Our Environment: Everything You Need to Know

Our Environment: Everything You Need to Know — page 7
Oceans The oceans keep the planet’s climate in balance They absorb and store the Sun’s heat and that heated water sets ocean currents in motion The currents move the heat around the planet like a giant conveyor belt Warm water from the tropics is transported to the poles on the surface of the ocean At the same time cold currents flow in deep water The ocean is home to tiny algae called phytoplankton that are invisible to the naked eye These microscopic algae are carried on the surface waters by the currents and they play an essential role Like green plants they act as small chemical factories Through photosynthesis they absorb much of the carbon dioxide from the atmosphere and release more than half of the oxygen we breathe