ORCID Profile
0000-0003-4288-8530
Current Organisation
Australian National University
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Oceanography | Chemical Oceanography | Biological Oceanography | Marine Geoscience | Chemical Oceanography | Geochronology And Isotope Geochemistry | Physical Oceanography | Isotope Geochemistry | Biochemistry And Cell Biology Not Elsewhere Classified | Geology | Environmental Science and Management | Geochemistry | Global Change Biology | Natural Resource Management | Glaciology | Climatology (Incl. Palaeoclimatology) | Geochronology | Climate Change Processes | Ecological Impacts of Climate Change | Environmental Chemistry (Incl. Atmospheric Chemistry) | Environmental Sciences Not Elsewhere Classified | Geochemistry Not Elsewhere Classified
ANZSRC Socio-Economic Objective (SEO)
Effects of Climate Change and Variability on Antarctic and Sub-Antarctic Environments (excl. Social Impacts) | Antarctic and Sub-Antarctic Oceanography | Climate change | Effects of Climate Change and Variability on Australia (excl. Social Impacts) | Physical and chemical conditions | Physical and Chemical Conditions of Water in Marine Environments | Oceanic processes (excl. climate related) | Physical and Chemical Conditions of Water in Coastal and Estuarine Environments | Expanding Knowledge in the Earth Sciences | Ecosystem Adaptation to Climate Change | Land and water management | Climate Variability (excl. Social Impacts) | Marine Oceanic Processes (excl. climate related) | Climate variability | Physical and chemical conditions | Expanding Knowledge in the Environmental Sciences | Expanding Knowledge in the Physical Sciences | Marine Flora, Fauna and Biodiversity |
Related Links
Publications
Zinc speciation in Lakes Manapouri and Hayes, New Zealand
Publisher: CSIRO Publishing
Date: 2001
DOI: 10.1071/MF00073
Abstract: A study of zinc complexation in Lakes Manapouri and Hayes revealed that zinc speciation in both lakes is dominated by its complexation to natural organic ligands. In Lake Manapouri, dissolved zinc concentrations increased from 0.9 nM in surface waters to ~1.4 nM at depth. Ligand concentrations for this lake were relatively uniform with depth, with values ranging between 2.9 and 4.2 nM. A similar ligand concentration was measured for Lake Hayes, which had a surface zinc concentration of 0.46 nM. Conditional stability constants (log K) for the complexation of zinc to these ligands were high,with values ranging between 10.0 and 11.1. Calculated free Zn 2+ concentrations for both lakes were in the low picomolar range (5—48 pM). Such low free Zn 2+ levels may limit the growth of some phytoplankton in both lakes.
Pelagic iron cycling during the subtropical spring bloom, east of New Zealand
Publisher: Elsevier BV
Date: 03-2014
Seasonality of phytoplankton growth limitation by iron and manganese in subantarctic waters
Publisher: Wiley
Date: 06-2022
Chromium biogeochemistry and stable isotope distribution in the Southern Ocean
Publisher: Elsevier BV
Date: 10-2019
Arsenic species determination in biological tissues by HPLC-ICP-MS and HPLC-HG-ICP-MS
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/CH04094
Abstract: The use of high-pressure liquid chromatography coupled directly or by a hydride generation system to an inductively coupled plasma mass spectrometer for the unambiguous measurement of 13 arsenic species in marine biological extracts is described. The use of two chromatography systems a Supelcosil LC-SCX cation-exchange column eluted with a 20 mM pyridine mobile phase adjusted to pH 2.2 and 2.6 with formic acid, with a flow rate of 1.5 mL min−1 at 40°C, and a Hamilton PRP-X100 anion-exchange column eluted with 20 mM NH4H2PO4 buffer at pH 5.6, with a flow rate of 1.5 mL min−1 at 40°C, was required to separate and quantify cation and anion arsenic species. Under these conditions, arsenous acid could not be separated from other arsenic species and required the use of an additional hydride generation step. Arsenic species concentrations in a locally available Tasmanian kelp (Durvillea potatorum), a certified reference material (DORM-2), and a range of commercially available macroalgae supplements and sushi seaweeds have been measured and are provided for use as in-house quality control s les to assess the effectiveness of s le preparation, extraction, and measurement techniques.
A simple colorimetric method for determining seawater alkalinity using bromophenol blue
Publisher: Wiley
Date: 07-2018
DOI: 10.1002/LOM3.10253
Trace metal cycling in the Whau Estuary, Auckland, New Zealand
Publisher: CSIRO Publishing
Date: 2008
DOI: 10.1071/EN07077
Abstract: Environmental context. The accumulation of trace metals from urban runoff is a serious environmental concern. In the present paper we show that, in the case of the Whau Estuary, Auckland, New Zealand, there is a significant particulate Zn input, of which a significant amount of Zn is lost from the particulate phase into the dissolved phase within the water column, and via molecular diffusion across the water–sediment interface. The present study shows that changes in the chemical speciation of Zn, associated with changes in salinity, play a major role in regulating the recycling of this metal between the particulate and dissolved phases. Abstract. Dissolved Zn, Cd, Cu, Fe, and Pb concentrations were measured along a salinity gradient in the Whau Estuary, Auckland, New Zealand. We found a mid-salinity maximum in dissolved Zn and Cd concentrations, consistent with significant loss of these metals from the particulate phase into the dissolved phase. Changes in the chemical speciation of these two metals were coupled to changes in salinity and this was the major driver for Zn and Cd loss from particulate material. Contrastingly, Cu concentrations were conservative with salinity, whereas there was significant scavenging of Fe and Pb from the dissolved phase into the particulate phase. Analysis of sediment pore-water metal concentrations indicated a peak in Zn concentration within the suboxic layer. The peak occurred at a shallower depth than those for Mn and Fe. The concentration gradient across the sediment–water interface suggests that diffusional loss of Zn from the sediment pore water into the overlying water column was occurring. Conversely, the diffusion of Cu from the water column into the sediment pore water was likely to occur because pore-water Cu concentrations were lower than the overlying water column concentrations. The results from the present study show the importance of chemical speciation and the lability of metals attached to particulate material as potentially being a critical determinant on sediment metal concentrations.
