By Ron Pifer
B.S Mechanical Engineering, Duke University
M.A. Environmental Biology, University of Colorado
Once when I was a young boy, standing on a beach in Florida, I looked skyward and noticed a low flying plane, dropping what looked like water out of it’s bomb bay doors. “What’s that,” I asked. “Why that’s DDT, Ronnie, and it’s going to kill those pesky mosquitoes that are always trying to carry you away!” Well, what a relief, I thought, isn’t life great?
Now I am much older, and more experienced, and as Paul Harvey so aptly reports, I have learned the rest of the story! That story was first chronicled for me in Rachel Carson’s classic book. Silent Spring, when she stated how insidious poisons become concentrated, as they move up food chains, resulting in illness and death for animals at the top. A new term was even coined to characterize this phenomenon, biological magnification, and in recent years, children all over the country have been taught this concept in schools. As a result a new understanding and beginning was founded.
Unfortunately, real life considerations have their practical side; and poisons are still used and embraced by most of us working in the turf, landscaping, and farming industries. Fortunately, alternatives have always existed, and they are being implemented with increasing frequency in all of those industries. In these cases, the result is a more stable and healthy environment, which is more capable of sustaining harmful hits from weather, pests, and harmful toxins. In addition, the bottom line for using these alternatives can be lower operating costs and more money in the operating budget!
The Basic Ecological Approach to Pond Management
I was recently asked by one of the most esteemed, environmentally oriented superintendents in the golf course industry to stale the main components of ecological pond management. Here is what I told him:
1) Restrict or Reduce the Source of Nutrients Entering your Pond(s). This objective can be accomplished by (a) reducing the use of fertilizer around the border of your pond; (b) placing drainage pathways around the pond, to divert the nutrient-rich runoff away from it; (c) placing impermeable catchment basins in strategic locations to catch, divert, and evaporate the incoming water: and (d) placing a border of native wetland vegetation along the edge of the pond to absorb the incoming nutrients and to provide an attractive border.
2) Employ Biological Controls to Keep the Pond(s) in Ecological Balance and Maintain its Long-Term Health. This objective is designed to help the pond manager offset the nutrient loading to the pond, which causes algae blooms and can cause bad odors, fish kills, and unsightly appearances. There are two main approaches to accomplishing this objective and they can be used in combination with each other. The first one, the most basic is to introduce high concentrations of pond bacteria and enzymes, to act as “packmen” and eat up the nutrient-rich film on the submerged surfaces. This attacks the problem at its source and keeps the pond in proper ecological balance. The second approach is to introduce plant-eating fish to consume the algae that the nutrients have produced. This approach is legal in some states, while illegal in others. However, it can be partially effective when the stocking rate is optimal and the biological conditions are proper. In both cases, the beneficial results are gradual, when compared to using poisons, but the long-term health of the pond is far superior to the “kill ‘em with poisons” approach.
3) Use Mechanical Measures to Maintain High Oxygen Levels. This approach is often used to support the pond bacteria in digesting the nutrient input and controlling the algae blooms and aquatic weed problems. It can and should be used in conjunction with the previous strategy, since it enhances the health vitality, and productivity of both the beneficial bacteria and the plant-eating fish. It can be accomplished by a variety of devices, including propeller-driven fountains, normal air blowers and diff users, or the more expensive ozonators and diffusers. Furthermore, some pond managers create beautiful waterfalls that accomplish a similar objective in an aesthetically pleasing manner.
4) Use Sun Screens or Tinting Dyes. This approach is often useful for restricting incoming light and slowing the photosynthetic processes of the algae. It is most economically feasible in smaller ponds than are not used for pumping or do not have excessive turnover or water loss. However, this approach is ecological only if the sunscreen is not toxic and is easily biodegradable by natural pond bacteria)
5) Physically Remove and Dispose of Any Remaining Algae. As you might expect, a properly managed pond system will clean itself, yet the removal of nutrients may also produce some dead or dying algae. Some of this biomass will sink to the bottom for future decomposition, while some will float on the water surface. The dead, floating algae can be removed by physical means, if so desired. However, if this is done, the algae mass should be taken to a location outside of the immediate pond drainage area, so that future decomposition does not provide a source of future nutrients for the pond.
The Basic Approach to Pond Management
The normal approach to managing ponds is to use algaecides, which are usually copper based poisons that are approved and regulated by government agencies. These chemical strategies often provide a “quick-fix” if applied properly, but they can also result in fish deaths if applied to heavily. More importantly, this approach introduces a toxin into an aquatic ecosystem that also kills or inhibits the pond’s beneficial bacteria and will eventually become incorporated into the aquatic food chain.
