Oregon Water Science Center Glossary
This glossary is to aid with understanding science topics. As science project web pages come online more terms are added as needed.
A
Acoustic velocity meter
Acoustic velocity meter
A device that uses sound waves to track velocity of particles moving in the water column.
Akinetes
Akinetes
Dormant cells found in some species of cyanobacteria. These cells enable phototrophic bacteria to endure harsh and starvation conditions.
Aphanizomenon
Aphanizomenon
A type of cyanobacteria or blue-green algae commonly found in freshwater phytoplankton assemblages. In nutrient-rich waterbodies it can form dense blooms.
B
BOD5
BOD5
BOD5 refers to the five-day biochemical oxygen demand of bacteria and microorganisms decomposing nitrogenous and carbonaceous matter in water.
Backwater
Backwater
Water backed up in its course by an obstruction (such as a dam), an opposing current, or the tide.
C
CBOD
CBOD
Oxygen demand of bacteria and microorganisms decomposing carbonaceous matter in water.
CE-QUAL-W2
CE-QUAL-W2
A water quality and hydrodynamic model in 2D (longitudinal-vertical) for rivers, estuaries, lakes, reservoirs and river basin systems. W2 models basic eutrophication processes such as temperature-nutrient-algae-dissolved oxygen-organic matter and sediment relationships.
Coagulant
Coagulant
A substance that causes a liquid to thicken or clump
Cyanobacteria
Cyanobacteria
Also known as blue-green algae, these photosynthetic bacteria naturally inhabit freshwater ecosystems. However, an excess of nutrients in warm water can create conditions that cause cyanobacterial blooms that can produce toxins. These blooms often appear as floating mats of foul-smelling, decaying, scum in lakes and can also form mats on the bottoms of streams.
Cyanotoxins
Cyanotoxins
Cyanotoxins are produced by cyanobacteria, also known as blue-green algae, found in freshwater, estuarine, and marine waters. Once these toxins are released, they can cause numerous health effects ranging from minimal (i.e., diarrhea, headaches, and skin irritation) to life threatening (i.e., death).
D
Diatoms
Diatoms
Diatoms are the base of the food chain in aquatic ecosystems. Any of a class (Bacillariophyceae) of minute planktonic unicellular or colonial algae with silicified skeletons that form diatomite.
Dolichospermum
Dolichospermum
A type of cyanobacteria genus that is commonly found in freshwater phytoplankton assemblages. In nutrient-rich waterbodies it can form dense blooms.
E
Eutrophic
Eutrophic
A body of water that is rich in dissolved nutrients.
Evapotranspiration
Evapotranspiration
The process by which water is transferred from the land to the atmosphere, by water leaving the soil (evaporation) and water lost through plant leaves and stems (transpiration).
G
Gage height
Gage height
The height of the water surface above the gage datum (zero point). Gage height is often used interchangeably with the more general term, stage, although gage height is more appropriate when used with a gage reading.
Geomorphic
Geomorphic
landform evolution
Groundwater
Groundwater
Liquid water stored underground, within rocks of all kinds, stored in cracks and in the pore spaces of sediments and sedimentary rocks. Groundwater can be fresh, saline, or brackish. The term “aquifer” refers to rocks that can hold substantial amounts of water.
Groundwater discharge
Groundwater discharge
Processes through which water leaves a groundwater system. Examples: water resurfaces naturally in springs, lakes, rivers and other water bodies, and from plants consuming water through roots. Human caused discharge occurs from withdrawals through wells.
Groundwater recharge
Groundwater recharge
Processes through which water can enter a groundwater system. Examples: rain and snowmelt infiltration, seepage from water bodies such as lakes, rivers, etc.
H
High-head dams
High-head dams
A dam that stores water at a higher elevation for better power generation.
Hydraulic modeling
Hydraulic modeling
Hydraulic modeling simulates and analyzes the behavior of water flow in various systems, such as rivers, channels, pipelines, or stormwater networks.
Hypereutrophic
Hypereutrophic
Extremely rich in nutrients.
I
Impoundments
Impoundments
A body of water formed by a dam.