Measurement of methyl mercury (I) and mercury (II) in fish tissues and sediments by HPLC-ICPMS and HPLC-HGAAS
Publisher: Elsevier BV
Date: 07-2011
DOI: 10.1016/J.TALANTA.2011.03.022
Abstract: A procedure for the extraction and determination of methyl mercury and mercury (II) in fish muscle tissues and sediment s les is presented. The procedure involves extraction with 5% (v/v) 2-mercaptoethanol, separation and determination of mercury species by HPLC-ICPMS using a Perkin-Elmer 3 μm C8 (33 mm×3 mm) column and a mobile phase 3 containing 0.5% (v/v) 2-mercaptoethanol and 5% (v/v) CH(3)OH (pH 5.5) at a flow rate 1.5 ml min(-1) and a temperature of 25°C. Calibration curves for methyl mercury (I) and mercury (II) standards were linear in the range of 0-100 μgl(-1) (r(2)=0.9990 and r(2)=0.9995 respectively). The lowest measurable mercury was 0.4 μgl(-1) which corresponds to 0.01 μgg(-1) in fish tissues and sediments. Methyl mercury concentrations measured in biological certified reference materials, NRCC DORM - 2 Dogfish muscle (4.4±0.8 μgg(-1)), NRCC Dolt - 3 Dogfish liver (1.55±0.09 μgg(-1)), NIST RM 50 Albacore Tuna (0.89±0.08 μgg(-1)) and IRMM IMEP-20 Tuna fish (3.6±0.6 μgg(-1)) were in agreement with the certified value (4.47±0.32μgg(-1), 1.59±0.12 μgg(-1), 0.87±0.03 μgg(-1), 4.24±0.27 μgg(-1) respectively). For the sediment reference material ERM CC 580, a methyl mercury concentration of 0.070±0.002 μgg(-1) was measured which corresponds to an extraction efficiency of 92±3% of certified values (0.076±0.04 μgg(-1)) but within the range of published values (0.040-0.084 μgg(-1) mean±s.d.: 0.073±0.05 μgg(-1), n=40) for this material. The extraction procedure for the fish tissues was also compared against an enzymatic extraction using Protease type XIV that has been previously published and similar results were obtained. The use of HPLC-HGAAS with a Phenomenox 5 μm Luna C18 (250 mm×4.6 mm) column and a mobile phase containing 0.06 moll(-1) ammonium acetate (Merck Pty Limited, Australia) in 5% (v/v) methanol and 0.1% (w/v) l-cysteine at 25°C was evaluated as a complementary alternative to HPLC-ICPMS for the measurement of mercury species in fish tissues. The lowest measurable mercury concentration was 2 μgl(-1) and this corresponds to 0.1 μgg(-1) in fish tissues. Analysis of enzymatic extracts analysed by HPLC-HGAAS and HPLC-ICPMS gave equivalent results.
Measurement of arsenic species in environmental, biological fluids and food samples by HPLC-ICPMS and HPLC-HG-AFS
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5JA00155B
Abstract: The importance of measuring arsenic (As) species has been appreciated for a long time mainly because of the wide spread knowledge of arsenic's toxicity and its use as a poison.
Estimates of late Quaternary mode and intermediate water silicic acid concentration in the Pacific Southern Ocean
Publisher: Elsevier BV
Date: 04-2016
A Review of the Stable Isotope Bio-geochemistry of the Global Silicon Cycle and Its Associated Trace Elements
Publisher: Frontiers Media SA
Date: 30-01-2018
The copper isotope geochemistry of rivers and the oceans
Publisher: Elsevier BV
Date: 09-2008
Primary productivity induced by iron and nitrogen in the Tasman Sea: An overview of the PINTS expedition
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/MF13137
Abstract: The Tasman Sea and the adjacent subantarctic zone (SAZ) are economically important regions, where the parameters controlling the phytoplankton community composition and carbon fixation are not yet fully resolved. Contrasting nutrient distributions, as well as phytoplankton biomass, bio ersity and productivity were observed between the North Tasman Sea and the SAZ. In situ photosynthetic efficiency (FV/FM), dissolved and particulate nutrients, iron biological uptake, and nitrogen and carbon fixation were used to determine the factor-limiting phytoplankton growth and productivity in the North Tasman Sea and the SAZ. Highly productive cyanobacteria dominated the North Tasman Sea. High atmospheric nitrogen fixation and low nitrate dissolved concentrations indicated that non-diazotroph phytoplankton are nitrogen limited. Deck-board incubations also suggested that, at depth, iron could limit eukaryotes, but not cyanobacteria in that region. In the SAZ, the phytoplankton community was dominated by a bloom of haptophytes. The low productivity in the SAZ was mainly explained by light limitation, but nitrogen, silicic acid as well as iron were all depleted to the extent that they could become co-limiting. This study illustrates the challenge associated with identification of the limiting nutrient, as it varied between phytoplankton groups, depths and sites.
Zinc cycling in the Tasman Sea: Distribution, speciation and relation to phytoplankton community
Publisher: Elsevier BV
Date: 05-2016
Production of viruses during a spring phytoplankton bloom in the South Pacific Ocean near of New Zealand
Publisher: Oxford University Press (OUP)
Date: 06-12-2011
DOI: 10.1111/J.1574-6941.2011.01251.X
Abstract: Lagrangian studies of virus activity in pelagic environments over extended temporal scales are rare. To address this, viruses and bacteria were examined during the course of a natural phytoplankton bloom in the pelagic South Pacific Ocean east of New Zealand. Daily s les were collected in a mesoscale eddy from year days 263-278 (September 19th-October 4th, 2008). The productive bloom transitioned from a diatom to a pico- and nanoplankton-dominated system, resulting in chlorophyll a concentrations up to 2.43 μg L(-1) . Virus abundances fluctuated c. 10-fold (1.8 × 10(10) -1.3 × 10(11) L(-1) ) over 16 days. The production rates of virus particles were high compared with those reported in other marine systems, ranging from 1.4 × 10(10) to 2.1 × 10(11) L(-1) day(-1) . Our observations suggest viruses contributed significantly to the mortality of bacteria throughout the bloom, with 19-216% of the bacterial standing stock being lysed daily. This mortality released nutrient elements (N, Fe) that likely helped sustain the bloom through the s ling period. Parametric analyses found significant correlations with both biotic (e.g. potential host abundances) and abiotic parameters (e.g. nutrient concentrations, temperature). These observations demonstrate that viruses may be critical in the extended maintenance of regeneration-driven biological production.
Reconstruction of paleo-particulate organic carbon fluxes for the Campbell Plateau region of southern New Zealand using the zinc content of sponge spicules
Publisher: American Geophysical Union (AGU)
Date: 30-08-2005
DOI: 10.1029/2004PA001095
Inter-calibration of a proposed new primary reference standard AA-ETH Zn for zinc isotopic analysis
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6JA00282J
Abstract: We have prepared and calibrated a large volume of pure, concentrated and homogenous zinc standard solution.
