Q. Consider the following kinds of organisms :
1. Copepods
2. Cyanobacteria
3. Diatoms
4. Foraminifera
Which of the above are primary producers in the food chains of oceans?

[A] 1 and 2

[B] 2 and 3

[C] 3 and 4

[D] 1 and 4

Answer: B

Why this question:  

  • Recently (November 2020), scientists from the Central Marine Fisheries Research Institute (CMFRI), Mangaluru have reported that sea sparkle in the Karnataka coast has displaced microscopic algae called diatoms, which form the basis of the marine food chain. 
  • Also, an important static topic 

Ans) b 

Exp) Option b is correct. 

Primary producersare the organisms who synthesis their own food using photosynthesis or chemosynthesis.   

Option 1 is incorrect. Copepodsare a group of smallcrustaceansfound in nearly everyfreshwaterand saltwaterhabitat. They are major primary consumers in the World Ocean. Copepods are generally herbivores, feeding only on plant plankton which they filter from the water. 


Option 2 is correct. Cyanobacteria, also calledblue-green algae, are microscopic organisms found naturally in all types of water. These organisms are primary producers who use sunlight to make their own food. 

organism 2


Option 3 is correct. Diatoms are photosynthesising algae. They are found in almost every aquatic environment including fresh and marine waters. They are primary producer in oceanic food chain. 

organism 3

Option 4 is incorrect. Foraminifera are single-celled organisms that are found in most marine environments. They are characterized by streaming granular ectoplasm for catching food. Foraminifera are heterotrophic organisms which consumes smaller organisms and organic matter. 

organism 4

 Source:  Seasonal changes in the abundance and biomass of copepods in the south-eastern Baltic Sea in 2010 and 2011 – PubMed (nih.gov) 

Diatoms (ucl.ac.uk) 



Subject) Environment