Why Do Oceans Matter?

1. The oceans are Earth’s life support system.

50-70% of the oxygen we breathe is generated by our oceans. Phytoplankton, single-celled organisms that drift along the ocean’s surface, photosynthesize, using sunlight and carbon dioxide to create food, releasing oxygen as a byproduct. The ocean also regulates global climate and weather patterns, supports the vastest array of life on the planet, and provides the #1 source of protein for over 1 billion people worldwide.

2. More on Climate & Weather…

All of the weather we experience begins with interactions between our oceans and atmosphere. The majority of the heat that strikes Earth from the sun is absorbed by the surface layer of the ocean. Ocean currents then act as conveyor belts, transferring this heat throughout the globe. As warm water moves through currents, it evaporates, increasing the temperature and humidity of the air. This interaction causes rain and storms, which are carried by trade winds throughout the globe,  initiating the climate and weather patterns of the continents & playing a vital role in the water cycle.

3. Ocean Circulation

How it Works ~ Thermohaline Circulation is the flow of ocean water determined by differences in the density of seawater. It is vital to maintaining Earth’s habitable climate, and is one of many reasons why scientists fear the melting of Earth’s polar ice caps.

While winds cause currents to flow near the surface of the ocean (“surface currents”), Thermohaline Circulation occurs thousands of meters below in what are called “deep ocean currents,” & is driven by differences in water density. The density of seawater is dictated by differences in its temperature and salinity, (hence the name “Thermo”- “haline” circulation). Colder, saltier water sinks, and warmer, less-salty water rises towards the surface. This sinking, rising, and movement of water drives deep-ocean currents throughout the globe, affecting the entire Earth’s climate, weather, nutrient cycles. 

Why it Matters ~ As sea ice forms in Earth’s polar regions due to extremely cold water temperatures, large quantities of salt are left behind, increasing the salinity of the water. As its salinity increases, the water becomes denser, causing it to sink. This process of Thermohaline Circulation triggers the deep ocean currents that drive the global conveyor belt, Earth’s global system of ocean currents. The global conveyor belt cycles heat & nutrients throughout the planet, dictating Earth’s climate and weather patterns, and forming the foundation for marine food webs. 

As icecaps in Earth’s polar regions melt, the salinity of surrounding seawater changes… along with ocean currents, our global climate and weather, and important nutrient cycles.

Cool NASA animation demonstrating Thermohaline Circulation here.

4. Carbon Sink

Carbon sinks are natural systems that retain atmospheric carbon dioxide ~ & the ocean is a very important one. Absorbing enormous amounts of carbon dioxide from the atmosphere (through a physio-chemical process called “Air-sea gas exchange”, read about it here), the National Oceanic and Atmospheric Administration states that over the last 200 years, nearly half of anthropogenic CO2 has been absorbed by our oceans. While this helps buffer climate change by removing CO2 from the atmosphere, it’s changing the chemistry of our oceans. Read more from N.O.A.A. here.

5. Food, Economics, & Just About Everything Else

The ocean provides the #1 source of protein for over 1 billion people worldwide, and about half of the world’s population lives within a coastal zone. Marine ecotourism is a huge global industry, fueling the regional economies of many coastal communities, and currents support global trade and shipping. Our oceans also hold promising opportunities for the growth of renewable energy, through construction of offshore wind farms and other budding technology.

This post also includes information from the following literary source.

Starr, C., Evers, C. A., & Starr, L. (2016). Biology: today & tomorrow. Boston, MA: Cengage Learning.

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