
Also, electric wires must be taken to the motors out in the water. Insulation break-downs and shorts into the water can cause shock hazards and heavy power losses, so it's better if electricity can be kept away from the water. These surface units are boating and water skiing hazards as well.
Lake bed aeration is different since these systems add oxygen to all of the water in the lake, not only to the surface water, but to the water at the bottom of the lake as well. This is very important. Once the lake or pond is full of oxygen near the bottom, new insect larvae, snails and other fish food can begin to live on the bottom.
All systems that pump water use a lot of electricity for the amount of oxygen they put into the water. It takes much less energy to pump air than water because air weighs a lot less. Therefore, a one fourth horse power air pump can do the work of a water pump requiring four to six times as much electricity. The exceptions to electricity use are the wind mills. These usually mix very little oxygen into the water, especially on a cold, clear, still, star-lit winter night when everything in the woods freezes tight.
Water clarity governs the depth of light penetration in lakes. Periodic testing with a Secchi disc may show seasonal variations in clarity. Courtesy of the Upper Great Lakes Regional Commission
By pumping compressed air out into the lake bed aerator, the rising air bubbles bring the bottom water to the surface where it is exposed to the atmosphere. Large volumes of water thus lose bad gases to the air and pick up even more oxygen while on the surface.
Natural bacteria attack the oil, milk, whey, manure, or whatever, from canning plants, municipal sewage plants, farms, factories, and mills. Bacteria will breathe oxygen if it is available. They like this new "banquet" so well that they grow very fast, multiplying rapidly to gigantic numbers, using up all of the dissolved oxygen in the water. There being no oxygen left in the stream, or lake, due to the high biological oxygen demand of these bacteria, the fish die. The fish cannot breathe until all of the pollution is "burned up" by the bacteria.
Aeration speeds up this process of oxidizing or "burning up" the pollution. In fact, if there is sufficient aeration, the fish will be able to survive a surprising amount of pollution in a place like a feed lot run-off pond or tertiary sewage treatment lagoon. These are potentially good fishing spots. There is no reason for such places to be "bad," even if there are occasional spills or excessive draw-downs.
So "badness" nearly always has to be blamed upon decaying vegetation caused by excessive primary production in overly fertilized bodies of water. "Goodness" is fresh, sparkling clear, sweet-smelling water which supports abundant fish life, free from excessive algae and weeds.
A growing number of property owners and concerned anglers are discovering that scum, algae, and bubbling gases are no longer found only on "the other guy's" lake. Many are finding the problem creeping closer to their own backyard.
Some algae is necessary, being the first step up the fish food ladder. Zooplankton graze on the algae; they cannot manufacture their own food out of light, air and water as the algae do, giving off oxygen in the process. Zooplankton need oxygen to breathe, like most living things. Aeration of the water improves their environment. Their numbers increase over tenfold when aeration begins. They eat the algae, and the fish eat them.
IT'S A RACE
It's those special bacteria that determine if a lake is "good" or "bad" in North America. Do the bacteria digest the decaying vegetation faster that it's produced? The normal death of a lake over the centuries is for it to fill up with dead plant matter until there is no water left, just weeds, grasses, trees, or a meadow.
The key to keeping a lake "good" by proper lake management then, is to speed up the bacterial digestion of dead plant matter and to slow down the production of new plant matter to the point where the bacteria of decay can keep ahead.
In lakes, plants are eaten by animals and animals are eaten by each other. The predator of one species is the prey of another. This process continues from the lowest plant to the highest animal and constitutes the food web or pyramid (also called the food chain.)
The fixed amount of energy available to a lake is transferred up through the food web by plants and animals. The "energy pyramid" drawing depicts the transfer of energy in an ecosystem, from the microscopic plants (phytoplankton) to the final consumers, the carnivores, at the peak. These relationships impose a balancing effect even on the most complicated ecosystems.
