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Hi Folks:
Below are
a few articles on pond algae. The source of these articles are from Irrigation and
Green Magazine, September 2006, www.igin.com
which I subscribe to electronically. I know that you will find these
very
informative. After reading, please remember that while green water
and string algae are part of the natural eco system of a pond, it can be
controlled naturally without harming the eco system. We have proven
it here in Sonoma County with our
Mother Nature’s Pond Care Process Simplified
. Check out our Pond
Problems link to 'String Algae" & "Green
Water". Remember, a slight tweak here and some natural help to
Mother Nature's existing nitrifying process there can result in a balanced
pond.
Happy reading
Adele
Call me 707-584-4228
with any questions regarding our Mother Nature's Pond Care Process
Simplified.
Understanding Green Water and String Algae
Source: Irrigation and Green Magazine, July 2006, www.igin.com
We've all seen those
slimy green scums on ponds, lakes, or pools. They're called algae. And
they stubbornly occur in water - the one place in a landscape that
shouldn't look green. But what are algae? Where did they come from? What
kind of damage can they do? And are they really that bad?
The problem of algae is hard to escape - algae are everywhere. More than
30,000 varieties have been discovered, and scientists have found that
algae have been around for at least two billion years. They occur in
virtually every habitat on earth, as long as water and sunlight are found
there, even if the water is present for a very short time. They can
survive severe environments, from icy mountain glaciers to boiling hot
springs to excessively salty water. However, for the purposes of this
article, we will limit ourselves to algae that grow in ponds, lakes, and
streams.
So what are algae? You'll notice that we've been using the plural form to
talk about them - one alga is microscopic; masses of hundreds of millions
of alga are called algae. It's these masses that we see when we look at a
lake, and it's these masses that are the real enemy. Algae are
traditionally considered to be simple, primitive plants, some made of only
one or two cells. Most make their own food materials through
photosynthesis using sunlight, water, and carbon dioxide - just like any
other plant. While they also contain chlorophyll and produce oxygen, all
lack the leaves, roots, and flowers associated with the more familiar
higher plant forms.
Algae can float freely in water, coloring it green, or they can coat the
sides of a pond with a green or brownish slime. In the ocean, they provide
the food base for most marine food chains. Without algae, our waters would
not sustain life and mankind would not benefit from its countless
qualities and boundless beauty. However, in very high densities (called
algal blooms) algae not only discolors water, but can also out compete or
poison other life forms in it.
But how did it get to your pond or pool? That can be answered with another
question: where did you get your water? All water - even purified drinking
water - can have algae in it. Algae can form spores, which are special,
microscopic, and very tough cells that can survive just about anything -
even the local water purification system. Local water companies will kill
nearly all of the algae in water, but some is bound to survive, and it
only takes a single spore to birth a huge, visible, mucky colony. Algae
can also enter a pond with fish, fish food, or just about anything else
you put inside.
The most common kind of algae is called planktonic algae. These are the
single-celled culprits that create most algal blooms, although they also
bedevil pond owners worldwide. They reproduce rapidly, and can be green,
brown, or red in color. They can be toxic to animals and can give water an
unpleasant taste or odor.
Spirogyra are another common type of algae. These algae look like strings
or filaments, and are familiar as being the green "hair" on the rocks,
sides, or bottom of a pond. There are more than four hundred species of
Spirogyra worldwide, adapted to a variety of environments, but are not as
likely to "bloom" as planktonic algae.
Planktonic algae will bloom in nutrient-rich water. Nutrients can be
produced by a few fish, heavy feeding of fish, or even bird traffic. Any
of these circumstances can throw off the balance of a pond's ecosystem,
and algae will quickly take advantage of that imbalance, growing rapidly
and dying back when the nutrients are depleted. Even non-toxic chemicals
such as those running off of a farmer's field have been found to cause
algal blooms. If non-toxic runoff from a landscape is reaching a pond, or
even the rocks surrounding a pond, it might be inviting an algae
explosion.
This can be a problem even after the algae die back. They can sink to the
bottom of a pool or pond and form sludge. A lot of sludge - a couple acre
feet of water can easily sustain growth of several tons of algae per
season. This will decrease your water volume over time and possibly
necessitate dredging.
As the dead algae decompose, the decomposition may cause oxygen depletion
in the deeper waters. This can result in fish kills, or even chemical
changes in the mud on the bottom, which could release chemicals or toxic
gases. Some species of algae even produce neurotoxins, which, if present
in a high enough concentration of water, can cause serious health problems
in humans if that water is ingested.
Naturally, those are extreme instances. But smaller amounts of algae are
not without their own hazards. For one, algae aren't aesthetically
pleasing. They can make a pristine pond look like a cloudy, stagnant bowl
of pea soup. They can also make rocks or hard surfaces extremely slippery,
especially a problem around pools. They can clog screens, filters, or
pipelines, plug irrigation or pumping equipment, and stain and rot wood.
They can also lessen water flow and trap unsightly debris.
In small amounts in natural environments, algae are an important part of
the ecosystem, providing an essential link in the food chain. However, in
recreational or aesthetic water features, they can be a serious problem
that needs to be dealt with aggressively.
