 and functional organization comparable to that of a natural habitat in the region
Two divers work to reattach a large fragment of elkhorn coral, Acropora palmata, at Mona Island, Puerto Rico. The coral in the background has been attached to the reef framework using stainless steel wires. The wire binds the coral fragment to the living coral where it is expected to reattach to the live coral. (Photo: Erik Zobrist, NOAA Restoration Center)
ecosystem restoration - actions taken to modify an ecosystem for the purpose of re-establishing and maintaining desired ecological structures and processes
ecotone - a transitional area between two adjacent ecological communities
ecotope - the abiotic or non-living part of an ecosystem
ecotourism - travel undertaken to experience sites or regions of unique natural or ecological quality, or the provision of services to facilitate such travel
ecotype - a genetically differentiated subpopulation that is restricted to a specific habitat
ecotype - a population in a given ecosystem that is adapted to a particular set of environmental conditions
ecozone - an area at the earth's surface representative of large and very generalized ecological units characterized by various abiotic and biotic factors
ecteinascidin - a marine pharmaceutical derived from the sessile tunicate Ecteinascidia turbinata which acts by disrupting the structure of DNA in the cells of solid tumors
ecto- - a prefix meaning 'outside'
ectoderm - the outer germ layer of cells in an embryo that gives rise to the outer layer of skin (epidermis) and neural tissue
ectodermis - the outer cellular covering of a polyp
A marine ectoparasite lodged in a fish's mouth. (Photo: NOAA Ocean Explorer)
ectoparasite - a parasite which lives on the surface of its host
ectoplasm - the clear, nongranular portion of the cell cytoplasm just inside the cell membrane
The Ectoprocta (Bryozoa) are tiny colonial animals that superficially resemble coral polyps. Most species are marine, and may be found on all types of hard substrates. (Photo: Shane Anderson)
Ectoprocta - an animal phylum synonymous with the phylum Bryozoa, the "moss animals"
ectotherm - a cold-blooded animal, one which cannot internally regulate its body temperature, such as a reptile, fish, or amphibian, whose body temperature is mostly determined by the surrounding environment and behavior; poikiloltherm; cold-blooded organisms maintain their body temperatures in ways different from warm-blooded animals, such as mammals and birds
ectothermic - having an internal body temperature that is dependent on the surrounding temperature. Most aquatic animals are ectotherms; also caled poikilothermal or "cold blooded"
AVHRR image of eddy in the Gulf of Mexico. (Image: NOAA-14 Polar Orbiting Satellite/LSU Earth Scan Lab, Coastal Studies Institute)
eddy - a circular movement of water formed on the side of a main current
edentate - toothless
edge effect - habitat conditions created at or near the more-or-less well-defined boundary between ecosystems (ecotone). Typically there is an increased richness of organisms resulting from the mixing of two communities where they join
Eel grass meadows. (Photo: NOAA)
eelgrass - a common seagrass (Zostera marina) distributed from Greenland to Florida that serves as an important habitat for fishes and shellfish. Unfortunately, approximately 90 percent of all eelgrass throughout its range along the Atlantic coast has been destroyed
effector - a muscle or gland that receives a stimulus from a neuron
efferent - moving or carrying outward or away from a central part. Refers to blood vessels, nerves, etc. For example, blood vessels carrying blood away from the heart or nerve fibers conducting impulses from the brain or nerve cord
effluent - a discharge of pollutants into the environment, partially or completely treated or in its natural state. Generally used in regard to discharges into waters; in contrast to an emmission, which is generally used in regard to discharges of pollutants into the air
efflux - an outward flow; flux of water, elements or gases out of an ecosystem or ecosystem component
effort - the amount of time and fishing power used to harvest fish. Fishing power includes gear size, boat size, and horsepower
egestion - the elimination of undigested food materials from an organism
egg - a female sex cell or gamete with the haploid number of chromosomes. It may be fertilized by a sperm cell to produce a zygote with the diploid number of chromosomes for that particular species. The eggs of some species may develop into multicellular individuals without being fertilized by a sperm cell. This is the process of parthenogenesis
A skate egg case (Mermaid's purse) revealing the skate embryo contained within (Photo: David Siebenaller)
egg case - the leathery case which contains the developing embryo in hagfishes, sharks, rays, skates and chimaeras; also called a "mermaid's purse"
egg chamber - a cavity or chamber in the sand, excavated by a nesting seaturtle, into which eggs are deposited for incubation
Ekman layer - the thin horizontal layer of water riding on top of the ocean that is affected by wind
Graphic of sea surface temperatures show El Niño, May 1997.
