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Glossary of terms

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Abundance Index - Information obtained from samples or observations and used as a measure of the weight or number of fish which make up a stock.

Acid rain - Natural rainfall which contains nitric and sulfuric acids due to oxides of nitrogen and sulfur dioxide discharged into the air by industries, power plants, and automobiles.

Algae - Simple rootless plants that grow in bodies of water (e.g. estuaries) at rates in relative proportion to the amounts of nutrients (e.g. nitrogen and phosphorus) available in water.

Allowance - The allowed nutrient load a source may discharge.

Amphibian - a cold-blooded vertebrate that spends some time on land but must breed and develop into an adult in water. Frogs, salamanders, and toads are amphibians.

Amphipods - Small, shrimplike crustaceans.

Anadromous - Fish that spend most of their life in salt water but migrate into freshwater tributaries to spawn (i.e. salmon, sturgeon).

Angler - Someone who goes fishing: somebody who fishes with a hook, line, and rod

Anaerobic - Not containing oxygen or not requiring oxygen.

Anoxic - A condition where no oxygen is present. Much of the "anoxic zone" is anaerobic, with absolutely no oxygen, a condition in which toxic hydrogen sulfide gas is emitted in the decomposition process.

Anthropogenic - Of human origin.

Aquaculture - The farming of plants and animals that live in water (i.e. shellfish, fish, algae)

Aquatic - Living in water.

Arachnid - A group of animals including: spiders, ticks, scorpions, and mites that have four pairs of legs and whose body is divided into two segments.

Arthropod - A large group of invertebrate animals with jointed legs, including the insects, scorpions, crustaceans and spiders.

Artificial reef - A structure aggregated from material designed to attract living aquatic organisms (i.e. oyster reef)

Atmospheric deposition - When the air pollution hits the earth surface. Air pollution washed out of the sky by rain or snow is called "wet deposition." When air pollution deposits without benefit of rain its called "dry deposition."

Autotroph - Any organism that is able to manufacture its own food. Most plants are autotrophs, as are many protists and bacteria. Autotrophs may be photoautotrophic, using light energy to manufacture food, or chemoautotrophic, using chemical energy.


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Backwater - A still body of water or a still portion of a larger body of water, unaffected by the flow of the larger body of water. An example would be a small stagnant branch of a river.

Baseflow - Stream or river flows consisting entirely of groundwater contributions.

Bathymetry - The physical characteristics, including depth, contour, and shape of the bottom of a body of water.

Baseline - The numeric level of nutrient load at a particular point in time that serves to establish nurtient reduction goals and allowances.

Benthic macroinvertebrates - Macroinvertebrates are large, generally soft-bodied organisms that lack backbones. Benthic macroinvertebrates live in or on the bottom sediment in aquatic environments.

Benthos - A group of organisms, most often invertebrates, that live in or on the bottom in aquatic habitats (such as clams that live in the sediments) which are typically immotile or of limited motility or range.

Best Management Practices (BMP) - A practice or combination of practices that provide the most effective and practicable means of controlling point and nonpoint pollutants at levels compatible with environmental quality goals.

Bilateral Symmetry - A body design found in most animals in which if an imaginary plane divided the body into left and right halves, each side would be a mirror image of the other..

Bioaccumulation - The uptake and storage of chemicals (e.g. DDTs, PCBs) from the environment by animals and plants. Uptake can occur through feeding or direct absorption from water or sediments.

Bioassay - A simple biological test that uses an indicator organism to measure the potency of a given substance in a biological system. An example of a bioassay would be a test that measures algal growth in response to different nutrient concentrations.

Biological Nutrient Removal (BNR) - A temperature dependent process in which the ammonia nitrogen present in raw wastewater is converted by bacteria first to nitrate nitrogen and then to nitrogen gas.

Biomass - The quantity of living matter, expressed as a concentration or weight per unit area.

Biological Diversity - the variety of life in all its forms, levels and combinations including ecosystem diversity, species diversity and genetic diversity.

Bioretention - Bioretention sites, also called "Rain Gardens," are an innovative method for stormwater management that retains stormwater on site and uses plants and layers of soil, sand, and mulch to reduce the amount of nutrients and other pollutants that enter local waterways.

Biota - The flora and fauna of a region.

Bivalve - Mollusk with two shells connected by a hinge (i.e. clams, oysters).

Bloom - A population burst of phytoplankton that remains within a defined part of the water column

Bog - A wetland that has poorly drained acidic peat-soil dominated by sedges and sphagnum moss.

Brackish - Somewhat salty water, as in an estuary.

Bycatch - Fishes or other animals caught by accident in fishing gear. Bycatch is usually thrown back dead or dying.