By Denne Goldstein and Rebecca Peterson
Again the source of this document is: Irrigation and Green Magazine, July
2006,
www.igin.com
Some more great info on controlling algae:
 Green
Water and String Algae
Control
Let’s face it:
an algae-infested pond isn’t a pretty site. Algae can make a beautiful
water garden look like a pool of slime left over from a Halloween display.
They also complicate the maintenance of a pond—algae can clog filters and
equipment, ruin wood, and suffocate plants and fish. Some species of algae
double their population as often as every twenty minutes. But not only are
they quick to reproduce, they’re also stubborn. How can you get rid of
them?
First, you need to remember that algae are plants. Like any plant, they
need three elements to survive—light, water, and nutrients. Take away any
one of these necessities, and algae are controllable. Naturally, you can’t
take away water. But light and nutrients are different matters entirely.
At first, the thought that you can control the amount of light reaching a
pond sounds absurd—trees or buildings may provide a certain amount of
shade, but beyond that, it’s not like you can turn off the sun! However,
floating plants are a great—and aesthetic—way of controlling the amount of
light a pond receives.
Plants like water hyacinth, water lettuce, and water lilies are widely
available and will eagerly reproduce to cover the water’s surface. Some
experts suggest that plants with floating leaves should cover up to 50 to
75 percent of a pond.
Mike McGee, president of EP Aeration, San Louis Obispo, California, says
that, “The key in algae control is nutrient control.” Angela Hopko,
marketing manager for Otterbine Barebo, Inc., agrees: “There’s a direct
correlation in the level of available nutrients and the populations of
algae.”
Nutrient control starts even before a pond is built. Ponds should be
designed so that water running off the landscape doesn’t run into them.
The organic debris, fertilizers, and yard chemicals present in runoff are
all considered tasty snacks by algae invaders—you might as well set out an
algae buffet.
“Nutrient loading can be very high in waters adjacent to green areas or
turf grass,” Hopko warns. If a pond is already constructed, some kind of
barrier can be placed around the edge to stop the flow of runoff.
Overstocking a pond with fish and overfeeding fish can also give rise to
algal blooms. Fish waste and leftover food are perfect nutrients for algae
to feed on.
Adequate filtration is another important step towards limiting algae
propagation—whatever material the filter removes is not feeding algae. “I
tell contractors that algae problems in a client’s pond can almost always
be traced back to too many fish, too heavy feeding, and inadequate
filtration,” says Carolyn Weise, consumer relations manager for Ecological
Laboratories, Freeport, New York.
Submerged plants can also help. They feed off the nutrients in the pond
water before algae get a chance. “If the nutrients in a pond can be
consumed at the same rate as they’re being introduced, you can pretty much
solve an algae problem,” McGee says.
Some companies make products for aerating ponds by introducing air and
oxygen at their deepest level. Getting oxygen to this oxygen-depleted area
can be critical in the fight against algae.
“Oxygen works via a chemical reaction to sequester nutrients at the bottom
of the pond, where they can’t be used as food by algae,” McGee explains.
“Many of the most common nutrients found in ponds become insoluble in
oxygen-rich water. Being insoluble makes them heavy, and they sink to the
bottom.” Algae like to stay near the surface, where sunlight is readily
available, and can’t follow the nutrients down.
Proper oxygenation of water can also aid aerobic digestion of nutrients
and sludge. Aerobic organisms consume nutrients, but can only survive when
oxygen is present. Also referred to as microbes, aerobic organisms are
another big element of algae control.
“Aerobic bacteria feed on nutrients and digest them into compounds that
algae can’t use for food,” Hopko explains. Many manufacturers make
products that contain microbes for this precise purpose. “This is a great
approach to managing algae, because it’s organic; it doesn’t require
chemicals,” says Casey Coke of Natural Environmental Systems, Dallas,
Texas.
“I would highly recommend regular use of a microbial product to maintain a
stable ecosystem to any landscape contractor managing a pond,” says Weise.
She also advises not to wait until an algae problem has started before
using these products. “By the time the problem arises, the cure can be
worse than the problem,” she says.
A first thought to fight algae would be to go for an algaecide. However,
while these products can eliminate both planktonic and filamentous algae,
some are not safe for ponds with fish and aquatic plants, and should only
be used in decorative ponds and fountains.
Additionally, algaecides can sometimes work too well—if a product kills
algae too quickly, it can deplete the oxygen in a pond, or worse, the dead
algae can feed a whole new crop of algae, and the problem begins anew.
“This is another benefit to the organic approach,” says Coke. “It works at
a slower pace.”
But if your algae problem is already significant, you may not have a
choice but to use an algaecide. You can kill the algae you already have,
then start with a “clean slate” and begin fighting algae using other
techniques. Some manufacturers offer products that combine algaecides to
kill the algae with microbial products to consume the dead algae.
“It’s vital that contractors understand the importance of good pond care
and regular husbandry using microbes to prevent algae problems,” Weise
says. With knowledge like this in your back pocket, it should be easy to
keep water gardens crystal-clear and algae-free.
Again the source of this document is: Irrigation and Green Magazine, September 2006,
www.igin.com
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