Earth's Ocean Overview Quiz

Earth's Ocean: A Summary

• Earth's ocean covers approximately 70% of the planet's surface, a defining feature.

• The ocean is central to the water cycle, with evaporation returning as precipitation, vital for freshwater.

• The ocean is a single interconnected system with various basins (North Pacific, South Pacific, North Atlantic, South Atlantic, Indian, Southern, Arctic).

• Ocean basins are diverse, including seafloors with islands, deeps, ridges, trenches, rift valleys, and plateaus, shaped by plate tectonics.

• The ocean floor is rich in lifeforms, impacting the marine ecosystems.

• The ocean absorbs a significant portion of atmospheric CO2 and methane, playing a crucial role in the carbon cycle.

• Phytoplankton, microscopic plants and bacteria, form the base of aquatic food webs. They consume CO2 and produce oxygen.

• The ocean absorbs most solar radiation, moderating global temperatures and influencing weather patterns.

• Ocean-atmosphere interactions result in weather phenomena like El Niño Southern Oscillation and La Niña, hurricanes and cyclones.

Ocean Water Properties and Composition

• Ocean water is salty, with a slightly lower freezing point and higher density than freshwater.

• Ocean water has high electrical conductivity and a slightly basic pH.

• Ocean water is a buffer solution, maintaining pH balance critical for marine life and absorbing atmospheric CO2.

• A change in ocean pH can impact CO2 absorption and potentially make the ocean a CO2 source.

• Ocean water is a complex system of organic and inorganic substances, with salinity varying in different locations impacting currents.

The Ocean and Human Interdependence

• The ocean affects all human lives—providing freshwater as rain, oxygen and moderating climate.

• We rely on the ocean for food, medicine, resources, jobs, transportation, national security, inspiration, and recreation.

• Human activities affect ocean health, causing pollution, ocean acidification, and physical modifications.

• These human activities impact marine organisms, leading to coral bleaching and decreased biological diversity.

• Coastal areas, home to much of the world's population, are vulnerable to natural hazards like tsunamis, hurricanes, and sea level changes.

Ocean Exploration and Understanding

• Less than 15% of the ocean has been explored, leaving vast areas for discoveries.

• Understanding ocean systems is vital for human survival.

• Oceanography is an interdisciplinary field relying on biologists, chemists, climatologists, computer programmers, engineers, geologists, meteorologists, physicists, animators, and illustrators.

• Exploration involves ships, research vessels, robots, subsea observatories, unmanned submersibles and satellites.