ORCID Profile
0000-0002-8659-3833
Current Organisation
University of Tasmania
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Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/MF05141
Abstract: Effective management of introduced species requires an understanding of their effects on native species and the processes that structure the habitat. The introduced European polychaete Sabella spallanzanii dominates epifaunal assemblages in south-eastern Australia, yet little is known about how it affects the structure of the surrounding assemblages. The present study investigated the differences between infaunal assemblages in the presence and absence of S. spallanzanii using clumps of real and mimic polychaetes. Both the real and mimic clumps had the same effect on an existing assemblage with fewer numbers of small crustaceans in the sediment under the clumps. The effects of S. spallanzanii on infaunal colonisation and larval abundances above and below the S. spallanzanii canopy were also investigated. Larval effects varied among taxa, depending on position (above and below the canopy) for bivalve larvae and presence/absence of S. spallanzanii for gastropod larvae. There was no effect of the S. spallanzanii clumps on infaunal colonisation. These results suggest that the effects of S. spallanzanii on larval abundances and colonisation may not be as significant as the effects on post-colonisation processes that structure macrofaunal assemblages in soft sediment habitats.
Publisher: Regional Euro-Asian Biological Invasions Centre Oy (REABIC)
Date: 2016
Publisher: Elsevier BV
Date: 03-2013
DOI: 10.1016/J.MARPOLBUL.2013.01.002
Abstract: We investigated the effects of the burrowing cirratulid polychaete Cirriformia filigera (Delle Chiaje, 1828) on benthic respiration and nitrogen regeneration in metal-contaminated estuarine sediments using laboratory mesocosms. C. filigera is a dominant component of assemblages in the most severely contaminated sediments within the Derwent estuary, southern Australia. In the presence of C. filigera sediment O2 consumption doubled, with approximately 55% of this increase due to their respiration and the remaining 45% attributable to oxidation reactions and increased microbial respiration associated with burrow walls. Combined NO3 and NO2 fluxes were unaffected. The addition of labile organic matter did not affect benthic fluxes, in the presence or absence of C. filigera, presumably due to the short timeframe of the experiment and naturally enriched test sediments. The results suggest that a combination of tolerance and burrowing activity enables this species to provide an ecosystem service in the removal of N from contaminated sites.
Publisher: Elsevier BV
Date: 04-2003
Publisher: Elsevier BV
Date: 03-2012
DOI: 10.1016/J.SCITOTENV.2012.01.033
Abstract: Nutrient inputs to estuarine and coastal waters worldwide are increasing and this in turn is increasing the prevalence of eutrophication and hypoxic and anoxic episodes in these systems. Many urbanised estuaries are also subject to high levels of anthropogenic metal contamination. Environmental O(2) levels may influence whether sediments act as sinks or sources of metals. In this study we investigated the effect of an extended O(2) depletion event (40 days) on fluxes of trace metals (and the metalloid As) across the sediment-water interface in sediments from a highly metal contaminated estuary in S.E. Tasmania, Australia. We collected sediments from three sites that spanned a range of contamination and measured total metal concentration in the overlying water using sealed core incubations. Manganese and iron, which are known to regulate the release of other alent cations from sub-oxic sediments, were released from sediments at all sites as hypoxia developed. In contrast, the release of arsenic, cadmium, copper and zinc was comparatively low, most likely due to inherent stability of these elements within the sediments, perhaps as a result of their refractory origin, their association with fine-grained sediments or their being bound in stable sulphide complexes. Metal release was not sustained due to the powerful effect of metal-sulphide precipitation of dissolved metals back into sediments. The limited mobilisation of sediment bound metals during hypoxia is encouraging, nevertheless the results highlight particular problems for management in areas where hypoxia might occur, such as the release of metals exacerbating already high loads or resulting in localised toxicity.