This consequence becomes important when you consider that some or most of the algae being killed by the algaecide are sinking to the pond’s bottom, where they enter the pond’s decay cycle. Here, the small aquatic organisms and the beneficial bacteria normally do their job of digesting the plants and maintaining the health of the pond. However, continual use of algaecides reduces their numbers and inhibits their ability to do their job.
This condition results in a bottom layer of organic slime and sediment that becomes a partial dead zone, where anaerobic and facultative aerobic bacteria work very slowly in a low- or no-oxygen environment. It is also a zone that is favorable for pathogens, including E.Coli, and other organisms that are harmful to both aquatic life and humans. Furthermore, the by-products of these bacteria are often hydrogen sulfide, which smells like rotten eggs, and/or methane gas. In addition, there may be a “dead fish” smell, further emphasizing the pond’s sick state of existence.
At this point. Superintendents are often told by consultants that they need to install expensive aeration systems, in order to deal with the odor problem. This approach should help the odor problem, as well as some of the decay processes in the pond bottom. Unfortunately, such a pond will still be out of ecological balance, if poisons are still used in conjunction with this aeration. This means that as the nutrients build up on the pond bottom, heavier doses of algaecides will be needed in order to maintain proper weed control. This consequence will require additional funding from maintenance budgets and will keep the pond headed towards further eutrophication, or the accumulation of nutrients, and the resultant accumulation of more algae!
The Bacterial Approach to Pond Management
Normal pond bacteria are useful for recycling nutrients and keeping the pond in proper ecological balance. However, these bacteria do not necessarily dispose of the nutrients that are a key component of algae blooms. Therefore, when a net gain of nutrients is occurring in a pond environment, it becomes necessary to supplement the native bacteria with special formulations that emphasize nutrient disposal, versus nutrient recycling. Some of these introduced bacteria break down carbohydrates, proteins, and fats into their main components. Others break them down further until the end products are carbon dioxide and water. Yet the most important part of any bacterial formulation is the addition of those types of bacteria that dispose of the primary nutrients for algae blooms: nitrates and phosphates. Most importantly, the better formulas should contain de-nitrifying bacteria, which convert nitrate into nitrogen gas and those bacteria that bind up the phosphates. The resultant millions of such bacteria can then convert the nutrients into carbon dioxide gas, nitrogen gas, and water. In order to accomplish this kind of result, a beneficial bacterial formula must contain multiple bacteria species. For example, H2Organic, contains 11 species of bacteria and seven different enzymes. Most of them perform multiple functions, yet, when taken in total, they cover the full spectrum of decomposition activities that are required in this type of management strategy. This is the kind of total and complete formula that is needed for a successful program.
Other components for a successful Bacterial Program are:
(1) an awareness of the biological conditions existing in the pond;
(2) a high concentration of bacteria:
(3) s superior viability of the bacteria; and
(4) an effective means of dispersal into the pond(s).
Good pond conditions exist when there is adequate aeration, or water movement, which may be mechanical or natural; when the temperature is between 60° F and 90′F; and when the pH is between 6.0 and 9.0. Ponds that are stagnant, or have little natural or artificial water movement, may require heavier or more frequent treatments.
Most pond bacterial formulations are sold in the powder form, being freeze-dried and containing startup growth nutrients, while some are sold in the liquid form. The bacterial concentration varies according to the product being sold. For example, the liquid formulation may have 100 billion or more cells per gallon. On the other hand, the powder formulations may have from several billion to over 10 billion cells per gram, resulting in about 1/2-to-l trillion cells per gallon, for one pound of product. Furthermore, another formulation may be “brewed” up to ultra-high concentrations, exceeding 15 trillion, or 1,500 billion, cells per gallon, for one pound of product. This formulation was designed Co reduce shipping costs when servicing fish and shrimp farming clients in the Orient.
From the standpoint of dispersion, the least productive approach may be the bacteria that are sold in bio-disposable bags. They are designed to be placed on the pond’s surface, to be blown around by the wind and to slowly disperse into the water column. Perhaps a better way is to disperse the product is by hand, throwing it into the water, walking around the pond’s edge. If the product is already liquid, it is ready to go; if it is in the powder form, it needs to be brewed in non-chlorinated and non-toxic water and then dispersed. Of course, the best means of dispersal may be a water pump, if the pond is big enough, or at a headgate, if major volumes of water are flowing into the pond.
Once you try a bacterial product, make sure that you use enough to product to achieve noticeable results. This may require you to use 1.5X to 2.OX the maintenance dosage the first time, in order to kick off the process. Also, make sure to carefully follow the brewing instructions, if there are any, and disperse the product in the most effective manner possible. Repeated treatments may be needed every 2-to-6 weeks, depending on conditions and treatment strength. Your representative can usually help you if you just ask.
