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?

1. 1 and 2
2. 2 and 3
3. 3 and 4
4. 1 and 4

Explanation

Copepods are incorrect

• Copepods are a class of small crustaceans that are widespread and naturally abundant in all aquatic ecosystems as a key link between primary producers and higher predators. They serve as major primary consumers in the World Ocean.

Cyanobacteria and Diatoms are correct

• Phytoplankton are the primary producers in the oceans. They include:
  • diatoms (unicellular algae),
  • coccolithophores (unicellular, eukaryotic protist),
  • Cyanobacteria (Bluegreen algae)– Synechococcus, Prochlorococcus, Nostoc, spirogyra etc.
  • Dinoflagellates (flagellated protists).

Foraminifera is incorrect

• Foraminifera are single-celled organisms present in most marine environments. As heterotrophic organisms, foraminifera consume smaller organisms and organic matter. Foraminifera are recorded as feeding chiefly upon bacteria, small diatoms, and nannoplankton in a wide variety of marine environments.

Answer: (b) 2 and 3; Difficulty Level: Easy