In:
Marine and Freshwater Research, CSIRO Publishing, Vol. 50, No. 6 ( 1999), p. 589-
Abstract:
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.
Type of Medium:
Online Resource
ISSN:
1323-1650
Language:
English
Publisher:
CSIRO Publishing
Publication Date:
1999
detail.hit.zdb_id:
1283028-8
SSG:
12
SSG:
21,3
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