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Canopy - The top part of a forest. This top layer provides protection for birds and butterflies and shade to cool the forest in summer.

Cap - The total nutrient load that is allowed to be discharged into a given water body. The cap is the baseline minus the amount of load reduction needed to meet the goal. The cap is equal, or greater than, the sum of the allowances.

Carapace - A bony or chitenous case or shell covering the back or part of the back of an animal, such as a crab.

Carnivore - Literally, an organism that eats meat. Most carnivores are animals, but a few fungi, plants, and protists are as well.

Catadromous - Fish that live in freshwater and migrate to saltwater to spawn (i.e. American eel).

Cephalopod - A member of the group of molluscs that includes octopuses, squid, nautiluses and cuttlefishes.

Cetacean - Any member of the group of marine mammals that includes whales, dolphins and porpoises.

Chlorophyll a - A pigment contained in plants that is used to turn light energy into food. Chlorophyll also gives plants their green color.

Cilia - a tiny projecting thread, found with many others on a cell or microscopic organism, that beats rhythmically to aid the movement of a fluid past the cell or movement of the organism through liquid

Class - Subdivision of a phylum containing a group of related orders.

Coastal plain - The level land with generally finer and fertile soils downstream of the piedmont and fall line, where tidal influence is felt in the rivers.

Coelom - Body cavity or space between the body wall and the digestive tract.

Coliform bacteria - A group of bacteria primarily found in human and animal intestines and wastes. These bacteria are widely used as indicator organisms to show the presence of such wastes in water and the possible presence of pathogenic (disease-producing) bacteria. Escherichia coli (E. coli) is one of the fecal coliform bacteria widely used for this purpose.

Colliblast - An adhesive or glue-like cell situated on the tentacles of ctenophores (comb jellyfish) that may be used to capture prey.

Commensal - Having benefit for one member of a two-species association but neither positive nor negative effect on the other.

Consumer - Any organism which must consume other organisms (living or dead) to satisfy its energy needs.

Contaminant - Anything that to make something impure, unclean, or polluted, especially by mixing harmful impurities into it or by putting it in contact with something harmful.

Copepod - A type of small planktonic crustacean. Copepods are a major group within the mesozooplankton, and are both important grazers of phytoplankton and food for fish.

Credits - The amount of nutrient load reduced below the allowance.

Crustaceans - The class of aquatic Arthropods including copepods, isopods, amphipods, barnacles, shrimp, and crabs which are characterized by having jointed appendage and gills.


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DDT - A group of colorless chemicals used as insecticides. DDTs are toxic to man and animals when swallowed or absorbed through the skin.

Decreased drought flow - inadequate groundwater recharge causes diminished or loss of flow in watercourses.

DEM - digital elevation model. Data files which are digital representations of cartographic information.

Denitrification - The conversion of nitrite and nitrate nitrogen (after nitrification) to inert nitrogen gas. This treatment process requires that little or no oxygen be present in the system and that an organic food source be provided to foster growth of another type of bacteria. The organic food source can be either recycled waste activated sludge or methanol. The resultant nitrogen gas is released to the atmosphere.

Dermo - Oyster disease caused by the protozoan parasite, Perkinsus marinus.

Designated use - An element of a water quality standard, expressed as a narrative statement, describing an appropriate intended human and/or aquatic life objective for a water body. Designated uses for a water body may include: recreation, shellfishing, water supply and/or aquatic life habitat.

Detritus - Accumulated organic debris from dead organisms, often an important source of nutrients in a food web.

Detrivore - Any organism which obtains most of its nutrients from the detritus in an ecosystem.

Diadromous - Species that use both marine and freshwater habitats during their life cycle. Species can be anadromous, living primarily in at sea but migrating up rivers to spawn, or catadromous, living primarily in lakes, ponds, and rivers but migrating out to sea to spawn.

Diatoms - Microscopic algae with plate like structures composed of silica. Diatoms are considered a good food source for zooplankton.

Dicot - (dicotyledon) a flowering plant that produces two seed leaves or cotyledons when it germinates. This includes most herbaceous plants, trees, and shrubs.

Dinoflagellate - Algae of the order Dinoflagellata.

Dischargers - The sources that emit, give off, or dispose of a gas or liquid.

Dissolved Inorganic Nitrogen (DIN) - An important nutrient for the growth of plants. DIN is nitrogen that is readily usable by plants.

Dissolved Oxygen - Microscopic bubbles of oxygen that are mixed in the water and occur between water molecules. Dissolved oxygen is necessary for healthy lakes, rivers, and estuaries. Most aquatic plants and animals need oxygen to survive. Fish will drown in water when the dissolved oxygen levels get too low. The absence of dissolved oxygen in water is a sign of possible pollution.

