In ecology, what term describes the single essential nutrient that is in the shortest supply relative to demand and therefore limits primary productivity in an ecosystem?

• A. Trophic efficiency
• B. Keystone species
• C. Limiting nutrient
• D. Carrying capacity

Answer: (C)

Verified step by step guidance

1. Understand the concept of nutrients in an ecosystem and their role in supporting primary productivity, which is the rate at which plants and other photosynthetic organisms produce organic compounds.
2. Recognize that among all essential nutrients, the one that is in the shortest supply relative to the needs of organisms can restrict the growth and productivity of the ecosystem.
3. Learn that this specific nutrient is called the 'limiting nutrient' because it limits the overall productivity despite the availability of other nutrients.
4. Differentiate the term 'limiting nutrient' from other ecological terms such as 'trophic efficiency' (which relates to energy transfer between trophic levels), 'keystone species' (a species with a large effect on its ecosystem), and 'carrying capacity' (the maximum population size an environment can sustain).
5. Conclude that the correct term describing the single essential nutrient limiting primary productivity is 'limiting nutrient'.