WHAT DO STONE FLY AND MAY FLIES HAVE TO DO WITH WATER QUALITY?

It's hard to imagine that observing two simple creatures such as the stone fly and may flies would help us understand the nature of our water quality. But it can. By bio monitoring, the analysis of a natural ecosystem (such as a stream or river, etc.) can tell us important information about the health of the water. In essence, if something begins to change in the quality of the water, it will show up in the effects upon the life there. Take sedimentation for example. So, why is all this sediment bad for our stream?

There are several reasons to be concerned about sedimentation. First, sediment has a profound effect on the type of animals that can survive and reproduce in a stream. An undisturbed mountain or upper piedmont stream will have a streambed composed of cobble (small to medium-sized stones with many voids between the stones). If sediment is introduced into a stream; the voids between the cobbles are quickly filled, leaving no space for organisms such as stoneflies and mayflies; both of which provide food for fish species such as trout. Trout also need those voids between the cobble to deposit and hatch their eggs. Earth, in distributing the diversity of life, has its favorite places. The diversity of life can be found within the tropical forests within the equatorial region as well as in the great coral reefs of the western Pacific. The aquatic inhabitants of the world's rivers and lakes of the southeastern United States show the most dizzying abundance of aquatic species.

According to the Nature Conservancy's William Stolzenburg, U.S. Rivers flaunt a cast of aquatic organisms unparalleled in the most vaunted of tropical Eden's. Freshwater mussels, Stoneflies, Crayfish, Snails and Mayflies show a remarkable diversity unmatched elsewhere in the world. The U.S. ranks first in the world diversity for many groups of well-studied animals. Crayfish in this country represent 61% of the world's species. Freshwater Mussels represent 30% and two-thirds of these are vulnerable to extinction or are already extinct. More than one in 10 mussels may have become extinct in this century alone. Aquatic systems are under stress nationwide.

Bio-monitoring...more than just watching mayflies.

Bio-monitoring, the use of living organisms to monitor the effect of pollutants, is an evolving way to identify whether complex chemicals in today's environment are causing health risks to humans and other animals. At least three advantages are immediately apparent: 1) bio-monitoring may detect chemicals for which standard numeric criteria have not been developed and may describe health risks caused by a number of chemicals in combination; 2) It is able to detect toxic and sub lethal effects, even when the concentrations of the chemical causing the damage are below analytical limits; and 3) Bio-monitoring and bioassays may tell us about the damage contaminants cause to living organisms in terms of mortality, mutations, increased incidence of cancers, and other symptoms.

As the list of potential pollutants becomes more lengthy and complex, regulators and scientists are turning to an ancient concept called bio-monitoring to observe and protect water quality. Bio-monitoring may be a new term but it has been used for centuries. Simply put, bio-monitoring uses living organisms to gauge damage that pollutants or toxic substances can or may have caused. For example, medieval kings used a kind of biomonitor - the food taster - to determine if rivals were poisoning the evening meal.

During the industrial revolution, miners took caged canaries with them as they ventured deep into the shafts. If the bird got sick or died, the miners knew it was time to get back to the surface. Three types of bio-monitoring have specific applications to today's water issues. First, stream surveys can provide useful information on water quality by inventorying the diversity of species that are present or absent. If particularly sensitive species can't be found or if massive numbers of fish suddenly die (the fish kills on the Trinity and Pecos rivers come to mind), a pollution problem may exist. Excessive water abstraction from within the catchment reduces the volume of water reaching the lake. This in turn will decrease the rate at which water moves out of the lake, increasing the time available for nutrient uptake by aquatic plants, increasing their growth.