A

AERATION | The process of adding air to water. Air can be added to water by either passing air through water or passing water through air.
AEROBIC | A condition in which "free" (atmospheric) or dissolved oxygen is present in the water.
ALGAE | Microscopic plants which contain chlorophyll and live floating or suspended in water. They also may be attached to structures, rocks or other submerged surfaces. They are food for fish and small aquatic animals. Excess algal growths can impart tastes and odors to potable water. Algae produce oxygen during sunlight hours and use oxygen during the night hours. Their biological activities appreciably affect the pH and dissolved
oxygen of the water.
ALGAL BLOOM | Sudden, massive growths of microscopic and macroscopic plant life, such as green or blue-green algae, which develop in lakes and reservoirs.
ALGAECIDE | Any substance or chemical specifically formulated to kill or control algae.
ALKALINITY | Acid neutralizing (buffering) capacity of water. The ability of water to resist changes in pH. Expressed in units of milligrams per liter of calcium carbonate.
ALUM | Aluminum sulfate—when added to water it forms an aluminum hydroxide flocculant used to precipitate water-column phosphorus or inactivate sediment phosphorus.
AMMONIA | NH3—a form of nitrogen that is toxic to fish and other aquatic organisms.
ANAEROBIC | A condition in which "free" (atmospheric) or dissolved oxygen is NOT present in water.
ANOXIA | Absence of dissolved oxygen.
APHOTIC ZONE | Dark region of a lake, to which sunlight does not penetrate.
AQUIFER | A geologic formation or structure that stores or transfers water (e.g., to springs or wells).

B

BACTERIA | Singular: bacterium. Microscopic living organisms usually consisting of a single cell. Bacteria can aid in pollution control by consuming or breaking down organic matter in sewage, or by similarly acting on oil spills or other water pollutants. Some bacteria
in soil, water or air may also cause human, animal and plant health problems.
BENTHIC ORGANISM | Organisms that live in, on or near the bottom of a stream or lake.
BERM | A raised mound or bank of earth, typically used as a barrier.
BEST MANAGEMENT PRACTICE (BMP) | One or more conservation practices that is accepted by the US Clean Water Act (or other legislation) to control nonpoint source pollution.
BIOCHEMICAL OXYGEN DEMAND (BOD) | The amount of oxygen consumed by microorganisms (mainly bacteria) and by chemical reactions in the biodegradation of organic matter.
BIODEGRADATION | Decomposition of a substance into more elementary compounds by microorganisms such as bacteria.
BIODIVERSITY | The entire variety of plant and animal life within a given area (the biodiversity of two adjacent lakes may be different).
BIOMASS | The total mass of living material (currently or previously living) within a given area, or for a particular organism or group of organisms.
BIOREMEDIATION | A process of adding nutrient to ground water to speed up the natural process in which bacteria break down gasoline into harmless compounds.
BIOTA | The plant and animal life within a given area (e.g., a stream's biota).
BLUE-GREEN ALGAE | Aka cyanobacteria; a group of phytoplankton often associated with noxious, unsightly and even toxic blooms (massive explosion of growth). They often cause problems when they die, forming floating mats of scum or sinking to bottom and
causing oxygen depletion as they decompose.
BUFFERSTRIP | A protective vegetated strip that serves to reduce erosion, slow water or remove nutrients.