Which organism is associated with fast nutrient cycling?

• A. Fungi
• B. Bacteria
• C. Algae
• D. Nematodes

Answer: (B)

Microorganisms drive nutrient cycling, converting organic matter into nutrients plants can use. Bacteria are the ones most closely tied to fast turnover because they reproduce quickly and have versatile metabolisms that mineralize a wide range of substrates. This allows rapid breakdown of organic matter and quick release of inorganic forms like ammonium and nitrate that plants uptake. Fungi excel at decomposing tough plant compounds (like lignin) but their mineralization tends to be slower, contributing to longer-term nutrient release. Algae contribute mainly to primary production in moist environments rather than speeding mineralization of existing soil organic matter, so they aren’t the drivers of rapid cycling. Nematodes affect nutrient cycling indirectly by grazing on microbes and organic matter, but the fastest turnover is driven by bacteria.