SLIME 



slime — Soft, fine, oozy mud or other substance of 

 similar consistency. (68) 



slime film — See primary film. 



slob ice — An accumulation of sludge, so dense 

 as to make the passage of small craft impossible. 

 (59) 



slope — The degree of inclination to the horizontal. 

 Usually expressed as a ratio, such as 1 : 25 or 1 

 on 25, indicating 1 unit rise in 25 units of hori- 

 zontal distance; or in a decimal fraction (0.04) ; 

 degrees (2°18') ; or percent (4%). It is some- 

 times described by such adjectives as: steep, 

 moderate, gentle, mild, or flat. (61) 



slope current — See gradient current. 



slope of foreshore — The angle between the tan- 

 gent to the beach at the high water line ( or some 

 reference point) and the horizontal. (73) 



slough — 1. A small muddy marshland or tidal 

 waterway which usually connects other tidal 

 areas. 



2. A tideland or bottomland creek. 

 (61) 



slud — See young ice. 



sludge — 1. Spongy whitish ice lumps a few cen- 

 timeters across. They consist of slush, snow 

 slush, and sometimes of spongy ice lumps 

 formed on the bottom of a shallow sea and 

 emerging at the surface. 



2. (also called sZm.s A, creams ^ce). An accumu- 

 lation of ice crystals which remain separate or 

 only slightly frozen together. It forms a thin 

 layer and gives the sea surface a grayish or 

 leaden-tinted color. With light winds no ripples 

 appear on the surface. See grease ice, ice 

 slush. (74) 



sludge cake — An accumulation of sludge 

 hardened into a cake strong enough to bear the 

 weight of a man. (59) 



sludge floe — A large sludge cake. (59) 



sludge lump — An irregular mass of sludge 

 shaped by the action of strong winds. ( 59 ) 



slump^(or slide). The slippage or sliding of a 

 mass of unconsolidated sediment down a sub- 

 marine or subaqueous slope. Slumps occur fre- 

 quently at the heads or along the sides 

 of submarine canyons. The sediment usually 

 moves as a unit mass initially but often becomes 

 a turbidity flow. It may be triggered by any 

 small or large earth shock. 



slush — See sludge (sense 2) ; ice slush. 



slush pond — A pool or lake containing slush. 

 (Slush ponds are common in summer on ablation 

 surfaces of glaciers and ice caps.) (59) 



small calorie — (abbreviated cal). See calorie. 



small diurnal range — The average difference in 

 height between mean lower high water and mean 

 higher low water, measured over a 19-year 

 period, or its computed equivalent. See diurnal 

 range. (50) 



small field of ice — See small ice field. 



small floe — See small ice floe. 



small ice cake — An ice cake less than 2 meters 

 (6.6 feet) across. (74) 



small ice field — (or small field of ice). 1. An 

 ice field 10 to 15 kilometers (5.4 to 8.1 n. miles) 

 across. (74) 



2. A Russian term for an ice field between 

 500 meters and 2 kilomet-ers (1,640 feet to 1.1 n. 

 miles) in width; 



small ice floe — 1. See ice floe. 



2. A floe of sea ice 30 to 600 feet across. (59) 

 Obsolete. 



small ice skylight — See ice skylight. 



small scale — See scale. 



small tropic range — The average difference in 

 height between all tropic lower high waters 

 and all tropic higher low waters which occur 

 twice monthly when the moon's north and south 

 declinations are greatest. See lunar declina- 

 tion, tropic range. 



smoothing — An averaging of data in space or 

 time, designed to compensate for random errors 

 or fluctuations of a scale smaller than that pre- 

 sumed significant to the problem at hand. For 

 example, a thermometer smooths the tempera- 

 ture reading on the scale of its time constant. 



(5) 

 smooth sea — Sea with waves no higher than 



ripples or small wavelets. ( 68 ) 



snail — See gastropod. 



snapper — See clamshell snapper. 



snapping shrimp — (or -pistol shrknp). Certain 

 species of shrimp belonging to the family 

 Alpheidae, chiefly in the genera AlpJieus and 

 Synalpheus, that are capable of producing sharp 

 cracking sounds by the rapid closure of an en- 

 larged claw. These shrimps form large popula- 

 tions in warm shallow waters on shell, rock, or 

 coral bottoms where their sounds constitute a 

 major component of underwater background 

 noise. Shrimp noise ranges in frequency from 

 about 500 to 50,000 cps, with principal compo- 

 nents between 2,000 and 20,000 cps. 



Snell's law — When a wave (light or sound) 

 travels obliquely from one medium into another, 

 the ratio of the sine of the angle of incidence 

 to the sine of the angle of refraction is the 

 same as the ratio of the respective wave veloci- 

 ties in these mediums and is a constant for two 

 particular mediums. 



snow blink — (also called snow sky). A bright, 

 white glare on the underside of clouds, produced 

 by the reflection of light from a snow covered 

 surface. This term is used in polar regions 

 with reference to the sky map; snow blink is 

 lighter than ice blink, and much lighter than 

 Ian d sky or water sky. ( 5 ) 



snow-covered ice — Ice covered with snow. (74) 



snow ice — Ice crust on a water surface contain- 

 ing a large proportion of fallen or drifted snow.. 

 (59) See ice rind. 



snow sky — See snow blink. 



150 



