The world’s oceans play a crucial role in sustaining life on our planet. Not only do they provide a habitat for countless species, but they also contribute significantly to the amount of oxygen in the atmosphere.
According to researchers, the oceans are responsible for producing over half of the oxygen produced in the world.
Why are the oceans producing oxygen?
Photosynthesis is the primary process responsible for oxygen production in the oceans. This process occurs when tiny plants called phytoplankton convert carbon dioxide and sunlight into energy.
What are phytoplankton?
Phytoplankton are tiny, photosynthetic organisms that are found in the Earth’s oceans, lakes, and rivers.
Phytoplankton are single-celled or colonial organisms that are typically less than 0.02 inches (0.5 millimeters) in size. They are capable of photosynthesis, which is the process of converting light energy into chemical energy that can be used by the cell.
There are many different types of phytoplankton, each with their own unique characteristics and ecological roles. Some common types of phytoplankton include diatoms, dinoflagellates, and cyanobacteria.
How many plankton are there in the oceans?
According to researchers with MIT, there are a “billion billion billion phytoplankton in the world’s ocean.”
How phytoplankton contribute oxygen
As they photosynthesize, phytoplankton release oxygen into the water. This oxygen then diffuses into the atmosphere, contributing to the world’s oxygen supply.
Other sources of ocean oxygen
While phytoplankton is the main source of the ocean’s oxygen production, other marine organisms such as seaweed and algae also contribute to oxygen production through photosynthesis.
What affects the ability of oceans to produce oxygen?
The amount of oxygen produced by the oceans varies depending on several factors.
Ocean water temperature
One of the most significant factors is the temperature of the water. Colder water holds more dissolved oxygen, which means that areas with colder water tend to have higher oxygen concentrations.
Conversely, warmer water holds less dissolved oxygen, which can lead to areas of low oxygen known as hypoxic zones.
Nutrient availability in the oceans
Another factor that can affect oxygen production in the oceans is nutrient availability.
Phytoplankton require certain nutrients, such as nitrogen and phosphorus, to grow and photosynthesize. If these nutrients are in short supply, phytoplankton growth and oxygen production can be limited.
On the other end of the spectrum, excessive nutrient input, often caused by agricultural runoff or wastewater discharge, can lead to algal blooms and oxygen depletion in certain areas (which can lead to dead zones).
Cyanobacteria, also known as blue-green algae, are a type of phytoplankton. Cyanobacteria are able to fix atmospheric nitrogen, which means they can convert nitrogen gas into a form that is usable by other organisms.
Cyanobacteria can form large blooms, which can have harmful effects on aquatic ecosystems.
Increase in human activities
As carbon dioxide levels increase, the oceans absorb more of this gas, which can lead to ocean acidification. This process can reduce the ability of phytoplankton to photosynthesize, which in turn reduces the amount of oxygen produced by the oceans.
The oceans help to regulate the Earth’s climate
In addition to producing oxygen, the oceans also play a critical role in regulating the Earth’s climate.
The oceans act as a massive heat sink, absorbing and storing large amounts of heat from the sun. This heat is then transported by ocean currents, which can have a significant impact on regional and global weather patterns.
The world’s oceans are threatened
Despite their importance, the oceans are facing numerous threats from human activities.
Climate change, overfishing, pollution from such sources as plastic waste, runoff, and sewage, and habitat destruction are just a few of the factors that are impacting the health of our oceans. These threats not only impact marine ecosystems but can also have far-reaching consequences for the world’s planetary health.
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Dutkiewicz, S., & Krol, A. (2022, March 14). Phytoplankton. MIT Climate Portal. https://climate.mit.edu/explainers/phytoplankton
Evidence points to widespread loss of ocean oxygen by 2030s. (n.d.). NSF – National Science Foundation. https://www.nsf.gov/news/news_summ.jsp?cntn_id=138396
How much oxygen comes from the ocean? (23, February 1). NOAA’s National Ocean Service. https://oceanservice.noaa.gov/facts/ocean-oxygen.html