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Evidence for the decline in native fish communities in the lowland Goulburn Catchment has been based primarily on studies investigating changes to environmental conditions as a result of river regulation. The present study aggregates... more
Evidence for the decline in native fish communities in the lowland Goulburn Catchment has been based primarily on studies investigating changes to environmental conditions as a result of river regulation. The present study aggregates historical fisheries data to spatially compare native fish communities in different parts of the catchment. Multivariate analyses demonstrate that distinctly different community compositions are found in different parts of the catchment. Eildon Dam, a deep release reservoir, has drastically altered the hydrology and water quality of the upper Goulburn River, and ordination analyses show that this has created both physical and artificial barriers to movement of native fish into the main channel. Concurrently, fisheries data from the upper main channel show the community is highly divergent compared to the remaining catchment. Further downstream, Goulburn Weir creates a barrier to fish movement between Lake Nagambie and the lower Goulburn Catchment, and a...
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Estuaries provide the final stage of nitrogen processing before its release into coastal waters. However, residence time, oxygen conditions and hydraulic mixing determine the nitrogen removal capacity of an estuary. Long residence times... more
Estuaries provide the final stage of nitrogen processing before its release into coastal waters. However, residence time, oxygen conditions and hydraulic mixing determine the nitrogen removal capacity of an estuary. Long residence times can lead to low oxygen conditions significantly affecting nutrient transformation pathways including, but not limited to, inhibition of nitrification and the competition for nitrate between denitrification and dissimilatory nitrate reduction to ammonium (DNRA). The study site for this research, the Yarra River estuary, is a shallow (3 – 5m) salt wedge estuary prone to hypoxia resulting from the extended residence time of the bottom waters during low flow events. The estuary is one of the main freshwater nitrogen inputs into Port Phillip Bay (PPB), a nitrogen limited system. This research examined nitrogen processing over the period 2009 – 2011, extending over two summers of contrasting rainfall. Nitrogen loads were driven by rainfall in the catchment...
Nutrient spiralling measurements were conducted in Lyrebird Creek, a forested stream in the Dandenong Ranges, Victoria, Australia. Spiralling indices from several nutrient ( ${\text{NH}}^{ + }_{4} $ , ${\text{PO}}^{{3 - }}_{4} $ )... more
Nutrient spiralling measurements were conducted in Lyrebird Creek, a forested stream in the Dandenong Ranges, Victoria, Australia. Spiralling indices from several nutrient ( ${\text{NH}}^{ + }_{4} $ , ${\text{PO}}^{{3 - }}_{4} $ ) enrichment experiments were correlated with seasonal variation in factors thought to control nutrient uptake, i.e., temperature, light and algal biomass. It was hypothesized that nutrient uptake would be higher in summer as increased temperatures would promote both biotic and abiotic processes and higher light levels in summer would stimulate photosynthesis. However, results did not support this hypothesis. Uptake length for ${\text{NH}}^{ + }_{4} - {\text{N}}$ and ${\text{PO}}^{{3 - }}_{4} - {\text{P}}$ and uptake velocity were not correlated with chlorophyll-a, light or temperature (r 2 < 0.30, P > 0.1) despite the seasonality of these biophysical factors (r 2 > 0.42, P < 0.02). Lyrebird Creek might had no seasonal trend in nutrient uptake an...
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This study developed an analytical approach for sub-ppb level detection and confirmation of 13 pharmaceuticals and personal care products (PPCPs) in water samples using ultra high pressure liquid chromatography hyphenated with a... more
This study developed an analytical approach for sub-ppb level detection and confirmation of 13 pharmaceuticals and personal care products (PPCPs) in water samples using ultra high pressure liquid chromatography hyphenated with a quadrupole Orbitrap mass spectrometer (UHPLC- Q-Orbitrap-MS). Sample preparation was performed by using solid phase extraction (SPE) employing hydrophilic-lipophilic balance cartridges, with elution of sorbed analytes using methanol. Acceptable automatic gain control (AGC) target and maximum injection time (IT) were 1×10 and 200ms, respectively, resulting in a mass accuracy &lt;2ppm. High response signals with sufficient data points per peaks (20-30) were obtained whilst maintaining high resolution of approximately 70,000 full width at half maximum. Extracted ion chromatograms provided quantitative analysis with linearity (R) ranging from 0.9875 to 0.9993 and method detection limits ranging from 0.01-0.61ngmL. Compounds were further analysed by MS/MS analysis, with the MS operated in parallel reaction monitoring (PRM) mode under precursor ion analysis intervals and collision energies chosen for the different PPCPs. The developed method was applied to analyse water samples obtained from sources in Victoria, Australia.