Diurnal - Active during daylight.

Diversity - An ecological measure of the variety of organisms present in a habitat.

Dorsal - anatomy of or on the back: relating to or situated on the back of the body.

Dry Deposition - Atmospheric deposition that occurs when particles settle to a surface, collide with and attach to a surface (adsorption) or are absorbed.


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Easement - a limited right to make use of a property owned by another, for example, a right of way across the property.

Ebb tide - A falling tide.

Echinoderm - a marine invertebrate animal that has a radially symmetrical body, tube feet, and a system of calcareous plates under the skin. Starfish, sea urchins, sea lilies, and sea cucumbers are echinoderms.

Ecology - The study of interrelationships between living things and to their environment

Ecosystem - All the organisms in a particular region and the environment in which they live. The elements of an ecosystem interact with each other in some way, and so depend on each other either directly or indirectly.

Effluent - The discharge to a body of water from a defined source, generally consisting of a mixture of waste and water from industrial or municipal facilities.

Emergent Wetland - A wetland dominated by nonwoody, soft-stemmed plants.

Emissions - Refers to pollution being released or discharged into the air from natural or man-made sources. Pollutants may be released directly into the air from a structural device (i.e., smokestack, chimney, exhaust pipe) or indirectly via volatilization or dispersal (i.e., aerosol spraying).

Endangered - A species that is in immediate danger of becoming extinct and needs protection to survive.

Endemic species - A species that is restricted in its distribution to a particular locality or region.

Environment - The place in which an organism lives, and the circumstances under which it lives. Environment includes measures like moisture and temperature, as much as it refers to the actual physical place where an organism is found.

Environmental data - any measurements or information that describe environmental processes, location, or conditions; ecological or health effects and consequences; or the performance of environmental technology. For EPA, environmental data include information collected directly from measurements, produced from models, and compiled from other sources such as data bases or the literature.

Environmental technology - an all-inclusive term used to describe pollution control devices and systems, waste treatment processes and storage facilities, and site remediation technologies and their components that may be utilized to remove pollutants or contaminants from or prevent them from entering the environment. Examples include wet scrubbers (air), soil washing (soil), granulated activated carbon unit (water), and filtration (air, water). Usually, this term applies to hardware-based systems; however, it also applies to methods or techniques used for pollution prevention, pollutant reduction, or containment of contamination to prevent further movement of the contaminants, such as capping, solidification or vitrification, and biological treatment.

Epifaunal - Plants, animals and bacteria that are attached to the hard bottom or substrate (for example, to rocks or debris); are capable of movement; or that live on the sediment surface.

Epiphyte - A plant which grows upon another plant. The epiphyte does not "eat" the plant on which it grows, but merely uses the plant for structural support, or as a way to get off the ground and into the canopy environment.

Epiphytic - Substances that grow or accumulate on the leaves of submerged aquatic plants. This material can include algae, bacteria, detritus, and sediment.

Erosion - The disruption and movement of soil particles by wind, water, or ice, either occuring naturally or as a result of land use.

Estuarine species - A permanent resident of an estuary. Also called a resident species.

Estuary - A semienclosed body of water that has a free connection with the open sea and within which seawater (from the ocean) is diluted measurably with freshwater that is derived from land drainage (i.e. the Tillamook Bay). Brackish estuarine waters are decreasingly salty in the upstream direction and vice versa. The ocean tides are projected upstream to the fall lines.

Eutrophic - Describes an aquatic system with high nutrient concentrations. These nutrient concentrations fuel algal growth. This algae eventually dies and decomposes, with reduces the amount of dissolved oxygen in the water.

Eutrophication - The fertilization of surface waters by nutrients that were previously scarce. Eutrophication through nutrient and sediment inflow is a natural aging process by which warm shallow lakes evolve to dry land. Human activities are greatly accelerating the process. The most visible consequence is the proliferation of algae. The increased growth of algae and aquatic weeds can degrade water quality.

Exotic Species - Any introduced plant or animal species that is not native to the area and that may be considered a nuisance.

Extant species - A species which is currently in existence (the opposite of extinct).

Existing Use - Use actually attained in the waterbody on or after November 28, 1975, whether or not it is included in the water quality standards (40 CFR 131.3).

Extinct species - A species which has disappeared from existence due to either natural or human-induced means (opposite of extant).


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Fall Line - A line joining the waterfalls on several rivers that marks the point where each river descends from the upland to the lowland and marks the limit of navigability of each river.

