2.04 - ocean zones & factors of life

7/28/2019 2.04 - Ocean Zones & Factors of Life

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Biological Oceanography:

Factors AffectingLife and

Ocean Zones


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Factors Affecting Life:

Light

Dissolved Nutrients

Temperature Salinity

Dissolved Gases

pH Pressure


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Light

Needed for

photosynthesis. Must

occur in the first few

100 m of ocean.

Also trigger breeding

some species.


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Classification by Light:


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Dissolved Nutrients

Nutrients are substances that provide

nourishment and growth.

Required for production of organic (carbon

based) matter.

Problems: Phosphorous Loading detergents

Nutrient Loading in Halifax Harbour


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Dissolved Nutrients


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Temperature

The mixed layer is near the surfacewhere the temperature is roughlythat of surface water.

In the thermocline, the temperaturedecreases rapidly from the mixedlayer temperature to the muchcolder deep water temperature.

The mixed layer and the deepwater layer are relatively uniform intemperature, while the thermoclinerepresents the transition zone

between the two.


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Temperature

Cold Blooded:

Changes in temperature will directly affect

metabolic rate.

Warm Blooded:

Have blubber that acts as insulation.


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Salinity

Salt content in ocean directly effectsbuoyancy of organism.

Species have adapted physical features tocombat this problem.

Eg. Fish Swim Bladder

Interior salinity of most marine life is equal

to oceans salinity.


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Dissolved Gases

CO2 and O2 are needed to stay alive in the

ocean.

O2

does not dissolve easily in ocean.

100 X more gaseous oxygen in air than

ocean.

CO2 dissolves more easily in ocean.

60 X more carbon dioxide in ocean than air.


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Pressure

Pure Water =

7

Seawater = 8

Increases drastically with depth.

-Sea Level: 14.7 psi

-Under 33 feet: 30 psi

-Under one mile: 2 333 psi

pH


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Ocean Zones by Light


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1. Photic Zone 0-200m

sunlit layer at the oceans surface

upper part of photic zone is where photosynthesisoccur

2. Disphotic Zone 200 1000m

where animals can see but not enough light forphotosynthesis

3. Aphotic Zone 1000m and below

largest region, no light


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Ocean Zones by

Surface Location

1. Neritic zone

spans from the low-tide line to the edge

of the continental shelf in oceans

near coast

2.Oceanic zone

is the part of the open sea or ocean thatis not near the coast


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Ocean Zones by Depth

1. Pelagic = Belonging to the upper layers

of the open sea.

2. Benthic = relating to the ocean bottom,

living in or on the bottom of a body ofwater


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Pelagic zone

1. Photic zone receives

enough sunlight to support

photosynthesis.2. Disphotic zone, where only

small amounts of light

penetrate

3.Aphotic zone into which no

light penetrates.

Is subdivided into


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Sub-divisions of the Bottom Benthic Zone

1)Littoral Zone The shallow water area between high

and low tides.

2) Sublittoral Zone - Ocean bottom near shore and out

to edge of continental shelf3) Bathyal Zone- seabed on the slopes

4) Hadal Zone or Abyssal Zone - deepest sea bed,

trenches and floors

Marine Zonation


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Marine Zonation

Neritic Zone Oceanic ZoneLittoral Zone

Photic

Zone

Aphotic

Zone

Benthic Zone

Benthic Zone

The Benthic Zone includes the seafloor

and immediate substratum.

The Pelagic Zone is all the other open

waters of the ocean.

disphoticZone

Hadal Zone or Abyssal Zone

2.04 - ocean zones & factors of life

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