The Ocean Floor

Question 1

Abyssal plains

Answer 1

Deep, flat features
Likely the most level places on earth
Thick accumulations of sediment have buried an otherwise rugged ocean floor

Question 2

Oceanic ridges

Answer 2

Underwater mountain ranges
Form along divergent plate

Question 3

Sea floor sediment

Answer 3

Vast majority of the ocean floor is covered with sediment

Deposited by turbidity currents, snow settling

Organic debris that sinks from higher in the water column

Some flakes fall before finally reaching the ocean floor

Question 4

Three categories

Answer 4

Terrigenous - derived from water

Minerals from the weathering of terrestrial rock

Hydrogenous - derived from water

Minerals that crystallize directly from seawater through chemical reactions

Biogenous - derived from organisms

Shells and skeletons

Question 5

Salinity

Answer 5

Total amount of solid material dissolved in water

Parts per thousand
Average salinity of ocean water = 3.5 ppt

Salinity in saline prairie lakes can exceed 200 ppt

Temperature and precipitation determine salinity levels

At mid latitude and near the equator, lower salinities - extensive rainfall dilutes surface ocean water

At tropics evaporation is greater than precipitation resulting in higher salinity

At poles fresh water from melting ice decrease surface salinity

Question 6

Acidity

Answer 6

Anthropogenic changes to acidity

Question 7

Thermocline

Answer 7

Layer where temp changes with depth

Seen at low and mid latitudes

Question 8

Isothermal

Answer 8

Same temp

No thermocline

Seen at high latitudes