Publisher: Inter-Research Science Center
Date: 07-05-2012
DOI: 10.3354/MEPS09686
Publisher: Springer Science and Business Media LLC
Date: 02-11-2014
Publisher: Inter-Research Science Center
Date: 2005
DOI: 10.3354/MEPS298305
Publisher: Oxford University Press (OUP)
Date: 16-11-2011
DOI: 10.1111/J.1574-6941.2010.00988.X
Abstract: The effects of sediment hypoxia, resulting from increased carbon loads or decreased dissolved oxygen (DO), on nitrogen cycling in estuarine environments is poorly understood. The important role played by bacterial and archaeal ammonia oxidizers in the eventual removal of nitrogen from estuarine environments is likely to be strongly affected by hypoxic events. In this study, an analysis of the effects of different levels of sediment hypoxia (5%, 20% and 75% DO) was performed in a microcosm experiment. Changes in the nutrient fluxes related to nitrification at 5% DO were observed after 4 h. Quantification of the key nitrification gene ammonium monooxygenase (amoA) in both DNA and RNA extracts suggests that bacterial amoA transcription was reduced at both of the lower DO concentrations, while changes in DO had no significant effect on archaeal amoA transcription. There was no change in the ersity of expressed archaeal amoA, but significant change in bacterial amoA transcriptional ersity, indicative of low- and high-DO phylotypes. This study suggests that groups of ammonia oxidizers demonstrate differential responses to changes in sediment DO, which may be a significant factor in niche partitioning of different ammonia oxidizer groups.
Publisher: Wiley
Date: 31-05-2012
Publisher: Elsevier BV
Date: 04-2011
Publisher: Elsevier BV
Date: 09-2016
DOI: 10.1016/J.MARENVRES.2016.08.010
Abstract: In marine environments characterised by habitat-forming plants, the relative allocation of resources into vegetative growth and flowering is an important indicator of plant condition and hence ecosystem health. In addition, the production and abundance of seeds can give clues to local resilience. Flowering density, seed bank, biomass and epiphyte levels were recorded for the temperate seagrass Zostera nigricaulis in Port Phillip Bay, south east Australia at 14 sites chosen to represent several regions with different physicochemical conditions. Strong regional differences were found within the large bay. Spathe and seed density were very low in the north of the bay (3 sites), low in the centre of the bay (2 sites) intermediate in the Outer Geelong Arm (2 sites), high in Swan Bay (2 sites) and very high in the Inner Geelong Arm (3 sites). In the south (2 sites) seed density was low and spathe density was high. These regional patterns were largely consistent for the 5 sites s led over the three year period. Timing of flowering was consistent across sites, occurring from August until December with peak production in October, except during the third year of monitoring when overall densities were lower and peaked in November. Seagrass biomass, epiphyte load, canopy height and stem density showed few consistent spatial and temporal patterns. Variation in spathe and seed density and morphology across Port Phillip Bay reflects varying environmental conditions and suggests that northern sites may be restricted in their ability to recover from disturbance through sexual reproduction. In contrast, sites in the west and south of the bay have greater potential to recover from disturbances due to a larger seed bank and these sites could act as source populations for sites where seed production is low.
Publisher: American Chemical Society (ACS)
Date: 25-03-2011
DOI: 10.1021/ES103636D
Abstract: To determine the role of sediment denitrification in removing inputs of primary- (PE) and secondary-treated effluent (SE) from a pulp and paper mill (PPM), organic matter (OM) associated with PE (residual wood fiber) and SE (activated sludge biomass and phytoplankton) was added to estuarine intertidal sediments and denitrification rates were measured over 27 days. Labile sludge biomass and phytoplankton initially stimulated denitrification, including for pre-existing sediment N. After 2.5 d, however, denitrification was suppressed apparently due to microbial competition for N to process the refractory (high C:N) material remaining. Wood fiber suppressed denitrification throughout the experiment due to competition for N to process the refractory OM. Ultimate long-term denitrification suppression by phytoplankton is offset by initial enhanced denitrification rates. Although nutrient release during degradation of sludge biomass and wood fiber may stimulate phytoplankton production, N equivalent to 127% of the expected daily phytoplankton load was denitrified within 24 h, allowing for permanent removal of PPM-derived N. Compared to primary treatment, secondary treatment of PPM effluent has greater potential for N removal.
