Diatoms & Diatomaceous Earth — NEET Biology
✅ Asked in NEET 2018Which of the following organisms are known as chief producers in the oceans? NEET 2018
Which of the following organisms are known as chief producers in the oceans? NEET 2018
Select the wrong statement. NEET 2016
Answer & NCERT explanation
Correct answer: C — Diatoms
Diatoms are the chief producers in oceans as they contribute to about 25% of global primary productivity through photosynthesis. Their siliceous cell walls and massive numbers make them the dominant phytoplankton. While dinoflagellates and cyanobacteria also photosynthesize, diatoms are the major contributors.
Read more NCERT concept on the PYQ
This group includes diatoms and golden algae (desmids). They are found in fresh water as well as in marine environments. They are microscopic and float passively in water currents (plankton). Most of them are photosynthetic. In diatoms the cell walls form two thin overlapping shells, which fit together as in a soap box. The walls are embedded with silica and thus the walls are indestructible. Thus, diatoms have left behind large amount of cell wall deposits in their habitat; this accumulation over billions of years is referred to as 'diatomaceous earth'. Being gritty this soil is used in polishing, filtration of oils and syrups. Diatoms are the chief 'producers' in the oceans.
NTA tests diatoms as the primary producers in marine ecosystems with unique silica-embedded cell walls. Students often confuse diatoms with other algae or forget that their indestructible walls accumulate as diatomaceous earth over geological time. Key trap: mistaking diatoms for dinoflagellates or thinking their cell walls are made of cellulose—they're actually silica-based, making them gritty and useful for polishing and filtration. Remember: diatoms are unicellular, photosynthetic plankton found in both fresh and marine water, and their massive fossil deposits (diatomaceous earth) are a signature feature tested for understanding ecological and commercial significance.
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