Controlling Lake and Pond Algae

Lakes and ponds are the place we head to for enjoyment to swim, fish or relax. Unfortunately it is also the perfect environment for algae to grow. Where there is sun, water and nutrients pants will grow. And since algae is a very basic and simple form of life, it will be one of the first to establish itself and the quickest to rebound from steps taken to eradicate it such as herbicides.

A pond is a closed system functioning much like an organism with all the life within interacting to create a balance. Algae, rooted plants, zooplankton, fish, birds and so on all have their part and keep the other parts in check and under control. Too often this balance tips and the system spirals out of control. Algae, being the opportunist that it is, is usually the first to take charge. Thick mats of slime or pea green soup-like water are the result.

This is usually a sign of high nutrients and poor water conditions. In the summer and winter months a pond often becomes stagnant and a thermocline forms. As this forms, the water column is cut into two regions. An area of livable water near the surface and a layer of toxic oxygen deficient water closer to the bottom. This upper livable area is susceptible to wild swings in quality as the algae growth spikes and drops, first giving oxygen then sucking it back out as it goes through respiration near dawn or decomposes after a die off. In the spring and fall these two regions will suddenly and violently mix, called a turnover event. It is these turnover events that can trigger a fish kill as the toxins are released to the entire water column stressing all fish contained within the lake or pond.

One very effective technique to prevent this situation is to aerate the water column of the lake or pond. By aeration we mean using laminar flow methodology (bubblers) to move the water from surface to the bottom. Fountains do work in certain situations, such as shallow water areas. But only laminar flow has the ability to completely mix even the deepest of areas to get oxygen down to the sediment-water interface. The thermocline is prevented from ever setting up and the entire water column is improved.

The tiny bubbles pull the water with them as the travel to the surface. The water pulled up from the deep are exposed to the atmosphere and two things happen at the surface. Toxins from the natural bacterial digesting process are released harmlessly to the air while oxygen is absorbed into the water. This oxygen rich water is then pushed back down to the bottom to release the oxygen to the bacteria and move the toxins back to the surface. It functions as a toxin/oxygen conveyor belt that keeps the system in balance.

Once oxygen is in all areas natural bacteria are able to consume nutrients available in that water. Aerobic bacteria, those with oxygen available, can digest nutrients SEVEN times faster than bacteria forced to go through anaerobic, without oxygen, conditions. This reduces the available nutrients for algae to use to grow. It is an indirect method to outcompete the algae for the food they need to survive.

The Effects of Drought on Your Trees

Drought can affect your trees in many different ways. The longer the drought, the more severe the effects on your trees. The effects of drought are considered short-term or long-term, and your trees are more likely to recover from short-term effects.

Short-Term Effects

• Temporary Wilting. As the amount of moisture available in the soil decreases, the leaves on the tree dry out and begin to wilt. The amount of visible tree leaf wilting varies by tree species as well as the amount of soil moisture available. Temporary leaf wilting is usually resolved at night when the leaves are re-hydrated with dew and recover until the next day.

• Leaf Shedding and Coloration. Premature shedding of tree leaves and leaf coloration can be brought on by periods of drought. In many species, leaf mottling or partial browning occurs during droughts. It is quite common for yellow poplar trees to shed leaves during summer droughts, as well as sycamore and buckeye trees. Dogwood leaves wilt and die, rather than being shed during droughts. Summer droughts often cause early autumn leaf coloration, and the needles of conifers may turn yellow and brown.

• Growth Inhibition. Periods of drought decrease the seasonal growth potential of your trees. Drought affects the development of the tree shoots, the width of the annual growth ring in the tree trunk, and the root system. The young roots, which are the major water-absorbers, are the most easily damaged by drought.

Long Term Effects

• Signs of Die Back and Decline. If there is not enough moisture in the soil for an extended period, the roots cannot supply the crown of the tree with enough nutrients and moisture. The result is the crown beginning to die back in order to bring the tree and the root system into a better balance. Leaves, twigs and branches will begin to die, especially in the uppermost areas of the tree.

• Pest Problems. As trees' health decline from long-term drought, they become predisposed to pest attack and infestation. Many pests are unable to survive in healthy trees. However when trees have been deprived of moisture and nutrients for a lengthy period, their response to pest attack is weakened and they have poorer recovery from pest damage.

• Wounds and Disease. Long-term drought weakens the tree's ability to recover from minor wounds, and increases the chances of tree diseases. When a tree is unable to compartmentalize or isolate a small wound, pathogens readily invade and colonize, causing increasing damage. Stem canker disease is a common effect of long drought periods.