Water Nitrate

AUS-TMI-CON-WNI General Moderate confidence

Benchmark Value

0.1 mg/L
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 8 benchmarks together — the OptimalRange form drives the primary score, while 7 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary UpperThreshold Guard MaximumOnly Guard Point Guard MaximumOnly Guard MinimumOnly Guard MaximumOnly Guard UpperThreshold Guard

Evidence & Context

The research, conducted around Pacific islands, established a threshold of 0.10 mg/L of Dissolved Inorganic Nitrogen (DIN). Watersheds where DIN concentrations exceeded this level for 20% or more of the year were consistently associated with diminished diversity and a reduced size structure of coral assemblages.

Metric Definition:

Dissolved Inorganic Nitrogen (DIN) concentration threshold indicating onset of ecological stress in coral reef communities.

Benchmark Definition:

Threshold concentration of DIN above which negative impacts on coral reef biodiversity begin to manifest.

Justification:

Empirically derived from Pacific island studies associating DIN concentrations above 0.10 mg/L with coral diversity loss and structural changes.

Sources (1)

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.

Houk, P., et al. (2022). Nutrient thresholds to protect water quality, coral reefs, and nearshore fisheries. Marine Pollution Bulletin, 184, 114131. 26

View Source

Supporting Sources (24)

Additional references from the underlying research that informed this benchmark.

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

Gruber, R., et al. (2024). Marine Monitoring Program: Annual Report for Inshore Water Quality Monitoring 2022-23. Great Barrier Reef Marine Park Authority. 18

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
Preview of Department of Infrastructure and Regional Development. (2017). Christmas Island Groundwater Project Factsheet. 13
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
Preview of Development of basin-specific ecologically relevant water quality targets for the Great Barrier Reef, accessed August 3, 2025,
Development of basin-specific ecologically relevant water quality targets for the Great Barrier Reef, accessed August 3, 2025,
Contextual Support Journal

Lewis, S. E., et al. (2017). Development of basin-specific ecologically relevant water quality targets for the Great Barrier Reef. Reef Water Quality Protection Plan. 41

View Source
Preview of Diving deeper into nutrient pathways to help protect Lord Howe Island's marine haven, accessed August 4, 2025,
Diving deeper into nutrient pathways to help protect Lord Howe Island's marine haven, accessed August 4, 2025,
Contextual Support GreyLiterature

Australian Institute of Marine Science (AIMS). (2024, September 4). Diving deeper into nutrient pathways to help protect Lord Howe Island's marine haven. 9

View Source
Preview of Eutrophication and Water quality - Global Coral Reef Alliance, accessed August 1, 2025
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
Preview of Frequently asked questions | Report card 2021 and 2022 | Reef 2050 Water Quality Improvement Plan, accessed July 27, 2025,
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

Preview of Geoscience Australia. (1999). Christmas Island Water Resources GIS Data Layers. 12
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
Preview of Goreau, T. J. (n.d.). Coral Reefs, Sewage, and Water Quality Standards. Global Coral Reef Alliance. 23
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
Preview of Great Barrier Reef Marine Park Authority (GBRMPA). (2024). Marine Monitoring Program 2022-23 Summary Results Booklet.
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 Humphries, M. S., et al. (2017). Searching for water on Christmas Island. ResearchGate. 10
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
Preview of Latest Great Barrier Reef water quality Scientific Consensus Statement released - CSIRO, accessed August 1, 2025
Latest Great Barrier Reef water quality Scientific Consensus Statement released - CSIRO, accessed August 1, 2025
Contextual Support GreyLiterature

Latest Great Barrier Reef water quality Scientific Consensus Statement released - CSIRO, 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
Preview of Lord Howe Island Marine Park News Water Quality Research Collaboration, accessed August 3, 2025,
Lord Howe Island Marine Park News Water Quality Research Collaboration, accessed August 3, 2025,
Contextual Support Journal

Lord Howe Island Marine Park. (2024, June). Lord Howe Island Marine Park News. 8

View Source
Preview of Nitrate in freshwater and marine water - Water Quality Australia, accessed August 2, 2025,
Nitrate in freshwater and marine water - Water Quality Australia, accessed August 2, 2025,
Contextual Support

Nitrate - Water Quality Australia, accessed August 1, 2025

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
Preview of Parks Australia. (n.d.). Christmas Island on the frontline of battle against ocean plastic pollution. Australian Marine Parks. 42
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
Preview of Tangaroa Blue Foundation. (2024). Christmas Island Marine Debris Report. 11
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
Preview of Water quality guidelines - Queensland Environment Department, accessed August 4, 2025,
Water quality guidelines - Queensland Environment Department, accessed August 4, 2025,
Contextual Support Journal

Salinity | Murray–Darling Basin Authority, accessed August 8, 2025,

View Source
Preview of Water Quality Guidelines for the Great Barrier Reef Marine Park., accessed August 3, 2025,
Water Quality Guidelines for the Great Barrier Reef Marine Park., accessed August 3, 2025,
Regulatory Framework Journal

Great Barrier Reef Marine Park Authority (GBRMPA). (2010). Water Quality Guidelines for the Great Barrier Reef Marine Park. Rev. ed. 35

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 DegradationThreshold

Lifecycle

  • Status Active
  • Version 1
  • Effective From 17 Mar 2026

Notes

Represents a critical tipping point where the system begins to shift away from a coral-dominated state due to nutrient enrichment.

Related Benchmarks

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

0.007 mg/L High
Conservation / Protected Natural Areas · Conservation Target
Point Active v1