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Synthesized ferrihydrite (Fh) with the dosages of 0.3, 0.6 and 0.9 cm thickness (labeled as Fh, 2Fh and 3Fh respectively, equivalent to 248-774 g/m(2)) were deployed to serve as the reactive capping layer covering the Ornamental Lake... more
Synthesized ferrihydrite (Fh) with the dosages of 0.3, 0.6 and 0.9 cm thickness (labeled as Fh, 2Fh and 3Fh respectively, equivalent to 248-774 g/m(2)) were deployed to serve as the reactive capping layer covering the Ornamental Lake sediments, the Royal Botanic Garden of Melbourne. The sediments were exposed to an alternating regime of oxic/anoxic conditions using laboratory reactors for 45 days. Dynamics of dissolved oxygen (DO), pH, filterable reactive phosphorus (FRP), filterable ammonium (NH4(+)), nitrate and nitrite (NOx), total dissolved nitrogen (TDN) and dissolved iron (Fe) of overlying water were examined. After incubation, O2 and H2S profiles across the water-sediment interface were observed with microelectrodes. The element distributions in the upper sediments were tested as well. Results showed that DO and pH kept relatively stable during oxic period, while decreased significantly during anoxic period. Fh cappings decreased both DO and pH, and inhibited the release of F...
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... Additionally, a number of quantitative approaches (particularly Bayesian approaches andmulti-criteria decision-making) have been identified as having the potential to include ... InMulticriteria Decision-Making: Advances in MCDM... more
... Additionally, a number of quantitative approaches (particularly Bayesian approaches andmulti-criteria decision-making) have been identified as having the potential to include ... InMulticriteria Decision-Making: Advances in MCDM Models, Algorithms, Theory and Applications ...
Research Interests: Decision Making, Stakeholders, Natural Resource Management, Ecology, Risk Management, and 15 moreRisk assessment, Multi Criteria Decision Making, Risk Analysis, Aquatic Ecosystem, Ecological Risk Assessment, Expert Opinion, Decision making process, Bayesian model, Contaminants, Risk Assessment, Ecological Applications, Stakeholder Involvement, ENVIRONMENTAL SCIENCE AND MANAGEMENT, Ecological Risk, and Bayesian approach
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ABSTRACT Nitrate (NO3−) contamination in groundwater is a worldwide phenomenon and a pervasive environmental problem, particularly when NO3−-enriched groundwater discharges into a nitrogen-limited estuarine environment through submarine... more
ABSTRACT Nitrate (NO3−) contamination in groundwater is a worldwide phenomenon and a pervasive environmental problem, particularly when NO3−-enriched groundwater discharges into a nitrogen-limited estuarine environment through submarine groundwater discharge (SGD). SGD is often associated with eutrophication which ultimately alters the coastal ecology of the receiving surface water. Identifying the sources and transformation processes of NO3− in and within the groundwater discharged to the estuary provides baseline information underpinning effective management of the coastal environments. The aims of this study were to: (1) understand the linkages between aquifers at different depths and in different parts of a catchment in the south east of Australia which underlies a eutrophic estuary (the Werribee River estuary); (2) identify and apportion the NO3− source(s) to the aquifers; and (3) identify the major transformation processes of NO3− in the aquifer along the groundwater flowpath. The average δ15N–NO3− values of the deep groundwater (+21 ‰) at the SGD hotspot lies between the enriched δ15N–NO3− (~+33 ‰) at the western side of the estuary and relatively depleted δ15N–NO3− (~+14 ‰) at the eastern side; indicating that the aquifers from both sides of the estuary are connected at the SGD hotspot. The isotopic composition of NO3−, together with the concentrations of excess nitrogen (N2) gas also revealed that SGD-derived NO3− originated predominantly from agricultural activity. Denitrification was not the primary NO3− removal process in the oxic groundwater. Instead, mixing between sewage (69 %) and fertiliser-derived (31 %) NO3− appeared to be the main control over the observed NO3− concentrations (~1,000 µmol L−1) and the relatively enriched δ15N–NO3− values (+20 to +23 ‰) in the deeper sand and gravel aquifer at the groundwater discharge zone. These results suggest that groundwater is a critical source of NO3− to the receiving surface water and as such should always be included not only in the regional but also the global N budget. The outcome of the study is a key to sustainable management of coastal aquatic ecosystems.
