Microbial Biomass Carbon (MBC)

AUS-TMS-CON-SMB General Moderate confidence

Benchmark Value

No specific value — see range

Range: 300 to 350 mg/kg

Thresholds: Lower: 300, Upper: —

Optimal Range: 300 to 350

Direction: Higher is desirable ↑

Form: OptimalRange

Scoring Curve

Scoring curve unavailable

The scoring engine could not generate a curve for this benchmark context. The primary form is CompositeFramework, but the benchmark data may be missing required fields (e.g., optimal range bounds for an OptimalRange benchmark). This is typically a data quality issue in the benchmark pipeline.

Contributing Benchmarks

CompositeFramework Primary Point Guard LowerThreshold Guard Point Guard Point Guard OptimalRange Guard LowerThreshold Guard Point Guard OptimalRange Guard OptimalRange Guard

Evidence & Context

An MBC level below approximately 300-350 mg/kg is indicative of significant ecosystem degradation.

Metric Definition:

Microbial Biomass Carbon (MBC) level below which soil ecosystem functions are impaired.

Benchmark Definition:

The lower critical threshold of Microbial Biomass Carbon (MBC) below which soil ecosystem functions degrade, indicating significant ecosystem degradation in tropical savanna conservation areas.

Justification:

Based on literature from analogous tropical savanna ecosystems and soil science principles indicating loss of soil structure and function below this range.

Sources (1)

Microbial Biomass C, N and P in Disturbed Dry Tropical Forest Soils, India Journal

Microbial Biomass C, N and P in Disturbed Dry Tropical Forest Soils, India

View Source

Supporting Sources (4)

Additional references from the underlying research that informed this benchmark.

Altered soil microbial community at elevated CO2 leads to loss of soil carbon | PNAS, accessed August 5, 2025

Contextual Support

Altered soil microbial community at elevated CO2 leads to loss of soil carbon - PNAS, accessed July 28, 2025,

View Source

functions-of-soil-organic-matter-and-the-effect-on-soil-properties.pdf.pdf, accessed July 19, 2025,

Contextual Support Journal

The biodiversity cost of carbon sequestration in tropical savanna - PMC - PubMed Central

View Source

Interpreting Microbial Biomass Carbon | Fact Sheets | soilquality.org.au, accessed August 28, 2025,

Direct Evidence Government

Interpreting Microbial Biomass Carbon | Fact Sheets | soilquality.org.au, accessed July 18, 2025,

View Source

Preview of Supervising Scientist Report 671: Woody biomass dynamics at Paradise Farm, a long-term fire experiment in the savannas of northern Australia

Supervising Scientist Report 671: Woody biomass dynamics at Paradise Farm, a long-term fire experiment in the savannas of northern Australia

Direct Evidence

Supervising Scientist Report 671: Woody biomass dynamics at Paradise Farm, a long-term fire experiment in the savannas of northern Australia

View Source

Context

Region Australia
Biome Tropical Monsoonal Savannas
Land Use Conservation / Protected Natural Areas
Assessment Conservation Target
Vegetation Savanna
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 1
Effective From 20 Mar 2026

Notes

Below this threshold, soil aggregate stability and nutrient cycling are compromised, increasing erosion risk. No upper detrimental threshold — higher values are always better up to natural saturation.

Related Benchmarks

Other benchmarks in the AUS-TMS-CON-SMB family.