The Ocean is a massive system that controls rainfall, droughts, and the Earth’s climate. It holds 97% of the world’s water and helps to keep the carbon cycle balanced by absorbing a third of the planet’s CO2 emissions. It’s also home to more than 226,000 species of living things, from microscopic plankton to huge cetaceans like blue whales.
The ocean is a dynamic natural environment that has served the planet for eons. Its natural wonders are a source of inspiration and recreation, while also providing crucial resources for billions of people. The ocean is an integral part of the global economy, with more than one in six jobs involving marine-related activities.
A lot of energy and information travels through the ocean every day. This energy comes from wind, waves, and tides.
Waves are formed when air molecules are pushed by a current of wind across the surface of the ocean. The friction between the air molecules and the water molecules causes energy to transfer from the wind to the water, causing the water to move up and down in a wave.
Swells are rolling waves that travel long distances through the ocean, usually caused by distant storms. They can be smooth or choppy, and they are typically larger than wind waves.
The surface of the ocean is made of sand, while the deepest parts are composed of thicker rock and minerals. These materials help to hold the ocean’s water in place, keeping it from eroding away.
Density, Temperature and Salinity Control the Movement of Water
The density of water determines how it falls and rises in the ocean. The density of water varies throughout the ocean, with colder and saltier water becoming more dense as it moves deeper into the ocean. This density affects the way water moves from place to place and how it is influenced by other planetary processes such as surface currents.
Heat Transport and Circulation Shape the Ocean’s Weather
The ocean acts as a thermal ‘flywheel’ for the Earth’s climate system. This means that ocean temperature variations influence the weather on time scales from tens to hundreds of years.
In contrast, the ebb and flow of the ocean’s surface currents affects the weather on shorter timescales. In fact, the wind driven surface currents, called El Nio and La Nia cycles, play a major role in regulating global temperatures, bringing warm water to the equator and cool water to the poles.
Ocean currents are driven by surface winds and by the rotation of the Earth. They vary from region to region and change with plate tectonics, post-glacial rebound, and sea level rise.
Wind-driven surface currents are confined to the top hundreds of meters of the ocean, while ocean currents moving down into the deep waters are driven by the thermohaline circulation (AMOC, Atlantic meridional overturning circulation). These currents circulate water around the globe and take oxygen, nutrients and heat from the surface to deep layers of the ocean.