Publisher: Hindawi Limited
Date: 28-04-2015
DOI: 10.1111/ARE.12776
Publisher: American Chemical Society (ACS)
Date: 14-09-2010
DOI: 10.1021/ES101789V
Abstract: Stable isotope analysis of a novel combination of carbon and nitrogen pools traced inputs and processing of primary-treated (PE) and secondary-treated effluent (SE) from a paper and pulp mill (PPM) in a temperate Australian estuary. Distinct carbon stable isotope ratios of dissolved organic carbon (DOC) near the PPM outfall indicated large PE and reduced SE inputs of DOC. DOC was remineralized to dissolved inorganic carbon regardless of season, but rates were lower in winter. PE discharge in winter elevated DOC concentrations along much of the estuary. Distinct stable isotope ratios confirmed particulate organic matter (POM) input from PE and SE to the water column and into the sediment. This was relatively localized, indicating rapid POM settlement regardless of season. SE discharge increased nutrient inputs and enhanced algal productivity, particularly in summer when chlorophyll-a concentrations were elevated throughout the estuary. SE discharge reduced pCO(2) from levels associated with PE discharge. However, the estuary remained heterotrophic as subsequent respiration or decomposition of algal material offset reductions in PPM organic matter input. The influence of the PPM was apparent throughout the estuary, demonstrating the ability of anthropogenic inputs, and changes to these, to affect ecosystem functioning.
Publisher: Springer Science and Business Media LLC
Date: 03-02-2013
Publisher: American Chemical Society (ACS)
Date: 21-11-2013
DOI: 10.1021/ES402814U
Abstract: To determine the benthic transformation pathways and fate of carbon associated with secondary-treated pulp and paper mill (PPM) effluent, (13)C-labeled activated sludge biomass (ASB) and phytoplankton (PHY) were added, separately, to estuarine intertidal sediments. Over 28 days, (13)C was traced into sediment organic carbon, fauna, seagrass, bacteria, and microphytobenthos and into fluxes of dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) from inundated sediments, and carbon dioxide (CO2(g)) from exposed sediments. There was greater removal of PHY carbon from sediments (~85% over 28 days) compared to ASB (~75%). Although there was similar (13)C loss from PHY and ASB plots via DIC (58% and 56%, respectively) and CO2(g) fluxes (<1%), DOC fluxes were more important for PHY (41%) than ASB (12%). Faster downward transport and loss suggest that fauna prefer PHY, due to its lability and/or toxins associated with ASB this may account for different carbon pathways. Secondary-treated PPM effluent has lower oxygen demand than primary-treated effluent, but ASB accumulation may contribute to sediment anoxia, and respiration of ASB and PHY-derived DOC may make the water column more heterotrophic. This highlights the need to optimize secondary-treatment processes to control the quality and quantity of organic carbon associated with PPM effluent.
Publisher: Cold Spring Harbor Laboratory
Date: 08-08-2022
DOI: 10.1101/2022.08.08.503163
Abstract: Coastal aquaculture operations for feed additive species results in the release of waste into the surrounding environment, with the potential for adverse environmental change. Ubiquitous pelagic protists are sensitive to environmental changes making them potential sentinels for detecting and monitoring impacts. This study used 18S rRNA high-throughput licon sequencing as a molecular tool to study the pelagic protist community, with the aim of evaluating their potential as bioindicators of aquaculture activity in a low-oxygen, highly stratified marine embayment. S ling occurred at three different depths along a distance gradient from two leases and at three control sites. Our results showed that the ersity and composition of both phytoplankton and other protist communities were more strongly influenced by depth stratification than the aquaculture activity. Nonetheless, differential abundance and machine learning analyses revealed a suite of potential bioindicators for aquaculture activity this included the phytoplankton taxa Chrysophyceae , Gymnodiniphycidae ( Gyrodinium ), Cryptomonadales and Ciliophora ( Philasterides armatalis, Plagiopylida, and Strombidium). Among the other protists, ciliates were also more abundant in closer proximity to the leases in both surface and bottom s les. Overall, our findings indicated that the use of 18S rRNA sequencing of protist communities is a promising tool for identifying environmental changes from aquaculture in the water column.
