caddisflies - Aquatic macroinvertebrates of the order Trichoptera. Larvae have three pairs of legs, hooks on the end of their abdomen, and no wings. Larvae are sensitive to pollution. image

canopy - Overhanging tree cover. image

carnivore - A meat eater; a consumer that eats other consumers.

cattails - Typha spp., emergent vegetation of freshwater marshes and wetlands; tall perennial plants.

chlorinated - Water treated with chlorine as a disinfectant.

clam - An aquatic macroinvertebrate of the phylum Mollusca, the clam is enclosed within two shells and feeds by filtering stream water through its shells; it is somewhat sensitive to pollution. image

clarity - Clearness.

clay - Suspended sediment or bed material with a particle size of 0.00024-0.004 mm in diameter, smaller than a grain of sand.

cloud cover - The amount of sky covered by clouds, usually characterized as: partly cloudy (10% - 50% of sky covered by clouds); or cloudy (50% - 90% of sky covered by clouds).

coagulation - The process in which chemicals react with suspended particles in a liquid to form a sticky precipitate.

common reed - Phragmites australis, an exotic invasive plant that grows in intermittently flooded lowland forest. image

community - Two or more populations of different species living and interacting in the same area.

competitors - Individuals or species that both require the same limited resource to survive.

compost - A mixture of decaying organic matter, such as leaves and manure, that can be used as a plant fertilizer.

consumer - An organism that eats other organisms because it is unable to make its own food; a heterotroph.

contaminant - A substance that, when mixed with another substance, makes it impure.

control - A condition in a scientific experiment that remains the same.

coontail - A submerged aquatic vegetation (SAV), Ceratophyllum demersum; abundant in lakes, streams, marshes, and ditches in a depth of up to 18 feet; tolerant of nutrient-rich water and fluctuating water levels. It has leaves in whorls of 5-12 and can form thick masses.

crab - An aquatic macroinvertebrate of the phylum Arthropoda, class Crustacea. The crab is a bottom-dwelling predator.

crane fly - An aquatic macroinvertebrate of the order Diptera, a true fly. The larvae are large and fleshy with short tentacles at one end. Crane flies are somewhat sensitive to pollution. image

crayfish - An aquatic macroinvertebrate of the phylum Arthropoda, class Crustacea. Crayfish have more than three pairs of legs and two pairs of antennae, with eyes on stalks and a hard covering on the back; somewhat sensitive to pollution. image

croplands - Land used for agriculture.

crustacean - An aquatic macroinvertebrate of the phylum Arthropoda, class Crustacea; includes crayfish and crabs. They have more than three pair of legs and two pairs of antennae. image

cultivate - To prepare land for crops by plowing and fertilizing.

cultural eutrophication - Human-caused eutrophication; usually a very rapid process that can result in the death of an ecosystem. image

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damselfly - An aquatic macroinvertebrate of suborder Zygoptera. The larvae have three pairs of legs, one pair of antennae, and wing pads with feathery gills protruding from the abdomen. Larvae are somewhat sensitive to pollution. image

daphnia - Genus Daphnia; small freshwater crustaceans.

data - Recorded observations and information.

data analysis - An evaluation of collected observations and information.

decomposers - A group of organisms, mainly fungi and bacteria, that digest organic material and release nutrients into the environment.

decomposition - The process of decay; the breaking down of organic matter into its component parts.

degrade - To reduce; to decompose by stages; to wear away by erosion.

degrees of latitude/longitude - Angular units defined by circular lines around the Earth; used to measure distance north or south of the Equator (latitude) and east or west of the Prime Meridian (longitude).

density - The mass of a substance per unit volume; the number of inhabitants per unit in a geographical region; the degree to which anything is filled or occupied; the degree of thickness.

dependent variable - A responding variable; a factor or condition that might change as a result of a change in a manipulated independent variable.

diatoms - Phytoplankton of the class Bacillariophyceae. Diatoms are minute, unicellular or colonial algae having siliceous cell walls consisting of two overlapping, symmetrical parts. image

dinoflagellates - A type of protist that includes photosynthetic forms in which two flagella project thorough armor-like plates. Abundant in oceans, these sometimes reproduce rapidly, causing "red tides".

dissolved load - Sediment made up of organic and inorganic material carried in solution by moving water.

dissolved oxygen (DO) - The amount of oxygen dissolved in water; varies with water temperature and pressure; measured in milligrams of oxygen per liter of water, parts per million, or percent saturation.

distillation - A process used to clean water. Steam from a sample of boiling water is almost completely free of impurities. In distillation, the steam is collected and allowed to condense back into water.

diversity - Variety; difference.

diving beetle - Predatory aquatic beetles from the family Dytiscidae.

DNA - Deoxyribonucleic acid; nucleic acid macromolecule that stores and transmits the genetic information of all living cells from one generation to the next.

dragonfly - An aquatic macroinvertebrate of the suborder Anisoptera. The larvae have three pair of legs, one pair of antennae, and wing pads. Larvae are somewhat sensitive to pollution. image

drainage basin - A watershed; the land area where precipitation runs into streams, rivers, lakes, and reservoirs. It can be identified by tracing a line along the highest elevations, often a ridge, between two areas on a map.

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