Evidence of a successful treatment is apparent in several different ways:
(1) Within a week the bacteria should have started a to clean up the organic film, located along the edge of your pond. This action creates a kind of “vacuum cleaning effect”
(2) Within a week any odors should have disappeared, as the beneficial bacteria start to out-compete the resident bacteria for nutrients and reduce the hydrogen sulfide production
(3) Within a week, the green or blue-green color of the water should reduced and the water clarity should improve. This occurs because the phytoplankton populations are depleted as the nutrients are removed
(4) After several weeks the algae surface scum and some of the rooted aquatics may also start to turn yellow, then brown, as the nutrients are removed and their health deteriorates.
Fishery Management Options
Fishery options can be a favorable component of a well-managed ecological program. They should be chosen, according to your legal and financial constraints, as well as the type of plants that you expect them to consume. In general, there are two main types of aquatic plants in a freshwater pond:
(1) the phytoplankton, or single-celled, suspended algae, which give the water a green or blue-green color; and
(2) the rooted aquatic plants, or weeds, which grow from the bottom upwards. They include the normal leafy plants, as well as the “stringy” pond scum.
To remove the first type of plant, the phytoplankton, the Israeli Carp or the Tilapia is a possible choice. I am most familiar with the Tilapia, since my former company. Solar Aquafarms, Inc. is the largest Tilapia farm in North America. This fish is a superior filter feeder and can live almost exclusively on the tiny algae that they filter from the water. Solar Aquafarms uses this characteristic to recycle the fish waste into algae ponds which are, in turn, pumped back to the fish, to supplement their diet and reduce their feed costs!
The other popular algae eater is the grass carp, which is sometimes called the White Amur. It is popular due to its heavy appetite for some types of rooted aquatic vegetation and due to the fact that it is produced with three sets of chromosomes, instead of two, and is sterile. However, it does not eat all types of algae and often creates turbidity problems, due to heavy rooting activity in the shallow areas along the pond’s borders. As many of you know, it is also illegal in many states due to the concern of illegal releases and the potential harm to the preferred game fish. (more)
Suggestions for Long-Term Success
Superintendents, who have not tried all of the ecological strategies that are available to them, should consider the choices listed in this article. The two most important of these strategies are: (1) to minimize the source of the nutrients flowing into the pond and (2) to reduce the nutrients that make it to the pond. The first strategy is accomplished by drainage design, vegetation e patterns, and fertilizing patterns, while the second strategy is accomplished by a well-designed, bacterial treatment program. In both cases, you are attacking the algae at its source – by removing its life-giving, vital nutrients. Naturally, these ecological strategies are enhanced with good water movement or aeration; organic sun screens, when desirable and appropriate: the addition of algae-eating fish, such as grass carp when you can use them; and the periodic removal and remote disposal of dead algae when it appears.
Most of the strategies are already familiar to most of you, with the exception of the bacterial strategy. I hope I have given you a better understanding of how it works and how it can benefit you. If you haven’t tried it, I suggest that you do. It might even be fun for you to see your pond go through the improvement phases that normally accompany such an approach.
Notes on the Complementary Effects of Using Fish and
Beneficial Microorganisms for Controlling Pond Algae
by Ronald Pifer, Aquatic Ecologist
My previous article, published in August of 1998, focused on “Ecological Controls for Healthy Ponds.” This approach stressed the advantages of employing multiple management tools to reduce costs and to minimize environmental damage. These tools included:
(1) Restricting nutrients entering the pond;
(2) using biological controls, such as fish and beneficial bacteria;
(3) Using aeration systems, such as fountains, blowers. diffusers, and waterfalls;
(4) using aquatic sunscreens; and/or 5) physically removing filamentous or rooted algae, whenever possible.
In this update, we will focus on biological controls and show how they can help one another, to produce a more powerful and effective, algae-control program. This approach utilizes a subtle synergism, or cooperation, among control species. It is possible because the strength of one organism can often offset, or complement, the weakness of another. Thus, the combination produces stronger and more desirable results than are possible with individual controls, acting by themselves.
The fishery controls usually entail the use of grass carp, or white amur, because of their ability to gradually control many rooted aquatics. Other fish are sometimes used to control the microscopic algae, or phytoplankton. They include tilapia and Israeli carp, and in some cases, gold fish. However, it is the grass carp that are the most widespread, algae-control fish, and it is this species that can be used most effectively with the introduced pond bacteria.
Grass carp are beneficial because they are known to favor American elodea, hydrilla, naiad, and muskgrass, or chara. They have moderate inclination for duckweed, pondweeds, bladderwort, fanwort, coontail, water pennywort, and water primrose. Part of their downside is that they do not care for water lily, sedges, cattails, water meal, and water hyacinth (Georgia Cooperative Extension Service).