Review of the CALIMAS Team Contributions to European Space Agency’s Soil Moisture and Ocean Salinity Mission Calibration and Validation
Publisher: MDPI AG
Date: 04-05-2012
DOI: 10.3390/RS4051272
Elimination of equivalence point errors in the potentiometric titration of chloride, bromide and iodide mixtures with silver nitrate
Publisher: Elsevier BV
Date: 04-2003
Discovering the ocean's past through geochemistry
Publisher: Mineralogical Society of America
Date: 12-2018
Wintertime trace metal (Zn, Cu, Ni, Cd, Pb and Co) and nutrient distributions in the Subantarctic Zone between 40-52°S; 155-160°E
Publisher: Elsevier BV
Date: 11-2008
Germanium incorporation into sponge spicules: Development of a proxy for reconstructing inorganic germanium and silicon concentrations in seawater
Publisher: Elsevier BV
Date: 03-2006
Silicon isotopic fractionation in marine sponges: A new model for understanding silicon isotopic variations in sponges
Publisher: Elsevier BV
Date: 04-2010
A comparison of biogenic iron quotas during a diatom spring bloom using multiple approaches
Publisher: Copernicus GmbH
Date: 03-02-2012
Abstract: Abstract. Biogenic Fe quotas were determined using three distinct techniques on s les collected concurrently in the subtropical Pacific Ocean east of New Zealand. Fe quotas were measured using radioisotope uptake experiments (24 h incubation), bulk filtration and analysis by inductively-coupled plasma mass spectrometer (ICPMS), and single-cell synchrotron x-ray fluorescence (SXRF) analysis over a sixteen-day period (year days 263 to 278 of 2008) during a quasi-Lagrangian drifter experiment that tracked the evolution of the annual spring diatom bloom within a counter-clockwise open-ocean eddy. Overall, radioisotope uptake-determined Fe quotas (washed with oxalate reagent to remove extracellular Fe) were the lowest (0.5–1.0 mmol Fe:mol P 4–8 μmol Fe:mol C), followed by single-cell Fe quotas (2.3–7.5 mmol Fe:mol P 17–57 μmol Fe:mol C), and the highest and most variable quotas were from the bulk filtration ICPMS approach that used the oxalate reagent wash, corrected for lithogenic Fe using Al (0.8–21 mmol Fe:mol P 4–136 μmol Fe:mol C). During the evolution of the spring bloom within the eddy (year days 263 to 272), the surface mixed layer inventories of particulate biogenic elements (C, N, P, Si) and chlorophyll increased while Fe quotas estimated from all three approaches exhibited a general decline. After the onset of the bloom decline, the drogued buoys exited the eddy center (days 273 to 277). Fe quotas returned to pre-bloom values during this part of the study. Our standardized and coordinated s ling protocols reveal the general observed trend in Fe quotas: ICPMS SXRF radioisotope uptake. We discuss the inherent differences between the techniques and argue that each technique has its in idual merits and uniquely contributes to the characterization of the oceanic particulate Fe pool.
Glacial Silicic Acid Concentrations in the Southern Ocean
Publisher: American Association for the Advancement of Science (AAAS)
Date: 19-11-2010
Abstract: Silicon is a major structural component of many marine organisms, whose chemistry is affected by oceanic nutrient distributions. To constrain nutrient changes since the last glacial period, Ellwood et al. (p. 1088 , published online 21 October) measured the isotopic compositions of silicon obtained from the skeletons of deep-sea sponges found in deep cores from the Atlantic and Pacific sectors of the Southern Ocean and compared them to the silicon signatures in the skeletons of modern sponges. The results indicate that nutrient redistribution, related to iron fertilization from dust deposition, boosted the growth of organisms that transferred silicon to mid-latitudes during the last glacial period.
Zinc isotope fractionation byEmiliania huxleyicultured across a range of free zinc ion concentrations
Publisher: Wiley
Date: 18-09-2017
DOI: 10.1002/LNO.10658
Zinc and cadmium speciation in subantarctic waters east of New Zealand
Publisher: Elsevier BV
Date: 06-2004
A solvent extraction technique for the isotopic measurement of dissolved copper in seawater
Publisher: Elsevier BV
Date: 05-2013
DOI: 10.1016/J.ACA.2013.03.020
Abstract: Stable copper (Cu) isotope geochemistry provides a new perspective for investigating and understanding Cu speciation and biogeochemical Cu cycling in seawater. In this work, s le preparation for isotopic analysis employed solvent-extraction with amino pyrollidine dithiocarbamate/diethyl dithiocarbamate (APDC/DDC), coupled with a nitric acid back-extraction, to concentrate Cu from seawater. This was followed by Cu-purification using anion-exchange. This straightforward technique is high yielding and fractionation free for Cu and allows precise measurement of the seawater Cu isotopic composition using multi-collector inductively coupled plasma mass-spectrometry. A deep-sea profile measured in the oligotrophic north Tasman Sea shows fractionation in the Cu isotopic signature in the photic zone but is relatively homogenised at depth. A minima in the Cu isotopic profile correlates with the chlorophyll a maximum at the site. These results indicate that a range of processes are likely to fractionate stable Cu isotopes in seawater.
A method for determining the isotopic composition of dissolved zinc in seawater by MC-ICP-MS with a 67Zn–68Zn double spike
Publisher: Elsevier BV
Date: 05-2016
A novel comparative research platform designed to determine the functional significance of tree species diversity in European forests
Publisher: Elsevier BV
Date: 10-2013
Dissolved copper isotope biogeochemistry in the Tasman Sea, SW Pacific Ocean
Publisher: Elsevier BV
Date: 10-2014
Fe and Zn effects on the Si cycle and diatom community structure in two contrasting high and low-silicate HNLC areas
Publisher: Elsevier BV
Date: 10-2005
Oxidation of surface sediment: effects of disturbance depth and seawater flow speed
Publisher: Inter-Research Science Center
Date: 19-10-2009
DOI: 10.3354/MEPS08179
Dissolved copper speciation in the Tasman Sea, SW Pacific Ocean
Publisher: Elsevier BV
Date: 08-2014
Antimony measurements in environmental matrices: seven considerations
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7JA00391A
Abstract: A variety of approaches for measuring the content and speciation of Sb in environmental matrices are discussed.