Lakes that support rapid algae or plant growth are termed "eutrophic" lakes. Eutrophication comes from the Greek word for "over-fed" and that's just what the plants are when they tend to grow too fast. Such lakes are overly fertile with plant food, the same plant food used on lawns, gardens, and fields. In fact, agricultural run-off is an important source of fertilizer for ponds and lakes supporting excessive vegetation production. The important elements employed here are fixed nitrogen, potassium, and phosphorus, the three main plant foods.
Other elements are needed by growing plants and algae such as calcium and magnesium, always the cause of "hardness" in the water. Hard water lakes are always problem lakes with respect to algae and weed growth. Carbon dioxide supplies the carbon needed by the plants and is present in the air at 0.03-0.05% concentration. Hard water can hold a lot more carbon dioxide as dissolved carbonate and bicarbonate than soft water. This is the reason hard water lakes are troublesome.
Some lower forms of plant life such as blue-green algae require other substances such as vitamin B-12 in the water since they apparently cannot manufacture their own. The B-12 comes from air born pollen and from green algae, bacteria, and fungi in the water. In return, the blue-green algae give off substances which are poisonous to other plants so as to eliminate competition from other species for the food supply and sunlight. Sometimes these poisons are so toxic from the blue-green algae species that they kill birds, fish, and even livestock within five minutes after drinking the infected water!
We have discussed fertilizers for algae and weeds, but other factors also determine how fast vegetable matter is produced. Warmer water causes plants to grow faster. Those terrible blue-green algae, the worst kind of all, like warm surface water for their foul and often toxic habitat.
More sunlight means more primary production by photosynthesis in the chlorophyll of algae and weeds. This continues as long as the food supply holds out. When one of the nutrients is exhausted from the water, production stops for the most part. When production stops, the bacteria have some time to catch up with their digestion of dead algae and plant matter.
So, limiting the nutrients limits algae and weeds the natural way. Now, how can bubbling air through the water and exposing it to the atmosphere limit plant nutrients? To answer this we will take a close look at what happens to these nutrients in a lake when we aerate it.
STARVING SLOWS THEM DOWN
Plants need iron for photosynthesis. Plants need phosphorus for their enzymes. Dissolved oxygen in the water makes all iron oxidize to the ferric (or plus three) state from the ferrous (or plus two) state. Ferric phosphate is not soluble in water. There goes the iron and some of the phosphorus out of the ecosystem, precipitated out into the bottom mud as the insoluble iron phosphates. They are no longer available for plant nutrition and growth.
Plants need manganese for chlorophyll production. Dissolved oxygen "burns" the manganous ions in the water to manganese dioxide and insoluble manganic (or plus three) phosphate which settles to the bottom. There goes the manganese and some more of the phosphate.
Plants need nitrogen in a fixed, water soluble form (not as the gas nitrogen that makes up 3/4ths of the atmosphere.) Plants such as algae need nitrates, nitrites, and ammonia. The fixed nitrogen form most often found in the water, produced from decaying vegetation, is ammonia. When we aerate, we actually blow the ammonia right out of the lake, mechanically. The water and air exchange the ammonia, but the air moves away in the wind. There goes the nitrogen by "phase distribution."
Plants need carbon dioxide and water to turn into sugar, using sunlight by photosynthesis. We simply say six molecules of water and six of carbon dioxide unite to form one molecule of glucose and six molecules of oxygen in the chloroplast. While not strictly the story, it's the result and you can see oxygen is put into the water by this process. Glucose is the plant's building block for cellulose. What does aeration do about this? Phase distribution again. The carbon dioxide at the surface blows away in the wind.
Report On A gen-AIR-ator Installation - This natural seven acre glacial kettle lake was found to be in an advanced state of eutrophication. The bottom was spongy peat, many feet deep, with more peat constantly being formed from a heavy load of oxygen-using organic matter. Readings were taken at depths of one, four, six, nine and 16 feet throughout the lake, then averaged to show the results below. Temperatures are Fahrenheit. The ppm. Readings indicate parts per million of oxygen dissolved in the water. Lake Readings Were Taken On May 27,1972. The gen-AIR-ator Was Installed At A Depth of 18 Feet That Same Day.
