|
|  | Lake & Pond Aeration Pond Aeration Lake & Pond Aeration Aeration | Pond Aeration The main purpose of pond and dugout aeration is to improve water quality by maintaining dissolved oxygen levels | aerobic bacteria | algae | Addition of air to water results in a rise of its dissolved oxygen level. In waste water treatment, aeration is used to maintain an appropriate oxygen concentration in the waste water in order to promote biological oxidation and to keep the activated sludge in suspension. Hey! Where's the price page? | Right Here ! This Article Explains The Benefits of Pond Aeration -- AND WHY IT WORKS! If you have a pond and you want to improve your water quality -- read this! WHAT IS POND BED AERATION? "Aeration" is the term that we use to mean adding air to the water. Because air contains 22% oxygen aeration adds oxygen to the water. Surface Splashers Several forms of pond aeration have been used in the past. Most of these older units are what we call "surface splashers." Various designs of a) "water fountains" or b) electric motor driven water pumps or c) propellers -- cause water to splash around on the surface and into the air. These may be workable in shallow water such as a fish hatchery. Unfortunately, these various units expose just surface water to the atmosphere. NOT deep water. As we shall see later, where the oxygen is really needed in a pond or a lake is at the bottom. The deepest water. The Older Type Surface Splashers 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. In a recreational lake these surface units are a boating and water skiing hazards as well. So it's better if the electricity can be kept away from the water and just a safe, no hazard Air Line is sent into the pond water. Pond Aeration -- Oxygen in the Water -- Bottom to Top Pond and lake bed aeration is different than using surface splashers. A pond aeration system -- like those we offer at Malibu Water Resources -- adds oxygen to all of the water in the pond or lake. A pond aeration system adds oxygen to the bottom water, not just the surface water. 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 at the bottom. Pond Aeration By pumping compressed air out into a pond or lake bed aerator -- an air diffuser that produces tiny air bubbles -- the rising air bubbles bring bottom water to the surface where it is exposed to the atmosphere. Large volumes of water thus lose bad gasses to the atmosphere and the water picks up even more oxygen while on the surface. Tiny Air Bubbles: Air Diffusers | An air bubble half the size will release 4 times as much oxygen. Natural bacteria attack the oil, milk, whey, manure, or whatever, from canning plants, municipal sewage plants, farms, factories, and mills. Bacteria will breath oxygen if it is available. They like this new "banquet" of oxygen so well that they grow very fast, multiplying rapidly to gigantic numbers. Aeration speeds up this process of oxidizing or "burning up" 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 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 drawdowns. Good Ponds & Bad Ponds 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. Algae and Zooplankton: Some algae is necessary, being the first step up the fish food ladder. Zooplankton graze on the algae. Zooplankton cannot manufacture their own food out of light, and water -- as the algae do, giving off oxygen in the process. Zooplankton need oxygen to breath, like most living things. Aeration of the water improves their environment. Zooplankton numbers increase over tenfold when aeration begins. Zooplankton eat the algae, and the fish eat them. Zooplankton are animals, whose swimming appendages are too small to enable them to swim effectively against the currents. They are typically microscopic, ranging in size up to a few centimeters long. Many can dart for short distances in short bursts of energy, however these bursts are mainly reserved for flight from danger, or pursuit of prey. Some zooplankton are different life stages of larger marine adults. Site: http://www.cnas.smsu.edu/zooplankton/default.htm | Site:http://lakes.chebucto.org/zoo.html | Site: http://www.pmel.noaa.gov/bering/pages/env_zoo.html | Small floating or weakly swimming animals that are transported with the water currents Phytoplankton are known as primary producers. They build organic materials from inorganic elements. Zooplankton are microscopic animals that eat other plankton. It's A Race It's those special bacteria that determine if a pond or lake is "good" or "bad." -- Do the bacteria digest the decaying vegetation faster than it is produced? The normal death of a pond or 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. Speed Up and Slow Down The key to keeping a pond or lake "good" by proper pond 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 can keep ahead. Plants Over-Fed -- Too Much Plant Food Ponds that support rapid algae or plant growth are termed "eutrophic" ponds. Eutrophication comes from the Greek word for "over-fed" and that's just what the plants are when the tend to grow too fast. Such ponds 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. Eutrophic Water | Eutrophic: In lake aging pertains to an old-age lake and indicates high supply of nutrients supporting high biologic productivity. The important elements employed here are: -- fixed nitrogen -- potassium -- phosphorus The three main plant foods. Other elements are needed by growing plants and algae such as -- calcium -- magnesium These elements are the cause of "hardness" in the water. Hard Water Hard water ponds are always problem ponds with respect to algae and weed growth. Carbon dioxide supplies the carbon needed