(Preliminary article: will be updated very soon)
As carbon sink
Phytoplankton and seaweeds release O2 in the water body keeping it aerobic in one hand and as Carbon sink by fixing CO2 on the other hand.
A comparison of the amount of carbon fixed by terrestrial plants with that of marine phytoplankton and seaweeds revealed that the total fixation by terrestrial plants (1010-2304 gCm-1yr-1 ) is far below the marine environment (2595-6960 gCm-1yr-1, combining phytoplankton = 455-1460 and seaweeds and coral reefs= 2140-5500 gCm-1yr-1.
Carbon dioxide in the atmosphere can dissolve in water, and the colder and more turbulent regions of the oceans tend to absorb carbon dioxide, while the warmer and less turbulent regions release it, carbon dioxide being less soluble in warm water than in cold water.
In the early 1990s, the oceans were thought to be a net carbon sink, with the North Atlantic Ocean accounting for 60 percent of the carbon dioxide absorbed by the world’s oceans, which amounted to about 2 Gt a year.
A thriving phytoplankton and seaweed population would tend to remove more carbon dioxide through photosynthesis than is returned through respiration by the entire community, and the ocean works as an effective carbon sink.
Cleanser of the atmosphere
We can imagine the world’s oceans as the heart, blood, kidney and liver of our planet, and in a way the lungs as well.
Ocean currents that pump vast quantities of water from the equator to the poles and then back again can be thought of as the circulatory system of the world.
The water movement dilutes and distributes any pollutants, transporting nutrients from the polar waters to the equatorial regions.
In 2010, the world’s first, comprehensive census of marine life was published. It showed that we know substantially less about life in the sea than we thought.
For example, in the 1950’s marine biologists predicted that there were about 100,000 microbes per litre of sea water. The 2010 census has shown that the number is greater than a billion.
The total weight of all the microbes in the ocean is estimated as equivalent to 280 billion elephants. That’s 40 elephants for every human on the planet.
These microbes act as the kidneys, liver and lungs of the planet by converting all the waste into useable molecules, which are then precipitated to the ocean floor, which in turn cleans and purifies the water.
Although not all microbes help to clean up the ocean, they are all essential for maintaining the sustainable food web that marine life inhabit.
Cooling of the earth
Phytoplankton affect our planet far more than their size suggests.
Phytoplankton influence the climate of the whole planet.
They are the most abundant form of life in the oceans, in both weight and numbers.
They absorb and scatter light, affect the levels of carbon dioxide in the atmosphere.
Phytoplankton, the single celled plants that perform more than half of the world’s photosynthetic activity, are sensitive to climate change. The phytoplankton, other algae and sea weeds release
O2 in the water body
It has been estimated that marine phytoplankton and seaweeds contribute about 80% O2 in the atmosphere and maintain O2 and N2 balance of the air and reduce global warming through CO2 fixation.
(This article is completely based on the Lecture sheet provided by respected Dr. Mohammad Azmal Hossain Bhuiyan, Professor, Department of Botany, University of Dhaka.
Some pictures and info have been added by the author. Any mistake, error, misinformation and other related things found in this article is only author’s to blame)