Algae on Water Supplies Page 2

Heavy blooms can overtake water bodies, and even choke out portions of streams or rivers. It is difficult to predict when a bloom will occur. Some species bloom only in spring, others more frequently in the fall. These organisms can bloom in flowing or standing water. Blooms may even occur under the ice in the middle of winter. As seawater freezes, algae living in the water are frozen in the ice, where they later can be released during a thaw. These algae are a vital source of food for krill and shrimp-like organisms. Large, nuisance blooms commonly form following periods of hot, calm weather when the water is warm. They are also more likely to occur when water nutrient levels, and in particular phosphorus, are high. Heightened nutrient levels result when water bodies receive runoff or leaching from such sources as: fertilized fields, lawns, poorly managed manure, storm drain discharges, poorly contained septic systems, or soil and sediment transport in runoff water. These nutrients lead to blooms in coastal waters to a greater extent than in the open ocean. Algae blooms in the open ocean are not usually harmful. Instead, Algae blooms provide benefits, largely from the fact that the open ocean is relatively low in nutrients.

Large blooms of algae and cyanobacteria can clog intake pipes and filter lines, and are aesthetically unappealing. During these blooms, a liter of water can contain millions of algae! When blooms of algae or cyanobacteria die and decay, the dead cells often produce objectionable odors as a result of oxygen depletion in the surrounding water. When a bloom dies in a pond or shallow lake, severe oxygen depletion can even cause fish deaths. Algae do not produce substances that are toxic to humans or animals. In contrast, some cyanobacteria produce substances that are extremely toxic, and are capable of causing serious illness or even death if consumed. These substances are called cyanotoxins. There are currently over 70 different cyanotoxins, which are grouped by their method of toxicity. One cannot tell if a cyanobacterial bloom is producing toxins simply by looking at the bloom. Instead, you should assume toxins are present and avoid using the water.

So as algae is a very normal and naturally positive component of the aquatic arena, benefiting overall water quality, aquatic life and even humans, it can also pose many water quality issues if the wrong type of algae forms under the ideal conditions. In this case, the saying is true that too much of something good is not always for the best! Moderation is the key and the right balance of good is what makes for a stable and fruitful life. Find your balance!