Of Ecosystem Processes Flashcards

Which term describes the process by which water moves from the soil through a plant and evaporates from its leaves?

Answer: Transpiration

Transpiration is the evaporation of water from plant leaf surfaces, and together with soil evaporation forms evapotranspiration.

In a food web, which group is responsible for the bulk of decomposition of dead organic matter?

Answer: Detritivores and decomposers

Detritivores (e.g., millipedes, earthworms) fragment dead matter while decomposers (bacteria, fungi) chemically break it down.

Which ecosystem process is directly responsible for moving carbon from the atmosphere into living organisms?

Answer: Photosynthesis

Photosynthesis captures atmospheric CO₂ and fixes it into organic compounds, making it the primary entry point for carbon into the biotic world.

What ecological term describes the ratio of net primary productivity to gross primary productivity?

Answer: Production efficiency

Production efficiency (NPP/GPP) indicates what fraction of energy fixed by photosynthesis remains after autotrophic respiration.

What is 'eutrophication' in aquatic ecosystems?

Answer: Nutrient enrichment leading to algal blooms and oxygen depletion

Eutrophication occurs when excess nutrients (often nitrogen and phosphorus) cause rapid algal growth, which upon decomposition depletes dissolved oxygen.

Which process converts nitrates back to atmospheric nitrogen gas in the nitrogen cycle?

Answer: Denitrification

Denitrification, performed by anaerobic bacteria, converts nitrate (NO₃⁻) back to N₂ gas, completing the nitrogen cycle.

In which ecosystem type is gross primary productivity typically highest per unit area?

Answer: Tropical rainforest

Tropical rainforests have the highest GPP per unit area due to abundant sunlight, warmth, and moisture year-round.