On the other hand, beneficial pond bacteria are more effective in controlling the floating, filamentous algae and the microscopic, suspended algae, which the grass carp don’t like or cannot eat. The downside of the beneficial bacteria is that they are less effective in controlling those rooted aquatics that the grass carp prefer. Therefore, in terms of preferences or weaknesses, the grass carp and the beneficial bacteria can complement each other very nicely.
When grass carp are stocked properly in a pond, their feeding activities will generate a multitude of plant by-products, which natural pond bacteria will turn into nitrates and phosphates. These nutrients will eventually cause a phytoplankton bloom, resulting in green or blue-green water (University of Florida 1998). Once this happens, the stage is set for a phytoplankton “crash,” or massive die-off. At this point, the native pond bacteria work “overtime” to degrade the extra dead algae, resulting in lowered oxygen levels and, sometimes, bad odors. As you know, this condition often leads to stressed fish and, possibly, to fish moralities.
Fortunately, the laboratory-cultured, beneficial bacteria have been designed to alleviate this situation by consuming those nutrients that are released by carp and processed by native pond bacteria. They also can improve the bottom environment by taking over the decay process from anaerobic bacteria, and thus, they can eliminate bad odors and improve public relations.
Their success is dependent on several factors, however. First, the bacterial formula must contain those species of bacteria that consume nitrates, turning them into nitrogen gas, which is harmless and represents about 80% of the air we breathe. Secondly, the bacteria must be able to bind up the phosphates and render them unavailable as plant nutrients. Thirdly, the formula should contain facultative aerobic bacteria, which can operate with or without oxygen. Fourthly, the formula must contain sufficient concentrations to be effective. And finally the cultured bacteria must be suited to the pond’s environment, with regard to its temperature and pH.
Another benefit of the beneficial microorganisms is their ability to have a positive impact on the control of the filamentous algae. This type of plant grows upward from the bottom and spreads into stringy mats on the surface. If not attended to, it can rot and cause odor and visual problems. The grass carp, on the other hand, do not particularly care for this common type of pond algae. Chuck Cichra of the University of Florida (1998) stated that he has seldom noticed grass carp feeding on this type of plant. Only once did he see it happen, when a lone, large carp had eaten every other plant out of a small farm pond and was left to either starve or eat the filamentous algae. Gee, I wonder what it did!
In conclusion, several points should be taken into account when considering how to best manage these biological controls. First, if you are allowed to use grass carp, you need to determine the proper stocking rate and size for your conditions. Secondly, you need to determine the proper bacterial formula and the treatment timing. And thirdly, you need to realize that biological results are gradual, compared with poisons, yet their long-term benefits are favorable for the environment, are usually more affordable, and are good for public relations…
If you would like any help or assistance in implementing these strategies, please do not hesitate to contact me. A knowledgeable and cooperative partnership makes both players stronger and their joint efforts more powerful.
Mr. Pifer has spent over 15 years in Ecological Consulting, five years in Aquaculture R &; D, seven years as a Science Teacher at the junior high, high school, and college levels, and approximately five years in the Bacterial Products Industry.
PLANKTONIC ALGAE are often times called microscopic algae. This is because they are invisible to the human eye. The only way to physically see the algae is under a microscope. This is why they get the nick-name microscopic algae! Even though you can not see each individual algae cell, the combination of billions and billions of them give a greenish tint to the water. This is also why it is said that the planktonic algae give a “pea-soup” green look to the water.
DUCKWEED can be distinguished by simply looking to see if the floating mat is made up of small single plants (all appearing like very small clover plants – anywhere from one to two tiny leaves per plant). These small duckweed plants almost always have a tiny half inch root that hangs down from the bottom of each plant as it floats on the surface of the water. As far as scale, each single duckweed plant (all leaves) will usually fit within your small fingernail. These plants grow so close together in a pond, that from a distance they all appear as one huge “mat”.
FILAMENTOUS ALGAE are easily visible to the human eye, usually floating on the surface of the water. As you should recall, the filamentous algae starts on the bottom the pond, where the sunlight hits. Then if floats to the surface. However, regardless if the filamentous algae are still under the water, or if it has already started floating, it still looks the same. It looks like moss. Filamentous algae gets its name from the fact that if you reach down and grab a handful of it, the pull upward, it stretches into long stringy filaments. Filamentous algae are the ONLY type of algae that forms moss-like filamentous, and floats. There are several different varieties of filamentous algae, but they all look like floating moss. Some are different colors than others. The varieties can range from green, black or red, to a yellowish appearance.