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Mammal– the class of animals including humans that nourish their young with milk secreted from mammary glands.

Metals– Referring to “heavy metals”: metallic elements with high atomic weights; (e.g. mercury, chromium, cadmium, arsenic, and lead); can damage living things at low concentrations and tend to accumulate in the food chain.

Microbe– microorganisms such as bacteria, algae, diatoms, plankton, and fungi.

Midden– Mounds or ridges of clam and/or oysters shells deposited near the shore of the bay or its tributaries by the early Native Americans. These were laid down from circa 8000 until shortly before European American settlement.

Migratory– characterized by migration; species that periodically pass from one region or climate to another for feeding or breeding.

Mollusk– Soft-bodied invertebrates of the phylum Mollusca, usually possessing a calcium carbonate shell; examples include chitons, oysters, clams, nautiluses, squids and octopuses.


National Estuary Program– A program established under the Clean Water Act Amendments of 1987 to develop and implement conservation and management plans for protecting estuaries and restoring and maintaining their chemical, physical, and biological integrity, as well as controlling point and nonpoint pollution sources.

National Pollution Discharge Elimination System (NPDES)– A federal regulatory program to control discharges of pollutants to surface waters of the United States; see also TPDES.

Nekton– Free-swimming animals of the water column (contrasted with most plankton, which are at the mercy of currents.

Neotropical– Living and migrating within the region that includes South America, the West Indies and tropical North America.

Non-contact Recreation– Human activity on water but not involving bodily contact with water, e.g. boating.

Non-Point Source (NPS)– Constituents in water (including pollutants) originating from diffuse, land?based sources, and generally transported in runoff from precipitation. This contrasts with point sources, or “end of the pipe” constituents generally transported in wastewater from a discrete source. The regulatory definition of non-point source is “anything not a point source.”

Nutrient– Any substance assimilated by living things that promotes growth. The term is generally applied to nitrogen and phosphorus in wastewater, but is also applied to other essential and trace elements.

Nutrient Cycle– Chemical transformation of nitrogen, phosphorus and silica compounds in continuous cycles of organic and inorganic phases in an ecosystem.


Oak Motte– Isolated islands of live oak-dominated woodlots surrounded by coastal prairie. An important habitat that provides food and shelter for our area birds.

Open-Bay Bottom– The second largest Galveston Bay habitat, consisting of those areas of the bay bottom not covered with oyster reef or seagrass meadow.

Open-Bay Water– A large volume of water consisting of many water masses having different salinity, and at times, oxygen and temperature, values. Also referred to as the “water column.”

Organic Pollutant– Pollutants containing carbon that persist in the environment, bioaccumulate through the food web and pose a threat to human heath and the environment due to their toxic effects. These pollutants include organochlorine pesticides.

Organochlorine Pesticide– Pesticides (generally insecticides) that are hydrocarbon compounds containing chlorine. They are not easily broken down and can persist in the environment for many years. Includes DDT, dieldrin, chlordane, and aldrin.

Outfall– A site where there is a large point loading of domestic, industrial or heat wastes to an aquatic system; a discharge point for a wastewater stream, e.g. a sewage treatment plant or refinery.

Oxygen-Demanding Substance– see Biochemical Oxygen Demand (BOD)

Oyster Reef– An ecosystem based on the formation of a three-dimensional structure from the growth of oyster shells.


Pathogen– A disease?causing microbe.

Pelagic– Organisms living in open waters; not associated with the bottom or other structures, e. g. sharks of the open ocean.

Photosynthesis– The incorporation of solar energy into carbon compounds by green plants, chemically combining atmospheric carbon dioxide and water. The chemical opposite of respiration (the “burning” of carbon compounds to power metabolism), ultimately powering the vast majority of life on earth.

Phytoplankton– Green plants (for example algae) inhabiting waters, unattached and drifting with the currents.

Piscivorous– Fish?eating.

Planktivore– Plankton?eater.

Planktonic– Drifting unattached in water, the plankton include both plants and animals ranging from microscopic to those weighing several pounds or more (e.g. jellyfish).

Point Source Pollution– Pollutants are discharged from a stationary location or fixed facility; any single identifiable source of pollution; e.g. a pipe, ditch, ship.

Pollutant– Any substance, as certain chemicals or waste products, that renders the air, soil, water, or other natural resource harmful or unsuitable for a specific purpose. The term “Pollution” also includes such things as impairment to habitat and barriers to fish passage.

Polychlorinated Biphenyls (PCBs)– A family of organic compounds; mixtures of up to 209 individual chlorinated compounds. They have been used as coolants and lubricants in transformers, capacitors, and other electrical equipment because they don’t burn easily and are good insulators. Many commercial PCB mixtures are known in the US by the trade name Aroclor.

Polynuclear Aromatic Hydrocarbons (PAHs)– A family of organic compounds deriving from fossil fuels and their combustion. The higher the molecular weight, the more environmental concern due to their bioaccumulation in organisms and their toxic, carcinogenic metabolic activity.

Population Density– the average number of people in a given unit area (e.g. number of people per square mile).

Prairie Pothole– A type of freshwater wetland consisting of various depressions interfingered with upland prairie habitat. The difference between a pothole and fresh marsh is mostly size -marshes occur in larger and generally less well-defined depressions than potholes. On the upper coast, potholes and marshes occur in complexes with pimple mounds (small hummocks 1-2 feet tall) and intermound flats.

Primary Consumer– An organism deriving its energy directly from green plants.

Primary Producer– Green plants capable of photosynthesis; the base of the food chain.

Produced Water– unwanted by-product of petroleum production; oil field brine water of potential detrimental salinity concentrations and containing toxicants such as polynuclear aromatic hydrocarbons (PAHs), heavy metals.


Relative Sea Level Rise– The change in the position and height of sea relative to the land; determines the location of the shoreline. A rise in relative sea level may create or destroy coastal wetlands and salt marshes and induce salt-water intrusion into estuarine waters. Human actions including withdrawal of groundwater may to a local rise in relative sea level due to subsidence.

Revetment– a facing made of stone, concrete or other material to prevent erosion and/or collapse of an embankment or shoreline feature.

Riparian– Associated with the bank of a watercourse, for example the riparian woodlands bordering a river.

Risk Analysis– The estimation of hazards associated with containments or other environmental conditions, as they affect exposed humans or selected elements of the ecosystem. Seafood consumption risk analysis procedures normally follow a standardized EPA protocol.