earth science 14

Question 1

how much percent of the eaerth is covered by the ocean

Answer 1

71%

Question 2

what is bathymetry

Answer 2

the measurment of the oceans depth

Question 3

what was the first ship that explored the ocean floor

Answer 3

the hms challenger

Question 4

what were some things that people used for exploring the oceans

Answer 4

Sonar, Satellites, and submersibles

Question 5

what is a continental margin

Answer 5

it is the area of transition between a continent and the adjacent ocean basin floor.

Question 6

what is the continental shelf

Answer 6

it is the first area of ocean floor you would encounter . it is the gently sloping submerged surface extending from the shoreline.

Question 7

what is the continental slope

Answer 7

it starts at the end of the continental shelf and is steeper. is boundary between continental and oceanic crust.

Question 8

what are submarine canyons

Answer 8

they are steep sided valleys that are cut into the continental slope.

Question 9

what are turbidity currents

Answer 9

occasional movements of dense sidemeat-rich water against the continental shelf

Question 10

what is continental rise

Answer 10

occurs in areas of no trenches, and consists of a thick layer of sediments that moved from the shelf to deep ocean

Question 11

what is the ocean basin floor

Answer 11

Between the continental margin and mid ocean ridges lies the ocean basin floor.

Question 12

what is an abyssal plain

Answer 12

extremely flat and deep areas-usually 4,000-6,000m deep.

Question 13

what are deep ocean trenches

Answer 13

long steep sided depressions in the ocean floor.

Question 14

what are seamounts

Answer 14

seamounts are volcanic peaks that are not tall enough to break through the ocean surface, are steep sided like volcanoes on land.

Question 15

what are guyots

Answer 15

results from a volcanic island that erodes away by running water or waves. Once the island is submerged by water its referred to as a guyot.

Question 16

what are mid ocean ridges

Answer 16

an interconnected system of mostly underwater mountains that have developed on newly formed ocean crust.

Question 17

what is seafloor spreading

Answer 17

it occurs at divergent plate boundaries where two lithospheric plates are moving apart. NEW OCEAN FLOOR IS FORMED AT MID OCEAN RIDGES AS MAGMA RISES BETWEEN THE DIVERGING PLATES AND COOLS

Question 18

what are hydrothermal vents

Answer 18

they form along mid ocean ridges. These are zones where mineral rich water, heated by the newly formed crust escapes through cracks in oceanic crust.

Question 19

where do reefs grow

Answer 19

above continental shelves or around volcanic islands

Question 20

what are the different type of coral reef

Answer 20

a reef may evolve overtime into an atoll.
it begins as a fringing reef that surrounds the volcanic island edge. As the seafloor sinks and the volcano gets dense and sinks the reef still keeps growing.

Question 21

a barrier reef

Answer 21

it is formed as more water separates the reef from the island, this is because as the volcano island sinks the top of the volcano is narrow.

Question 22

at atoll

Answer 22

an atoll forms as the island continues to sink until it is entirely underwater. and atoll is a ring-shaped reef surrounding a shallow lagoon.

Question 23

life around a reef

Answer 23

reefs can have a variety of shapes and animals.

Question 24

resources from the seafloor

Answer 24

besides living organisms the ocean contains valuable nonliving resources but because of depth it is too hard.

Question 25

what are the main energy resources from the ocean

Answer 25

oil and natural gas as the main energy resource. they form from the remains of dead marine organisms.

Question 26

what are gas hydrates

Answer 26

they are compact chemical structures made of water and natural gas. The most common type is methane.
Most form when bacteria break down organic matter trapped in ocean floor-sediments.

Question 27

what are some other resources from the ocean

Answer 27

evaporative salts, sand, gravel, manganese

Question 28

evaporative salt

Answer 28

as seawater evaporates the salt concentration increases until they are no longer dissolved, they precipitate out of solution forming salt deposits.

Question 29

what is desalination

Answer 29

the process of extracting freshwater from seawater

Question 30

sand and gravel

Answer 30

sand and gravel which includes rock fragments that are washed out to sea and shells of marine organisms are mined by offshore barges. They could be used to full in beaches or make concrete.

Question 31

manganese nodules

Answer 31

they are hard lumps of manganese, iron, and smaller amounts of copper, nickel and cobalt. They precipitate around smaller objects

Question 32

what are some sources of sea salts

Answer 32

rivers and ground water slowly dissolves calcium sulfate sodium and magnesium from rocks and minerals. another source is underwater vents and volcanoes that release gases.

Question 33

salinity

Answer 33

the measurement of the amount of solids dissolved in water.

Question 34

what are the processes that effect salinity (lower)

Answer 34

1. adding freshwater to it by rain, snow melting icebergs.
2. mouths of large rivers add lots of fresh water

Question 35

what are some processes that effect salinity (higher)

Answer 35

1.evaporation near dry tropical areas.
2.near the poles the salt water freezes into ice leaving the salt behind.

Question 36

factors affecting sewater density

Answer 36

seawater density is influence by two main things: salinity and temperature.

Question 37

density variation with depth

Answer 37

temp and salinity and the waters resulting density vary with depth.

Question 38

what is the pycnocline

Answer 38

the layer of ocean water between about 300m-1000m where there is a rapid change of density.

Question 39

what is the surface mix zone

Answer 39

it has the highest temp due to direct solar contact. this layer has mixing of water by waves currents and tides.

Question 40

what is the transition zone

Answer 40

the temp drops abruptly with depth. this layer is where the thermocline and pycnocline is located.

Question 41

what is the deep zone

Answer 41

sunlight does not reach this zone. it has 80% of ocean water in this zone. water temperature is a few degrees above 0 degrees celcius.

Question 42

what are plankton

Answer 42

are tiny algae and animals that float in the water and are carried by wave and currents. planktos=wondering

Question 43

what are nekton

Answer 43

they are free swimming animals that can move throughout the water column independently of ocean currents. nectos=swimming

Question 44

what are benthos

Answer 44

organisms that live on or in the ocean floor, like crabs lobsters etc. most live in the shallow part of the ocean.

Question 45

the availability of sunlight`

Answer 45

the part of the ocean into which sunlight penetrates is called photic zone.
Euphoric zone is near the surface where light is strong enough for photosynthesis.
the lower photic zone does not have enough light for photosynthesis.
the aphotic zone is the zone below the photic zone and has no light.

Question 46

distance from shore

Answer 46

this is another wat to subdivide marine life zones. the physical conditions of each zone help determine which organisms can live in that zone.