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Ocean Water and Ocean Life. Chapter 15. 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. Where did the salt come from??.
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Ocean Water and Ocean Life Chapter 15
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.
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
Processes that Affect Salinity • Less salty • Precipitation • Runoff • Melting ice • More salty • Evaporation • Formation of ice
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.
Density • Mass per volume unit • Mass ÷ Volume • Affects water’s vertical position. • Factors that affect density: • Salinity • Temperature
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
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
Marine Life Zone Factors • Availability of sunlight. • Distance from shore • Water depth
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
Distance from shore • Intertidal zones: • 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.
Depth of Ocean • Pelagic 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.
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.
Factors that Affect a Region’s Photosynthetic Productivity • Availability of nutrients • Amount of solar radiation/sunlight.
Trophic Levels • A trophic level is a nourishment level in a food chain.
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