FOULING 



ing or fouling the ground or other obstructions 

 exists. /S'ee foul bottom. (68) 



fouling — The mass of living and nonliving bodies 

 and particles attached to or lying on the surface 

 of a submerged manmade or inti-oduced object; 

 more commonly considered to be only the living 

 or attached bodies. See foul. 



fouling community — (or fmding compl-ex). 1. 

 The assemblage of plants and animals growing 

 on a specific artificial surface or a specific type 

 of surface. 



2. An assemblage of plants and animals on an 

 artificial surface dominated by one or more or- 

 ganisms, such as the Mytilus (mussel) commu- 

 nity. 



fouling complex — See fouling community. 



fouling organism — (or fouler). A plant or ani- 

 mal that attaches to the surface of submerged 

 manmade or introduced objects. 



fouling panel — (or fouling -plate., test panel, test 

 plate, test hoard). An object of wood, metal, 



flass, or other solid material placed in water to 

 etennine various physical and/or biological 

 aspects of fouling; the objects may be flat, 

 curved, or bent plates or boards and square or 

 rectangular blocks. 



fouling plate — See fouling panel. 



fracture — Breaks in rocks due to intense folding 

 or faulting. (2) 



fracture zone — An extensive linear zone of un- 

 usually irregular topography of the sea floor 

 characterized by large seamounts, steep-sided 

 or asymmetrical ridges, troughs, or escarp- 

 ments. (62) 



frazil — (or frazil crystals; also called needle ice) . 

 Ice crystals which foiTn in supercooled water 

 that is too turbulent to i^ermit coagulation into 

 sheet ice. This is most common in swiftly flow- 

 ing streams, but also is found in a turbulent sea 

 (where it is called lolly ice) . It may accumulate 

 as anchor ice on submerged objects and obstruct 

 the water flow. ( 5 ) 



frazil crystals — See frazil, ice crystals. 



frazil ice — (or needle ice, lolly ice, underwater 

 ice). An accumulation of frazil in a body of 

 water. (5) 



free-air anomaly — The difference between ob- 

 served gravity and theoretical gravity which 

 has been computed for latitude and corrected for 

 elevation of the station above the geoid, by 

 application of the normal rate of change of 

 gravity for change of elevation, as in free air. 



The elevation correction is for height above 

 the geoid. No correction is applied for the effect 

 of topography and isostatic compensation. 

 (37) 



free-air correction— A correction factor, usually 

 expressed as milligals per meter, which is ap- 

 plied to observed gravity to reduce the value to 

 sea level. 



free sound field — A field in a homogeneous, iso- 

 tropic medium free from boundaries. In 

 practice it is a field in which the effects of the 

 boundaries are negligible over the region of 

 interest, (3) 



free wave — Any wave not acted upon by any 

 external force except for the initial force that 

 created it; a wave solution satisfying a homo- 

 geneous equation of motion and homogeneous 

 boundary conditions. 



A free wave on a water surface is one created 

 by a sudden impulse, thereafter influenced only 

 by friction, the dimensions of the basin, and the 

 dispersive character of the water medium it 

 inoves in. Most ocean surface waves except 

 tidal waves are free waves. (5) See oscilla- 

 tion. 



freezeup — The formation of a continuous ice 

 cover. Generally, freezeup is restricted to the 

 hardening of locally formed young ice, although 

 the freezing together of pieces of drift ice also 

 can be called freezeup. 



freezing point — (also called apparent freezing 

 point). The temperature at which a liquid 

 solidifies under any given set of conditions. 

 Pure water under atmospheric pressure freezes 

 at 32°F (0°C). However, the freezing point 

 of water is depressed with increasing salinity; 

 thus sea water with a salinity of 35 per mille 

 will freeze at about — 1.9°C or 28.6°F. Both 

 freezing point and melting point can be defined 

 as the temperature at which both the solid and 

 liquid forms of a substance can coexist. 



frequency — The frequency of a function periodic 

 in time is the reciprocal of the primitive period. 

 The unit is the cycle per unit time and must be 

 specified. 



frequency distribution — A tabulation of fre- 

 quency or relative frequency of occurrence of a 



36° 



3 

 < 



10 20 30 



SALINITY (PARTS PER THOUSAND) 



40 



RELATIONSHIP BETWEEN FREEZING POINT AND TEMPERATURE 

 OF MAXIMUM DENSITY FOR WATER OF VARYING SALINITY 



66 