Overview of hyphenated techniques using an ICP-MS detector with an emphasis on extraction techniques for measurement of metalloids by HPLC–ICPMS
Publisher: Elsevier BV
Date: 11-2012
Variations in the Zn/Si record over the last interglacial glacial transition
Publisher: American Geophysical Union (AGU)
Date: 10-2000
DOI: 10.1029/1999PA000470
Zinc speciation in the Northeastern Atlantic Ocean
Publisher: Elsevier BV
Date: 02-2000
Corrigendum to “Pelagic iron cycling during the subtropical spring bloom, east of New Zealand” [MARCHE: 160 (2014) 18–33]
Publisher: Elsevier BV
Date: 07-2014
The [simple carbon project] model v1.0
Publisher: Copernicus GmbH
Date: 18-04-2019
Abstract: Abstract. We construct a carbon cycle box model to process observed or inferred geochemical evidence from modern and paleo settings. The [simple carbon project] model v1.0 (SCP-M) combines a modern understanding of the ocean circulation regime with the Earth's carbon cycle. SCP-M estimates the concentrations of a range of elements within the carbon cycle by simulating ocean circulation, biological, chemical, atmospheric and terrestrial carbon cycle processes. The model is capable of reproducing both paleo and modern observations and aligns with CMIP5 model projections. SCP-M's fast run time, simplified layout and matrix structure render it a flexible and easy-to-use tool for paleo and modern carbon cycle simulations. The ease of data integration also enables model–data optimisations. Limitations of the model include the prescription of many fluxes and an ocean-basin-averaged topology, which may not be applicable to more detailed simulations. In this paper we demonstrate SCP-M's application primarily with an analysis of the carbon cycle transition from the Last Glacial Maximum (LGM) to the Holocene and also with the modern carbon cycle under the influence of anthropogenic CO2 emissions. We conduct an atmospheric and ocean multi-proxy model–data parameter optimisation for the LGM and late Holocene periods using the growing pool of published paleo atmosphere and ocean data for CO2, δ13C, Δ14C and the carbonate ion proxy. The results provide strong evidence for an ocean-wide physical mechanism to deliver the LGM-to-Holocene carbon cycle transition. Alongside ancillary changes in ocean temperature, volume, salinity, sea-ice cover and atmospheric radiocarbon production rate, changes in global overturning circulation and, to a lesser extent, Atlantic meridional overturning circulation can drive the observed LGM and late Holocene signals in atmospheric CO2, δ13C, Δ14C, and the oceanic distribution of δ13C, Δ14C and the carbonate ion proxy. Further work is needed on the analysis and processing of ocean proxy data to improve confidence in these modelling results.
Iron limitation of kelp growth may prevent ocean afforestation
Publisher: Springer Science and Business Media LLC
Date: 06-06-2023
DOI: 10.1038/S42003-023-04962-4
Abstract: Carbon dioxide removal (CDR) and emissions reduction are essential to alleviate climate change. Ocean macroalgal afforestation (OMA) is a CDR method already undergoing field trials where nearshore kelps, on rafts, are purposefully grown offshore at scale. Dissolved iron (dFe) supply often limits oceanic phytoplankton growth, however this potentially rate-limiting factor is being overlooked in OMA discussions. Here, we determine the limiting dFe concentrations for growth and key physiological functions of a representative kelp species, Macrocystis pyrifera , considered as a promising candidate for OMA. dFe additions to oceanic seawater ranging 0.01-20.2 nM Fe′ ‒ Fe′ being the sum of dissolved inorganic Fe(III) species ‒ result in impaired physiological functions and kelp mortality. Kelp growth cannot be sustained at oceanic dFe concentrations, which are 1000-fold lower than required by M. pyrifera . OMA may require additional perturbation of offshore waters via dFe fertilisation.
The interplay between regeneration and scavenging fluxes drives ocean iron cycling
Publisher: Springer Science and Business Media LLC
Date: 31-10-2019
DOI: 10.1038/S41467-019-12775-5
Abstract: Despite recent advances in observational data coverage, quantitative constraints on how different physical and biogeochemical processes shape dissolved iron distributions remain elusive, lowering confidence in future projections for iron-limited regions. Here we show that dissolved iron is cycled rapidly in Pacific mode and intermediate water and accumulates at a rate controlled by the strongly opposing fluxes of regeneration and scavenging. Combining new data sets within a watermass framework shows that the multidecadal dissolved iron accumulation is much lower than expected from a meta-analysis of iron regeneration fluxes. This mismatch can only be reconciled by invoking significant rates of iron removal to balance iron regeneration, which imply generation of authigenic particulate iron pools. Consequently, rapid internal cycling of iron, rather than its physical transport, is the main control on observed iron stocks within intermediate waters globally and upper ocean iron limitation will be strongly sensitive to subtle changes to the internal cycling balance.
Bacterioplankton responses to iron enrichment during the SAGE experiment
Publisher: Elsevier BV
Date: 03-2011
Iron Availability Influences the Tolerance of Southern Ocean Phytoplankton to Warming and Elevated Irradiance
Publisher: Frontiers Media SA
Date: 11-2019
Measurement of arsenic species in marine macroalgae by microwave-assisted extraction and high performance liquid chromatography–inductively coupled plasma mass spectrometry
Publisher: Elsevier BV
Date: 04-2002
Organic complexation of cobalt across the Antarctic Polar Front in the Southern Ocean
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/MF05097
Abstract: There is compelling evidence to demonstrate that phytoplankton in major regions of the world’s oceans are limited by the availability of certain trace elements, notably iron. Cobalt concentrations in open-ocean waters generally range between 10 and 120 pmol L−1 but such levels were not thought to limit phytoplankton growth. Herein, we present data for total dissolved cobalt and cobalt-complexing ligands for two stations located south (station 200) and north (station 204) of the Antarctic Polar Front (APF) along 20°E in the South Atlantic sector of the Southern Ocean. Results indicate that there was little difference between total cobalt concentrations south and north of the APF, whereas ligand concentrations were significantly higher (15–20 pmol L−1) for the upper water column south of the APF. Productivity in these waters was low at the time of this study however, numbers of large eukaryotic algal species were higher south of the APF, while north of the APF small eukaryotic and prokaryotic species dominated. The higher ligand concentrations measured at the southern station are probably related to higher algal numbers at this site. Because ligand concentrations were higher, inorganic cobalt concentrations (Co′) south of the APF are extremely low, at femtomolar levels, whereas north of the APF calculated Co′ are much higher at picomolar levels where ligand concentrations were lower.
Distinct iron cycling in a Southern Ocean eddy
Publisher: Springer Science and Business Media LLC
Date: 11-02-2020
DOI: 10.1038/S41467-020-14464-0
Abstract: Mesoscale eddies are ubiquitous in the iron-limited Southern Ocean, controlling ocean-atmosphere exchange processes, however their influence on phytoplankton productivity remains unknown. Here we probed the biogeochemical cycling of iron (Fe) in a cold-core eddy. In-eddy surface dissolved Fe (dFe) concentrations and phytoplankton productivity were exceedingly low relative to external waters. In-eddy phytoplankton Fe-to-carbon uptake ratios were elevated 2–6 fold, indicating upregulated intracellular Fe acquisition resulting in a dFe residence time of ~1 day. Heavy dFe isotope values were measured for in-eddy surface waters highlighting extensive trafficking of dFe by cells. Below the euphotic zone, dFe isotope values were lighter and coincident with peaks in recycled nutrients and cell abundance, indicating enhanced microbially-mediated Fe recycling. Our measurements show that the isolated nature of Southern Ocean eddies can produce distinctly different Fe biogeochemistry compared to surrounding waters with cells upregulating iron uptake and using recycling processes to sustain themselves.
