Water Nitrate

AUS-TMI-CON-WNI General Moderate confidence

Benchmark Value

0.007 mg/L

Direction: Lower is desirable ↓

Form: Point

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 7 benchmarks together — the OptimalRange form drives the primary score, while 6 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary Point Guard MaximumOnly Guard Point Guard Point Guard MaximumOnly Guard OptimalRange Guard

Evidence & Context

Based on an analysis of the data from this high-health reference site, the recommended benchmark for Water Nitrate is 0.007 mg/L (as NO3).

Metric Definition:

Water Nitrate concentration as nitrate (NO3) in water

Benchmark Definition:

This benchmark represents the concentration of nitrate in water that reflects the best natural condition for conservation areas in tropical and subtropical maritime island ecosystems.

Justification:

This benchmark is derived from the 80th percentile of nitrate/nitrite concentrations at the Annan-Endeavour focus region, the only site meeting GBRMPA water quality guidelines for NOx in 2022-23, representing a high ecological health state.

Sources (1)

Preview of Reef Water Quality Report Card 2021 and 2022 Great Barrier Reef Marine Monitoring Program Methods, accessed August 3, 2025,

Reef Water Quality Report Card 2021 and 2022 Great Barrier Reef Marine Monitoring Program Methods, accessed August 3, 2025, Journal

Gruber, R., et al. (2024). Marine Monitoring Program: Annual Report for Inshore Water Quality Monitoring 2022-23. Great Barrier Reef Marine Park Authority.

View Source

Supporting Sources (25)

Additional references from the underlying research that informed this benchmark.

(PDF) Marine Monitoring Program: Annual Report for Inshore Water Quality Monitoring 2022-23 - ResearchGate, accessed July 20, 2025,

Direct Evidence GreyLiterature

Water Quality, River Discharge and Remote Sensing Data Base

View Source

Preview of Australian and New Zealand Governments (ANZG). (2018). Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Canberra ACT, Australia. 32

Australian and New Zealand Governments (ANZG). (2018). Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Canberra ACT, Australia. 32

Regulatory Framework Journal

Environmental Values, Water Quality Objectives and Targets for the Black Ross Water Quality Improvement Plan Appendices December - Creek to Coral, accessed July 31, 2025,

View Source

Preview of Department of Climate Change, Energy, the Environment and Water (DCCEEW). (n.d.). Lord Howe Island Marine Park (Commonwealth Waters) Management Plan. 38

Department of Climate Change, Energy, the Environment and Water (DCCEEW). (n.d.). Lord Howe Island Marine Park (Commonwealth Waters) Management Plan. 38

Contextual Support Journal

Department of Climate Change, Energy, the Environment and Water (DCCEEW). (n.d.). Lord Howe Island Marine Park (Commonwealth Waters) Management Plan. 38

View Source

Department of Infrastructure and Regional Development. (2017). Christmas Island Groundwater Project Factsheet. 13

Contextual Support Journal

Department of Infrastructure and Regional Development. (2017). Christmas Island Groundwater Project Factsheet. 13

View Source

Development of basin-specific ecologically relevant water quality targets for the Great Barrier Reef, accessed August 3, 2025,

Contextual Support Journal

Queensland Reef Water Quality Program | Environment, land and water, accessed August 3, 2025

View Source

Diving deeper into nutrient pathways to help protect Lord Howe Island's marine haven, accessed August 4, 2025,

Contextual Support GreyLiterature

Managing urban and non-agricultural run-off to the Reef ..., accessed August 2, 2025

View Source

Eutrophication and Water quality - Global Coral Reef Alliance, accessed August 1, 2025

Contextual Support GreyLiterature

Eutrophication and Water quality - Global Coral Reef Alliance, accessed August 1, 2025,

View Source

Frequently asked questions | Report card 2021 and 2022 | Reef 2050 Water Quality Improvement Plan, accessed July 27, 2025,

Contextual Support Government

Queensland Government. (2024). Reef Water Quality Report Card 2021 and 2022: Frequently asked questions. 45

View Source

Preview of Gattuso, J-P., et al. (2015). Contrasting futures for ocean and society from different anthropogenic CO2 emissions scenarios. Science, 349(6243). 27

Gattuso, J-P., et al. (2015). Contrasting futures for ocean and society from different anthropogenic CO2 emissions scenarios. Science, 349(6243). 27

Direct Evidence

Gattuso, J-P., et al. (2015). Contrasting futures for ocean and society from different anthropogenic CO2 emissions scenarios. Science, 349(6243). 27

Geoscience Australia. (1999). Christmas Island Water Resources GIS Data Layers. 12

Contextual Support Government

Geoscience Australia. (1999). Christmas Island Water Resources GIS Data Layers. 12

View Source

Goreau, T. J. (n.d.). Coral Reefs, Sewage, and Water Quality Standards. Global Coral Reef Alliance. 23

Contextual Support GreyLiterature

Goreau, T. J. (n.d.). Coral Reefs, Sewage, and Water Quality Standards. Global Coral Reef Alliance. 23

View Source

Great Barrier Reef Marine Park Authority (GBRMPA). (2024). Marine Monitoring Program 2022-23 Summary Results Booklet.