Fecundity - The number of eggs produced per female per unit time (often: per spawning season)

Filter feeder - An organism which filters food from the environment via a straining mechanism (such as gills)(i.e. barnacle)

Flagellum - A long, threadlike or whiplike appendage found in certain cells or unicellular organisms that functions as an organ of locomotion.

Flood tide - A rising tide.

Food chain / food web - The network of feeding relationships in a community as a series of links of trophic levels, such as primary producers, herbivores, and primary carnivores. Includes all interactions of predator and prey, along with the exchange of nutrients into and out of the soil. These interactions connect the various members of an ecosystem, and describe how energy passes from one organism to another.

Freshet - An increase of water flow into an estuary during the late winter or spring, owing to increased precipitation and snow melt in the watershed.


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Gastropod - the largest and most successful class of mollusks (phylum Mollusca), containing over 35,000 living species and 15,000 fossil forms. Most gastropods have a one piece shell (univalve), however in some, such as slugs and nudibranchs there is no shell at all. Gastropods have a well defined head, with one or two sensory tentacles and a mouth. They travel by using a single large muscular foot.

Geomorphologic change - changes in the folds, faults, structural shapes and effects of the earth's surface and the processes that create them.

Groundwater - subsurface water that accumulates and returns to the surface in wells springs and watercourses.

Habitat - The place and conditions in which an organism lives.

Heavy Metals - any metallic chemical element that has a relatively high density and is toxic or poisonous at low concentrations.

Herbivore - Literally, an organism that eats plants or other autotrophic organisms. The term is used primarily to describe animals.

Hermaphroditic - An organism having both sexes: a plant or animal having both male and female reproductive organs and secondary sexual characteristics.

Hydrologic - the cyclic phenomena of waters of the earth - precipitation, runoff, storage and evaporation

Hydrological - The scientific study of the properties, distribution, and effects of water on the earth's surface, in the soil and underlying rocks, and in the atmosphere.

Hypoxic - A condition where only very low levels of oxygen are present.

Indigenous Species - A species which evolved on the North American continent, was present at the time of European Colonization, and is resident within Oregon's North Coast without human manipulation.

Integrated pest management (IPM) - A sustainable pest management approach which combines the use of biological, cultural, physical, and chemical tactics in a way that minimizes economic, health and environmental risks. One aspect of IPM involves regular monitoring (scouting) to determine if and when treatments are needed based on biological and/or aesthetic thresholds to keep pest numbers low enough to prevent intolerable damage or annoyance (economic threshold).

Impaired waters list (or impairments) - Impaired waters are waters that do not meet State water quality standards. Under the Clean Water Act, section 303(d), States, territories and authorized tribes are required to develop lists of impaired waters. The law requires that these jurisdictions establish priority rankings for waters on the lists and develop TMDLs for these waters.

Impervious - Surfaces that will not allow things to pass through. Such as hard surfaces that do not allow water to pass through.

Infrastructure - the physical systems and that support community function (roads, sewers, water lines)

Insectivorous - Feeding on insects

Interstitial - Space between

Intertidal - The area of shore located between high and low tides.

Introduced Species - Species which have been intentionally or inadventently brought into a region or area. Also called exotic species.

Invertebrate - Animals which lack a backbone and include such as squids, octopuses, lobsters, or shrimps, crabs, shellfishes, sea urchins and starfishes.


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Jetty - a wall or other barrier built out into a body of water to shelter a harbor, protect a shoreline from erosion, and/or redirect water currents

Juvenile - Strictly speaking, a juvenile is any of a species which is not yet sexually mature. In the context of many surveys, however, it is most often used interchangeably with young-of-year (YOY).

Keystone species - A predator at the top of a food web, or discrete subweb, capable of consuming organisms of more than one trophic level beneath it.

Land cover - Anything that exists on, and is visible from above, the earth's surface. Examples include vegetation, exposed or barren land, water, snow, and ice.

Land use - The way land is developed and used in terms of the kinds of anthropogenic activities that occur (e.g. agriculture, residential areas, industrial areas).

Larva - A discrete stage in many species, beginning with zygote formation and ending with metamorphosis.

Light attenuation - Absorption, scattering, or reflection of light by water, chlorophyll a, dissolved substances, or particulate matter. Light attenuation reduces the amount of light available to submerged aquatic vegetation.

Littoral zone - The intertidal area, also known as the splash zone.

Low impact development (LID) - A comprehensive land planning and engineering design approach with a goal of maintaining and enhancing the pre-development hydrologic regime of urban and developing watersheds. This design approach incorporates strategic planning with micro-management techniques to achieve superior environmental protection, while allowing for development or infrastructure rehabilitation to occur.

