Question

What role do decomposers play in an ecosystem?

• A. They produce oxygen
• B. They break down dead organisms and recycle nutrients
• C. They provide energy to producers
• D. They regulate the temperature of the ecosystem

Hint:

\textbf{Decomposers} (e.g., bacteria, fungi) break down dead organic matter (detritus).
\textbf{Key Roles:}
Decomposition of dead plants, animals, and waste.
\textbf{Nutrient cycling:} Release essential nutrients (C, N, P, etc.) back into the ecosystem, making them available for producers.
They are vital for maintaining ecosystem health and productivity.
Producers produce oxygen. Producers use sunlight for energy.

Answer 1

The Correct Option is B

Decomposers are organisms (primarily bacteria and fungi) that play a crucial role in ecosystems by breaking down dead organic matter. Their role includes:
Decomposition of dead organisms and waste products: They feed on dead plants, dead animals, and animal waste products (detritus).
Nutrient cycling: As they break down complex organic compounds, they release simpler inorganic substances (nutrients like carbon, nitrogen, phosphorus, sulfur) back into the soil, water, and air. These nutrients then become available for uptake by producers (plants and algae), thus completing the nutrient cycle. This recycling of nutrients is essential for the continued productivity of ecosystems.
Formation of humus: In soil, decomposition contributes to the formation of humus, which improves soil structure and fertility. Let's evaluate the options:
(a) They produce oxygen: Oxygen is primarily produced by producers (plants, algae, cyanobacteria) through photosynthesis. Decomposers generally consume oxygen (aerobic decomposers) or operate in anaerobic conditions.
(b) They break down dead organisms and recycle nutrients: This accurately describes the primary ecological role of decomposers.
(c) They provide energy to producers: Producers (autotrophs) obtain energy from sunlight (photosynthesis) or chemical sources (chemosynthesis). Decomposers do not provide energy to producers; rather, they release nutrients that producers use for growth, using energy from sunlight.
(d) They regulate the temperature of the ecosystem: While biological activity (including decomposition) generates some heat, decomposers are not primary regulators of ecosystem temperature, which is mainly influenced by climatic factors (solar radiation, air currents, etc.) and physical features. Therefore, the key role of decomposers is to break down dead organic matter and recycle nutrients back into the ecosystem. \[ \boxed{\text{They break down dead organisms and recycle nutrients}} \]