Oceanic Zones Notes

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

We’ve Already Discussed Plankton and Zooplankton

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

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

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

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

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

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.)

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

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

Divided into two zones: pelagic zone benthic zone

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

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

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)

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