1. Biological Oceanography:
Factors Affecting Life and
Ocean Zones

2. Factors Affecting Life:
Light
Dissolved Nutrients
Temperature
Salinity
Dissolved Gases pH
Pressure

3. Light
Needed for photosynthesis. Must occur in the first few 100 m of ocean.
Also trigger breeding some species.

5. 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

6. Dissolved Nutrients

7. Temperature
The mixed layer is near the surface where the temperature is roughly that of surface water.
In the thermocline, the temperature decreases rapidly from the mixed layer temperature to the much colder deep water temperature.
The mixed layer and the deep water layer are relatively uniform in temperature, while the thermocline represents the transition zone between the two.

8. Temperature Cold Blooded: Warm Blooded:
Changes in temperature will directly affect metabolic rate.
Warm Blooded:
Have blubber that acts as insulation.

9. Salinity Salt content in ocean directly effects buoyancy of organism.
Species have adapted physical features to combat this problem.
Eg. Fish – Swim Bladder
Interior salinity of most marine life is equal to ocean’s salinity.

10. 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.

11. pH Pressure Pure Water = 7 Seawater = 8
Increases drastically with depth.
-Sea Level: 14.7 psi
-Under 33 feet: 30 psi
-Under one mile: psi

12. Ocean Zones by Light

13. 1. Photic Zone 2. Disphotic Zone 3. Aphotic Zone 0-200m
sunlit layer at the ocean’s surface
upper part of photic zone is where photosynthesis occur
2. Disphotic Zone
200 – 1000m
where animals can see but not enough light for photosynthesis
3. Aphotic Zone
1000m and below
largest region, no light

14. Classification by Light:

16. Ocean Zones by Surface Location
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 that is not near the coast

18. Ocean Zones by Depth
Pelagic = Belonging to the upper layers of the open sea.
Benthic = relating to the ocean bottom, living in or on the bottom of a body of water

19. Pelagic zone
Is subdivided into the epipelagic, mesopelagic, and bathypelagic zones.
1. Epipelagic zone receives enough sunlight to support photosynthesis.
2. Mesopelagic zone, where only small amounts of light penetrate
3.Bathypelagic zone into which no light penetrates.

20. 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 shelf
3) Bathyal Zone- seabed on the slopes
4) Hadal Zone or Abyssal Zone - deepest sea bed, trenches and floors

21. OCEAN ZONES