Streamwatchers GLOSSARY
click a term in the activity guide to see what it means
Acid: corrosive substances with a pH less than 7.0: acidity is caused by high concentrations of hydrogen ions.
Acid Rain: rainwater carrying acidic atmospheric pollutants (commonly nitrous or sulfuric oxides) in solution, scientifically known as acidic deposition.
Adaptation: changes an organism makes to adjust to a different or changing environment.
Aerobic: processes requiring oxygen.
Algae: simple plants which do not grow true roots, stems, or leaves, and live mainly in water providing food for the food chain.
Aquatic: organisms that live in or frequent water.
Aquatic area: water area of a stream lake, or wetland measured at the high water level.
Aquifer: layers of porous underground rock that act as water reservoirs.
Autotrophy: production of organic compounds from inorganic compounds by plants and bacteria.
Benthic: pertaining to the bottom of a body of water.
Boulders: rocks larger than 12 inches in diameter.
Braided: a stream channel that splits and comes back together.
Buffer strips: strips of vegetation left to protect streams during forest operations or other types of human activities.
Canopy: upper layer formed by forest trees.
Carrying capacity: number of organisms a particular habitat can support throughout a year without damage to either organisms or habitat.
Coarse particulate organic matter (CPOM): primarily leaf, needle, and fine woody debris larger than 1 mm in diameter.
Cobble: rock from 3 to 12 inches in diameter; also called rubble.
Collectors: aquatic invertebrates that feed on fine material in water.
Condensation: conversion of water from vapor to liquid.
Consumers: organisms that depend on other organisms for their food.
Cover: vegetation or other features that provide shelter for wildlife.
CPOM: coarse particulate organic matter.
Deciduous: trees that shed their leaves.
Decompose: breakdown of organic materials to inorganic materials.
Deposition: depositing of material by a stream, generally at points of reduced velocity.
Dissolved oxygen concentration (DO): amount of oxygen dissolved in water.
Diversity: number of species in a particular community or habitat.
DO: dissolved oxygen concentration.
Drought: extended period of less than average rainfall.
Ecosystem: community of organisms in a given area together with their physical environment and its characteristic climate.
Effluent: waste material discharged into the environment.
Engulfers: organisms that ingest their prey whole.
Ephemeral: stream flow that only occurs during and shortly after extreme precipitation or snowmelt conditions.
Erosion: movement of soil by water and wind.
Evaporation: conversion of water from liquid to vapor.
Filtering collectors: aquatic invertebrates that feed by filtering small organic particles from the water.
Fine particulate organic matter (FPOM): organic material less than 1 mm in diameter.
Fine sediments: particles in water less than 0.2 of an inch in diameter.
First-order stream stream channel with no tributaries.
Flood: stream flow greater than the channel can contain.
Flow: the direction of movement of a stream or river.
Floodplain: area along a stream or river that is subject to flooding.
Forage: vegetation consumed by wild or domestic grazing animals.
FPOM: fine particulate organic matter.
Fry: recently hatched fish, after yolk sac has been absorbed.
Functional feeding groups: classification of aquatic invertebrates according to their mode of feeding.
Gathering collectors: aquatic invertebrates that feed on particles deposited or growing on the bottom of a stream channel.
Gradient: degree of slope, or steepness of a geographic feature.
Gravel: rock that is 0.2 to 3 inches in diameter.
Groundwater: a supply of fresh water under the earth's surface, which forms a natural reservoir.
Herbaceous: plants with soft rather than woody stems.
Humus: decayed organic matter in or on the soil's surface.
Hydrology: study of the distribution, circulation and properties of water.
Infiltration: entry of water into soil.
Intermittent stream: a stream that does not flow year around
Leaching: movement of dissolved particles by the percolation of water through soils.
Lethal limits: extremes in the range of conditions in which an organism can survive.
Limiting factors: conditions that establish the population or range of a specific animal or species.
Meanders: curved "S" shaped stream channels.
mg/l: milligrams of a substance per liter of total; equal to parts per million (ppm).
Midreaches: larger streams carrying the water from several tributaries, generally 25 to 250 feet wide.
Multiple-use: a system of management that uses an area for a variety of purposes.
