Bedrock nitrogen weathering stimulates biological nitrogen fixation

Area of Science:

• Biogeochemistry
• Ecology
• Geology

Background:

• Bedrock nitrogen (N) weathering is a significant N input to terrestrial ecosystems, supplying over 38% in temperate forests.
• The influence of rock N weathering on ecological processes and biogeochemical fluxes remains poorly understood.

Purpose of the Study:

• To investigate the relationship between bedrock N content and nitrogen fixation rates in temperate forests.
• To elucidate the mechanisms driving observed differences in nitrogen fixation.

Main Methods:

• Comparative analysis of temperate forest ecosystems with varying bedrock N content.
• Assessment of soil carbon and phosphorus accumulation.
• Measurement of free-living nitrogen fixation rates.

Main Results:

• Temperate forests on N-rich bedrock exhibit higher free-living nitrogen fixation rates compared to those on N-poor bedrock.
• Increased soil carbon and phosphorus accumulation were observed in N-rich bedrock sites.
• These soil conditions provide enhanced energy and nutrient availability for nitrogen-fixing microorganisms.

Conclusions:

• Bedrock N weathering influences nitrogen fixation rates through soil C and P dynamics.
• A novel ecosystem biogeochemical framework incorporating plant-soil-microbe feedbacks is proposed.
• Findings have broad implications for understanding global biogeochemical cycles.