Influence of natural amphipod (Victoriopisa australiensis) (Chilton, 1923) population densities on benthic metabolism, nutrient fluxes, denitrification and DNRA in sub-tropical estuarine sediment

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Title Influence of natural amphipod (Victoriopisa australiensis) (Chilton, 1923) population densities on benthic metabolism, nutrient fluxes, denitrification and DNRA in sub-tropical estuarine sediment
Author Dunn, Ryan Jay Keith; Welsh, David Thomas; Jordan, Mark; Teasdale, Peter; Lemckert, Charles James
Journal Name Hydrobiologia
Year Published 2009
Place of publication Netherlands
Publisher Springer Netherlands
Abstract The influence of natural populations of the sub-surface deposit-feeding amphipod Victoriopisa australiensis on sediment biogeochemistry was assessed by randomly collecting 21 sediment cores in a zone of Coombabah Lake, southern Moreton Bay, Australia, where the benthic infauna was dominated by this species. Cores were incubated sequentially to determine sediment–water column fluxes of oxygen, dissolved inorganic carbon and inorganic N species, followed by incubations to determine rates of denitrification and dissimilatory nitrate reduction to ammonium (DNRA) using the isotope pairing technique. Finally, each core was sieved in order to determine the population and biomass of amphipods present. Whilst all measures of overall benthic metabolism (sediment oxygen demand, and effluxes of inorganic carbon and nitrogen) showed increased with amphipod density, with rates being stimulated 70–220% at the highest categorised density range of 2,500–3,500 ind m−2, only the correlation with dissolved inorganic carbon was statistically significant. In contrast, there were no discernable trends between amphipod densities and any of the N-cycle processes with the slopes of all correlations being very close to zero. These results highlight the differences in mesocosm simulations of fauna effects, which primarily relate to shifts in rates of organic matter turnover, compared to natural sediments where fauna effects relate more to induced changes in rates of organic matter deposition. Therefore, while mesocosms represent a powerful tool to investigate the mechanisms by which fauna influences microbial metabolism in the sediment, only studies of natural sediments can determine to what extent these mechanisms function in situ.
Peer Reviewed Yes
Published Yes
Alternative URI http://dx.doi.org/10.1007/s10750-009-9748-2
Copyright Statement Copyright 2009 Springer Netherlands. This is the author-manuscript version of this paper. Reproduced in accordance with the copyright policy of the publisher. The original publication is available at www.springerlink.com
Volume 628
Issue Number 1
Page from 95
Page to 109
ISSN 0018-8158
Date Accessioned 2010-02-24
Date Available 2010-07-19T04:42:03Z
Language en_AU
Research Centre Environmental Futures Research Institute; Centre for Infrastructure Engineering and Management
Faculty Faculty of Science, Environment, Engineering and Technology
Subject Biological Oceanography
URI http://hdl.handle.net/10072/30290
Publication Type Journal Articles (Refereed Article)
Publication Type Code c1

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