Terminology

Common Acronyms

CASM – Comprehensive Aquatic Simulation Model
DLBRM – Distributed Large Basin Runoff Model
ECOFOR(E) – Ecological Forecasting
HAB – Harmful Algal Bloom(s)
IA – Integrated Assessment
IBM – Individual Based Bioenergetics Model
IFYLE – International Field Years Lake Erie
N – Nitrogen
NOAA – National Oceanic and Atmospheric Administration
P – Phosphorus
SE-GRP – Spatially-Explicit Growth Rate Potential
SWAT – Soil and Water Assessment Tool

Term Definitions

Anoxia
Absence of oxygen or referring to severe hypoxia.

Atmospheric deposition
Atmospheric pollutants or chemical constituents that release through wet (precipitation) or dry methods (dust particles), hence the uses of “wet deposition” (or “dry”) to land or water systems.

Bathymetry
Measurement of the depth of a water body.

Benthic
The lowest level of a body of water; does not receive light.

Biomass
The actual amount of organism(s) as measured by volume, mass, plant and animal materials that can be converted into fuel.

Denitrification (also see Nitrification)
A chemical reduction process whereby nitrates are converted into nitrite, nitrous oxide, ammonia or elemental nitrogen; occurs in the absence of oxygen, and accelerates loss of natural and synthetic fertilizers from soil.

Ecosystem
As defined by Eugene Odum, distinguished ecologist and author of Fundamentals of Ecology (1953): a unit that includes all organisms in a given area interacting with the physical environment so that a flow of energy yields a clearly defined trophic structure, biotic diversity, and material cycle (material exchange between living and non-living parts) within the system.

Effluent
Discharge from a point source (a discernible, confined and discrete conveyance such as a pipe, ditch, channel, tunnel, conduit, etc.) that is generally regulated by the Clean Water Act.

Estuary
Coastal body of water where chemical and physical conditions modulate in an intermediate range between the freshwater rivers that feed into them and the salt water of the ocean; important nutrient-rich nursery ground for developing young; Chesapeake Bay is the largest in the U.S.

Eutrophication
An overly nutrient-rich aquatic environment leading to over-production of plant life, thereby reducing available dissolved oxygen, driving species to other areas, to morbidity or mortality.

Food web
With the denominator component being sunlight enabling photosynthetic reactions in green plants, the food web refers to the network of energy acquisition and transference processes from plants being consumed by herbivorous animals and other animals eating these herbivores, etc.

Harmful algal blooms (HAB)
The proliferation of single cell phytoplankton (i.e. red tides) that upsets the balance of the food web for the consumers because they reduce the availability of dissolved oxygen for other marine life.

Hydrodynamics
Refers to fluid dynamics or the motion of fluids.

Hydrologic cycle
The circulation of water on earth as sustained by solar energy. Water evaporates to the atmosphere, returns as precipitation and runoff from streams, rivers and groundwater. Water is also evaporated from soils and plants to the atmosphere through evapotranspiration.

Hypolimnion
The bottom dense layer of water, in the benthic zone area; coldest layer in summer and warmest in winter.

Hypoxia
A condition of very low oxygen in aquatic environments.

Lagoon
A shallow body of water separated from a larger open body; examples include coastal or coral reef lagoons.

Load
The quantity or burden of something carried into a system, example sediment carried into a stream or river.

Loading
The contribution of some component to a system.

Mass balance
An accounting or quantification of material entering or leaving a system.

Meteorology
The study of atmospheric phenomena and its interactions with the planet’s surface; related to weather forecasting.

Nitrification (also see Denitrification)
A biological oxidation process of converting nitrogen-containing organic compounds into nitrites and nitrates.

Phytoplankton
Microscopic organisms (mostly) that drift throughout the water column; rely on photosynthesis and thus reside in light receiving areas of the water body.

Residence time
The length of time that a substance (example a hazardous material) can be detected in a given environment.

Sediment
A mixture of sand, silt, clay and potentially organic compounds; soil eroded from one location and deposited in another.

Stratification
The process by which a region is divided into relatively distinct, horizontal-like layers; a change in temperature at different depths especially as related to change in seasons repeated year to year.

Time series
A sequence of data points that can be statistically analyzed and modeled to enable prediction of events, especially as based on past occurrences or events.

Tributary
A secondary stream or river that flows into a main river or body of water.

Trophic level
The feeding level in an ecosystem (who eats or is eaten by whom); species may belong to multiple trophic levels, i.e. being consumers of both plants and animals; general changes in one level due to pollution or other factors may affect others.

Watershed
A drainage basin that is the total area of land that drains into a water body such as a river, lake or other receiving aquatic area.