Mo-Cr isotope evidence for a reducing Archean atmosphere in 3.46-2.76Ga black shales from the Pilbara, Western Australia
Publisher: Elsevier BV
Date: 02-2013
Transitioning global change experiments on Southern Ocean phytoplankton from lab to field settings: Insights and challenges
Publisher: Wiley
Date: 25-06-2022
DOI: 10.1002/LNO.12175
Abstract: The influence of global change on Southern Ocean productivity will have major ramifications for future management of polar life. A prior laboratory study investigated the response of a batch‐cultured subantarctic diatom to projected change simulating conditions for 2100 (increased temperature/CO 2 /irradiance/iron decreased macronutrients), showed a twofold higher chlorophyll‐derived growth rate driven mainly by temperature and iron. We translated this design to the field to understand the phytoplankton community response, within a subantarctic foodweb, to 2100 conditions. A 7‐d shipboard study utilizing 250‐liter mesocosms was conducted in March 2016. The outcome mirrors lab‐culture experiments, yielding twofold higher chlorophyll in the 2100 treatment relative to the control. This trend was also evident for intrinsic metrics including nutrient depletion. Unlike the lab‐culture study, photosynthetic competence revealed a transient effect in the 2100 mesocosm, peaking on day 3 then declining. Metaproteomics revealed significant differences in protein profiles between treatments by day 7. The control proteome was enriched for photosynthetic processes (c.f. 2100) and exhibited iron‐limitation signatures the 2100 proteome exposed a shift in cellular energy production. Our findings of enhanced phytoplankton growth are comparable to model simulations, but underlying mechanisms (temperature, iron, and/or light) differ between experiments and models. Batch‐culture approaches hinder cross‐comparison of mesocosm findings to model simulations (the latter are akin to “continuous‐culture chemostats”). However, chemostat techniques are problematic to use with mesocosms, as mesozooplankton will evade seawater flow‐through, thereby accumulating. Thus, laboratory, field, and modeling approaches reveal challenges to be addressed to better understand how global change will alter Southern Ocean productivity.
Arsenic and antimony species in surface transects and depth profiles across a frontal zone: The Chatham Rise, New Zealand
Publisher: Elsevier BV
Date: 11-2002
The Zn abundance and isotopic composition of diatom frustules, a proxy for Zn availability in ocean surface seawater
Publisher: Elsevier BV
Date: 2011
High-resolution Cd isotope systematics in multiple zones of the Southern Ocean from the Antarctic Circumnavigation Expedition
Publisher: Elsevier BV
Date: 12-2019
Iron Availability Influences Silicon Isotope Fractionation in Two Southern Ocean Diatoms (Proboscia inermis and Eucampia antarctica) and a Coastal Diatom (Thalassiosira pseudonana)
Publisher: Frontiers Media SA
Date: 07-07-2017
Contribution of Electroactive Humic Substances to the Iron‐Binding Ligands Released During Microbial Remineralization of Sinking Particles
Publisher: American Geophysical Union (AGU)
Date: 11-04-2020
DOI: 10.1029/2019GL086685
Seawater 234U/238U recorded by modern and fossil corals
Publisher: Elsevier BV
Date: 03-2018
Resupply of mesopelagic dissolved iron controlled by particulate iron composition
Publisher: Springer Science and Business Media LLC
Date: 28-10-2019
Biotic and abiotic retention, recycling and remineralization of metals in the ocean
Publisher: Springer Science and Business Media LLC
Date: 03-2017
DOI: 10.1038/NGEO2876
Marine biogeochemical cycling of cadmium and cadmium isotopes in the extreme nutrient-depleted subtropical gyre of the South West Pacific Ocean
Publisher: Elsevier BV
Date: 05-2019
Zinc/silicon ratios of sponges: A proxy for carbon export to the seafloor
Publisher: American Geophysical Union (AGU)
Date: 06-2004
DOI: 10.1029/2004GL019648
Controls on Polar Southern Ocean Deep Chlorophyll Maxima: Viewpoints from Multiple Observational Platforms
Publisher: Authorea, Inc.
Date: 14-06-2023
DOI: 10.22541/ESSOAR.168677216.63458355/V1
Abstract: Deep Chlorophyll Maxima (DCMs) are ubiquitous in low-latitude oceans, and of recognized biogeochemical and ecological importance. DCMs have been observed in the Southern Ocean, initially from ships and recently from profiling robotic floats, but with less understanding of their onset, duration, underlying drivers, or whether they are associated with enhanced biomass features. We report the characteristics of a DCM and DBM (Deep Biomass Maximum) in the Inter-Polar-Frontal-Zone (IPFZ) south of Australia from CTD profiles, shipboard-incubated s les, a towbody, and a BGC-ARGO float. The DCM and DBM were ~20 m thick and co-located with the nutricline, in the vicinity of a subsurface ammonium maximum characteristic of the IPFZ, but ~100 m shallower than the ferricline. Towbody transects demonstrated that the co-located DCM/DBM was broadly present across the IPFZ. Large healthy diatoms, with low iron requirements, resided within the DCM/DBM, and fixed up to 20 mmol C m-2 d-1. The BGC-ARGO float revealed the DCM/DBM persisted for months. We propose a dual environmental mechanism to drive DCM/DBM formation and persistence within the IPFZ: sustained supply of both recycled iron within the subsurface ammonium maxima and upward silicate transport from depth. DCM/DBM cell-specific growth rates were considerably slower than those in the overlying mixed layer, implying that phytoplankton losses are also reduced, possibly as a result of heavily silicified diatom frustules. The light-limited seasonal termination of the observed DCM/DBM did not result in a ‘diatom dump’, rather ongoing diatom downward export occurred throughout its multi-month persistence.
Oceanic distribution of inorganic germanium relative to silicon: Germanium discrimination by diatoms
Publisher: American Geophysical Union (AGU)
Date: 06-2010
DOI: 10.1029/2009GB003689
Determination of organic complexation of cobalt in seawater by cathodic stripping voltammetry
Publisher: Elsevier BV
Date: 07-2001
Organic iron(III) speciation in surface transects across a frontal zone: the Chatham Rise, New Zealand
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/MF05209
Abstract: Iron (Fe) is a critical nutrient in marine systems and the organic complexation of Fe is a central factor of the marine biogeochemistry of Fe. In the present study, total dissolved Fe and its organic speciation were measured in filtered seawater s les ( .2 μm) collected along three surface transects across the subtropical (ST) front, east of New Zealand, in austral spring (October 2000). Total dissolved Fe concentrations were low (~0.1 nm) in the subantarctic (SA) waters. The highest Fe concentration (~0.8 nm) was observed at the mixing boundary north of the Subtropical Convergence (STC) and then decreased relatively quickly both southward and northward. Cathodic stripping voltammetry was used to determine Fe speciation. The dissolved Fe(iii) was fully complexed ( .9%) by natural organic ligands, which were found to occur in excess of the dissolved Fe concentration at 1.29 ± 0.33 nm (equivalent to an excess over Fe of ~1.0 nm), and with a complex stability of log K ′ FeL,F e 3+ -- K′FeL,Fe3+ = 22.67 ± 0.22. The total ligand concentrations were consistently higher (~0.5 nm) in the ST and STC waters than in the SA waters. Our Fe data imply that the regional currents may be an important vehicle for transporting the elevated Fe across the front.
