Consumer-driven nutrient dynamics in freshwater ecosystems: from individuals to ecosystems

Area of Science:

• Ecology
• Ecosystem Science
• Limnology

Background:

• Consumer-driven nutrient dynamics (CND) are recognized as crucial for aquatic community structure and ecosystem function.
• Significant variability exists in CND's influence across species and ecosystems, with underlying causes often unclear.
• Research on CND has surged, particularly in North America and focusing on fish, with recent emphasis on nutrient excretion and indirect impacts.

Purpose of the Study:

• To review and synthesize the mechanisms driving consumer-driven nutrient dynamics in freshwater ecosystems.
• To identify factors influencing CND across different biological organization levels.
• To highlight unexplored aspects and suggest future research directions for CND.

Main Methods:

• A comprehensive literature review of 131 articles on CND published between 1973 and June 2015.
• Analysis of trends in CND publication rates and geographical focus.
• Synthesis of identified mechanisms influencing CND.

Main Results:

• Several mechanisms influence CND, including consumer stoichiometric plasticity (affected by body size, feeding history, ontogeny) and ecosystem abiotic characteristics.
• Consumer metabolic processes, nutrient supply, and ecosystem nutrient demand are modulated by consumers.
• Shifts in consumer community composition, biomass, and eco-evolutionary factors significantly impact CND but remain understudied.

Conclusions:

• Consumer traits and abiotic conditions are vital for predicting CND effects on ecosystem-level nutrient dynamics across scales.
• Future CND research should integrate physiology and ecosystem ecology for a mechanistic understanding.
• Comparative and experimental studies are needed to test CND assumptions and assess its significance across freshwater ecosystems.