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ABSTRACT Herein, we report the synthesis of two lanthanide-based chemosensors, Tb-5 and Eu-6, designed to sense free zinc ions (Zn2+) in aqueous solutions. The Tb-5 complex features a bis(2-pyridinylmethyl)amine moiety as a... more
ABSTRACT Herein, we report the synthesis of two lanthanide-based chemosensors, Tb-5 and Eu-6, designed to sense free zinc ions (Zn2+) in aqueous solutions. The Tb-5 complex features a bis(2-pyridinylmethyl)amine moiety as a zinc(II)-responsive lanthanide-sensitising &#39;antenna&#39;, while Eu-6 incorporates a quinoline-based moiety for this purpose. Luminescence enhancements of 210% and 340% are observed upon addition of Zn2+ ions to Tb-5 and Eu-6, respectively. Both sensors are selective for Zn2+ ions over several other cations of environmental significance.
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A reverse flow injection method (rFIA) based on the Winkler titration chemistry, is reported for the determination of dissolved oxygen (DO) in natural waters. Manganese(II) sulfate is injected into a continuously flowing stream of sample... more
A reverse flow injection method (rFIA) based on the Winkler titration chemistry, is reported for the determination of dissolved oxygen (DO) in natural waters. Manganese(II) sulfate is injected into a continuously flowing stream of sample and subsequently merges with a reagent stream of sodium hydroxide and sodium iodide. Manganese(II) hydroxide that is formed reacts with DO in the sample to form an oxidized manganese hydroxyoxide floc. Addition of 10% sulfuric acid dissolves this floc, and under acidic conditions, the triiodide ion formed is detected by photometry in a flow through cell at a wavelength of 440 nm. The method is rapid (48 measurements per h), repeatable (R.S.D. ca. 3%, n=3), and has a calculated detection limit of 0.25 mg l(-1) (P=0.001). No interference from nitrite or ferrous ions was observed at concentrations typically found in natural waters. The method has been successfully applied to on-line measurement of DO in sediment respiration reactors.
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A severe protracted drought between 1997 and 2009 has altered the physical and chemical hydrology of a series of lakes in the Corangamite Basin of southeast Australia. Leading up to the drying out of most lakes (many for the first time on... more
A severe protracted drought between 1997 and 2009 has altered the physical and chemical hydrology of a series of lakes in the Corangamite Basin of southeast Australia. Leading up to the drying out of most lakes (many for the first time on record), we document the changes in lakes&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; water quantity (water levels and inundation), salinity (Cl concentrations), salinity processes (Cl/Br ratios), nutrient concentrations and ratios (ammonia, phosphate and NOx (nitrate and nitrite)) and algae (as chlorophyll-a) for six lakes. All lakes show record declines in inundated areas and increases in salinity from pre-drought (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;1997) to drought conditions. However, the magnitude of change in salinity varies for different lakes, and there is no systematic change in the controls on lake salinity processes. Four lakes show no change in salinity processes, one lake shows the beginnings of change; where halite dissolution reactions increased closer to the time of the lake drying up, and another lake shows a marked shift from predominantly evaporation to the cyclic dissolution and precipitation of halite. Changes in filterable reactive phosphorus (FRP) values and lake N and P limitation predictions also showed little systematic correlation with changes in lake salinity, and nutrient values varied between lakes and over time. The decline in NO(x) concentrations in lakes where electrical conductivity (EC) values were above 100 mS/cm indicates some correlation with changes in salinity. Largely, these lakes exhibit individual changes in water quality parameters and salinity processes in response to the drought, indicating that while the stress of drought is regional, the hydrochemical response is local. In future changing climates, these results suggest that the catchment adaption strategies will require comprehensive plans for individual lake systems.