Intraspecific variability in Phaeocystis antarctica's response to iron and light stress
Publisher: Public Library of Science (PLoS)
Date: 10-07-2017
Elemental quotas and physiology of a southwestern Pacific Ocean plankton community as a function of iron availability
Publisher: Inter-Research Science Center
Date: 18-03-2013
DOI: 10.3354/AME01611
Salt tolerance of cowpea genotypes in the emergence stage
Publisher: CSIRO Publishing
Date: 2001
DOI: 10.1071/EA00055
Abstract: The effect of NaCl salinity (0, 85 and 170 mmol/L) during emergence of 25 genotypes of cowpea [Vigna unguiculata (L.) Walp.] was studied under growth chamber conditions. Seed emergence percentage and rate, root:shoot ratio, and biomass per plant were affected by genotype, salinity and genotype salinity interaction this interaction showed that salinity effects differed among genotypes. The criterion used to classify genotypes with respect to their salt tolerance was based on their germination percentages in both 85 and 170 mmol NaCl/L. One genotype was grouped into class ‘A’ (CB27) which had the highest salt tolerance at emergence, and was classified as salt tolerant. Another group consisting of Pace& ntilde o, CB88, CB3, CB5, Tard& oacute n, Cuarente& ntilde o and CB46 was placed into class ‘B’ these genotypes showed total emergence percentages up to 75% in both 85 and 170 mmol NaCl/L. A third group of genotypes was placed into class ‘C’ which had the lowest emergence percentages in both 85 and 170 mmol NaCl/L. It was confirmed that salinity treatments affect the emergence of cowpea, delaying both emergence percentage and rate. We conclude that selection and classification for salt tolerance in cowpea genotypes can be successfully undertaken at early seedling stages, because the same genotypes were classified similarly during the germination stage in previous research.
The GEOTRACES Intermediate Data Product 2017
Publisher: Elsevier BV
Date: 08-2018
Trace metal contents of autotrophic flagellates from contrasting open‐ocean ecosystems
Publisher: Wiley
Date: 26-05-2022
DOI: 10.1002/LOL2.10258
Abstract: Nano‐ and picophytoplankton are a major component of open‐ocean ecosystems and one of the main plankton functional types in biogeochemical models, yet little is known about their trace metal contents. In cultures of the picoeukaryote Ostreococcus lucimarinus , iron limitation reduced iron quotas by 68%, a fraction of the plasticity known in diatoms. In contrast, a commonly co‐occurring cyanobacterium, Prochlorococcus , showed variable iron contents with iron availability in culture. Synchrotron X‐ray fluorescence was used to measure single‐cell metal (Mn, Fe, Co, Ni, Zn) quotas of autotrophic flagellates (1.4–16.8‐ μ m diameter) collected from four ocean regions. Iron quotas were tightly constrained and showed little response to iron availability, similar to cultured Ostreococcus . Zinc quotas also did not vary with zinc availability but appeared to vary with phosphorus availability. These results suggest that macronutrient and metal availability may be equally important for controlling metal contents of small eukaryotic open‐ocean phytoplankton.
Occurrence and chemical form of arsenic in marine macroalgae from the east coast of Australia
Publisher: CSIRO Publishing
Date: 2002
DOI: 10.1071/MF01230
Abstract: Arsenic concentrations were measured in thirteen macroalgal species from Sydney, Australia. Brown macroalgae contained, on average, more arsenic (range, mean ± s.e.: 5–173 μg g–1, 39 ± 4 μg g–1) than either green (0.12–30.2 μg g–1, 10.7 ± 0.7 μg g–1) or red macroalgae (0.11–16.9 μg g–1, 4.3 ± 0.3 μg g–1). Despite the overlap in arsenic concentrations between different macroalgal species, inter-species arsenic variation was apparent with arsenic concentrations following the order brown green red macroalgal species. It was concluded that the main contribution to the variation in arsenic concentration was from natural variability expected to occur between in iduals of any species as a result of physiological differences.Most of the arsenic compounds in macroalgae (70–108%) could be extracted using methanol/water mixtures, with 38–95% of the arsenic compounds present in characterizable forms. All macroalgal species contained arsenoribosides (9–99%). The distribution of arsenoribosides followed a general pattern glycerol-arsenoriboside and phosphate-arsenoriboside were common to all macroalgal species. Sulfonate-arsenoriboside and sulfate-arsenoriboside were found in brown macroalgal species and one red macroalgal species. Six macroalgal species contained high concentrations of inorganic arsenic (14.2–62.9%) and four species contained high concentrations of dimethylarsinic acid (13.3–41.1%). The variation in the distribution of arsenic compounds in marine macroalgal species appears to be related to taxonomic differences in storage and structural polysaccharides.
Observations on the measurement of total antimony and antimony species in algae, plant and animal tissues
Publisher: Royal Society of Chemistry (RSC)
Date: 2005
DOI: 10.1039/B509202G
Abstract: This paper describes our experiences with undertaking measurements of total antimony and antimony speciation in algae, plant and animal tissues. Digestion with nitric acid alone is suitable to release antimony from animal tissues. When organisms have high silica contents, e.g. some plants and algae, the addition of tetrafluorboric acid is required to dissolve silica as some antimony is retained by silica in extracts. Antimony in digested extracts is present as Sb5+ and hydride generation procedures can be used to determine total antimony concentrations, as total antimony in extracts will not be under estimated. Relatively non-aggressive solvents such as water, dilute nitric acid, sodium hydroxide and enzymes remove highly variable amounts of antimony (2-84%) from algae, plant and animal tissues. Addition of Sb3+ and Sb5+ to NIST CRM 1572 Citrus Leaves, pre- and post-extraction with water showed that Sb3+ is oxidised to Sb5+ while Sb5+ is redistributed amongst binding sites giving rise to artefacts. DOLT-2 and algae extracts indicated the presence of only inorganic antimony. A moss s le had inorganic antimony and a number of unknown antimony species in extracts. Future studies should explore the nature of the binding of antimony in tissues as solvents commonly used to extract metals and metalloids from algae, plant and animal tissues are not appropriate.