El Niño - an irregular variation of ocean current that from January to March flows off the west coast of South America, carrying warm, low-salinity, nutrient-poor water to the south. It is associated with the Southern Oscillation. These two effects are known as the El Niño Southern Oscillation (ENSO). El Niño usually occurs during the Christmas season when the equatorial counter current strengthens and flows eastward to overlie the cold, nutrient-rich waters of the Peru current. It does not usually extend farther than a few degrees south of the equator, but occasionally it does penetrate beyond 12 deg S, displacing the relatively cold Peru Current. The effects of this phenomenon are generally short-lived, and fishing is only slightly disrupted. Occasionally, the effects are major and prolonged
The manta ray is a large, graceful, mostly plankton-feeding elasmobranch. They also feed on small fishes. (Photo: Jackie Reid/Flower Garden Banks National Marine Sanctuary)
elasmobranch - a member of the Subclass Elasmobranchii of cartilaginous fishes. These include sharks, rays, and skates
elastic - capable of returning to an initial form or shape after deformation; resilient
electric field - the region extending outward in all directions from an electrically charged material that affects other electrically charged objects; the area around an electrified object where other charges are affected
electrocyte - a cell that generates electricity. The electric currents produced by some species of fishes, such as torpedo rays and electric eels, are generated in stacks or columns of electrocytes.The electrocytes of most 'electric fishes' are modified muscle cells. They are usually arranged in columns within electric organs. When an electrocyte is stimulated, a movement of ions (electrically charged atoms) across the cell membrane results in an electric discharge
electrogenic - capable of generating electric currents and a painful electric shock, as in electric rays
electromagnetic radiation - energy that travels through space in the form of waves. The highest frequencies in the spectrum of electromagnetic radiation are gamma-rays; the lowest frequencies are radio waves. All electromagnetic radiation travels at the speed of light. Shorter wavelength radiation (eg, ultraviolet) carries more energy and is likely to be more harmful to living tissue
electromagnetic receptor - a neurological receptor that responds to light, electricity, and magnetism. Photoreceptors respond to light and electroreceptors detect electrical energy
electron microscope - a microscope which beams electrons, instead of light beams, at and through the object of interest. This type of microscope provides the greatest resolution of extremely small details in the nanometer size range. Magnification may be up to x300,000
electron spin resonance - a chronometric dating technique that estimates dates from observation of radioactive atoms trapped in calcite crystals present in a number of materials, such as limestone, coral, shells, teeth, and bones; also called "Electron Paramagnetic Resonance (EPR)"
electroreceptor - a receptor organ that senses changes in an electrical current in the surrounding water, for example, the ampullae of Lorenzini in sharks
electrotaxis - the movement of organisms in response to an electric field
eleutherobin - a marine pharmaceutical initially isolated from the soft coral Eleutherobia sp. from Western Australia, and more recently from Erythropodium caribaeorum, an encrusting coral found in South Florida and the Caribbean. Eleutherobin is a potent cancer cell inhibitor
elevation - the height of a geographic location above a fixed reference point, often the mean sea level
ELISA (enzyme-linked immunosorbent assay) - a rapid test where an antibody or antigen is linked to an enzyme as a means of detecting a match between the antibody and antigen; a technique for detecting specific proteins by using antibodies linked to enzymes
The caudal fin of this trout has an emarginate shape. (Image: U.S. Fish and Wildlife Service)
emarginate - a notched margin, but not so deeply as to be forked. As an example, a trout possesses an emarginate caudal fin
embayment - an indentation in the shoreline that forms a bay
embryo - the stage of early growth and differentiation of tissues and the formation of primitive organs and organ systems of