Isotope
Isotope
Isotopes are atoms of the same element with different numbers of neutrons. For example, carbon always has 6 protons, or else it wouldn't be carbon. Carbon 12 has 6 protons and 6 neutrons to equal carbon 12. An isotope of carbon - carbon 14 still has 6 protons but has 8 neutrons to equal 14.
L
Lidar
Lidar
Light Detection and Ranging (LiDAR) systems use lasers to measure the elevation of objects on the ground, in forests, under water and even in buildings.
M
Macroinvertebrates
Macroinvertebrates
Small organisms without a backbone that are visible to the naked eye. The most common in aquatic systems, living in water as nymphs or larvae at least until they reach their adult stages. Common types include dragonflies, caddisflies, stoneflies, beetles, midges, and mayflies.
Mesocosm
Mesocosm
An outdoor environment that is designed to determine the effects that different changes have on an ecosystem.
Microcystin
Microcystin
A potent liver toxin and possible human carcinogen. Cyanotoxins can also kill livestock and pets that drink affected waters.
Microcystis
Microcystis
A genus of cyanobacteria commonly found in freshwater phytoplankton communities. In nutrient-rich waterbodies, it can form dense blooms.
O
Organochlorine pesticides
Organochlorine pesticides
Organochlorine pesticides are chlorinated hydrocarbons used extensively from the 1940s through the 1960s in agriculture and mosquito control. As neurotoxicants, many organochlorine pesticides were banned in the United States, although a few are still registered for use in this country.
Oscillatoria
Oscillatoria
A type of cyanobacteria or blue-green algae commonly found in freshwater. Its name refers to the oscillating movement of its filaments as they slide against each other, positioning the colony to face a light source.
P
Per- and polyfluoroalkyl substances
Per- and polyfluoroalkyl substances
PFAS are a group of synthetic chemicals used in a wide variety of common applications, from the linings of fast-food boxes and non-stick cookware to fire-fighting foams and other purposes. Their persistence in the environment and occurrence across the country make them a unique water quality concern.
Periphyton
Periphyton
A plant assemblage including microbial communities of algae and cyanobacteria living attached to submerged aquatic vegetation.
Permeability
Permeability
Describes the ability of groundwater to flow through rocks or sediments.
Photosynthesis
Photosynthesis
Photosynthesis, the process by which green plants and certain other organisms transform light energy into chemical energy. During photosynthesis in green plants, light energy is captured and used to convert water, carbon dioxide, and minerals into oxygen and energy-rich organic compounds.
Phreatophytes
Phreatophytes
A deep-rooted plant that obtains its water from near the water table. Phreatophytes often have their roots in constant contact with groundwater.
Polybrominated Diphenyl Ethers
Polybrominated Diphenyl Ethers
PBDEs belong to a class of chemicals that are added to certain manufactured products in order to reduce the chances that the products will catch on fire. Finished products that may contain PBDEs are furniture foam padding; wire insulation; rugs, draperies, and upholstery; and plastic cabinets for televisions, personal computers, and small appliances.
Polychlorinated biphenyls
Polychlorinated biphenyls
PCBs belong to a broad family of man-made organic chemicals known as chlorinated hydrocarbons. PCBs were domestically manufactured from 1929 until manufacturing was banned in 1979. PCBs may be present in products and materials produced before the 1979 PCB ban.
Polycyclic Aromatic Hydrocarbons
Polycyclic Aromatic Hydrocarbons
Polycyclic aromatic hydrocarbons (PAHs) are a group of over 100 different chemicals that are formed during the incomplete burning of coal, oil and gas, garbage, or other organic substances like tobacco or charbroiled meat.
Pumpage
Pumpage
The amount of liquid raised by pumping.
S
Suspended sediment
Suspended sediment
Suspended sediment is primarily fine particles of clay and silt. It also may include fine sand and particles of organic matter suspended in the water column.
T
Turbidity
Turbidity
The measure of relative clarity of a liquid. Turbidity is an optical characteristic of water and is a measurement of the amount of light that is scattered by materials in the water.
W
Water year
Water year
The 12-month period October 1, for any given year through September 30, of the following year. Commonly used in hydrology to describe the time period for which precipitation totals are measured.