Direct Evidence

Great Barrier Reef Marine Park Authority (GBRMPA). (2024). Marine Monitoring Program 2022-23 Summary Results Booklet. 21

View Source

Preview of Houk, P., et al. (2022). Nutrient thresholds to protect water quality, coral reefs, and nearshore fisheries. Marine Pollution Bulletin, 184, 114131.

Houk, P., et al. (2022). Nutrient thresholds to protect water quality, coral reefs, and nearshore fisheries. Marine Pollution Bulletin, 184, 114131.

Direct Evidence Government

Houk, P., et al. (2022). Nutrient thresholds to protect water quality, coral reefs, and nearshore fisheries. Marine Pollution Bulletin, 184, 114131.

View Source

Humphries, M. S., et al. (2017). Searching for water on Christmas Island. ResearchGate. 10

Contextual Support

Humphries, M. S., et al. (2017). Searching for water on Christmas Island. ResearchGate. 10

View Source

Latest Great Barrier Reef water quality Scientific Consensus Statement released - CSIRO, accessed August 1, 2025

Contextual Support GreyLiterature

5.7 Nitrates | Monitoring & Assessment | US EPA, accessed August 1, 2025

View Source

Preview of LORD HOWE ISLAND A Summary of Current and Projected Scientific and Environmental Activities - Australian Museum, accessed July 30, 2025

LORD HOWE ISLAND A Summary of Current and Projected Scientific and Environmental Activities - Australian Museum, accessed July 30, 2025

Contextual Support Journal

Baseline high-resolution maps of organic carbon content in Australian soils - PMC

View Source

Lord Howe Island Marine Park News Water Quality Research Collaboration, accessed August 3, 2025,

Contextual Support Journal

Diving deeper into nutrient pathways to help protect Lord Howe Island's marine haven, accessed August 4, 2025

View Source

Nitrate in freshwater and marine water - Water Quality Australia, accessed August 2, 2025,

Contextual Support

Memorandum - Nitrate guideline values in ANZECC 2000

View Source

Preview of Parks Australia. (2025). Director of National Parks Report on comments for the Christmas Island and Cocos (Keeling) Islands draft management plans. 44

Parks Australia. (2025). Director of National Parks Report on comments for the Christmas Island and Cocos (Keeling) Islands draft management plans. 44

Regulatory Framework Government

Department of Climate Change, Energy, the Environment and Water (DCCEEW). (n.d.). Lord Howe Island Biodiversity Management Plan. 40

View Source

Parks Australia. (n.d.). Christmas Island on the frontline of battle against ocean plastic pollution. Australian Marine Parks. 42

Contextual Support Government

Parks Australia. (n.d.). Christmas Island on the frontline of battle against ocean plastic pollution. Australian Marine Parks. 42

View Source

Tangaroa Blue Foundation. (2024). Christmas Island Marine Debris Report. 11

Contextual Support Journal

Tangaroa Blue Foundation. (2024). Christmas Island Marine Debris Report. 11

View Source

Water quality guidelines - Queensland Environment Department, accessed August 4, 2025,

Contextual Support Journal

Seasonal changes in water quality and macrophytes and the ...

View Source

Water Quality Guidelines for the Great Barrier Reef Marine Park., accessed August 3, 2025,

Regulatory Framework Journal

Determining Tipping Points and Responses of Macroinvertebrate Traits to Abiotic Factors in Support of River Management - PubMed Central

View Source

Preview of Webb, K. L., & Wiebe, W. J. (1978). The kinetics and possible significance of nitrate uptake by several algal-invertebrate symbioses. Marine Biology, 47, 21-27. 5

Webb, K. L., & Wiebe, W. J. (1978). The kinetics and possible significance of nitrate uptake by several algal-invertebrate symbioses. Marine Biology, 47, 21-27. 5

Contextual Support

Webb, K. L., & Wiebe, W. J. (1978). The kinetics and possible significance of nitrate uptake by several algal-invertebrate symbioses. Marine Biology, 47, 21-27. 5

Preview of Wiedenmann, J., et al. (2013). Nutrient enrichment can increase the susceptibility of reef corals to bleaching. Nature Climate Change, 3, 160-164. 24

Wiedenmann, J., et al. (2013). Nutrient enrichment can increase the susceptibility of reef corals to bleaching. Nature Climate Change, 3, 160-164. 24

Contextual Support

Wiedenmann, J., et al. (2013). Nutrient enrichment can increase the susceptibility of reef corals to bleaching. Nature Climate Change, 3, 160-164. 24

Context

Region Australia
Biome Tropical & Subtropical Maritime Islands
Land Use Conservation / Protected Natural Areas
Assessment Pristine Reference
Evidence Type ReferenceCondition

Lifecycle

Status Active
Version 1
Effective From 2 Jun 2026

Notes

No upper detrimental threshold — higher values are always worse beyond this conservative upper limit. This value is a conservative upper limit for a high-health system in oligotrophic tropical maritime island ecosystems. The concept of a lower critical threshold is not ecologically relevant as these systems are naturally nutrient-limited. Any significant increase above this value indicates potential ecosystem stress.

Related Benchmarks

Other benchmarks in the AUS-TMI-CON-WNI family.