by the plants and is present in 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 ponds are troublesome. Vitamin B-12 Some 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 Vitamin B-12 comes from -- air born pollen -- green algae -- fungi in the water Blue-Green algae -- Toxic 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 from the blue-green algae species are so toxic that they kill birds, fish, and even livestock within five minutes after drinking the infected water! Blue-Green Algae | Pond Scum Blue-Green algae is a single celled organism that produces its own food through photosynthesis. Hawaii: blue green algae | | http://www.hc-sc.gc.ca/ehp/ehd/catalogue/general/iyh/algea.htm | | http://www.environment.act.gov.au/ie4/airandwater/whatarebluegreenalgae.html | Site: http://www.nrm.qld.gov.au/water/| Site: http://www.envimed.com/emb05.shtml | Site: http://mbgnet.mobot.org/salt/plants/blue.htm | Site: http://www.hlth.gov.bc.ca/hlthfile/hfile47.html | Site: http://www.schs.state.nc.us/epi/hab/bluegreen.html | Site: http://www.ag.ndsu.nodak.edu/drought/ds-7-97.htm | Site: http://www.chebucto.ns.ca/Science/SWCS/cyano.html | Site: http://www.encyclopedia.com/articlesnew/01593.html | Site: http://www.thekrib.com/Plants/Algae/cyanobacteria.html | Site: http://www.ext.nodak.edu/extpubs/ansci/animpest/v1136w.htm | Site: http://www.netpets.com/fish/reference/reefref/cyanobacteria.html | Arizona | Blue-Green Algae | UC Berkeley: http://www.ucmp.berkeley.edu/bacteria/cyanointro.html | Smithsonian: http://www.nmnh.si.edu/botany/projects/algae/xxxx.htm | Algae Blue-Green Algae Blue-Green Algae | Pond Scum Warm 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. Nutrients -- Food Supply 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. Then 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. Air Bubbles Now, how can bubbling air through the water and exposing the water to the atmosphere limit plant nutrients? To answer this we will take a closer look at what happens to these nutrients in a pond when we aerate it. Starving Slows Them Down Plants need -- iron for photosynthesis -- 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 maganous ions in the water -- to manganese dioxide and -- insoluble manganese (or plus three) phosphate which settles to the bottom of the pond. 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 3/4 of the atmosphere.) Plants such as algae need -- nitrates -- nitrites, and -- ammonia The fixed nitrogen form most often found in water -- produced from decaying vegetation -- is ammonia. Ammonia ---> Out When we aerate, we actually blow the ammonia right out of the pond, mechanically. The water and air exchange 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 molecules of carbon dioxide unite to form -- one molecule of glucose and -- six molecules of oxygen in the chloroplast. While not strictly the story, it is 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. Hydrogen Sulfide Another dissolved gas coming from decaying plant matter in a "bad" pond 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 dioxide is formed. Where the pond or lake is "bad" aeration causes more phase distribution and the smell of rotten eggs is strong above the aerator for the first period of time. Tasty Fish Soon the pond or lake is "good" again. Most of the off-flavors in fish flesh taken from a "bad" pond or 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 pond bottom are toxic to the sulfate producing bacteria responsible for the hydrogen sulfide. Aeration makes fish taste better, so now this pond is "good." Aerobic bacteria | the "good guys." They like oxygen. They grow and eat 20 to 30 times faster than anaerobic bacteria (no oxygen). 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 Note: Facultative bacteria are those that can grow with or without oxygen. Aerobic bacteria and anaerobic bacteria are different in another way. Aerobic bacteria (they like oxygen) grow and eat 20 to 30 times faster than anaerobic bacteria (no oxygen). 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 digests and change into carbon dioxide and water the amount of dead vegetation that anaerobic bacteria take 30 years to digest! Dead Vegetation -- digest and change into carbon dioxide: aerobic bacteria: one year anaerobic bacteria: thirty years Bottom Muck So, if oxygen is present at the pond 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 anaerobic bacteria 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 is natural for aerobic bacteria to eat up dead vegetation and algae and keep it "good." A Constant Supply of Oxygen Thus aeration and pond water destratification keep these aerobic bacteria on the job by assuring them a constant supply of oxygen. Pond Aeration Systems A pond or lake may be "saved" by the installation of a pond bed aeration system that oxygenates the water at the bottom, and eliminates the hypolimnion by low cost, low-powered, continuous destratification. Pond Aeration Pond Aeration 1. Epilimnion: http://www.broadwaters.fsnet.co.uk/epilimni.htm | The topmost and warmest layer of water in an unfrozen lake. The epilimnion also contains the most oxygen of any part of the lake The epilimnion is the warmer, upper region, that is mixed thoroughly by surface winds. This layer of water is said to be an isothermal layer, with the same temperatures throughout. The warmer water temperatures and the higher oxygen levels of this layer provide a suitable environment for the majority of the flora and fauna species. 