Biologicals: Your Lake’s Invisible Cleanup Crew

A lake may look quiet from the shoreline, but beneath the surface, billions of tiny workers are constantly on the job.

They do not wear uniforms. They do not drive trucks. Most are so small that they can only be seen through a microscope. Yet without them, a lake or pond can quickly become overwhelmed by muck, odors, excessive nutrients, algae and decaying plants.

These workers are bacteria and they are essential to a healthy aquatic ecosystem.

Every Lake Has a Cleanup Crew

Think of a lake as a small city.

Fish, birds, plants, insects and people all contribute something to the environment. Leaves fall into the water. Aquatic plants die back. Fish produce waste. Grass clippings, fertilizer and soil can wash into the lake after irrigation or rain.

All of this material eventually begins sinking toward the bottom.

If nothing broke it down, layer after layer would continue accumulating. Water depth would gradually decrease, unpleasant odors could develop and the lake would hold more of the nutrients that feed algae and nuisance plant growth.

Fortunately, nature provides its own cleanup crew.

Bacteria consume and decompose much of this organic material. Large bacterial populations live throughout the water, but many are concentrated in the bottom sediment, also known as the benthic zone.

This is where much of the lake’s cleanup work takes place.

What Happens When the Cleanup Crew Falls Behind?

Even a strong cleanup crew can become overwhelmed.

Imagine asking five people to clean an entire stadium after a major event. They may work hard, but if trash is arriving faster than they can remove it, the mess will continue growing.

The same thing can happen in a lake.

Large amounts of leaves, dead algae, plant material, fertilizer and fish waste can create more organic matter than the lake’s natural bacterial population can efficiently process. Low dissolved oxygen, poor circulation, extreme temperatures and certain contaminants can make the problem worse.

The results may include:

• Increasing layers of soft muck
• Unpleasant or “rotten egg” odors
• Reduced water depth
• Cloudy or discolored water
• Excessive algae and aquatic plant growth
• Clogged pumps, filters and irrigation equipment
• A stressed and unstable ecosystem

Once these problems become visible, the lake may already have been struggling below the surface for months or even years.

That is where supplemental biological products may help.

Bacteria: More Workers for the Cleanup Crew

Professional lake managers may apply specially selected bacteria to support the microorganisms already living in the water.

Many of these products contain aerobic bacteria, which require oxygen to survive and perform effectively. When water conditions are suitable, these bacteria help consume organic material and process excess nutrients.

In simple terms, adding beneficial bacteria is like sending more workers to a cleanup job.

They do not make leaves, dead plants or fish waste magically disappear overnight. Instead, they support the lake’s natural decomposition process. When used consistently as part of a larger management program, bacteria may help slow muck accumulation, reduce odors and make nutrients less available to nuisance algae and plants.

However, bacteria are not a cure-all.

They cannot overcome every problem caused by severe oxygen depletion, excessive nutrient loading, poor circulation or years of accumulated sediment. If a lake receives a constant flow of fertilizer, grass clippings or other organic material, bacteria alone will not eliminate the source of the problem.

Successful lake management begins by identifying what is entering the water and why.

Enzymes: Tools That Help the Workers

If bacteria are the cleanup crew, enzymes are some of the tools they use.

An enzyme is a protein that helps a natural chemical reaction happen more efficiently. In a lake or pond, enzymes can help break large pieces of organic material into smaller pieces that bacteria can consume more easily.

Picture a crew trying to remove a fallen tree.

The workers might eventually move it without equipment, but the job becomes much easier once they have saws and woodchippers. The tree is broken into smaller, manageable pieces.

Enzymes work in a similar way. They do not replace bacteria and are not living organisms. They help prepare organic material so naturally occurring and supplemental bacteria can process it more efficiently.

Some lake programs use bacteria and enzymes together. Others may use enzymes to support the bacterial populations already present in the water.

The correct approach depends upon the lake, its water chemistry, oxygen levels, temperature, circulation and the type of organic material being treated.

Can Biological Products Replace Algaecides?

No and they should not be sold that way.

Algaecides are designed to control an existing algae problem. Biological products are generally used to support the lake’s underlying ecology and reduce the conditions that allow problems to become worse.

One is often corrective. The other is largely preventive.

If a lake is covered with algae today, adding bacteria will not necessarily produce the immediate visible result that a properly selected algaecide can provide. However, repeatedly treating visible algae without addressing nutrients, muck, circulation and oxygen may create an endless cycle:

1. Algae grows.
2. The algae is treated.
3. Dead algae sinks.
4. The dead material decomposes.
5. Nutrients become available again.
6. New algae grows.

Biological products can become valuable when they are used to help interrupt this cycle.

Are Biological Products Worth the Cost?

That depends on how the lake is managed and what the owner expects the products to accomplish.

Consider someone building a new pond. After spending money on excavation, plants, fish and equipment, the owner purchases the least expensive filtration pump available.

At first, it appears that money was saved.

Several months later, the pump begins struggling. The owner spends time cleaning it, replacing parts and dealing with poor water quality. Eventually, the inexpensive pump must be replaced with the better pump that should have been purchased originally.

The cheapest decision became the most expensive decision.

Biological treatments should be viewed in much the same way. They are not simply another container being added to the lake. They are an investment in the lake’s ability to process waste and withstand environmental pressure.

The cost must also be compared with the potential expense of:

• Repeated emergency algae treatments
• Pump and filter cleaning
• Mechanical sediment removal
• Dredging
• Odor complaints
• Fish stress or loss
• Declining appearance and property value

A biological program will not eliminate every future expense. It can, however, help reduce the conditions that create larger and more expensive problems.

More Is Not Automatically Better

Biological products generally have a wider margin of safety than many conventional aquatic treatments, but that does not mean they should be applied carelessly.

Every product should be selected and applied according to its label, recommended dosage and the actual conditions of the water. A lake manager should consider dissolved oxygen, temperature, water volume, circulation, nutrient levels and the amount of organic material present.

Pouring in more product without understanding the lake is not a management plan.

The strongest programs combine biological products with good aeration, proper circulation, responsible fertilizer practices, debris removal, routine water testing and professional observation.

Give Nature the Help It Needs

A healthy lake is not necessarily a lake with no algae, no plants and crystal-clear water every day. Natural water changes with the seasons.

The goal is balance.

When a lake’s natural cleanup system can keep pace with the material entering it, the water is more resilient. When that system becomes overwhelmed, small issues can grow into expensive problems.

Bacteria and enzymes will not fix every aquatic problem. They will not replace good maintenance, proper diagnosis or responsible chemical treatment. But when used correctly, they can strengthen the biological foundation upon which a healthier lake depends.

The most important work in your lake may be performed by organisms you will never see.

Take care of the invisible cleanup crew, and it can help take care of your water.

Patrick Simmsgeiger is President of Diversified Waterscapes and a Certified Lake Manager. Patrick can be reached at contactus@dwiwater.com.