JSON format icon JSON RDF format icon RDF ISO19115-3 XML

Denitrification and Denitrifying Efficiencies in Sediments of Port Phillip Bay: Direct Determinations of Biogenic N2 and N-metabolite Fluxes with Implications for Water Quality

Created 20/01/2026

Updated 20/01/2026

JSON format icon JSON RDF format icon RDF ISO19115-3 XML

High-precision measurements of N2 in benthic chamber waters indicated that denitrification occurs within the major sedimentary facies in Port Phillip Bay. The integrated fluxes of biogenic N2 , ammonia, nitrate and nitrite showed that the stoichiometric relationship between organic C and N in the muddy sediments, occupying about 70% of the seafloor, was 5.7, this being similar to the Redfield ratio of 6.6. High denitrifying efficiencies (75-85%; denitrification rates ~1.3 mmol N2 m-2 day-1) at organic carbon loadings of ~15-25 mmol m-2 day-1 indicate that most N processed through the sediments was returned to the overlying waters as biologically (generally) unavailable N2. At sites of high organic carbon loadings to the sediments (>100 mmol m-2 day-1) denitrification rates and denitrifying efficiencies were near zero and most N is returned to the Bay waters as biologically available ammonium. In chambers 'spiked' with 15NO3 , denitrifyers used nitrate produced in the sediments in situ, rather than the exogenous nitrate in overlying waters. The sedimentary microbial processes of ammonification, nitrification and denitrification are therefore tightly coupled.

Files and APIs

Tags

Additional Info

Field Value
Title Denitrification and Denitrifying Efficiencies in Sediments of Port Phillip Bay: Direct Determinations of Biogenic N2 and N-metabolite Fluxes with Implications for Water Quality
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/74de0328-7e89-4608-a715-9d7327f5495a
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 22/04/2018
Geospatial Coverage
Map data © OpenStreetMap contributors
{
  "coordinates": [
    [
      [
        144.3,
        -38.4
      ],
      [
        145.1,
        -38.4
      ],
      [
        145.1,
        -37.8
      ],
      [
        144.3,
        -37.8
      ],
      [
        144.3,
        -38.4
      ]
    ]
  ],
  "type": "Polygon"
}
Data Portal Data.gov.au