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Research Interests: Microbiology, Carbon, Microbial Ecology, Ecology, Ecological Indicator, and 15 moreMagnesium, Denitrification, Bacteria, Nitrogen, Community Structure, Environmental Variables, Grain size, Environmental Impact, Fresh water, Chemical Properties, Community Composition, Geologic Sediments, Microbial community, Molecular Sequence Data, and Environmental factor
Urban land use degrades stream ecosystems, but the nature and mechanisms of its effects on ecological processes, such as leaf breakdown, are poorly understood. Leaf litter breakdown has pivotal effects on energy and nutrient flows in... more
Urban land use degrades stream ecosystems, but the nature and mechanisms of its effects on ecological processes, such as leaf breakdown, are poorly understood. Leaf litter breakdown has pivotal effects on energy and nutrient flows in stream ecosystems. Our goals were to ...
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ABSTRACT The reaction between sulfate and the Cr(III) hydrolytic dimer, [(H2O)4Cr(μ-OH)2Cr(OH2)4]4+, has been followed in the pH range 3.5–4.4, [sulfate]=0.1–0.3 M, T=25 °C and I=1.0 M and shown to involve two clearly separable processes:... more
ABSTRACT The reaction between sulfate and the Cr(III) hydrolytic dimer, [(H2O)4Cr(μ-OH)2Cr(OH2)4]4+, has been followed in the pH range 3.5–4.4, [sulfate]=0.1–0.3 M, T=25 °C and I=1.0 M and shown to involve two clearly separable processes: monodentate attachment of sulfate (anation) to give [(H2O)4Cr(μ-OH)2Cr(SO4)(OH2)3]2+ followed by ring closure to give a sulfato bridged dimer, [(H2O)3Cr(μ-OH)2(μ-SO4)Cr(OH2)3]2+. Equilibrium measurements have shown that the first step is irreversible under the conditions of the kinetic measurements. Although definite conclusions about the reversibility of bridge formation could not be made this process is also likely to be irreversible. The observed rate constant for the anation process was found to be independent of [sulfate] suggesting that extensive ion-pairing occurs between the oppositely charged reactants. The rate constants for both anation and bridge formation were found to be linearly dependent on 1/[H+]. This is attributed to deprotonation of dimer-sulfate ion-pairs (charge 2+) and the monodentate sulfato complex (charge 2+). The linear dependence also suggests that the concentration of deprotonated species is low in the pH range 3.5–4.4. This is reasonable since pKa1 for ions of this charge are usually greater than 5. From the kinetic data, rate accelerations of at least 30-fold have been estimated to accompany deprotonation of the reactants. They are of similar magnitude to those reported previously for other reactions involving the Cr(III) hydrolytic dimer, viz. dimerization of dimer to give tetramer and intramolecular interconversion between singly and doubly bridged dimer forms. It is concluded that deprotonated sulfato-dimer species play an important part in the tanning process since their greater reactivity in substitution processes will aid in the cross-linking of collagen.
