Lec 9

Question 1

is defined as the ocean depth where light begins to fade, at an approximate depth of 200 metres or the point of transition from continental shelves to continental slopes.

Answer 1

Deep sea

Question 2

• Sunlight zone or epipelagic zone
• surface layer down to 150-200 m
• there is enough light

Answer 2

Euphotic Zone

Question 3

• Mesopelagic Zone
• surface layer from 200-1000 m
• There is still some dim light

Answer 3

Dysphotic Zone

Question 4

• Bathypelagic, Abyssopelagic, & Hadopelagic Zones
• depth below 1000 m
• no sunlight

Answer 4

Aphotic Zone

Question 5

Animals migrate to the surface at night.

Answer 5

Vertical Migration

Question 6

Only about ……. of surface primary production sinks to the
mesopelagic .

Answer 6

20%

Question 7

Have:
● swim bladder
● Well developed muscles and bones

Answer 7

Vertically migrating fishes

Question 8

They help mid water animals see in the dim light

Answer 8

Sense organs

Question 9

Some mid water fishes have developed tubular eyes that give very acute vision in the direction that the eyes are pointed, either upward or forward, but are not good for lateral vision.

Answer 9

Tubular eyes

Question 10

Most mid water animals have evolved an even more effective way to mask their silhouettes

Answer 10

Bioluminescence

Question 11

includes depths between 1,000 and 4,000 m

Answer 11

bathypelagic zone

Question 12

lies from 4,000 to 6,000 m.

Answer 12

abysso pelagic zone

Question 13

consists of the waters of the ocean trenches, from below 6,000 m to 11,000 m.

Answer 13

hadopelagic, or hadalpelagic, zone

Question 14

• always dark
• always cold
• temperature remains nearly constant, typically at 1-2°C

Answer 14

World of Perpetual Darkness

Question 15

• prey attraction
• communication
• courtship

Answer 15

uses of bioluminescence

Question 16

Many deep-sea animals have functional eyes, especially in

Answer 16

upper parts of the deep sea

Question 17

mesopelagic fishes spend less energy on …… and more on ……

Answer 17

growth, reproduction

Question 18

females apparently release a special chemical that the male can detect and follow. Such chemicals are called

Answer 18

pheromones.

Question 19

pressure in the deep sea is

Answer 19

tremendous

Question 20

deepest known fish was recorded at a depth of

Answer 20

8,370 m.

Question 21

Bacteria that live in the deep sea where there is pressure and cold, known to be

Answer 21

slow bacterial growth