‘Trees’ is what most of us will be tempted to say. That may be true, but not the whole truth. You will be surprised to know that more than 50 percent of the earth’s oxygen comes from the oceans. Before we get into the details, let’s take a quick look at the current composition of various gases in the atmosphere.
The atmosphere of Earth, most commonly referred to as air, comprises of two primary gases. These are nitrogen (78.09%) and oxygen (20.95%). Argon is 0.93% and carbon dioxide is 0.04%. There are other gases as well, but in very minute quantities.
How oceans generate oxygen?
We are often told to plant trees and that may be right. But, we should also be told to protect the oceans. That’s because oceans are the primary source of oxygen on the planet. If you are wondering how, the process is the same as that of trees and plants. The process is called photosynthesis, which is used by trees, plants and algae to convert sunlight into energy. One of the by-products of this process is oxygen and we, along with all other animals that breathe oxygen, should be thankful for it.
But where are trees and plants in oceans? You are right, but oceans have very tiny plants called phytoplankton. These are microscopic and form the base of aquatic food chain. These are lighter and can be found floating in upper parts of oceans. They absorb sunlight to carry out the process of photosynthesis. With more than 70% of earth covered by oceans, it’s easy to imagine the volume of phytoplankton floating in the oceans.
The oxygen produced by these microscopic plants is much more than the amount produced by trees and plants on land. Earth’s land area is around 30% and only a small part of it is available for trees and plants. That’s why the amount of oxygen produced through oceans is much more than that produced by trees and plants.
Finding exact figures is not possible because it is very difficult to measure the amount of phytoplankton floating in oceans. One also has to understand that the amount of phytoplankton varies from region to region.
Another interesting fact about Earth’s atmosphere is that it was once completely devoid of oxygen. Before 2.4 billion years ago, earth’s atmosphere was mostly nitrogen and carbon dioxide. Around 2.4 billion years ago, the Great Oxidation Event (GOE) occurred, which significantly increased the oxygen level of earth. This event was primarily linked to growth of cyanobacteria, a type of bacteria that uses photosynthesis to generate energy. Without oxygen, multicellular organisms would have never developed on Earth.
Now that you know the primary sources of oxygen on earth, it’s important to take steps to protect all of these sources. Share the information with others, so that they too can contribute towards protecting the planet.