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ABSTRACT For the reduction of aqueous Fe(H2O)6(3+) by Co([9]aneS3)2(2+), over a wide range (0.02-0.8 mol kg-1) of ionic strength I, the rate constant k12 varies according to ln(k12/k12(0)) = 2AZ1Z2I1/2/(1 + BaI1/2), where A and B are the... more
ABSTRACT For the reduction of aqueous Fe(H2O)6(3+) by Co([9]aneS3)2(2+), over a wide range (0.02-0.8 mol kg-1) of ionic strength I, the rate constant k12 varies according to ln(k12/k12(0)) = 2AZ1Z2I1/2/(1 + BaI1/2), where A and B are the Debye-Huckel parameters and k12(0) = 369 +/- 7 with a = 798 +/- 10 pm for CF3SO3- media at 25-degrees-C. The pressure dependence of the electrode potential difference DELTAE gives the volume of reaction DELTAV12(0) = -17.1 +/- 0.4 cm3 mol-1 at I = 0.26 mol kg-1. The volume of activation DELTAV12double-dagger (-15.9 +/- 0.3 and -13.7 +/- 0.4 cm3 mol-1 for 0.1 mol kg-1 CF3SO3- and ClO4-media, respectively) agrees well with that calculated from a volume cross relation DELTAV12double-dagger = 1/2(DELTAV11double-dagger + DELTAV22double-dagger + DELTAV12(0)) + C, derived from the Marcus cross relation for k,2 (J. Phys. Chem. 1968, 72, 891), where DELTAV11double-dagger and DELTAV22double-dagger are for the Fe(H2O)6(3+/2+) and Co([9]aneS3)2(3+/2+) self-exchange reactions and the small contribution C incorporates the pressure dependence of Marcus&#39; f. For the reduction of aqueous Fe(H2O)6(3+) by Co(sepulchrate)2+ at 1.8-degrees-C, for which DELTAE is large (1.03 V), k12 is 130-fold slower, and DELTAV12double-dagger (-5.0 cm3 mol-1) is 4-5 cm3 mol-1 more positive, than predicted by the cross relations. These results suggest the usefulness of the volume cross relation as a mechanistic criterion, at least for reactions with moderate DELTAE; in particular, they militate against nonadiabaticity as the cause of the perceived slowness of cross reactions involving the Fe(H2O) 6(3+/2+) couple. Conversely, the volume cross relation affords a means of obtaining experimentally inaccessible volumes of activation for adiabatic outersphere redox processes in water.
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ABSTRACT The Yarra River Estuary is a salt wedge estuary prone to hypoxia in the bottom waters during low flow periods. Rates of denitrification and dissimilatory nitrate reduction to ammonium (DNRA) were quantified using 15N in relation... more
ABSTRACT The Yarra River Estuary is a salt wedge estuary prone to hypoxia in the bottom waters during low flow periods. Rates of denitrification and dissimilatory nitrate reduction to ammonium (DNRA) were quantified using 15N in relation to oxygen, nitrate and available reductants. Denitrification was the dominant nitrate reduction pathway under all oxygen conditions, however, DNRA increased from &lt;1% under hypoxic conditions (&lt;50 μmol L−1 O2) to ∼18% of total nitrate reduction under oxygen saturation in the water column in intact core incubations. Microprofiles of nitrate reduction pathways in intact cores using diffusive equilibrium in thin layer (DET) gels showed significant rates of DNRA only occurred under oxic conditions in the presence of Fe2+. Cores incubated anoxically, developed free sulfide within the porewater, had very low concentrations of Fe2+ and low rates of DNRA. Slurry incubations with varying concentrations of NO3− showed that denitrifying bacteria had a higher affinity than nitrate ammonifying bacteria with Km values of 49 and 86 μmol L−1 for denitrification and DNRA, respectively, however, this could not explain the change in the rates of DNRA relative to denitrification observed. Further slurry incubations to investigate the relationship between DNRA and Fe2+ oxidation were inconclusive and complicated by very high backgrounds of sorbed (HCl extractable) Fe2+. Addition of Fe2+ to the slurry did not stimulate denitrification compared to a control (no Fe2+ addition), however, there was a significant decrease in the Fe2+ concentration over the period where DNRA occurred in the Fe2+ addition treatment, and no significant decrease in the control treatment. The ratio of DNRA to Fe2+ consumption was 15 ± 6 and 7 ± 3 for the Fe2+ and control treatments, respectively. We suggest reduced rates of DNRA under anoxic conditions can be explained by the binding of Fe2+ with free sulfides and the formation of FeS removing available Fe2+ for DNRA.