Another dissolved gas coming from decaying plant matter in a "bad" lake bottom is deadly hydrogen sulfide. This has the smell of rotten eggs and is highly toxic to fish. If oxygen is present in the water, no hydrogen sulfide is formed. Where the lake is "bad," aeration causes more phase distribution and the smell of rotten eggs is strong above the aerator for the first several days. Soon the lake is "good" again. Most of the off-flavors in fish flesh taken from a "bad" lake are due to the presence of sulfur compounds coming from this hydrogen sulfide. We note that even small amounts of dissolved oxygen in the water at the lake bottom are toxic to the sulfate- reducing bacteria responsible for the hydrogen sulfide. Aeration makes the fish taste better, so now this lake is "good."
WE WANT BACTERIA ON OUR SIDE
There are two kinds of bacteria all around us: those that need oxygen to live, called aerobic bacteria, and those that live and grow in the absence of oxygen, called anaerobic bacteria. They are different in another way.
Aerobic bacteria grow and eat 20 to 30 times faster than anaerobic bacteria. We scientists like to say it this way: "Aerobic systems are characterized by high pE values and high energy availability following introduction of organic matter, while anaerobic systems are characterized by low pE and redox values and low energy availability."
Here, pE means electron activity which is important to the scientist. It all boils down to this: In one year, aerobic bacteria will digest and change into carbon dioxide and water the amount of dead vegetation that anaerobic bacteria take 30 years to digest! So, if oxygen is present at the lake bed, called the benthic zone, dead weeds and peat do not accumulate as bottom muck. Such muck is quickly eaten by our aerobic friends, not slowly chewed upon by anaerobics who fall behind in their work, and lose the race, allowing the pretty pond or lake to go " bad," filling up with peat. That's how coal was formed eons ago. It's the natural death of a lake, just as it's natural for aerobes to eat up dead vegetation and algae and keep it "good." Thus aeration and destratification keep these aerobic bacteria on the job by assuring them a constant supply of oxygen.
In really "bad" lakes, the bacteria can be helped tremendously if the excessive growth of aquatic weeds is removed by mechanical harvesting. There may be so much plant food in the water that unsightly weed growth results. Harvesting these weeds not only removes much nutrient physically, but takes a big load off our aerobic friends. The removed weeds, applied to fields as green manure, are an agricultural asset instead of an aquatic liability.
Oxygen distribution in a stratified lake - Note that oxygen has been depleted in the hypolimnion and fish are absent. The thermocline acts as a barrier to mixing, and prevents aeration of the hypolimnion. Furthermore, because of the depth and lack of sunlight, the hyplimnion does not benefit from photosynthetic oxygen production. The lake is reoxygenated during the spring and fall overturn and then fish may inhabit the deeper waters.
*(Unless they are killed by the poisonous/methane, ammonia, hydrogen sulfide/bottom water as it rises to the surface when the oxygen-rich surface water descends.)Footnote by : Dr. Mervin M. Browne.
Occasionally, chemicals are applied to slow down production. This must be considered an emergency shock treatment for the lake of short term benefit. It gives the bacteria some extra time to catch up since primary production is temporarily halted. Compared to aeration alone, chemicals are an expensive last resort and other forms of wild life generally suffer a set-back following any chemical application. The dangers require an expert be used to balance the risks of application. Repeated use of chemical toxicants can only be harmful, as this is an unnatural introduction into the ecosystem even though sometimes necessary, especially in the warm South where hydrilla, water hyacinths, and water lilies get out of control.
HOT OR COLD
Speaking of the warm South where primary production goes on all year round, you would think that the bacteria could never catch up and dead vegetation would be mountainous. Such is not the case, obviously. The reason is that our friendly bacteria digest the dead plants much faster at warmer temperatures. (For example, glucose from cellulose is eaten only one tenth as fast at 45*F as at 85*F by aerobic bacteria.)
