Context: Recently, the National Centre for Polar and Ocean Research (NCPOR) has carried out the study of Coccolithophores (microscopic ancient marine algae) and found that there is a decrease in the concentration of oceanic calcium carbonate (CaCO3) in the southern Indian ocean.
About the study

• A study of microscopic ancient marine algae (Coccolithophores) led by the National Centre for Polar and Ocean Research (NCPOR) has found that there is a decrease in the concentration of oceanic calcium carbonate (CaCO3) in the Southern Indian Ocean.
• This decrease in CaCO3 is attributed to the increase in the concentration of another single-celled alga known as diatoms.
• This will affect the growth and skeleton structure of coccolithophores, with potential significance for the world ocean ecosystem.

About Coccolithophores

• Coccolithophores are single-celled algae living in the upper layers of the world’s oceans.
• They have been playing a key role in marine ecosystems and the global carbon cycle for millions of years.
• Coccolithophores calcify marine phytoplankton that produces up to 40 per cent of open ocean calcium carbonate are responsible for 20 per cent of the global net marine primary productivity.  
• Coccolithophores build exoskeletons from individual CaCO3 plates consisting of chalk and seashells building the tiny plates on their exterior.
• Though carbon dioxide is produced during the formation of these plates, coccolithophores help in removing it from the atmosphere and ocean by consuming it during photosynthesis.
• At equilibrium, coccolithophores absorb more carbon dioxide than they produce, which is beneficial for the ocean ecosystem.

Additional Facts

• Abundance and diversity enrichment of coccolithophores in the southern Indian Ocean is highly dependent on time and influenced by various environmental factors such as silicate concentrations, calcium carbonate concentration, diatom abundance, light intensity and availability of macro and possibly micronutrient concentrations.
• The study points to climate change as a major reason for the altered coccolithophore calcification rate which is important for bringing positive changes in the marine ecosystem and the global carbon cycle.