Descriptionary

Puerto Rico Trough the deepest spot in the Atlan­tic and the second deepest in all the oceans, 30,246 feet or 9,219 meters.

red tide a bloom of phytoplankton that colors the water red and releases powerful toxins that kill large masses of fish and other sea life; the toxin released by some phytoplankton accumulates in mussels and clams and often proves fatal to humans who eat these shellfish.

ring a meander that has broken off from the main current.

sapropel black organic ooze or sludge, the source material for petroleum and natural gas, found in great accumulations under the ocean.

Sargasso Sea not actually a sea in itself but a section of the North Atlantic (a section the size of the conti­nental U.S.) between the West Indies and the Azores, noted for its small, floating meadows of seaweed.

Sargasso weed the free-floating seaweed, known for its centuries-long life span, that occupies the Sar­gasso Sea.

sea elements the elements that make up the sea, pri­marily (96.5 percent) oxygen and hydrogen, followed in order of prevalence by chlorine, sodium, magne­sium, sulfur calcium, potassium, bromine, carbon, strontium, boron, silicon, and others.

seafloor spreading the expanding of the seafloor along mid-ocean ridges, forming new crust.

sea high an abyssal hill.

seamount a submarine mountain over 700 meters in elevation.

seamount chain

a series of seamounts.

seascarp a long, high cliff or wall, often part of a fracture zone.

seaway a sea route taken by vessels.

seiche a wave that oscillates from a few minutes to a few hours, due to either seismic or atmospheric disturbances.

shoal a shallow area, a hazard to navigation.

sill the ridge or saddle between two basins, troughs, or trenches.

slick a patch of smooth surface water surrounded by rippled water, the result of internal wave flow but often mistaken for an effect of wind action.

sounding measurement of the depth of water.

spiller a wave with a concave back and a crest that breaks gradually and continuously, usually found offshore.

spindrift sea spray.

spring tide the very high tide occurring at new and full Moon and reinforced by the gravitational pull of the Sun.

submarine bar

an underwater sandbar.

submarine fan a large, offshore deposit of sedi­ment, sometimes stretching for hundreds of miles and fanning out into the shape of a cone or apron, origi­nating from the mouth of a large river. Also known as a submarine delta or submarine apron.

submarine spring a freshwater spring upwelling from the seafloor.

terrace a steplike section of the seafloor.

Tethys Sea one of the names for the huge, universal sea that hypothetically surrounded the superconti- nent of Pangaea before it divided. Also known as Panthalassa.

thalassic pertaining to the oceans.

thalassophobia the fear of the ocean.

tidal bore a high, dangerous wave caused by a surg­ing incoming tide upstream in a narrowing estuary or by the collision of tidal currents. Also known as an eagre.

trench a steep-sided, narrow depression in the seafloor.

trough same as a trench but gently sided.

tsunami a seismic sea wave, caused by an earth­quake, frequently large and dangerous. Erroneously referred to as a tidal wave.

turbidity current

an avalanche of sediment-laden water, moving as fast as 50 miles per hour down a continental slope into deeper water and stirring up silt; known to gouge out channels in the seafloor.

upwelling an upwelling of cold, deep water into upper, warmer water layers.

vent an opening on the seafloor releasing heat or volcanic debris.

zooplankton drifting sea worms, jellyfish, and crus­taceans.

mesic of soils, moist but well drained.

mulch collective term for any material such as straw, leaves, or sawdust spread on soil to cut down water loss and weed growth.

mull an upper mineral layer mixed with organic matter.

peat partially decomposed plant material having little inorganic matter and accumulated in wet areas such as bogs.

pedology the study of soil.

permeability the quality of allowing the penetration of water or other material through the soil.

pores any spaces between solid particles in soil.

stratification

individual layers or beds of soils.

soil

acidic soil soil with a high hydrogen-ion content, sometimes referred to as sour.

agrology soil science.

alkaline soil soil with a high hydroxyl-ion content, sometimes referred to as sweet.

alluvium soil deposited by water such as a flowing river.

duff on a forest floor, leaf litter and other organic debris in various stages of decay.

edaphic pertaining to the soil.

eluvium soil and mineral particles blown and depos­ited by the wind.