Oceanic Physical & Chemical Properties

Oceanic Physical & Chemical Properties

• Oceans cover 71% of the Earth's surface and are made up of one world ocean with 5 ocean basins.
• Oceans regulate the atmosphere’s chemical composition with 70% of the oxygen in the atmosphere coming from photosynthesis in the oceans.
• Oceans modify Earth’s climate and weather systems.
• Approximately half the world's population depends on oceans as the main source of food.

Light Penetration Zones

• Oceans are divided into three zones based on depth and light level.
• Euphotic (sunlight) zone: The zone where sunlight penetrates.
• Dysphotoic (twilight) zone: The zone where little light penetrates.
• Aphotic (midnight) zone: The zone where no sunlight penetrates.

Ocean Salinity

• Ocean salinity is the concentration of dissolved minerals in water.
• The salinity of seawater is approximately 35 parts per thousand (3.5% of seawater by weight are salts).
• Salinity is measured in Practical Salinity Units (PSU) which are equal to parts per thousand (ppt).
• Sources of salinity in ocean water include runoff from the land, openings in the seafloor and hydrothermal vents.

Ocean Salinity Variations

• Salinity varies with temperature, evaporation, precipitation, and freshwater input from rivers.
• Salinity is higher in areas with high evaporation rates.
• Salinity is lower in areas with high precipitation and freshwater input.
• The Arctic Ocean has lower salinity due to freshwater from melting ice and rivers, high precipitation, and low evaporation.

Ocean Acidity

• The average pH of ocean water is 8.16 which is alkaline.
• The oceans absorb atmospheric CO2 which creates carbonic acid (H2CO3), decreasing the pH of seawater.
• There has been a 30% increase in seawater acidity since the industrial revolution, approximately 200 years ago.

Oceanic Circulation

• Oceanic circulation is essential in sustaining global energy balance and exchanges heat between low and high latitudes.
• Ocean currents are driven by wind, density differences, Coriolis effect, tides, and the shape of ocean basins.

Surface Ocean Currents

• Currents help move warmer water towards the poles and cooler water (that has upwelled from below) towards the equator.
• Warm currents are usually found on the east coast of continents, while cold currents are found on the west coast.

Gyres

• Gyres are large circular currents that are driven by wind and the Coriolis effect.
• Major gyres include the North Pacific, South Pacific, North Atlantic, South Atlantic, and Indian Ocean gyres.
• Gyres rotate in a clockwise direction in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.

Upwelling Zones

• Upwelling zones are areas where deep, cold water rises to the surface.
• Upwelling zones are found on the west side of continents and are productive fishing areas.

Great Ocean Conveyer

• The Great Ocean Conveyer is also known as the Thermohaline Circulation and driven by density differences caused by temperature and salinity.

Antarctic and Arctic Circulation

• The Antarctic Circumpolar Current is the largest current in the world and flows eastward around Antarctica.
• The Arctic Ocean has complex circulation patterns with a strong influence from the Atlantic Ocean.

Explore the essential characteristics of oceans, including their physical and chemical properties, light penetration zones, and salinity. This quiz examines how oceans influence climate, weather, and sustain human life. Test your knowledge about the complexities of our world's oceans.