1. Ocean Water and Ocean Life
Chapter 15

2. Salinity The total amount of solid material dissolved in water.
Measured in Parts Per Thousand (ppt ‰)
Average Ocean Salinity = 35‰
Most of the salt in seawater is NaCl, or common table salt.

3. Where did the salt come from??
Chemical weathering and erosion of rocks and minerals.
Earth’s interior:
Gases emitted into the air by volcanoes throughout geologic history

4. Processes that Affect Salinity
Less salty
Precipitation
Runoff
Melting ice
More salty
Evaporation
Formation of ice

5. Temperature and Thermocline
Ocean temperature is highest at the surface.
Thermocline- the layer of ocean water where there is a rapid change of temperature with depth.
Creates a vertical barrier for ocean life.

6. Density Mass per volume unit Factors that affect density:
Mass ÷ Volume
Affects water’s vertical position.
Factors that affect density:
Salinity
Temperature

7. Ocean Layers
Mixed Zone –water is mixed by waves and circulation currents and tides
Transitional Zone –temperature falls abruptly
Deep Zone –Little to no sunlight. Density is the same as well as temperature.
Ocean Floor

8. Classification of Marine Organisms
Classified by where they live and how they move.
Plankton: float or drift with ocean currents.
Nekton: free swimmers found in all area of the ocean.
Benthos: Live on ocean floor

9. Marine Life Zone Factors
Availability of sunlight.
Distance from shore
Water depth

10. Photic vs. Aphotic zones
Photos=light
Photic Zone: upper part of the ocean where light can penetrate.
Euphotic: portion of the photic zone where there is enough light to support photosynthesis.
Aphotic Zone:
no sunlight
Deep ocean

11. Distance from shore Intertidal zones: Neritic Zone: Oceanic Zone-
Area where land and ocean meet and overlap.
Neritic Zone:
Seaward from the low-tide line to the continental shelf break.
Oceanic Zone-
Beyond the continental shelf.

12. Depth of Ocean Pelagic Zone Benthic zone Abyssal zone
Open ocean of any depth.
Benthic zone
Any sea-bottom surface at any distance from shore.
Abyssal zone
Deep area with high pressure zones, low temps and low oxygen levels.

13. Ocean Productivity
Primary Productivity is the production of organic compounds from inorganic substances .
Photosynthesis- uses light energy to convert water and carbon dioxide into glucose.
Chemosynthesis- uses chemical energy to create organic molecules from inorganic nutrients.

14. Factors that Affect a Region’s Photosynthetic Productivity
Availability of nutrients
Amount of solar radiation/sunlight.

15. Productivity in the Oceans
Productivity in Polar Oceans
Productivity in Tropical Oceans
Productivity in Temperate Oceans
High amounts of nutrients
Small amounts of nutrients
Winter: Low productivity. Days are short and sun angle is high
Small amounts of sunlight
High amounts of sunlight
Spring: Phytoplankton quickly depleted. Productivity is limited.
Summer: Strong thermocline develops so surface nutrients are not replaced.
Fall: Nutrients are near surface when waters are being mixed due to winds.

16. Trophic Levels A trophic level is a nourishment level in a food chain.
Tertiary Consumers:
Top of the pyramid
Carnivores or secondary consumers.
Consume the herbivores.
Herbivores or primary consumers.
Consume the producers
Producers/Autotrophs
Lowest level

17. Food Chain vs. Food Web
Food Chain: sequence of organisms through which energy is transferred, starting with the primary producer.
Food Web: group of interrelated food chains