1. Oceanic Zones Notes

2. Overview More than 250,000 identified marine species
Most live in sunlit surface seawater
Species success depends on ability to:
Find food
Avoid predation
Reproduce
Cope with physical barriers to movement

3. We’ve Already Discussed Plankton and Zooplankton

4. Nekton Independent swimmers; can migrate Most adult fish and squid
Marine mammals
Marine reptiles

5. Benthos Most abundant in shallower water. Three types:
Epifauna live on or near the bottom of the sea floor.
Oysters, sponges, sea squirts, sea stars, barnacles
Infauna live buried in sediments.
Worms, clams
Nektobenthos swim or crawl through water above seafloor.
Cephlapods, turtles & other reptiles, marine mammals

6. Marine Division by Light
Photic Zone (photo- means light):
the sunlit layer of the ocean’s surface that extends to a depth of 600 meters (2000 feet)
Euphotic Zone- upper part of photic zone,
lots of light for plant production to support photosynthesis
Disphotic Zone- lower part of photic zone,
animals can see but there is insufficient light for photosynthesis
Aphotic Zone (a- means without):
the deepest and largest region
of the open ocean that extends
to the ocean bottom

7. Photic Zone More than 90% of all marine life lives in the photic zone
of the ocean

8. Photic Zone
Euphotic Zone
Euphotic Zone: Top layer of the ocean

9. Photic Zone Euphotic Zone Disphotic Zone
Disphotic Zone: Only a small amount of light penetrates the water. (Plants do not grow here due to the insufficient amount of light.)

10. Photic Zone Euphotic Zone Disphotic Zone
Aphotic Zone: Entirely dark; no light

11. Marine Division by Location
Pelagic Zone - open water, divided into Neritic Zone (near shore over continental shelf) and Oceanic Zone (deep water beyond the continental shelf)
Benthic Zone -division of ocean bottom

12. Divided into two zones:
pelagic zone
benthic zone

13. Pelagic Environments Epipelagic- photic zone/sunlight zone
Mesopelagic- disphotic zone/twilight zone
Bathypelagic- aphotic zone/midnight zone
Abyssopelagic-
abyssal zone/abyss
Hadalpelagic-
deep trench/hadal

14. Benthic Environments Supralittoral Subneritic Suboceanic Littoral
Sublittoral
Inner
Outer
Suboceanic
Bathyal
Abyssal
Hadal

15. Sublittoral Zone- past the littoral, divided into:
Supralittoral Zone- the splash zone, right above the high intertidal zone Subneritic: Littoral Zone- where the coast is covered and uncovered by tidal action
Sublittoral Zone- past the littoral, divided into:
Inner Sublittoral (ocean bottom near the shore)
Outer Sublittoral (ocean bottom out to the edge of the continental shelf)

16. Suboceanic:
Bathyal Zone- bottom that covers the areas on
the continental slopes down to great depths
Abyssal Zone- the dark, lower regions which includes the deepest sea floor but not the trenches
Hadal Zone- deepest of all the sea floor, trench walls and bottom of trenches