Lacustrine - permanently flooded lakes and reservoirs, intermittent lakes, and tidal lakes with low ocean-derived salinities.


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Macro-organism - An organism visible without the aid of a microscope.

Macrophyte - An individual alga large enough to be seen easily with the unaided eye.

Macroplankton - Planktonic organisms that are 200-2,000 micrometers in size.

Mammal - Any of a large class called Mammalia; warm blooded, usually hairy vertebrates whose offspring are fed with milk secreted by the mammary gland.

Mandible - Either of a pair of jaw-like parts, found in insects and crustaceans used for biting or cutting food.

Marine - Refers to the ocean.

Marsh - An emergent wetland that is usually seasonally flooded or wet, and often dominated by one or a few plant species.

Maxilliped - Claw-like structures located near the mouth on the heads of crustaceans, which are found in pairs. There are three pairs of maxilliped on a typical crustacean.

Mesohaline - Pertaining to moderately brackish water with low range salinities (from 5-18 parts per thousand)

Mesotrophic - Describes an aquatic system somewhere between eutrophic (nutrient enriched) and oligotrophic (nutrient poor).

Metadata - Documenting data is critical to preserving its usefulness throughout time. Metadata is a component of data which describes the content, quality, condition, and other characteristics of data. It is "data about data." A good example is a library catalog card, which contains data about the nature and location of a book: It is data about the data in the book referred to by the card.

Micro-organism - An organism requiring magnification to see/study (microscopic).

Micron - A unit of measure equal to one thousandth of a millimeter

Migratory - Describing groups of organisms which move from one habitat to another on a regular or seasonal basis.

Mollusk - The invertebrate phylum which contains bivalves (i.e. oysters), gastropods (i.e. snails), and squids.

Molt - To shed the exoskeleton (outer covering)or prior to new growth (i.e. blue crab).

Monoecious - Having unisexual cones or flowers with female and male reproductive structures on the same plant.

MSX - An oyster disease caused by the protozoan parasite, Haplosporidium nelsoni.


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Native Species - Species which have lived in a particular region or area for an extended period of time.

Natural Infrastructure - physical systems provided by the earth that support life (water cycle, nitrogen cycle, water purification)

Needle - A long slender leaf, such as those seen on the Douglas fir.

Nematocyst - stinging organ found in members of the anthozoan class of animals, which includes jellyfish, corals and anemones. It is comprised of a fluid-filled sac within which is a coiled hollow thread that is rapidly turned outward (everted) to capture food or for defense.

Nekton - Organisms with swimming abilities that permit them to move actively through the water column and to move against currents (i.e. fish, crabs).

Neritic - A part of the pelagic zone which extends from the high tide line to the bottom.

Nesting - To build a nest: to make or live in a nest, especially in preparation for giving birth to young.

Niche - A general term referring to the range of environmental space occupied by a species.

Nitrification - the process to which bacterial populations under aerobic conditions, gradually oxidize ammonium to nitrate with the intermediate formation of nitrite. Biological nitrification is a key step in nitrogen removal in wastewater treatment systems.

Nitrogen - (N) is used primarily by plants and animals to synthesize protein. Nitrogen enters the ecosystem in several chemical forms and also occurs in other dissolved or particulate forms, such as tissues of living and dead organisms.

Nocturnal - Active only at night.

Nonpoint Source - A diffuse source of pollution that cannot be attributed to a clearly identifiable, specific physical location or a defined discharge channel. This includes the nutrients that runoff the ground from any land use - croplands, feedlots, lawns, parking lots, streets, forests, etc. - and enter waterways. It also includes nutrients that enter through air pollution, through the groundwater, or from septic systems.

Notochord - A flexible rodlike structure that forms the main support of the body in the lowest chordates, such as the lancelet; a primitive backbone.

Nutrients - Compounds of nitrogen and phosphorus dissolved in water which are essential to both plants and animals. Too much nitrogen and phosphorus act as pollutants and can lead to unwanted consequences - primarily algae blooms that cloud the water and rob it of oxygen critical to most forms of aquatic life. Sewage treatment plants, industries, vehicle exhaust, acid rain, and runoff from agricultural, residential and urban areas are sources of nutrients entering the Bay.

Nutrient removal technology (NRT) - Also known as biological nutrient removal (BNR). The process whereby nutrients are removed from wastewater in addition to the organic content.

Nutrient Trading - The transfer of nutrient reduction credits, specifically those for nitrogen and phosphorus.

Nymph - Insect larva: the larva of some insects that resembles the adult and develops into the adult insect directly, without passing through the intermediate pupa stage.


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Oligohaline - Pertaining to moderately brackish water with low range salinities (from .5-5 parts per thousand)

Oligotrophic - Refers to water bodies or habitats with low concentrations of nutrients.