Research Interests: Geology and Geochemistry
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ABSTRACT The effectiveness of revegetation is usually gauged by responses in biodiversity, which may differ between isolated replanted patches. The ecological value of revegetation may be detected more effectively by monitoring ecosystem... more
ABSTRACT The effectiveness of revegetation is usually gauged by responses in biodiversity, which may differ between isolated replanted patches. The ecological value of revegetation may be detected more effectively by monitoring ecosystem processes. In‐stream metabolism has been much modified by the degradation of riparian vegetation in agricultural landscapes around the world. We sought to determine whether the spatial scale typical of most riparian replanting projects (i.e. Metabolism is a functional measure that incorporates gross primary production (GPP), ecosystem respiration (ER) and the difference between them [net ecosystem productivity (NEP)]. We hypothesised that replanted reaches would have lower GPP (due to greater canopy shading) and greater ER (governed by larger terrestrial energy inputs) compared with pasture reaches.We measured metabolism in paired reaches within four agricultural streams. Two streams had an untreated pasture reach contrasted with a reach replanted with native woody vegetation &gt;17 years ago. The other two streams had similar riparian vegetation condition adjacent to both reaches, to act as reference sites.Mean daily GPP (0.27–4.9 g O2 m−2 day−1) and ER (1.1–22 g O2 m−2 day−1) were within the range of values recorded previously in agricultural streams elsewhere. Replanted reaches had rates of NEP lower than upstream untreated reaches at treatment sites, but NEP was similar between reaches at reference sites.The effects of replanting on stream ecosystem processes are detectable even when the spatial scale of restoration is relatively small in a whole‐of‐catchment context. Land managers can protect and restore vegetation at feasible spatial scales and benefit ecosystem processes. Ecosystem metabolism should be included in the range of responses that need to be monitored to provide a complete picture of the effectiveness of stream restoration.
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ABSTRACT Organic matter provides energy and nutrients to aquatic systems. Alterations to its sources and processing have repercussions for water quality and food-web stability and structure. Despite worldwide recognition of the impacts of... more
ABSTRACT Organic matter provides energy and nutrients to aquatic systems. Alterations to its sources and processing have repercussions for water quality and food-web stability and structure. Despite worldwide recognition of the impacts of urbanisation, there is limited understanding of the relative importance of catchment-scale urban stormwater drainage connection and reach-scale riparian vegetation on organic matter sources.We investigated the effects of catchment-scale urban stormwater drainage connection and reach-scale riparian vegetation cover on organic matter sources in small streams. Using stable isotopes and elemental ratios (i.e. δ13C, δ15N and C : N), we traced the origin of microbially respired carbon and standing stocks of dissolved organic carbon (DOC), suspended particulate organic matter (POM) and benthic coarse particulate organic matter (CPOM).Catchment-scale urban stormwater drainage connection significantly increased the contribution of labile organic matter to POM and DOC standing stocks. Greater POM lability was a product of increased inputs of autochthonous organic matter in more heavily urbanised streams, although the origin of labile DOC was less clear.While reach-scale riparian vegetation was the most likely source of the terrestrially dominated CPOM observed across most sites, increasing cover had no significant effect on the origin of POM or DOC standing stocks. We conclude that catchment-scale stormwater drainage impacts overwhelm the effects of reach-scale riparian vegetation on the sources and lability of POM and DOC in small streams.Our results suggest that the protection or restoration of riparian vegetation, in the absence of modifications to catchment-scale stormwater drainage connection, is insufficient to mitigate the effects of urbanisation on organic matter sources, lability and processing in these small streams.
