Shared Flashcard Set


ocean zones and lifestyles
ocean zones
11th Grade

Additional Science Flashcards








Reasons why Scientist the Seas 


Scientist divide the Seas into many different regions based on physical characteristics


  • There are basic classifications based on distance from the shore and depth . 
  • Most basic division of the ocean is between the water column and the bottom.



Water Portion

Called the pelagic zone
  • Divided into Subdivisions 



Sea Bottom 



Called the Benthic Zone
  • Divided into subdivisions  



Pelagic Zone 

Is divided into two horizontal zones, neritic and oceanic.
  • Neritic Zone water area between low tide mark and edge of the continental shelf.
  • Oceanic zone further divided verticle region."open ocean". Further divided into:
       Epipelagic Zone- Top layer that sunlight penetrates "Photic zone".
Mesopelagic Zone- Sunlight reaches  but not enough to support life"Dysphotic Zone".
Photic Zone- Most biologically productive region(photosynthesize occurs here)as 200m includes: Euphotic zone where photosynthetic organisms bring light energy into biological cycle.

Dysphotic Zone - Area of photic zone sun does reach but not enough for photosynthesis most of the ocean with a fraction of marine life.

Aphotic Zone -Where light doesnt reach; most of the ocean with a fraction of marine life includes:

Bathy Pelagic Zone- Deep water in open ocean.
Abyssal Palagic Zone- Even deeper water in the oceanic trenches.
Hadal Palagic Zone- Deepest water only at the bottom of oceanic trenches. 



Benthic Zone



is divided based on depth
  •  Moving from shore toward the open ocean.
First zone is the Supralittoral zone(Supra=upper, Litus=shore) is where water splashes but does not remain submerged.(Fluffy sand:does not get wet.)
Next Zone is the Littoral zone - Bottom area between high tide and low tide mark.(Wet sand: does get wet)
Beyond this is the continental shelf. Bathyal zone is the bottom along the continental slope.
Abyssal Zone = Deep open ocean bottom
Hadal Zone- Deepest zone in areas below 6,000m
Bathyal, Abyssal and Hadel Zones together commonly called the deep sea floor. 



Three  Lifestyles of Marine Organisms

  • Plankton
  • Nekton
  • Benthos





  • Name From Greek planktos meaning Wanderer
  • Plankton  are groups of plants and animals that drift in the ocean Currents.
  • Most are very small and Microscopic .
  • Plankton cannot swim against currents and waves.
  • Vital to life with out plankton we would die
  • Ex: Phytoplankton-Photosynthesize,are plants,   Zoo Plankton- are small animals,often Juveniles or larval forms of other animals.
  • Subgroup of Plankton is Neuston,those Plankton that float on the surface.                  Ex: Portuguese manofwar-Has a special gas filled float that allow the wind to push it along the surface to help it capture prey.




  • Can swim
  • Can be small invertibrates to large whales
  • Most Sea Predators are Nekton
  • Most Nekton are Vertebrates , but not all            Ex: Squid




  • Organisms that live in or on the ocean bottom
  • Benthos can be Sessile organisms (permanently attached; not freely moving)that are attached like barnicles and seafans.
  • Divided into:                                                   Epifauna:animals like crabs that live on the sea floor.                                                      Epiflora : Plants like sea grasses that live on the sea floor.                                                 Infauna: oraganisms that live partly or completely buried in the sea floor                  
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