Summer mixing of lakes by wind - Shallow lakes are kept well mixed by wind action. Winds mix only a portion of deeper lakes. Courtesy of Upper Great Lakes Regional Commision
Reversing the photosynthesis equations: six molecules of oxygen are combined by the bacteria with one glucose molecule to form six molecules of carbon dioxide gas and six molecules of water. All of this talk about molecules may sound unrealistic, so let's put it as: 18 pounds of cellulose combines with 19 pounds of oxygen to yield 26 pounds of carbon dioxide and 11 pounds of water. The rate of these reactions is predicted at different temperatures by biologists using the famous Arrhenius equation which students usually refer to jokingly as the "erroneous" equation. Bacteria have strict temperature limitations. Fortunately, there are thousands of kinds of bacteria and some like it hot while others like it cold.
Up north in New England, Michigan, Wisconsin, Minnesota, and in the mountains and Canada, the lakes are covered with ice half of the year. Algae and plants grow only during the warm "open" months. Why can't the bacteria keep up with plant production in these areas? Why so much peat bog and muck accumulation in the north country?
If we look at a "bad" lake in New York State, we see a typical glacial lake dying. The winter months find the bottom at 39.5*F, and no oxygen - water being most dense at this temperature. The ice seals off the lake surface so that no atmospheric oxygen can get into the water all winter. When the ice melts out in the late spring, the cold heavy water stays at the bottom even while the sun and air warm the surface water up to above 80*F. This lighter weight, warmer water stays on the surface until cold autumn nights chill it again six months later. We call the warm upper layer the "epilimnion" and the cold, dead, bottom layer the "hypolimnion." We put food in refrigerators to keep bacteria from growing in it, called "spoiling." Our New York State lake bottom is refrigerated, seldom getting over 55*F in sixty-five feet of water. It still has no oxygen, but even anaerobic bacteria can't digest the dead plant life and algae raining down from above at those low temperatures.
Some experimenters have tried adding oxygen to this cold hypolimnion as in Lake Waccabuc in New York. All attempts to improve a "bad" lake by oxygenation of only the cold bottom layers of water should be reexamined with a more practical analysis of the problem to be solved in mind. High power costs and expensive equipment have yielded only inconclusive results. If we want our friendly aerobic bacteria to eat up the bottom debris in a hurry, we have to warm them up as well as give them oxygen.
THE SIMPLE SOLUTION
A northern lake may be "saved" by the installation of the lake bed aerator that oxygenates the water at the bottom, and destroys the hypolimnion by low cost, low-powered, continuous destratification. Bottom temperatures come up to 60-65*F while the mixing of the cooler bottom water with the surface water brings down the surface water temperatures to 70-75*F during June. On a windy day, or during a Cold Front passage, winds of 35 to 40 miles per hour, mix up the whole lake. We see 72* F from top to bottom and plenty of dissolved oxygen also - over 7 parts per million - enough for game fish as well as for our friendly aerobes. They are eating the bottom debris at four times the rate they would in an aerated hypolimnion and 60 to 70 times faster than if we had left the lake to its own natural death. If man has added his own pollution, lake bed aeration restoration results are even more dramatic.
Vegetation can offer cover and concealment for bait fish and game fish alike. However, there are times when Mother Nature may need a helping hand to prevent the needless and premature death of a lake.
Above the Lake Bed Aerator in the winter, a hole in the ice remains open, 20 to 40 feet in diameter, The lake waters are not sealed off from light and the atmosphere by ice. Dissolved oxygen levels remain high all winter. There are no distressed fish and our bacteria keep on slowly eating. This is quite a change from normal winter. The ice goes out 3 weeks sooner, too. This opens up the lake to the atmosphere sooner, and the results are apparent. Spawns are more successful. Soon the "bad" lake is once again a "good" lake and it didn't take an act of Congress or a "megabuck" program to get the job done. Even the individual property owner can install this lake bed aerator system in less than two hours with a friend, maybe a six-pack, a screw driver, and a pair of pliers.
When installed and running, the lake bed aerator makes an unbelievably active fishing hole according to some Illinois State Fishery Biologists and many gen-AIR-ator owners. The unit is designed to run day and night all year round without maintenance. Don't worry about the effects of mixing a "nutrient-rich hypolimnion water" with surface water - there isn't any hypolimnion any more, just "good" fishing water.