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Environmental Context.Effective management of eutrophication and resultant major algal blooms requires accurate assessment of the importance of internal (sediment-based) as well as external, sources of phosphorus to susceptible aquatic... more
Environmental Context.Effective management of eutrophication and resultant major algal blooms requires accurate assessment of the importance of internal (sediment-based) as well as external, sources of phosphorus to susceptible aquatic ecosystems. The high spatial variability in pore water filterable reactive phosphorus (FRP) necessitates extensive sampling, and rapid flow injection methods overcome many of the difficulties in maintaining sample integrity. A simple flow injection manifold has been developed to prevent major sulfide interference with FRP determination and therefore enable accurate phosphate measurements. .Simple on-line sulfide removal using potassium permanganate (KMnO4) was incorporated into a spectrophotometric flow injection (FI) system for phosphate determination using molybdenum blue with ascorbic acid as the reductant. Excess KMnO4 was reduced before the sample zone passed through the detector and the method effectively removed all sulfide interference. Withou...
Research Interests: Earth Sciences, Computational Chemistry, Climate Change, Atmospheric Chemistry, Electrochemistry, and 15 moreCatalysis, Biotechnology, Astrochemistry, Biogeochemical cycles, Capillary electrophoresis, Environmental Chemistry, Chemical Oceanography, Ab initio calculations, DNA, Educational, Biomagnification, Ecosystems, CHEMICAL SCIENCES, Contaminants, and Environmental
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Experimental studies assessing climatic effects on ecological communities have typically applied static warming treatments. Although these studies have been informative, they have usually failed to incorporate either current or predicted... more
Experimental studies assessing climatic effects on ecological communities have typically applied static warming treatments. Although these studies have been informative, they have usually failed to incorporate either current or predicted future, patterns of variability. Future climates are likely to include extreme events which have greater impacts on ecological systems than changes in means alone. Here, we review the studies which have used experiments to assess impacts of temperature on marine, freshwater and terrestrial communities, and classify them into a set of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;generations&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; based on how they incorporate variability. The majority of studies have failed to incorporate extreme events. In terrestrial ecosystems in particular, experimental treatments have reduced temperature variability, when most climate models predict increased variability. Marine studies have tended to not concentrate on changes in variability, likely in part because the thermal mass of oceans will moderate variation. In freshwaters, climate change experiments have a much shorter history than in the other ecosystems, and have tended to take a relatively simple approach. We propose a new &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;generation&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; of climate change experiments using down-scaled climate models which incorporate predicted changes in climatic variability, and describe a process for generating data which can be applied as experimental climate change treatments.
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Understanding effects of climate change on ecosystems will require a diverse range of approaches. We proposed using downscaled climate models to generate realistic weather scenarios as experimental treatments. Kreyling et al. propose a... more
Understanding effects of climate change on ecosystems will require a diverse range of approaches. We proposed using downscaled climate models to generate realistic weather scenarios as experimental treatments. Kreyling et al. propose a gradient approach to determine the shape of response functions. These approaches are different, but highly complementary.
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Clustering of multivariate data is a commonly used technique in ecology, and many approaches to clustering are available. The results from a clustering algorithm are uncertain, but few clustering approaches explicitly acknowledge this... more
Clustering of multivariate data is a commonly used technique in ecology, and many approaches to clustering are available. The results from a clustering algorithm are uncertain, but few clustering approaches explicitly acknowledge this uncertainty. One exception is Bayesian mixture modelling, which treats all results probabilistically, and allows comparison of multiple plausible classifications of the same data set. We used this
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... Des 1 ; Parsons, Tony 2 ; Moore, Natasha 3 ; Grace, Mike 4 ; Liang, Ashley 5. Abstract: Norske Skog Paper Mills (Australia) Ltd has, over the last 2 years, been conducting an Ecological Risk Assessment (ERA) on its effluent discharge... more
... Des 1 ; Parsons, Tony 2 ; Moore, Natasha 3 ; Grace, Mike 4 ; Liang, Ashley 5. Abstract: Norske Skog Paper Mills (Australia) Ltd has, over the last 2 years, been conducting an Ecological Risk Assessment (ERA) on its effluent discharge into the upper Derwent estuary, in southern ...