Microbial Respiration

AUS-TSR-FOR-SMR General Moderate confidence

Benchmark Value

10 mg/kg/day

Direction: Lower is desirable ↓

Form: MinimumOnly

Scoring Curve

This curve shows how a field measurement for this indicator would score across all available benchmark forms in this context. The scoring engine uses 4 benchmarks together — the OptimalRange form drives the primary score, while 3 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary Point Guard MinimumOnly Guard MaximumOnly Guard

Evidence & Context

A respiration rate that remains consistently below 10 mg C/kg/day in the growing season should be considered an indicator of a critically impaired ecosystem.

Metric Definition:

Soil microbial respiration rate measured as mg CO2-C released per kg of soil per day.

Benchmark Definition:

This benchmark defines the lower critical threshold of soil microbial respiration below which the ecosystem is critically impaired and unable to sustain nutrient cycling and carbon processing.

Justification:

This threshold reflects severe depletion of soil organic matter and microbial biomass, indicating a critically degraded state.

Sources (1)

Preview of (PDF) Impact of temperature and moisture on heterotrophic soil respiration along a moist tropical forest gradient in Australia - ResearchGate, accessed August 9, 2025

(PDF) Impact of temperature and moisture on heterotrophic soil respiration along a moist tropical forest gradient in Australia - ResearchGate, accessed August 9, 2025 Journal

(PDF) Impact of temperature and moisture on heterotrophic soil respiration along a moist tropical forest gradient in Australia - ResearchGate, accessed August 4, 2025,

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Supporting Sources (3)

Additional references from the underlying research that informed this benchmark.

Maycock, Colin Rulzion (1998) Plant-soil nutrient relationships in ...

Direct Evidence Journal

Maycock, Colin Rulzion (1998) Plant-soil nutrient relationships in ...

View Source

Preview of Soil Microbial Biomass, Basal Respiration and Enzyme Activity of Main Forest Types in the Qinling Mountains | PLOS One - Research journals, accessed August 5, 2025,

Soil Microbial Biomass, Basal Respiration and Enzyme Activity of Main Forest Types in the Qinling Mountains | PLOS One - Research journals, accessed August 5, 2025,

Direct Evidence

Major and persistent shifts in below‐ground ... - yadvinder malhi

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Soil Respiration - Natural Resources Conservation Service

Contextual Support Journal

Reforestation, carbon sequestration and relationships between soil attributes in the Wet Tropics of Australia (Schmidt et al., 2014)

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Context

Region Australia
Biome Tropical & Subtropical Rainforests
Land Use Production Forestry
Assessment Conservation Target
Vegetation Tropical & Subtropical Rainforests
Season growing season
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 1
Effective From 5 Jun 2026

Notes

Below this threshold, the ecosystem is severely impaired in nutrient cycling and carbon processing. No upper detrimental threshold — higher values are always better up to natural saturation.

Related Benchmarks

Other benchmarks in the AUS-TSR-FOR-SMR family.