Algae blooms- Elevated growth of one or more species of algae, which may result from excessive nutrient loading, in combination with adequate light, temperature and other environmental factors. Algae are an important food source for aquatic life in our waters, but algae blooms may result in an unbalanced food web or contribute to low dissolved oxygen conditions, during the night or early morning hours.
Ambient monitoring system-A network of sampling stations where water quality measurements are collected on an established schedule to determine general water quality conditions and changes over time.
Conductivity-A measure of a solution's (i.e. water) ability to carry an electrical current. The measurement is used in fresh water analyses to obtain a rapid estimate of dissolved solids or salts content of a water sample. A pristine mountain stream may have a conductivity as low as 15 µmhos/cm, and natural levels in North Carolina are generally less than 100 µmhos/cm. In estuarine and marine waters, salinity is a more appropriate measurement.
Dissolved Oxygen-A measure of oxygen contained in the water. Adequate dissolved oxygen is critical to most aquatic organisms and is one of the more important indicators of environmental health.
Fecal coliform-A group of bacteria that lives in the intestines of warm-blooded animals. Elevated measurements of these bacteria in surface waters may indicate the presence of human and/or animal waste. Health advisories may be posted when measurements indicate an increased risk to human's from exposure.
Fish kills-A variety of factors, including microorganisms, lack of dissolved oxygen, rapid changes in temperature or salinity, and others can result in serious stress to fishes and in fish death. People are advised not to swim or gather fish for consumption in an area where dead fish are present.
pH-measures the acid or alkaline condition of a solution, and is reported as a range from 0 (very acidic) to 14 (very alkaline) pH units. pH in surface waters usually ranges between 4 and 9 units. Sudden changes in pH values may serve as a warning signal that water quality may be affected by the introduction of contaminants or biological events.
Phytoplankton-microscopic plants that are generally at the mercy of the currents. Under certain conditions, Some are capable of altering their buoyancy and float nearer the surface, which gives them a competitive advantage for light and creates a surface bloom. Blooms, whether on the surface or in the water column, can lead to problems of dissolved oxygen.
Salt wedge-is formed in estuaries when salt waters (which are heavier) move inland on and near the bottom and fresh waters (which are lighter) move toward the sound on top. A density gradient (wall) is formed and the bottom waters have no way of replenishing oxygen unless a strong wind mixes the waters together.
Temperature-Water temperature has an important effect on the chemical, physical, and biological processes occurring in aquatic environments. Sudden fluctuations or high temperatures can stress or kill fish.
Water clarity-Clear water helps optimize water quality conditions and allows sunlight to penetrate into the water column. Materials that become mixed and suspended in the water including sediment and algae can affect the clarity of the water and make the water cloudy or turbid.