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

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Presentation on theme: "15. 2 Diversity of Ocean Life & 15.3 Oceanic Productivity."— Presentation transcript:

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

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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

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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

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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

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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)

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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

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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?


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