Oceanic Zonage Notes

Marine Zonage:

- continental shelf: the edge of a continent that is under water extending out to the shelf break

By Chris_huh - Own work, Public Domain.

- continental slope: the downward slope seaward to the continental rise
- continental rise: the region at the base of the continental slope where the slope decreases to 1 degree extending to the abyssal plain.
- abyssal plain: a flat seafloor at depths of 3,000 to 6,000 feet. 

Benthic and Pelagic regions: bottom

• benthic organisms: live on/ burrowed in the bottom
• some are sessile: attached and immobile (corals) 
• or mobile: crawl around/ move
• pelagic organisms: live up in the water column (fish) 
• subdivided according to size and swimming ability
• plankton: drifters
• phytoplankton: algae, tiny plants
• zooplankton: tiny animals and protozoans
• nekton: swim well enough against currents, fish, squid
• benthic zonation:



Oceanic zonation by By Photoguy2801 - Own work.

• intertidal zone: shallowest, tides
• subtidal: always submerged (coral reefs)
• deep ocean floor: bathyal, abyssal, halal zones 
• pelagic zonation: 
• neritic zone: the pelagic environment that lies above the continental shelf 
• oceanic zone: pelagic waters after the shelf break
• photic zone: where light can penetrate
• aphasic zone: no light goes through, no photosynthesis 

Physical properties of water 

Ocean water. By William Waterway. 

• humidity:
• prevents drying out or desiccation
• exposed respiratory surfaces (gills)
• external fertilization and development
• direct excretion of wastes
• high density: 
• organisms and particles can be suspended or float
• rigid skeleton not necessary
• filter feeding is possible
• locomotion (swimming and drifting)
• high heat capacity: 
• temperature of water remains stable 
• high nutrient and mineral content:
• salts and nutrients readily available for absorption