Omnivore - Literally, an organism that will eat anything. Refers to animals who do not restrict their diet to just plants or other animals.

Open Space - an area of land that is valued for natural processes and wildlife, for agricultural and sylvan production, for active and passive recreation, and providing other public benefits.

Ovipositor - A tubular organ at the end of the abdomen of some female fish or animals, especially insects, that is used to deposit eggs.


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Palps - A sensory appendage found in many invertebrate species, that is located near the mouth, and used to assess or manipulate food before it is eaten.

Palustrine - The group the vegetated wetlands traditionally called by such names as marsh, swamp, bog, fen, and prairie, which are found throughout the United States. It also includes the small, shallow, permanent or intermittent water bodies often called ponds.

Parasite - A plant or animal which lives on or in an organism of another species from which it derives its nutrition and/or protection; usually without benefit to the host and often with harmful effects.

Parapodia - Paired appendages or feet that are found on each segment of many segmented marine worms (Polychaeta). These appendages or feet are commonly used for swimming, crawling or holding objects.

Pelagic - The open ocean, excluding the ocean bottom and shore.

Perennial - A term used in botany used to describe plants that live for more than two growing seasons. Such plants either die back after each season, as some herbaceous plants do, or grow continuously, as some shrubs do.

Pervious - porous, able to be penetrated by water.

Pesticides - A general term used to describe chemical substances that are used to destroy or control insect or plant pests. Many of these substances are manufactured and do not occur naturally in the environment. Others are natural toxics that are extracted from plants and animals.

pH - Measure of the acidity or basicity of water (-log10 of the activity of hydrogen ions in water).

Phosphorus - (P) A key nutrient in the Bay's ecosystem, phosphorus occurs in dissolved organic and inorganic forms, often attached to particles of sediment. This nutrient is a vital component in the process of converting sunlight into usable energy forms for the production of food and fiber. It is also essential to cellular growth and reproduction for organisms such as phytoplankton and bacteria. Phosphates, the inorganic form are preferred, but organisms will use other forms of phosphorus when phosphates are unavailable.

Photic zone - Layer of a body of water that recieves ample sunlight for photosynthesis (usually less than 100m).

Photosynthsis - The process by which plants convert carbon dioxide and water into carbohydrates and oxygen. The carbohydrates are then available for use as energy by the plant or other consuming organisms. (CO2+ H2O +SUNLIGHT= C6H12O6 + O2 ). This process is also referred to as "primary production."

Phytoplankton - Plankton are usually very small organisms that cannot move independently of water currents. Phytoplankton are any plankton that are capable of making food via photosynthesis.

Plankton - Small or microscopic algae and organisms associated with surface water and the water column.

Plumage - All of the feathers that cover a birds body.

Point Source - A source of pollution that can be attributed to a specific physical location; an identifiable, end of pipe "point". The vast majority of point source discharges for nutrients are from wastewater treatment plants, although some come from industries.

Pollinate - to transfer pollen grains from the male structure of a plant, to the female structure of a plant to fertilize the plant.

Polycyclic Aromatic Hydrocarbon (PAH) - a chemical compound composed of fused six carbon rings.

Polychlorinated Biphenyl (PCB) - a chemical compound composed of a bi-phenyl group and chlorine atoms.

Polyhaline - Pertaining to waters with salinities of 18-30 parts per thousand.

ppt - Parts per thousand (used as a measurement of salinity).

Predator - Organism which hunts and eats other organisms. This includes both carnivores, which eat animals, and herbivores, which eat plants.

Prey - Organism hunted and eaten by a predator.

Primary Producers - organisms, such as algae, that convert solar energy to organic substances through the molecule, chlorophyll. Primary producers serve as a food source for higher organisms.

Probable Effects Level (PEL) - An estimate of the concentration of a potentially toxic substance in the sediment above which the substance is likely to cause adverse effects to aquatic organisms.

Proboscis - long or tubular mouthparts of certain insects, worms, and spiders, used for feeding, sucking, and other purposes. Can also be the long flexible snout of some mammals.

Propagule - seeds or fragments of vegetation capable of producing new plants.

Pycnocline - The zone between waters with different densities. An example from an estuary would be a pycnocline separating deep, more saline water and shallow, more fresh water.

Quality Assurance (QA) - an integrated system of management activities involving planning, implementation, documentation, assessment, reporting, and quality improvement to ensure that a process, item, or service is of the type and quality needed and expected by the customer.

Quality Assurance Project Plan - a document describing in comprehensive detail the necessary quality assurance, quality control, and other technical activities that must be implemented to ensure that the results of the work performed will satisfy the stated performance criteria.

