Ocean Currents and Their Global Significance

Introduction: The Rubber Duck Incident

• 1992 Cargo Ship Incident: A storm caused shipping containers with 28,000 rubber ducks and toys to spill into the North Pacific Ocean.
• Educational Impact: The paths of these ducks helped researchers understand ocean currents.

Ocean Currents Overview

• Driving Forces:
  • Wind
  • Tides
  • Water density changes
  • Earth's rotation
• Influences: Ocean floor topography and shoreline modify current speed and direction.

Types of Ocean Currents

• Surface Currents:
  • Affect top 10% of ocean water.
  • Near shore: Driven by wind and tides.
  • Open ocean: Primarily driven by wind.
  • Influence of wind extends to 400 meters deep.
• Deep Ocean Currents:
  • Affect bottom 90% of ocean water.
  • Driven primarily by seawater density changes.

Surface Currents

• Formation of Gyres: Large loops influenced by Earth's rotation (Coriolis Effect).
  • Northern Hemisphere: Clockwise
  • Southern Hemisphere: Counter-clockwise
• Earth's Rotation Impact:
  • Causes deflection of moving air and water, forming loop-like wind patterns.
  • Coriolis Effect: Winds push oceans into rotating gyres.
• Heat Redistribution: Oceans help in global heat distribution due to water's heat retention.

Deep Ocean Currents

• Density-driven Movement: Colder, saltier water sinks, forming thermohaline circulation.
• Thermohaline Circulation:
  • Sets vertical currents.
  • Combines with surface currents to form the Global Conveyor Belt.

The Global Conveyor Belt

• Characteristics:
  • Longest current globally.
  • Moves nutrients from ocean depths to surface, supporting food chains.
  • Moves slowly - a full trip can take a thousand years.
• Impact of Rising Sea Temperatures:
  • Potential slowing of the conveyor belt.
  • Forecasts suggest potential disruption in Atlantic weather systems.

Conclusion

• Need for Continued Research: To better predict and prepare for changes in ocean currents and their global impacts.