E

ECOLOGY | The scientific study of the processes that determine the distribution and abundance of organisms within their environment, the interactions among organisms and the influence organisms have on the transformation and movement of food and energy.
ECOSYSTEM | A specific environment defined by its interrelated physical and chemical characteristics and biological community.
EFFLUENT | Something that flows out. Often refers to wastewater discharged from water treatment plants, industry and the like.
ELECTROSHOCKING / ELECTROFISHING | Using electricity to stun, capture and collect fish. A method used to quantitatively sample fish in lakes and streams.
ENVIRONMENT | External factors that influence the growth, development and distribution of organisms or communities within a certain area.
EPILIMNION | The upper layer of water in a thermally stratified lake or reservoir. This layer consists of the warmest water and has a fairly uniform (constant) temperature. Readily mixed by wind action.
EPIPHYTE | A plant which grows on another plant, but is not parasitic. It makes its own food by photosynthesis.
EROSION | The weathering and wearing away of earth, usually from wind, rain or moving water.
EUTROPHIC | Reservoirs and lakes which are rich in nutrients and very productive in terms of aquatic animal and plant life.
EUTROPHICATION | The increase in the nutrient levels of a lake or other body of water. This usually causes an increase in the growth of aquatic animal and plant life.
EXOTIC SPECIES | Any species that is not native to a given ecosystem and whose introduction causes harm to humans, the economy or the environment.

F

FACULTATIVE | Facultative bacteria can use either molecular (dissolved) oxygen or oxygen obtained from food material such as sulfate or nitrate ions. I.e., facultative bacteria can live under aerobic or anaerobic conditions.
FALL TURNOVER | Fall turnover refers to lake mixing that occurs in the fall when surface waters cool and reach a temperature similar to underlying water. Upon cooling, surface waters sink, causing the lake to mix.
FECAL COLIFORM BACTERIA | Bacteria found in the intestinal tracts of animals. Their presence in water or sludge is an indicator of pollution and possible contamination by pathogens.
FERRIC IRON | The oxidized form of iron. Form of iron that predominates in surface lake sediments that are overlain with oxidized water. Phosphorus is tightly bound to ferric iron.
FERROUS IRON | The reduced form of iron. Form of iron that predominates in surface lake sediments that are overlain with anoxic water. Phosphorus becomes mobile when ferric iron is reduced to ferrous iron.
FISHKILL | Sudden death of a large number of fish. Caused by natural or human-induced changes in the environment, such as oxygen depletion, temperature change or change in acidity.
FLOC | Short for flocculant. A substance which causes suspended particles to coaggulate, aggregate and precipitate.
FLORIDONE | An herbicide used to control aquatic weeds. Works on milfoil, curly leaf pondweed, duckweed and watermeal.
FLUSHING RATE | Refers to how often a lake's entire volume of water is replaced. Determined by the ratio of drainage area to lake volume.
FOOD WEB | A complex network of interconnected food chains and trophic relationships.
FORAGE FISH | Small fish that have a high reproductive rate and serve as food for larger predatory fish.
FORK LENGTH | The length of a fish from its mouth to the fork in its tail.