Central Idea: The ocean is a dynamic system that covers most of Earth's surface; its characteristics are unique and allow it to support a diverse number of organisms.

OCEAN FEATURES

• The ocean’s geological and physical properties affect the interactions among organisms .

• Important features of the ocean floor are the continental shelf, continental slope, continental rise, abyssal plain, and ocean trenches.
  • Most areas are covered with thick layers of sediments (e.g., sand, mud, rocks).
• The depth of the ocean varies.
  • Ocean trenches are very deep and the continental shelf is relatively shallow.

OCEAN WATER

• Ocean water is a complex mixture of gases, water, and dissolved solids.
  • Marine organisms are dependent on dissolved gases for survival
• Salinity is the measure of all salts dissolved in water.
  • The salinity of ocean water varies in some places, depending on rates of evaporation, the depth of the water, melting icebergs, and amount of runoff from nearby land

OCEAN MOTION

• Ocean currents, including the Gulf Stream, are caused by wind patterns and the differences in water due primarily to temperature differences.
• Ocean currents affect the mixing of ocean waters.
  • This can affect plant and animal populations.
  • Currents also affect navigation routes

OCEAN LIFE

• In oceans, both plants and floating organisms such as algae serve as producers within a food chain
• Organisms in the ocean environment are grouped according to their movement: floating organisms (e.g., plankton), swimming organisms, and organisms that are non-moving and adhere to surfaces on the ocean floor.
• These organisms play a role in ocean food chains.