2.A Metalimnion The metalimnion is between the epilimnion and hypolimnion and is several meters thick. Within this unit, the temperature drops rapidly with depth, by at least 1 degree with each metre increase in depth. Since the density of the water changes with temperature, the water does not easily rise or sink in this layer (Strahler & Strahler, 1992). The upward diffusion of nutrients within the metalimnion, creates the next best environment to support the flora and fauna species. 2.B Thermocline: The thermocline occurs in the metalimnion, and is where the temperature and oxygen content decrease with depth. The layer in a lake which divides the warm upper current-mixed zone (epilimnion) from the colder lower deep-water stagnant zone (hypolimnion). During the warm summertime, the thermocline is the middle layer of the lake. Lying between the two layers, the thermocline loses heat rapidly. Also called the metalimnion. Site: http://www.broadwaters.fsnet.co.uk/thermocl.htm | 3. Hypolimnion: The hypolimnion is the lowest layer, and is directly beneath the metalimnion. This region is less insulated from the sun, therefore, the waters are colder, and more dense. The temperature of the hypolimnion are close to 4 degrees Celsius (Strahler & Strahler, 1992). The stagnant waters of the hypolimnion are too deep to be significantly impacted by surface winds and currents. The cooler temperatures and decreased solar radiation received, makes the hypolimnion the least productive layer, and the least favorable layer for species to inhabit. The cold stagnant deep-water layer of a lake. The layer of water in a thermally stratified lake that lies below the thermocline, is noncirculating, and remains perpetually cold. Hypolimnion In a lake, the layer of cold, dense waters extending below a depth of 15'-30'. Separated from the warm, oxygen-rich water of the epilimnion by the thermocline and only mixing during spring and fall turnover. Water that is remote from surface influences and has a relatively small temperature gradient. In eutrophic lakes, this lower layer of water has no oxygen and is loaded with toxic and decaying materials. Hypolimnion Site: http://www.broadwaters.fsnet.co.uk/hypolimnion.htm | Site: | http://www.cwr.uwa.edu.au/~ttfadmin/cwrsoft/doc/dyresm_science/ch7.html | Turnover: The mixing of the lower and upper layers of a lake, generally occurring in the spring and the fall, caused by temperature change and density equalization. Also called overturn. In northern lakes, a spring and fall phenomenon where the the temperatures of the upper (epilimnion) and lower (hypolimnion) layers of lake water converge to a point where intermixing can occur. The spring turnover is more gradual and wind driven; the fall turnover more sudden, occurring when the upper waters cool below the temperature of the water below and drop to the bottom, forcing the now warmer deep waters to the surface. Stratification: Site: http://www.science.mcmaster.ca/Biology/Harbour/STRATIF/CAUSES.HTM | Site: http://www.science.mcmaster.ca/Biology/Harbour/STRATIF/EFFECTS.HTM | Site: http://www.science.mcmaster.ca/Biology/Harbour/STRATIF/FACTORS.HTM | Water Temperature Bottom temperatures come up to 60-65° F. while the mixing of the cooler bottom water with the surface water brings down the temperature of the surface water temperatures to 70-75°F. during June. On a windy day, or during a Cold Front passage, winds of 35 to 30 mile per hour, mix up the whole lake. We see 72°F. from top to bottom and plenty of dissolved oxygen also -- over 7 part per million -- enough for game fish as well as for our friendly aerobic bacteria. Aerobic Bacteria The aerobic bacteria 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 pond or lake to it won natural death. If man has added his own pollution, pond and lake bed aeration restoration results are even more dramatic. Summary The benefits of aeration -- elimination of the thermocline (stratification) -- less nitrogen in the form of ammonia -- lower iron levels -- lower soluble phosphates -- less potentially toxic blue-green algae -- more Zooplankton (fish food) -- less total green algae, owing to less nutrients such as nitrogen and phosphate -- more algae-eating grazers -- which themselves serve as fish food. by Mervin F. Browne, PH.D. Oxygen is the main factor in pond water quality. Not only do fish and other aquatic animals need it, but oxygen breathing aerobic bacteria decompose organic matter. Pond bottoms of organic soils demand larger amounts of oxygen. When oxygen concentrations are in danger of becoming low -- set up a pond aeration system. Aeration Animation: http://www.agr.gc.ca/pfra/water/aerate/dugout.htm | Malibu Water Resources Pond Aeration Lots of Aeration in the pond | adding Oxygen to the water Pond Boss Magazine: http://PondBoss.com | very informative Message Board: http://www.pondboss.com/cgibin/ubbcgi/ultimatebb.cgi | Pond Aeration 2 | more pond aeration information | Aeration Animation: http://www.agr.gc.ca/pfra/water/aerate/dugout.htm | Our Pond Aeration Message Board | Guest book | Malibu Water Resources You can eMail this site to someone you know | eAnswers: http://www.E-AnswersOnline.org | Our site includes a lot of water quality related topics: So, please take a look at our Alphabetical Site Directory II | Malibu Water Resources Koenders Pond Aeration Windmills This site: http://MalibuWater.com/ | Please click here to ASK QUESTIONS | Search this site | To eMail us, please say "Malibu" in the subject line: Info@MalibuWater.com | Malibu Water Resources Our Sales and Corporate offices of MWR are in Carson City, NV. The Research and Development is in Malibu, CA. -- So, please call after 8:00 AM pacific time Tel: 800 490-9170, 818-992-4610 Fax: 818-992-4610
| |
| | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
