Aquatic Field Investigation

Abiotic index - A scale based on non-living characteristics such as pH, dissolved oxygen levels, and temperature readings.

Acidic - Any of various typically water-soluble and sour compounds that are capable of reacting with a base to form a salt, that redden litmus, that are hydrogen - containing molecules or ions able to give up a proton to a base, or that are substances able to accept an unshared pair of electrons from a base.

Amphipod - A small crustacean (such as the beach flea).

Aquatic worm - A worm that grows in, lives in, or frequently stays in water.

Base - Any of various typically water-soluble and bitter tasting compounds capable of reacting with an acid to form a salt that are molecules or ions able to take up a proton from an acid or substances able to give up an unshared pair of electrons to an acid.

Baseline study - A study designed to collect critical observations or data to be used for comparison or as a control in a later study.

Biodiversity - The variety of species of plants and animals in an environment.

Biotic index - A scale based on the types of organisms living in an environment.

Bog - A poorly drained area having wet, spongy, acidic ground rich in accumulated plant materials. Bogs frequently surround a body of open water; characteristic flora include sedges (tufted marsh plants with solid stems), heaths (shrubby evergreens), and sphagnum (moss).

Brackish - Somewhat salty; having a variable mixture of salt and freshwater. Brackish habitats are usually found near (but not on) coastlines.

Coral reef - A colony of coral polyps joined together to form a specialized habitat that provides shelter, food, and breeding sites for many plants and animals; found in ocean areas with shallow, warm water.

Crustacean - Primarily aquatic invertebrate with an exoskeleton (external skeleton) and antennae.

Current speed - The speed at which water flows.

Density - Amount of matter in a given amount of a substance; mass per unit volume.

Dissolved oxygen - The amount of oxygen dissolved in water.

Estuary - A site, such as the mouth of a river or bay, where fresh water and salt water meet.

Habitat - A place where a particular plant or animal grows or is normally found.

Invertebrates - Animals without a backbone.

Isopod - A small crustacean with attached (not raised) eyes and a body composed of seven segments, each of which has a pair of similar legs.

Larva - The immature, wingless, and often wormlike feeding form that hatches from the egg of many insects.

Mangroves - Tropical maritime trees or shrubs that send out many prop roots and form dense masses important in coastal land formation.

Marsh - An area of soft, wet, low-lying land, characterized by grassy vegetation and often forming a transition zone between water and land. Examples include both freshwater and saltwater marshes.

Mayfly - A fragile, short-lived insect with two pair of delicate wings (the front pair of which is much larger than the rear pair) and two or three long tail - like projections at the rear.

Midge - A tiny fly.

Nymph - An immature insect (see larva).

Peat - Soil formed by the decomposition (breakdown) of various plants (such as sphagnum moss) in water.

pH - A measure of acidity and alkalinity (hydrogen ion concentration) of a solution; expressed as a number from 1 to 14 where 7 represents neutrality, lower numbers indicate increasing acidity, and higher numbers indicate increasing alkalinity.

Phytoplankton - Very small floating plants in a body of water, especially water in an estuary.

Population - All organisms that constitute a specific group or occur in a specific habitat.

Rushes - Tufted marsh plants with hollow stems.

Salinity - The amount of dissolved salt in water.

Secchi disk - A tool for measuring the relative clarity of deep water to determine turbidity.

Sedges - Tufted marsh plants with solid stems.

Sediment - The solids that settle to the bottom of a liquid.

Silt - A type of sediment containing tiny rock particles (generally less than 0.05 mm in diameter).

Sphagnum - A type of moss that grows only in wet, acid areas where its remains become compacted with other plant debris to form peat.

Stream - A body of water running in a channel or bed; a small river.

Swamp - Seasonally flooded low-lying land with more woody plants than a marsh and better drainage than a bog.

Turbidity - The amount of sediment suspended in water.

Wetland - Area of land that is regularly wet or flooded; very fertile; home to one - third of the world's endangered species.

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Revised: 3 Nov 1995