Priming effect: bridging the gap between terrestrial and aquatic ecology.

Area of Science:

• Ecology
• Biogeochemistry
• Environmental Science

Background:

• Ecosystem carbon storage and release are critical 21st-century ecological challenges.
• Organic matter's varying recalcitrance influences carbon cycling, yet interactions are often overlooked in models.
• The priming effect, where labile organic matter enhances recalcitrant matter decomposition, is well-documented in soil science but neglected in aquatic ecosystems.

Purpose of the Study:

• To present evidence for the priming effect as a general phenomenon across terrestrial, freshwater, and marine ecosystems.
• To highlight the implications of the priming effect for ecosystem carbon cycling and CO2 emissions.
• To propose that global changes may modify priming effect intensity, affecting ecosystem responses.

Main Methods:

• Compilation of experimental results and field observations supporting the priming effect hypothesis.
• Review of studies on organic matter degradation in aquatic ecosystems.
• Analysis of potential interactions between priming effect and global change factors like eutrophication and rising atmospheric CO2.

Main Results:

• The priming effect is a general phenomenon occurring in diverse ecosystems.
• Labile organic matter can increase recalcitrant organic matter mineralization rates by 10% to 500% in aquatic systems.
• Recalcitrant organic matter mineralization is sensitive to labile organic matter availability, impacting CO2 emissions.

Conclusions:

• The priming effect significantly contributes to CO2 emissions from aquatic ecosystems.
• Global changes, including eutrophication and increased atmospheric CO2, can alter priming effect intensity.
• The priming effect plays a substantial role in ecosystem carbon and nutrient cycles, influencing responses to anthropogenic perturbations and climate change.