UPSC Prelims 2021 question on Primary Producers Oceans

Statement by statement

Statement 1 – INCORRECT: Copepods are a group of small crustaceans found in nearly every freshwater and saltwater habitat. They are major secondary producers in the World Ocean, representing an important link between phytoplankton, microzooplankton and higher trophic levels such as fish. Hence, option 1 is not correct.

Statement 2 – CORRECT: Cyanobacteria, also called blue-green algae, are microscopic organisms found naturally in all types of water. They are important primary producers and form a part of the phytoplankton. They may also form biofilms and mats (benthic cyanobacteria). Hence option 2 is correct.

Statement 3 – CORRECT: Diatoms are photosynthesising algae having a siliceous skeleton (frustule), found in almost every aquatic environment including fresh and marine waters. Diatoms are one of the major primary producers in the ocean, responsible annually for ~20% of photosynthetically fixed CO2 on Earth. Hence option 3 is correct.

Statement 4 – INCORRECT: Foraminifera are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses. Hence, option 4 is not correct.