Quality Control (QC) - the overall system of technical activities that measures the attributes and performance of a process, item, or service against defined standards to verify that they meet the stated requirements established by the customer; operational techniques and activities that are used to fulfill requirements for quality.

Quality Management - that aspect of the overall management system of the organization that determines and implements the quality policy. Quality management includes strategic planning, allocation of resources, and other systematic activities (e.g., planning, implementation, documentation, and assessment) pertaining to the quality system.

Quality Management Plan - a document that describes a quality system in terms of the organizational structure, policy and procedures, functional responsibilities of management and staff, lines of authority, and required interfaces for those planning, implementing, documenting, and assessing all activities conducted.

Quality System - a structured and documented management system describing the policies, objectives, principles, organizational authority, responsibilities, accountability, and implementation plan of an organization for ensuring quality in its work processes, products (items), and services. The quality system provides the framework for planning, implementing, documenting, and assessing work performed by the organization and for carrying out required quality assurance and quality control.


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Radial - body parts in circular arrangement: used to describe the arrangement of the bodies of invertebrate marine animals such as the starfish and sea anemone that have parts spreading out from a single center.

Raptor - A bird of prey (i.e. osprey, eagle, hawk)

Recruitment - The residue of those larvae that have: (1) dispersed; (2) settled at the adult site; (3) made some final movements toward the adult habitat; (4) metamorphosed successfully, and (5) survived to be detected by the observer.

Red tide - A dense outburst of phytoplankton (usually dinoflagellates) often coloring water red brown.

Resident - Species which are permanent living members of a particular area.

Retriever - a dog, usually large, that retrieves game: a large strong-bodied dog originally bred to retrieve game for a hunter

Rhizome - The underground portion of a plant's stem. Usually a thick underground horizontal stem that produces roots and has shoots that develop into new plants.

Riparian area - Riparian refers to the area of land adjacent to a body of water, stream, river, marsh, or shoreline. Riparian areas form the transition between the aquatic and the terrestrial environment.

Riparian Forest Buffers - An area of trees, usually accompanied by shrubs and other vegetation, that is adjacent to a body of water which is managed to maintain the integrity of stream channels and shorelines, to reduce the impact of upland sources of pollution by trapping, filtering, and converting sediments, nutrients, and other chemicals, and to supply food, cover, and thermal protection to fish and other wildlife.

Roe - Fish eggs, especially while still massed in the ovarian membrane; called caviar.


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Salinity - A measure of the salt concentration of water. Higher salinity means more dissolved salts. Usually measured in parts per thousand (ppt).

Salinity regime - A portion of an estuary distinguished by the amount of tidal influence and salinity of the water. The major salinity regimes are, from least saline to most saline:

  • Tidal Fresh - Describes waters with salinity between 0 and 0.5 parts per thousand (ppt). These areas are at the extreme reach of tidal influence.
  • Oligohaline - Describes waters with salinity between 0.5 and 5 ppt. These areas are typically in the upper portion of an estuary.
  • Mesohaline - Describes waters with salinity between 5 and 18 ppt. These areas are typically in the middle portion of an estuary.
  • Polyhaline - Describes waters with salinity between 18 and 30 ppt. These areas are typically in the lower portion of an estuary, where the ocean and estuary meet.

Salt marsh - A coastal habitat consisting of salt-resistant plants residing in an organic-rich sediment accreting toward sea level.

SAV - see submerged aquatic vegetation.

Scavenger - An opportunitic animal that feeds on decaying plants and animals or scraps of food abandon by other animals.

Scute(s) - Large dermal keratinous plates (i.e. the bony armor of a sturgeon).

Sediment - matter that settles and accumulates on the bottom of a body of water or waterway.

Sedimentation - the separation of suspended particles from water by gravity Decreased drought flow - inadequate groundwater recharge causes diminished or loss of flow in watercourses.

Sessile - Immobile because of an attachment to a substrate (i.e. oysters).

Shellfish - An aquatic animal, such as a mollusk (e.g. clams, oysters, and snails) or crustacean (e.g. crabs and shrimp), having a shell or shell-like external skeleton (exoskeleton).

Siltation - The process by which sedimentary material, or silt, is suspended and deposited in a body of water.

Spat - Juvenile, newly attached oysters (i.e. oyster spat).

Spawn - To release eggs and/or sperm into water.

Species - A population or group of populations that are in reproductive contact but are reproductively isolated from all other populations.

Spicule - Small hard needle-like projections, often composed of calcium, silicon and used for support in certain parts of some invertebrates such as sponges and corals.

