During Texas" hot summer months, many of our area waterways have an excessive growth of algae (small aquatic plants). Fertilizers and other nutrients can trigger this growth. Algae can cause water in our lakes, ponds and rivers to turn green, brown or black in color, have an unpleasant odor, and become a nuisance. In extreme cases, excessive algal growth may contribute to the death of fish and other aquatic organisms.

CAUSES OF ALGAL BLOOMS

Algae are aquatic plants that naturally occur in ponded or slow moving water. Blooms, excessive numbers of algae, occur when a nutrient, occurring naturally in a low amount, is added to the aquatic system. This extra amount of nutrients causes the algae to undergo a "population explosion. Where do these nutrients come from? Typically we introduce them by overly or improperly applying fertilizers to our lawns. Rainfall runoff and irrigation water can carry soil, leaves, and other organic wastes into our creeks, streams, and ponds which also provide nutrients. Fertilizer, washed from our lawns, often contributes to excess algal growth. Phosphorus, a component of fertilizer, is believed to be one of the prime causes of algal blooms. So, the appropriate amount of phosphorus needs to be applied and properly managed to minimize algal blooms. Fertilizer constituents are specified by three numbers, phosphorus is the middle number. Studies have indicated that only 30% of lawns in Tarrant County need phosphorus, one of the common ingredients of fertilizer. Usually the lawns with sandy loam soil require a small amount of phosphorus. Black clay soils usually do not need any phosphorus.