Denitrification Fluxes and Efficiencies in Port Phillip Bay Sediments

Direct determinations of biogenic N2 and N-metabolite fluxes from benthic chambers in Port Phillip Bay quantify denitrification processes. Measurements show denitrifying efficiencies of 75-85% at organic carbon loadings of ~15-25 mmol m-2 day-1, with rates near zero at loadings exceeding 100 mmol m-2 day-1. The data illustrate the tight coupling of ammonification, nitrification, and denitrification in marine sediments and their implications for water quality.

Use Cases

• Model the stoichiometric relationship between organic carbon and nitrogen in sediments using the reported ratio of 5.7.
• Analyze denitrifying efficiency trends against organic carbon loading rates to identify thresholds for nutrient release.
• Compare biogenic N2 flux rates (~1.3 mmol N2 m-2 day-1) with ammonia, nitrate, and nitrite fluxes to assess nitrogen cycling.
• Investigate the source of nitrate for denitrification using evidence from 15NO3 'spiked' chamber experiments.

Strengths

• Provides high-precision measurements of N2 and N-metabolite fluxes from direct benthic chamber methods.
• Reports specific quantitative findings, including a stoichiometric C:N ratio of 5.7 and denitrifying efficiencies of 75-85%.
• Covers major sedimentary facies, with muddy sediments representing about 70% of the studied seafloor.

Limitations

• Dataset structure is undefined; columns, rows, and sample data are unavailable, hindering direct computational analysis.
• Data is presented in an HTML format, not a structured tabular file, requiring significant extraction effort.

Provenance

Source

Geoscience Australia Data, from a scientific journal publication.

Collection Method

High-precision measurements from benthic chamber waters in Port Phillip Bay, including chambers 'spiked' with 15NO3.

Time Range

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Freshness

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Geography

Port Phillip Bay, Victoria, Australia (AU-VIC).