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Ocean Water and Ocean Life

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1 Ocean Water and Ocean Life
Ch 15 Ocean Water and Ocean Life

2 Composition of Seawater
Salinity total amount of solid material dissolved in water Expressed in parts per thousand Mostly sodium chloride Sources of Sea Salt Chemical weathering of rocks on the continents The Earth’s Interior

3 Processes Affecting Salinity
Decrease Salinity Precipitation Sea ice melting Icebergs melting Runoff from land Increase Salinity Evaporation Formation of sea ice D

4 Ocean Temperature Variation
Surface water temperature varies with the amount of solar radiation received Thermocline is the layer of ocean water between about 300 meters and 1000 meters where there is a rapid change of temperature with depth

5 Ocean Density Variation
Density is defined as mass per unit volume Seawater density is influenced by two main factors: Salinity temperature

6 Ocean Density Variation
Pycnocline is the layer of ocean water between about 300 meters and 1000 meters where there is a rapid change of density with depth

7 Ocean Layering 3 main zones – surface zone, transition zone, and deep zone Surface Zone Shallow (300 to 450 meters) Zone of mixing Sun-warmed zone

8 Ocean Layering Transition Zone Deep Zone
Between surface layer and deep zone Thermocline and pycnocline Deep Zone Sunlight never reaches this zone Temperatures are just a few degrees above freezing Constant high-density water

9 Classification of Marine Organisms
Marine organisms can be classified according to where they live and how they move. Plankton all organisms—algae(Phytoplankton), animals(Zooplankton), and bacteria—that drift with ocean currents. Nekton animals capable of moving independently of the ocean currents (swimming, etc) Benthos organisms living on or in the ocean bottom

10 Marine Life Zones Three factors are used to divide the ocean into distinct marine life zones: the availability of sunlight the distance from shore the water depth. Availability of Sunlight The photic zone is the upper part of the ocean into which sunlight penetrates.

11 Distance from Shore Intertidal Zone Neritic Zone Oceanic Zone
strip of land where the land and ocean meet and overlap Neritic Zone extends from the low-tide line out to the shelf break Oceanic Zone beyond the continental shelf

12 Hydrothermal Vents Zone where seawater seeps into the ocean floor through cracks in the crust. water temperatures of 100oC or higher support communities of organisms found nowhere else in the world

13 Ocean Productivity Primary productivity is the production of organic compounds from inorganic substances through photosynthesis or chemosynthesis

14 Primary Productivity Polar Oceans Tropical Oceans Temperate Oceans
Photosynthesis limited by low solar energy Tropical Oceans Productivity limited by lack of nutrients Temperate Oceans Sunlight and nutrient supply controls productivity

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