Sprawl - A form of land development that moves outward from urban areas in a manner which creates large areas of relatively low density.

Submerged Aquatic Vegetation (SAV) - rooted vegetation that grows under water in shallow zones where light penetrates. Also known as "Bay grasses".

Substrate - "Supporting surface" on which a sessile organism lives and grows. The substrate may simply provide structural support, or may provide water and nutrients. A substrate may be inorganic, such as rock or soil, or it may be organic, such as wood.

Subtidal - Submerged, not exposed at the lowest tide.

Suspended sediments - Particles of soil, sediment, living material, or detritus suspended in the water column.

Sustainability - The ability to continue existing.

Stream bank erosion - loss of bank material along a watercourse .

Storm Flow - rainfall runoff that reaches a stream channel during, or soon after a rainfall event that causes high rates of discharge.

Stratification - The formation, accumulation, or deposition of materials in layers, such as layers of fresh water overlying higher salinity water (salt water) in estuaries.

Swamp - a wetland dominated by woodsy vegetation.

Swim Bladder - an organ regulating the buoyancy in most teleost (bony) fishes.


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Thalweg - The middle of the chief navigable channel of a waterway.

Terrestrial - Living on land, as opposed to marine or aquatic.

Thermocline - A specific depth at which there is a layer of water where the temperature changes dramatically. Warmer surface water is seperated from the cooler deep water. This temperature gradient results in the formation of a density barrier.

Threatened - A species that is likely to become endangered if not protected.

Tidal mud flat - The unvegetated shore exposed to air during low tide.

Tides - Periodic movement of water resulting from gravitational attraction between the earth, sun, and moon.

TMDLs - "Total Maximum Daily Load" or TMDL. A TMDL defines the pollutant load that a water body can assimilate without causing violations of water quality standards, and allocates the loading between contributing point sources and non-point source categories.

Toxicant - A poisionous or toxic agent which is harmful to living resources either terrestrial or aquatic.

Trend Analysis - A formal statistical process that is used to determine the presence or absence of changes in measures of water quality over time or a geographic area.

Tributary - A body of water flowing into a larger body of water.

Tributary strategies - Tributary strategies are detailed implementation plans to achieve the nutrient and sediment cap load allocations and are developed in cooperation with local watershed stakeholders.

Trophic Level - Layer in the food chain in where one group of organisms serves as the source of nutrition of another group of animals.

Turbidity - The decreased clarity in a body of water due to the suspension of silt or sedimentary material.

Understory - Just beneath the canopy, this layer of the forest is composed of small trees and shrubs. As older trees die, they leave a gap in the canopy, which younger trees quickly grow to fill.

Use attainability analysis (UAA) - A UAA is a structured scientific assessment of the factors affecting attainment of the designated use component of water quality standards, based on physical, chemical, biological, and/or economic factors.

Venom - A poisonous fluid produced by an animal, which is transmitted by a bite or a sting. The venom is used to capture prey or as a means of defense.

Vertebrate - Animals with a backbone including fish, amphibians, reptiles, birds, and mammals.


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Wastewater - Water that has been used in homes, industries, and businesses that is not for reuse unless treated by a wastewater facility.

Water clarity - Measurement of how far you can see through the water. The greater the water clarity, the further you can see through the water.

Waterfowl - Any of various birds that swim on water, such as ducks, geese and swan or any bird species that is ecologically dependent on aquatic environments such as wetlands.

Water quality criteria - Criteria are part of a water quality standard, and may be numeric or narrative. Criteria represent a quality of water that supports a particular designated use. When criteria are met, water quality will generally protect the use.

Water quality standards - A provision of State or Federal law consisting of a designated use or uses for a water body and the quantifiable criteria protective of the use(s). Standards may be annual or seasonal, depending on the designated use.

Watershed - a region bounded at the periphery by physical barriers that cause water to part and ultimately drain to a particular body of water.

Weaned - When a baby or young animal is consuming food other than its mother's milk.

Wet Deposition - Atmospheric deposition that occurs when precipitation (rain and snow) carries gases and particles to the earth's surface.

Wetland - Low areas such as swamps, tidal flats, and marshes which retain moisture.


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Young-of-the-year - All of the fish of a species younger than one year of age. Usually scientists assign an arbitrary "birth date" to all fish of a species hatched over a two or three month period in one year. The fish are then assigned to Age 1 status on that birth date. By convention, this is usually January 1.

Zooplankton - a community of floating, often microscopic animals that inhabit aquatic environments. Unlike phytoplankton, zooplankton cannot produce their own food, and so are consumers.


Chesapeake Bay Program: A Watershed Partnership. Chesapeake Bay Program Glossary.