Summary of Oceans and Coasts

Overview of Oceans and Coasts

• Oceans cover 70.8% of Earth; vital for life and climate regulation.

• Oceanography expands understanding of ocean water, movements, and life.

• Key studies: HMS Challenger, Deep Sea Drilling Project, Integrated Ocean Drilling Program.

Ocean Structures and Landscapes

• Oceanic and continental lithospheres differ in buoyancy; ocean basins collect water.

• Sea floor features: continental shelf, slope, rise, abyssal plain.

• Continental margins can be active (near tectonic boundaries) or passive (far from boundaries).

• Submarine canyons, mid-ocean ridges, oceanic trenches reflect tectonic activity.

Ocean Water Properties

• Marine salinity averages 3.5%; influenced by evaporation, rainfall, and river input.

• Temperature varies with latitude; deeper waters are nearly freezing.

Currents and Tides

• Ocean currents influenced by wind (surface) and temperature/salinity (vertical).

• Tides arise from lunar and solar gravitational forces; vary by alignment.

Waves and Beach Dynamics

• Waves form due to wind friction; height and period depend on wind conditions.

• Longshore currents transport sediment along beaches; rip currents can be dangerous.

Coastal Features

• Variability includes beaches, barrier islands, wetlands, rocky coasts, estuaries, and fjords.

• Beaches develop seasonal profiles; sediment composition reflects local geology.

Coastal Variability and Problems

• Coastlines impacted by tectonics, eustatic sea-level changes, and climate.

• Coastal challenges: sea-level rise, beach erosion, pollution, and impacts of human development.

• Coastal management strategies include seawalls, artificial barriers, but may have unintended consequences.