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Effects of organic perturbation on marine sediment betaproteobacterial ammonia oxidizers and on benthic nitrogen biogeochemistry


Bissett, A and Cook, PLM and MacLeod, C and Bowman, JP and Burke, C, Effects of organic perturbation on marine sediment betaproteobacterial ammonia oxidizers and on benthic nitrogen biogeochemistry, Marine Ecology Progress Series, 392, (October) pp. 17-32. ISSN 0171-8630 (2009) [Refereed Article]


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Copyright 2009 Inter-Research

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DOI: doi:10.3354/meps08244


The failure of denitrification to remove nitrogen build-up from aquatic systems is often attributed to sediment chemical conditions inhibiting nitrification and therefore the supply of suitable substrates to be denitrified. We investigated the effects of organic fish farm pollution on nitrogen-cycle dynamics and betaproteobacterial ammonia-oxidizing bacteria (-AOB) community structure to elucidate the potential role of the nitrifier community on nitrogen biogeochemistry in marine sediments. Porewater nitrogen concentrations, denitrification rates, -AOB 16S rDNA gene quantification, denaturing gradient gel electrophoresis (DGGE) community fingerprints and infaunal counts were determined in samples collected from beneath fish cages and at adjacent, non-impacted control sites. The study was conducted over 2 full, 1 yr production cycles. Although nitrogen cycling was significantly altered beneath cages, changes appeared to result from a reduction in the proportion of ammonia nitrified rather than from inhibition of nitrification per se. DGGE revealed -AOB communities shifted rapidly and remained diverse at both cage and reference sites. Quantitative PCR (qPCR) showed -AOB numbers did not decline in absolute terms but did decline as a proportion of the total bacterial community at cage sites and at the end of the stocking periods. Sediment infaunal community analysis showed significant effects of organic loading and indicated more bioirrigation at impacted sites. Despite the induction of conditions thought to be detrimental to nitrification and to -AOB (low oxygen, reduced sediments, low pH, and high sulphide concentrations), these communities remained diverse and apparently viable, perhaps a result of heavy sediment bioirrigation. However, despite the increase in denitrification, nitrogen left the sediment predominantly as ammonia, thus producing potential point sources of eutrophication.

Item Details

Item Type:Refereed Article
Keywords:Eutrophication Nitrification Denitrification Sediment Ammonia-oxidising bacteria
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Fisheries sciences
Research Field:Aquaculture and fisheries stock assessment
Objective Division:Environmental Management
Objective Group:Terrestrial systems and management
Objective Field:Assessment and management of terrestrial ecosystems
UTAS Author:Bissett, A (Mr Andrew Bissett)
UTAS Author:MacLeod, C (Professor Catriona MacLeod)
UTAS Author:Bowman, JP (Associate Professor John Bowman)
UTAS Author:Burke, C (Dr Chris Burke)
ID Code:61069
Year Published:2009
Web of Science® Times Cited:14
Deposited By:TAFI - Marine Research Laboratory
Deposited On:2010-02-25
Last Modified:2015-02-02
Downloads:465 View Download Statistics

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