part 4: ocean life zones 1. factors that affect life in the ocean 1. amount of sunlight 2....

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Earth’s OceansPart 4: Ocean Life Zones

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Factors that Affect Life in the Ocean1. Amount of sunlight2. Temperature of the water3. Water pressure

How does depth affect each of these?

Where would you expect to find the greatest abundance of organisms?

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Three Major Groups of OrganismsGrouped according

to their habits and where in the water they live

1. Plankton - floaters2. Nekton -

swimmers3. Benthos – bottom

dwellers

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PlanktonFloat at or near the

surface (up to 200 m deep in open ocean)

Plankton comes from the Greek word planktos that means drifting

Many are microscopic

Foundation of the ocean food web

Whale shark eating planktonhttp://commons.wikimedia.org/wiki/File:Whale_shark_eating_plankton.JPG

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PlanktonPhytoplankton,

primarily diatoms and dinoflagellates along with brown algae and cyanobacteria, use photosynthesis to make food.

Source of food for zooplankton

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PlanktonZooplankton

includes animal-like protists (radiolarians, forminiferans, ciliates and zooflagellates), jellyfish, siphonophores such as the Portuguese man-of-war, and copepods and krill (two types of crustaceans)

KrillPhoto credit: Jamie Hall, NOAACopepod

photo by Uwe Kils

Model of a radiolarian atthe Smithsonian Museum

http://www.flickr.com/photos/23165290@N00/7282108674Photo by Hofikai

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NektonAll the organisms that

swim freely in the ocean, independent of current

Live in shallow or deep water

Three main types:Cordates - bony fish,

whales, sharks, turtles, snakes, eels, porpoises, dolphins and seals

Molluscan – octopus and squid

Arthropods - shrimp

Video of nekton in the depths of the ocean:http://ocean.si.edu/ocean-videos/sea-creatures-deep-video-national-geographic-and-census-marine-life

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Photo by Irvin Calicut A young loggerhead sea turtle

Great White Shark

Common OctopusPhoto by Albert KokBottlenose Dolphin

A Caridean Shrimp- moves primarily by swimming

Nekton

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BenthosOrganisms that live

on the ocean floorIncludes: Plants - seagrass

Protists – brown, red, and green algae (seaweed)

Many invertebrate animals – sea stars, sea anemones, sponges, sea urchins, oysters, clams, crabs, sponges, coral, etc.

Sally Lightfoot CrabPhoto by Peter Wilton

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Major Life ZonesThree major environments or life zones:

IntertidalNeritic Open-Ocean

Photosynthetic ZoneBathyalAbyssalHadal

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Intertidal ZoneThe region between

high tide and low tideMost changeable zoneVaries back and forth

from dry to under water twice a day

Organisms must also withstand the affects of waves breaking on the shore. Photo Credit: Eric Guinther

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Intertidal ZoneMany organisms attach

themselves to rocks so as to avoid being washed out to sea.

Others burrow into the wet sand

Starfish, barnacles, anemones, seaweed, sea urchins, clams, mussels, hermit crabs, etc. live here.

A beautiful array of starfish , sea urchins and mussel shells in the

rocky intertidal zone of Kachemak Bay.

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Neritic ZoneFrom low-tide line to

edge of continental shelf, down to about 200 meters

Also called coastal waters

Plenty of sunlight for photosynthesis

Plankton, nekton, and benthos all found here

Richest life zone in the ocean

A close-up of a small mass of sargassum weed. The numerous small round spheres are floats filled with carbon dioxide. These provide buoyancy to the algae.

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Open-Ocean ZonesPhotosynthetic Zone – Extends from the ocean surface to

approximately 200mSunlight penetrates the entire zonePlankton and nekton live in this zone

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Open-Ocean ZonesBathyal Zone: Begins at continental

slope and continues to depths of about 2,000 meters

Water temperature about 4°C

Little if any light, so no photosynthesis

Many forms of nekton live here including whales, squids, and octopuses

Benthos organisms also live here, including sponges and sea stars

Great biodiversity in this zone

Sperm WhalesPhoto credit:  Réunion Underwater Photography

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Open-Ocean ZonesAbyssal Zone:2,000-6,000 metersNo sunlightGreat pressureTemperature 2-4°CCreatures that live

here may be blind or bioluminescent

Giant SquidPhoto: 

NTNU Museum of Natural history and

Archeaology

Skeleton of a Glass Sponge

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Open-Ocean ZonesHadal Zone:Very deepest parts of

the ocean, below the abyssal zone

Totally darkImmense pressureCreatures removed

from this zone will die in the lower-pressure areas above. 

The most common creatures found here include jellyfish, viperfish, tube worms, sea cucumbers and deep sea angler fish.

Video: http://www.telegraph.co.uk/earth/earthvideo/9168817/James-Camerons-first-footage-from-the-deep.html