BACTERIAL FILM 



2. Water held back from the main flow, as 

 that which overflows the land and collects in low 

 places or that forming an inlet approximately 

 parallel to the main body and connected thereto 

 by a narrow outlet. ( 68 ) 



3. An arm of the sea, usually lying parallel 

 with the coast, behind a narrow strip of land. 

 (30) 



bacterial film — See primary film. 



Baffin Bay pack — (or middle pack). The drift- 

 ing ice floes west of Greenland between Davis 

 Strait and the southern limit of North Open 

 Water, which is roughly a line from Cape York 

 to the entrance of Lancaster Sound. (59) 



bafllie area — An area of approximately 30 degrees 

 to either side of the stern in which the chance of 

 holding a sonar contact is nearly impossible. 



Bahama Current — See Antilles Current. 



balancing — A maneuver that enables a stationary 

 submarine to float in a density layer. 



balancing layer — A density layer of sufficient 

 thickness, magnitude, intensity, and depth to 

 allow a submarine to balance safely. 



baleen — (or ivhalebone). The horny material 

 growing down from the upper jaw of large 

 plankton-feeding whales, which forms a strainer 

 or filtering organ consisting of numerous plates 

 with fringed edges. 



baleen whale — (also called mysticete, whalebone 

 tohale). A member of the cetacean suborder 

 Mysticeti, which comprises the right whales, 

 gray whales, and rorquals. 



ball — (also called longshore bar). A low sand 

 ridge which extends generally parallel with the 

 shoreline and is submerged at least by high 

 tides. It is generally separated from the beach 

 by an intervening trough. (2) (/See figure for 

 shore profile.) 



ballast — Broken stone, gravel, or other heavy ma- 

 terial which is used in a ship to improve its 

 stability or control the draft. Frequently, jet- 

 tisoned ballast is found in marine sediment 

 samples. (9) 



ball breaker — A device used in oceanographic op- 

 erations such as coring for determining when 

 the bottom is readied. It is a metal frame con- 

 taining a glass ball with a weight suspended 

 above it. When bottom contact is made the 

 weight drops on the glass ball and causes it to 

 implode. The sound wave generated by the im- 

 plosion is received aiboard ship by a listening 

 device. 



ball ice — Sea ice consisting of a large number of 

 soft, spongy spheres 1 to 2 inches in diameter. 

 This is a rare form of ice. (68) 



ballycadder — (or bellwatter). An ice foot. 

 (59) 



band elimination filter — A wave filter which has 

 a large insertion loss for one frequency band 

 with the cutoff frequencies for this band neither 

 zero nor infinite. 



band level — A given spectrum level is usually as- 

 sociated with a specific frequency. To identify 

 a transmission level measuring the power in a 

 specified frequency band, or the acoustic inten- 

 sity in a specified frequency band, it may be 

 designated as a band level. (28) 



band-pass filter — A wave filter which has a single 

 transmission band extending from a lower cut- 

 off frequency greater than zero to a finite upper 

 cutoff frequency. 



bandwidth — The number of imits (cycles, kilo- 

 cycles, etc.) of frequency required for trans- 

 mission. (66) 



bank — 1. An elevation of the sea floor located on a 

 continental (or island) shelf and over which 

 the depth of water is relatively shallow but suffi- 

 cient for safe surface navigation. It may sup- 

 port shoals or bars on its surface which are 

 dangerous to navigation. (62) 



2. In its secondary sense, a shallow area con- 

 sisting of shifting forms of silt, sand, mud, 

 gravel, etc., but in this case it is only used with 

 a qualifying word such as "sand-bank," "gravel- 

 bank," etc. (30) 



Bankia — A genus of moUuscan borers. See ship- 

 worm. 



bank-inset reefs — Coral reefs which are situated 

 well within the unrimmed outer edges of con- 

 tinental and insular shelves. (2) 



bank reef — A reef which lies within the outer 

 margin of rimless shoals in contrast to bar- 

 rier and atoll reefs which rise directly from 

 deep water. (2) 



bar — 1. A submerged or emerged embankment of 

 sand, gravel, or mud built on the sea floor in 

 shallow water by waves and currents. A bar 

 may also be composed of mollusk shells. When 

 it is a ridge generally parallel to shore and sub- 

 merged by high tides, it is a longshore bar. Off- 

 shore bars or barrier bars or beaches are built 

 principally by wave action on sand or gravel at 

 a distance from shore and separated from it by 

 a lagoon. Wlien a bar extends partly or com- 

 pletely across the entrance to a bay it is called a 

 baymouth bar. A crescentic bar commonly 

 found off the entrance to a harbor is a lunate 

 bar. (2) 



2. A unit of pressure, defined as 1 bar equals 

 10" dynes per square centimeter. 



barber — 1. A severe storm at sea during which 

 spray and precipitation freeze onto the decks 

 and rigging of boats. 



2. (also spelled herber). In the Gulf of St. 

 Lawrence, a local form of blizzard in which the 

 wind-borne ice particles almost cut the skin from 

 the face. 



3. /S^ee frost smoke. 



bare ice — Ice without snow cover. (74) 

 bar-finger sand — An elongated lenticular sand 

 body underlying a distributary in a bird-foot 

 delta. In the Mississippi delta it may be 15 to 



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