Volatile selenium fluxes from selenium-contaminated sediments in an Australian coastal lake
Publisher: CSIRO Publishing
Date: 2016
DOI: 10.1071/EN14228
Abstract: Environmental context Methylation of sedimentary selenium to volatile dimethylselenide is a natural remediation process for contaminated aquatic systems. We present flux estimates for the loss of dimethylselenide from sediments of an anthropogenically affected lake and observe a 6-fold difference between late autumn–early winter and summer. The loss of dimethylselenide represents a significant sediment loss vector, of the same order as the diffusive loss flux for inorganic selenium across the sediment–water interface. Abstract Overflows from ash dams associated with the operation of coal-fired power stations in Lake Macquarie, NSW, Australia, have been a historical source of selenium to the lake. Although dissolved selenium concentrations have been marginally elevated, sediments are the major sink. Methylation of sedimentary selenium to volatile dimethylselenide (DMSe) is known to be a natural remediation process. Sediments from north of Wyee Bay and the Vales Point Power Station were the subject of field s ling and monitoring to determine the extent to which selenium is being lost to the atmosphere as DMSe. Flux estimates were obtained by trapping volatile selenium species using benthic domes, followed by analysis in the field using a fully automated cryogenic trapping system with atomic fluorescence detection. The detection limit of the system was 0.1ngL–1 for DMSe and 1ngL–1 for dimethyl diselenide (DMDSe). Measurements in both summer and late autumn–early winter showed a distinct seasonal difference, with a higher summer DMSe flux of 53±25ng Se m–2h–1 (±s.d.) compared with 8±5ng Se m–2h–1 in late autumn–early winter. No DMDSe was detected. These fluxes are similar to those measured in Europe and North America, and represent an annual loss of 1.3kg of selenium per year from the nearby lake area. Lake-wide this would represent a significant loss to the atmosphere.
Insights Into the Biogeochemical Cycling of Iron, Nitrate, and Phosphate Across a 5,300 km South Pacific Zonal Section (153°E–150°W)
Publisher: American Geophysical Union (AGU)
Date: 02-2018
DOI: 10.1002/2017GB005736
Control of the phytoplankton response during the SAGE experiment: A synthesis
Publisher: Elsevier BV
Date: 03-2011
Did dilution limit the phytoplankton response to iron addition in HNLCLSi sub-Antarctic waters during the SAGE experiment?
Publisher: Elsevier BV
Date: 03-2011
Effects of iron limitation on silicon uptake kinetics and elemental stoichiometry in two Southern Ocean diatoms, Eucampia antarctica and Proboscia inermis
Publisher: Wiley
Date: 08-05-2017
DOI: 10.1002/LNO.10578
Iron isotope transformations in the meromictic Lake Cadagno
Publisher: Elsevier BV
Date: 06-2019
Keith Hunter’s legacy to Marine Science in New Zealand
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/MFV71N3_ED
FeCycle: Attempting an iron biogeochemical budget from a mesoscale SF6tracer experiment in unperturbed low iron waters
Publisher: American Geophysical Union (AGU)
Date: 12-2005
DOI: 10.1029/2005GB002494
The SOLAS air–sea gas exchange experiment (SAGE) 2004
Publisher: Elsevier BV
Date: 03-2011
Determination of the Zn/Si ratio in diatom opal: A method for the separation, cleaning and dissolution of diatoms
Publisher: Elsevier BV
Date: 08-1999
Response of surface nutrient inventories and nitrogen fixation to a tropical cyclone in the southwest Pacific
Publisher: Wiley
Date: 14-06-2011
Sponges as Proxies for Past Climate Change Events
Publisher: Springer International Publishing
Date: 2017
Measurement of selenomethionine and selenocysteine in fish tissues using HPLC-ICP-MS
Publisher: Elsevier BV
Date: 09-2016
Physical mixing effects on iron biogeochemical cycling: FeCycle experiment
Publisher: American Geophysical Union (AGU)
Date: 20-06-2007
DOI: 10.1029/2006JC003748
Constraints on the Cycling of Iron Isotopes From a Global Ocean Model
Publisher: American Geophysical Union (AGU)
Date: 09-2021
DOI: 10.1029/2021GB006968
Abstract: Although iron (Fe) is a key regulator of primary production over much of the ocean, many components of the marine iron cycle are poorly constrained, which undermines our understanding of climate change impacts. In recent years, a growing number of studies (often part of GEOTRACES) have used Fe isotopic signatures (δ 56 Fe) to disentangle different aspects of the marine Fe cycle. Characteristic δ 56 Fe endmembers of external sources and assumed isotopic fractionation during biological Fe uptake or recycling have been used to estimate relative source contributions and investigate internal transformations, respectively. However, different external sources and fractionation processes often overlap and act simultaneously, complicating the interpretation of oceanic Fe isotope observations. Here we investigate the driving forces behind the marine dissolved Fe isotopic signature (δ 56 Fe diss ) distribution by incorporating Fe isotopes into the global ocean biogeochemical model PISCES. We find that distinct external source endmembers acting alongside fractionation during organic complexation and phytoplankton uptake are required to reproduce δ 56 Fe diss observations along GEOTRACES transects. δ 56 Fe diss distributions through the water column result from regional imbalances of remineralization and abiotic removal processes. They modify δ 56 Fe diss directly and transfer surface ocean signals to the interior with opposing effects. Although attributing crustal compositions to sedimentary Fe sources in regions with low organic carbon fluxes improves our isotope model, δ 56 Fe diss signals from hydrothermal or sediment sources cannot be reproduced accurately by simply adjusting δ 56 Fe endmember values. This highlights that additional processes must govern the exchange and/or speciation of Fe supplied by these sources to the ocean.
Winter-time dissolved iron and nutrient distributions in the Subantarctic Zone from 40–52S; 155–160E
Publisher: American Geophysical Union (AGU)
Date: 10-06-2008
DOI: 10.1029/2008GL033699
Putting the silicon cycle in a bag: Field and mesocosm observations of silicon isotope fractionation in subtropical waters east of New Zealand
Publisher: Elsevier BV
Date: 07-2019
Why are biotic iron pools uniform across high- and low-iron pelagic ecosystems?
Publisher: American Geophysical Union (AGU)
Date: 07-2015
DOI: 10.1002/2014GB005014
Divergent physiological and molecular responses of light‐ and iron‐limited Southern Ocean phytoplankton
Publisher: Wiley
Date: 10-11-2022
DOI: 10.1002/LOL2.10223
Abstract: It has recently been shown that Southern Ocean phytoplankton species have evolved to optimize their light‐harvesting potential without increasing the high iron‐requiring proteins used for photosynthesis. We measured molecular and physiological responses of phytoplankton cultures under a combination of iron and light conditions. While iron‐replete cultures mostly increased biovolume, photochemical efficiency ( F v / F m ) and the relative abundance of photosystem II (PSII) and Cytochrome b 6 f protein compared to iron‐limited cultures, light also regulated cellular chlorophyll a content and played a role in controlling PSII protein abundance. Investment of protein resources into the carbon fixing enzyme Ribulose 1,5‐bisphosphate carboxylase oxygenase (Rubisco) was species‐specific, but increased growth rates correlated with increased investment into Rubisco for all species. Our results suggest that Proboscia inermis uses a ergent molecular strategy to compete for nutrients, light, and CO 2 in the Southern Ocean.