Non-point source pollution: pollutants that enter waterways from broad land areas as a result of the way the land is used.
NPDES - National pollutant discharge elimination system permits which are required for all industries discharging wastes into a waterway.
Nutrient: substance, which is necessary for growth of all living things.
Odonates: order of insects containing dragonflies and damselflies.
Operculum: gill cover of a fish.
Perennial: streams that flow throughout a year.
Periphyton: diatoms and other algae.
Pesticide: a chemical that kills insects and rodents.
pH: measure of the hydrogen ions that determine the acidity of alkalinity of a solution; the pH scale ranges from 1 (acid) to 14 (alkaline) with 7.0 as neutral; the scale is logarithmic, with a change of 1.0 representing a tenfold increase, a change of 2.0 representing a hundredfold increase, etc.
Piercers: predatory organisms that suck body fluids of their prey.
Plankton: microscopic plants and animals carried by currents.
Point source pollution: air or water pollutants entering the environment from a specific point or conveyance.
Pollutant: something that makes land, water, and air dirty and unhealthy.
Pools: deeper and slower waters in a stream or river.
Population: group of individuals of a specific kind, in a given area at a given time.
ppm: parts per million; units per equivalent million units; equal to milligrams per liter (mg/l).
Precipitation: rain, snow, hail, or sleet falling to the ground.
Predator: an animal that hunts and kills other animals for food.
Prey: an animal that is hunted or killed by another for food.
Primary production: organic material produced by plants and bacteria from inorganic material and sunlight; producers.
Producers: plants that manufacture food from inorganic nutrients.
Rearing habitat: places in a stream that provide food, resting places, and shelter for young fish.
Residual soils: soils developed in place from underlying rock formations and the surface plant cover.
Resources: matter and energy available for use by organisms.
Retention: amount of organic material kept in a stream and processed.
Riffles: fast, shallow waters of a stream.
Riparian area: wet soil areas directly influenced by the water of a stream, lake or wetland.
Riprap: rock covering used to protect stream banks from erosion.
River continuum: a conceptual model examining the change in composition of aquatic invertebrate communities in running water systems.
Rubble: rock from 3 to 12 inches in diameter; also called cobble.
Run: in a river, an area of smooth flow with slows to moderate velocity.
Runoff: water that drains over the surface of the land.
Sand: loose, gritty particles of worn or disintegrated rock, usually deposited along the shores of bodies of water, in riverbeds, or deserts.
Saturated soil: soil that has absorbed as much water as possible.
Scrapers: aquatic invertebrates that feed by scraping the surface of rocks, primarily harvesting algae.
Secondary production: organic material produced by processing other organic material; consumers.
Sediment: solid particles carried and deposited by water.
Shredders: aquatic invertebrates that feed on the leaves or wood that fall into a stream.
Silt: tiny, fine particles, such as soil or sand, suspended in and deposited by water.
Soil: loose upper layer of the earth in which plants grow; made up of inorganic material, organic material, air, and water.
Spawning: in fish, the act of laying and fertilizing eggs.
Spawning habitat: area a fish needs to spawn; frequently refers to gravel beds.
Stream order: a system used to classify and analyze streams.
Streambed: part of the stream over which a column of water moves.
Stream flow: volume of water carried by a stream.
Substrate: inorganic material that forms the bottom of a stream.
Suspended sediments: particles carried in water without being dissolved.
Thermal pollution: addition of heat energy to the environment. It may be transferred by heated air or water and causes localized temperature increases.
Transpiration: loss of water from plants through evaporation and as a byproduct of photosynthesis.
Transported soils: soils moved by gravity, wind, or water.
Tributary:A stream or river flowing into a larger river or into a lake.
Turbidity: degree to which light penetration is blocked because water is muddy or cloudy.
USGS: U.S. Geological Survey provides surveys for biology, geology, water, and mapping of the United States.
Water column: moving mass of water contained by a streambed.
Water spiral: corkscrew pathway a column of water travels; caused by the Corioulis effect (from the earth's rotation) and friction.
Water table: upper level at which the soil is saturated with water.
Watershed: all the land area that drains into a particular body of water.