Assistance with silting and sedimentation problems and rainfall and drainage data can be obtained from your local U.S. Department of Agriculture Soil Conservation Service Office. For professional advice and worthwhile literature on fish and water management, consult your County Agriculture Extension Office, your State Fish and Wildlife Management Agency or your Department of Natural Resources.
- Grzimek's Animal Life Encyclopedia by Barnhard Grzimek. Published by Van Nostrand Reinhold Co., New York. Volumes 1, 3 &4. (1974)
- McGraw-Hill Encyclopedia of Science and Technology by David G. Frey. Published by McGraw-Hill Book Company, New York. Vol. 5, pp.562-574.(1971)
- Encyclopedia Brittanica. Vo. 7, p.912. (1968)
- Environmental Protection Agency, Ecological Research Series EPA -660-/3-73-023, p.177. (1974) by George P. Fitzgerald and Paul D. Uttormark. U.S. Government Printing Office, Superintendent of Documents, Washingtion, D.C. 20402.
- Wastewater Use in the Production of Food and Fiber, Proceedings, Oklahoma City Conference, March 5-7, 1974.
Environmental Protection Technology, Series EPA - 660/2-74-041. (June, 1974) U.S. Government Printing Office, Superintendent of Documents, Washington, D.C., 20402. (Price, $5.35)
- The Biology of Blue-Green Algae, N.G. Carr and B.A. Whitton, Editors. The University of California Press, Berkeley and Los Angeles, California. (1973)
- Report No. REC -ERC - 72-73, Dale Toetz, Jerry Wilhmn & Robert Summerfelt. Engineering and Research Center, Bureau of Reclamation, Denver, Colorado. (October, 1972) Available from National Technical Information Service, 5285 Port Royal Road, Springfield, Virginia 22151.
"To summarize the benefits of aeration: elimination of the thermocline (destratification) - less nitrogen in the form of ammonia - lower iron and manganese levels - lower soluble phosphates - less potentially toxic blue-green algae - more zooplankton (fish food) - less total green algae, owing to less nutrients (nitrogen and phosphate), as well as to algae-eating grazers (which themselves serve as fish food)." -Mervin F. Browne, PH.D.
"Artificial destratification (aeration) cannot as yet be regarded as the panacea for every water quality problem in an impoundment, although it is probably a major breakthrough in the management of eutrophic impoundments."
- WATER POLLUTION MICROBIOLOGY, published by Wiley-Interscience Prof. Ralph Mitchell, Harvard University, editor. -from Chapter 17, by J.E. Ridley, Metropolitian Water Board, West Molesey, Surrey, England, and J.M. Symons, Bureau of Water Hygiene, U.S. Dept. of H.E.W.
"Adding chemicals to ponds may be a dangerous practice...No chemical will effectively control all types of vegetation without harming fish…Under certain conditions, fish may die with almost any chemical treatment."
"The best way to control plants is to create conditions which discourage their establishment and growth."
"...fertilization is not recommended. It causes heavy growth of vegetation, which not only makes angling impossible, but kills fish by using oxygen."
"Oxygen is the main factor...Not only do fish and other aquatic animals need it, but it decomposes organic matter. Pond bottoms of organic soils demand large amounts of oxygen... when oxygen concentrations are in danger of becoming low...mechanical aeration is useful."
- WISCONSIN FISH FARMS, Manual 3, published by the Cooperative Extension Program, U. of Wisconsin, by John H. Klingbiel, Wisconsin Department of Natural Resources, Bureau of Fish Management, La Verne C. Stricker, U.S.D.A. Soil Conservation Service, and Orrin J. Rongstad, U.W. Cooperative Extension Service.
"There is growing concern about the unknown environmental effects of...chemicals in lakes, and, in addition, plant nutrients (fertilizers) are not removed by poisoning."
- UNDERSTANDING LAKES AND LAKE PROBLEMS, a publication of the University of Wisconsin's Cooperative Extension Program and the Federally-sponsored UPPER GREAT LAKES REGIONAL COMMISSION.