1. 15. 2 Diversity of Ocean Life & 15.3 Oceanic Productivity

2. Classification of Marine Organisms
Classified based on where they live & how they move
Plankton: floaters
Nekton: swimmers
Benthos: bottom dwellers

3. Plankton Include all organisms – algae, animals, & bacteria
Move with the ocean currents
Can swim
Algae that undergoes photosynthesis = phytoplankton
Microscopic
Animal plankton = zooplankton

5. Nekton
Include all animals capable of moving independently of the ocean currents by swimming
Can migrate long distance
Include most adult fish, squid, marine mammals, & marine reptiles

7. Benthos Describes organisms living on or in the ocean bottom
Shallow coastal ocean floor contains a wide variety of physical conditions & nutrient levels
Deeper parts = photosynthesis can not occur
They feed on each other and whatever falls from above

9. Marine Life Zones 3 factors used to divide the ocean into life zones:
Availability of sunlight
Distance from shore
Water depth

10. Availability of Sunlight
Photic zone = sunlight
Euphotic zone = portion of the photic zone near the surface where photosynthesis can occur (up to 100 m deep)
Aphotic zone = no sunlight

11. Distance from Shore Subdivided based on distance
Intertidal Zone = land & ocean meet & overlap
Harsh living conditions due to crashing waves, drying out time to time, quick temperature changes, salinity, & oxygen concentrations
Adapted

12. Neritic Zone = covers gently sloping continental shelf
Narrow – hundreds of km from shore
Shallow enough for sunlight to reach ocean floor = photic zone
90 % of the worlds commercial fisheries because it is so rich

13. Oceanic Zone = beyond continental shelf
Surface waters have lower nutrient concentrations because nutrients sink out of the photic zone to the deep ocean floor
Smaller populations than the more productive neritic zone

14. Water Depth Pelagic Zone = open ocean of any depth
Animals = swim or float freely
Photic area of the pelagic zone home to: phytoplankton, zooplankton, nekton
Aphotic area fo the pelagic zone home to: giant squid & other species that have adapted to deep waters

15. Benthic Zone = any sea – bottom surface (regardless of the distance from shore)
Mostly inhabited by benthos organisms
Abyssal Zone = subdivision of the benthic zone
Extreme pressure
Low temperatures
No sunlight
Little life forms

17. Hydrothermal Vents Along the oceanic ridges
Seawater seeps into the ocean floor through cracks in the crust
Becomes heated and saturated with minerals
Minerals precipitate out when it comes in contact with cold ocean water (black smoke color)

19. 15.3 oceanic Productivity

20. Primary Productivity
Production of organic compounds from inorganic substances through photosynthesis or chemosynthesis
Photosynthesis – use of light energy to convert water and CO2 into glucose molecules
Chemosynthesis – process by which certain microorganisms create organic molecules from inorganic nutrients using chemical energy
2 factors influence a area’s photosynthetic productivity:
Available nutrients
Amount of solar radiation

21. Productivity in Polar Oceans
Density & temperature change very little with depth in polar regions
Summer = melting ice = lower salinity
Availability of solar energy is what limits photosynthesis productivity in polar areas

22. Productivity in Tropical Oceans
Productivity is low & limited bc of lack of nutrients
The sun is more directly overhead > light penetrates deeper into the tropical ocean than in temperate and polar waters
Solar energy is available year around
Permanent therocline prevents mixing btw surface waters and nutrient rich deeper waters

23. Productivity in Temperate Oceans
Found at mid-latitudes
Winter
Spring
Summer
Combination of these 2 limiting factors to control productivity
Sunlight
Nutrient supply

24. Oceanic Feeding Relationships
Tropic Levels
Feeding levels
Zooplankton = herbivores (eat algae)
Herbivores eaten by Carnivores
Transfer efficiency
The transfer of energy btw tropic levels is inefficient
Food Chain / Food Web
Sequence of organisms where energy is transferred starting with a primary producer
Feeding relationships = Food Web

26. Review Questions
What factors influence a region’s photosynthetic productivity?
Compare/Contrast Food Web & Food Chain
Compare/Contrast Photosynthesis & Chemosynthesis
How are marine organisms classified?
Why is the neritic zone rich in life?