Publisher: Springer Netherlands
Date: 2003
Publisher: Inter-Research Science Center
Date: 2007
DOI: 10.3354/MEPS340041
Publisher: Springer Science and Business Media LLC
Date: 04-2004
Publisher: Elsevier BV
Date: 03-2012
Publisher: Springer Science and Business Media LLC
Date: 03-07-2017
DOI: 10.1038/S41598-017-04806-2
Abstract: Understanding how aquatic species respond to extremes of DO and temperature is crucial for determining how they will be affected by climate change, which is predicted to increasingly expose them to levels beyond their optima. In this study we used novel animal-borne DO, temperature and depth sensors to determine the effect of extremes of DO and temperature on the vertical habitat use of Atlantic salmon Salmo salar in aquaculture cages. Salmon showed a preference for temperatures around 16.5 to 17.5 °C, however, selection of preferred temperatures was trumped by active avoidance of low DO ( % saturation) at the bottom of the cage. In addition to low DO, salmon also avoided warm surface waters ( .1 ° C), which led to a considerable contraction in the available vertical habitat. Despite their avoidance behavior, fish spent a large amount of time in waters with suboptimal DO ( % saturation). These results show that vertical habitat contraction could likely be a significant consequence of climate change if the reduction in DO outpaces the increase in hypoxia tolerance through local adaptation. They furthermore highlight that site-specific environmental conditions and stock-specific tolerance thresholds may need to be considered when determining stocking densities.
Publisher: Cold Spring Harbor Laboratory
Date: 08-03-2022
DOI: 10.1101/2022.03.07.483349
Abstract: Finfish aquaculture is one of the fastest-growing primary industries globally and is increasingly common in coastal ecosystems. Bacterioplankton is ubiquitous in marine environment and respond rapidly to environmental changes. However, little is known about the effect of the aquaculture in the bacterioplankton community. This study aims to examine aquaculture effects in the composition and functional profiles of the bacterioplankton community using licon sequencing along a distance gradient from two finfish leases in a marine embayment. Our results revealed natural stratification in bacterioplankton strongly associated to NOx, conductivity, salinity, temperature and PO 4 . Among the differentially abundant bacteria in leases, we found members associated with nutrient enrichment and aquaculture activities. Abundant predicted functions near leases were assigned to organic matter degradation, fermentation, and antibiotic resistance. This study provides a first effort to describe changes in the bacterioplankton community composition and function due to finfish aquaculture in a semi-enclosed and highly stratified embayment.
Publisher: Springer Science and Business Media LLC
Date: 2004
Publisher: Springer Science and Business Media LLC
Date: 02-07-2015
Publisher: Inter-Research Science Center
Date: 19-01-2016
DOI: 10.3354/MEPS11531
Publisher: Inter-Research Science Center
Date: 06-08-2013
DOI: 10.3354/AME01642
Publisher: Elsevier BV
Date: 05-2006
Publisher: Inter-Research Science Center
Date: 2002
DOI: 10.3354/MEPS241099
Publisher: Inter-Research Science Center
Date: 17-11-2006
DOI: 10.3354/MEPS326049
Publisher: Springer Science and Business Media LLC
Date: 19-10-2016
Publisher: Springer Science and Business Media LLC
Date: 22-02-2014
DOI: 10.1007/S00248-014-0376-7
Abstract: Sediment organic loading has been shown to affect estuarine nitrification and denitrification, resulting in changes to sediment biogeochemistry and nutrient fluxes detrimental to estuarine health. This study examined the effects of organic loading on nutrient fluxes and microbial communities in sediments receiving effluent from a paper and pulp mill (PPM) by applying microcosm studies and molecular microbial ecology techniques. Three sites near the PPM outfall were compared to three control sites, one upstream and two downstream of the outfall. The control sites showed coupled nitrification-denitrification with minimal ammonia release from the sediment. In contrast, the impacted sites were characterised by nitrate uptake and substantial ammonia efflux from the sediments, consistent with a decoupling of nitrification and denitrification. Analysis of gene ersity demonstrated that the composition of nitrifier communities was not significantly different at the impacted sites compared to the control sites however, analysis of gene abundance indicated that whilst there was no difference in total bacteria, total archaea or ammonia-oxidising archaea (AOA) abundance between the control and impacted sites, there was a significant reduction in ammonia-oxidising bacteria (AOB) at the impacted sites. The results of this study demonstrate an effect of organic loading on estuarine sediment biogeochemistry and highlight an apparent niche differentiation between AOA and AOB.
No related grants have been discovered for Donald Ross.