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Definition of Terms
There are many scientific terms used with stream science related to ecology, geology, hydrology, waste water, and the tools used to test our parameters. Below is a list of terms and an attempt to help you better understand concepts in Watershed Science.
Hydrology- the science dealing with the occurrence, circulation, distribution, and properties of the waters of the earth and its atmosphere.(The study of water in its many forms.)
Image courtesy of U.S Geological Survey
Geology- the science that deals with the dynamics and physical history of the earth, the rocks of which it is composed, and the physical, chemical, and biological changes that the earth has undergone or is undergoing. (The study of rocks and how the earth's features change.)
Biology- the science of life or living matter in all its forms and phenomena, esp. with reference to origin, growth, reproduction, structure, and behavior. (The study of living organisms or things.)
Watershed-a land area that drains to a particular point on the landscape, this can be a mouth of a river, a lake or even the ocean. A watershed can be identified by drawing a line along the highest elevations (often a ridge) between two areas on a map. Large watersheds are made up of several smaller ones.
Ecology- the branch of biology dealing with the relations and interactions between organisms and their environment, including other organisms. (The study of living and non living interactions.)
Water quality- the physical, chemical and biological characteristics of water in relationship to a set of standards.
pH- a measure of the realative acidity or alkalinty of water. Water with a pH of 7 is neutral, lower pH levels indicate increasing acidity, while pH levels higher than 7 indicate increasingly basic solutions. To the right is a pH scale with household items to help you get better aquainted with acidic and basic solutions.
This image was borrowed from wikimedia.org
Dissolved Oxygen (DO)- the amount of oxygen gas dissolved in a body of water. DO is an indication of the degree of health of the water and its ability to support a balanced aquatic ecosystem. DO is often expressed in percent saturation, since the amount of oxygen water can hold changes drastically with temperature. For most organisms around the Gallatin, specifically aquatic insects and fish, thrive when DO saturation is higher than 80%.
This image was borrowed from www-tc.pbs.org
Nitrate-is a form of nitrogen that is usable by plants and animals. Just like adding nitrogen (e.g. fertilizer) to a garden helps vegetables to grow, adding nitrogen to a stream can cause increased plant growth in the form of aquatic algae. Excessive algal growth can have negative impacts, including low dissolved oxyten, unsightly conditions, and poor habitat conditions for fish and other aquatic organisms. Sources of streamwater nitrate include organic matter, the atmosphere, geology, human and animal waste, and fertilizers. Nitrate is measured in miligrams per liter as Nitrogen (mg/L-N).
Temperature- a measure of the warmth or coldness of an object or substance with reference to some standard value. Temperature can effect aquatic life populations like fish, macro's and algal masses. BWTF measures temperature in degrees Celcius, for this system 0 degrees is when water freezes and 100 degrees is when water boils. The chart to the right compares Celcius to Farhrenheit. This image borrowed from www.timwerx.net
Turbidity- a measure of the amount of solid particles suspended in water that cause light to scatter. This scattering results in cloudy or opaque water. The units for turbidity are Nephelometric Turbidity Units (NTU). Turbidity is often low in the winter resulting in clear rivers, but notice how the river turns brown during snowmelt. This is because the melting snow will carry soil with it to the river. To the left are some examples of different turbidity levels ranging from 10- 250.
This image borrowed from www.water.ncsu.edu
Escherichia coli-(commonly E. coli;) is a bacterium that is commonly found in the lower intestine of warm-blooded animals. Most E. coli strains are harmless, but some can cause illness, especially in young children and the elderly.
Total coliform- the most basic test for bacterial contamination of a water supply is the test for total coliform bacteria. Coliform bacteria themselves are not toxic but the level at which they occur in water can indicate possible contamination of other bacteria that are more difficult and more expensive to test.
Bacteria is measured in colony forming units per 100 mililiters (cfu/100mL), that is the number of dots that appear on a petridish per 100mL of water used. Both E.Coli and Total Coliform are measured in the same test, an example is pictured to the left. The Red dots are total coliform units, the blue are E. Coli and the green are salmonella. Note: this example is not from the Gallatin River.
Image courtesy of http://www.micrologylabs.com/
Algal biomass- any of numerous groups of chlorophyll-containing, mainly aquatic eukaryotic organisms ranging from microscopic single-celled forms to multicellular forms 100 ft. (30 m) or more long, distinguished from plants by the absence of true roots, stems, and leaves and by a lack of nonreproductive cells in the reproductive structures. Algae growth is natural but an excessive amount (caused by excess nitrogen) can increase turbidity, decrease dissolved oxygen, and increase temperatures and therefore stress fish and other aquatic organisms.
Aquatic Benthic Macroinvertebrates- large aquatic organisms that have not skeleton and live on and under the rocks and substrate of a stream. These organisms or "macros" are a great indication of water quality as some are very senstive to pollution. When collecting macros the BWTF looks for the presence of sensitive species such as mayflies, stonfiles and caddisflies, variety of species and number of organisms collected.
This image borrowed from www.waterwatch.org.au
Conductivity- Electrical conductivity (EC) estimates the amount of total dissolved salts (TDS), or the total amount of dissolved ions in the water. Although salinity, measured as electrical conductivity, can be naturally high in some systems, waters with elevated salinity levels are usually the result of both nonpoint (non-traceable) and point (traceable) source pollution and can adversly impact aquatic ecosystems. High levels of EC can inhibit plant and animal life.
Total Maximum Daily Load (TMDL)- Under section 303(d) of the Clean Water Act, states, territories, and authorized tribes are required to develop lists of impaired waters. These are waters that are too polluted or otherwise degraded to meet the water quality standards set by states, territories, or authorized tribes. The law requires that these jurisdictions establish priority rankings for waters on the lists and develop TMDLs for these waters. A Total Maximum Daily Load, or TMDL, is a calculation of the maximum amount of a pollutant that a waterbody can receive and still safely meet water quality standards.
These definitions were borrowed from Dictionary.com, USGS.gov and EPA.gov