Relationships between nutrient stocks and inventories and phytoplankton physiological status along an oligotrophic meridional transect in the Tasman Sea
Publisher: Elsevier BV
Date: 02-2013
Inter-laboratory study for the certification of trace elements in seawater certified reference materials NASS-7 and CASS-6
Publisher: Springer Science and Business Media LLC
Date: 02-05-2018
DOI: 10.1007/S00216-018-1102-Y
Abstract: Certification of trace metals in seawater certified reference materials (CRMs) NASS-7 and CASS-6 is described. At the National Research Council Canada (NRC), column separation was performed to remove the seawater matrix prior to the determination of Cd, Cr, Cu, Fe, Pb, Mn, Mo, Ni, U, V, and Zn, whereas As was directly measured in 10-fold diluted seawater s les, and B was directly measured in 200-fold diluted seawater s les. High-resolution inductively coupled plasma mass spectrometry (HR-ICPMS) was used for elemental analyses, with double isotope dilution for the accurate determination of B, Cd, Cr, Cu, Fe, Pb, Mo, Ni, U, and Zn in seawater NASS-7 and CASS-6, and standard addition calibration for As, Co, Mn, and V. In addition, all analytes were measured using standard addition calibration with triple quadrupole (QQQ)-ICPMS to provide a second set of data at NRC. Expert laboratories worldwide were invited to contribute data to the certification of trace metals in NASS-7 and CASS-6. Various analytical methods were employed by participants including column separation, co-precipitation, and simple dilution coupled to ICPMS detection or flow injection analysis coupled to chemiluminescence detection, with use of double isotope dilution calibration, matrix matching external calibration, and standard addition calibration. Results presented in this study show that majority of laboratories have demonstrated their measurement capabilities for the accurate determination of trace metals in seawater. As a result of this comparison, certified/reference values and associated uncertainties were assigned for 14 elements in seawater CRMs NASS-7 and CASS-6, suitable for the validation of methods used for seawater analysis.
Selenium cycling in a marine dominated estuary: Lake Macquarie, NSW, Australia a case study
Publisher: CSIRO Publishing
Date: 27-07-2022
DOI: 10.1071/EN22032
Abstract: Environmental context Knowledge of the fate of selenium in estuaries receiving inputs from coal-fired power stations is essential as these environments are important nursery habitats for marine life and selenium has been shown to cause fish and bird mortality and sublethal effects including oedema, chromosomal aberrations and reproductive success. Understanding selenium cycling allows risk assessment to be undertaken and appropriate action to protect resident organisms. Abstract The fate of selenium (Se) inputs from coal-fired power station operations in a marine dominated estuary, Lake Macquarie NSW, is explored, as well as Se toxicity, including sublethal and population effects. Selenium is rapidly adsorbed to sediments, and food webs are based on benthic food sources. Selenium is remobilised from sediments by volatilisation and diffusional processes following bioturbation. It is then transferred into food chains via benthic microalgae, deposit feeders and filter-feeding organisms processing suspended sediments. Historically, Se has been found to accumulate in fish to levels above those considered safe for human consumption. After the remediation of a major ash dam in 1995, Se inputs to Lake Macquarie have declined, and the Se concentrations of sediments have also reduced partially due to the deposition of cleaner sediment but also due to the formation of volatile dimethyl selenide. Bioturbation of oxidised surface sediments also results in the release of inorganic Se. In response to decreases in sediment Se concentrations, molluscs and fish Se concentrations have also reduced below deleterious levels, with most fish now being safe for human consumption. Selenium cycling involves the transformation of inorganic species (Se0, SeII, SeIV, SeVI) in sediments and the water column to dimethylselenide and dimethyl diselenide by bacteria with the accumulation of organic Se species in plant detritus (selenomethionine) and animals (selenomethionine and selenocysteine). Dissolved Se concentrations in Lake Macquarie, except near ash dam inputs, have always been well below those that cause toxicity. There is evidence based on Se sediment-spiking studies, however, that Se is probably causing sublethal effects. When undertaking risk assessments of Se, careful consideration should be given to understanding the fate of Se inputs and remobilisation into food webs as not all systems act in accordance with published studies that generally have high Se concentrations in the water column and phytoplankton-based food webs.
Iron stable isotopes track pelagic iron cycling during a subtropical phytoplankton bloom
Publisher: Proceedings of the National Academy of Sciences
Date: 22-12-2014
Abstract: The supply and bioavailability of dissolved iron sets the magnitude of surface productivity for approximately 40% of the global ocean however, our knowledge of how it is transferred between chemical states and pools is poorly constrained. Here we utilize the isotopic composition of dissolved and particulate iron to fingerprint its transformation in the surface ocean by abiotic and biotic processes. Photochemical and biological reduction and dissolution of particulate iron in the surface ocean appear to be key processes in regulating its supply and bioavailability to marine biota. Iron isotopes offer a new window into our understanding of the internal cycling of Fe, thereby allowing us to follow its biogeochemical transformations in the surface ocean.
A simple radiocarbon dating method for determining the age and growth rate of deep-sea sponges
Publisher: Elsevier BV
Date: 04-2010
Dissolved zinc isotope cycling in the Tasman Sea, SW Pacific Ocean
Publisher: Elsevier BV
Date: 05-2017
The biogeochemical cycle of iron in the ocean
Publisher: Springer Science and Business Media LLC
Date: 26-09-2010
DOI: 10.1038/NGEO964
Microbial control of diatom bloom dynamics in the open ocean
Publisher: American Geophysical Union (AGU)
Date: 09-2012
DOI: 10.1029/2012GL053448
Author Correction: Resupply of mesopelagic dissolved iron controlled by particulate iron composition
Publisher: Springer Science and Business Media LLC
Date: 11-12-2019
Response of Subantarctic microbes to new versus regenerated Fe in a cold-core eddy
Publisher: Wiley
Date: 13-12-2021
A review of the Australian-New Zealand sector of the Southern Ocean over the last 30ka (Aus-INTIMATE project)
Publisher: Elsevier BV
Date: 08-2013
An automated hydride generation-cryogenic trapping-ICP-MS system for measuring inorganic and methylated Ge, Sb and As species in marine and fresh waters
Publisher: Royal Society of Chemistry (RSC)
Date: 21-01-2002
DOI: 10.1039/B109754G
Cycling of zinc and its isotopes across multiple zones of the Southern Ocean: Insights from the Antarctic Circumnavigation Expedition
Publisher: Elsevier BV
Date: 2020
Measurement of arsenic species in marine sediments by high-performance liquid chromatography–inductively coupled plasma mass spectrometry
Publisher: Elsevier BV
Date: 02-2003
Bioaccumulation of antimony and arsenic in a highly contaminated stream adjacent to the Hillgrove Mine, NSW, Australia
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/EN08097
Abstract: Environmental context. Concern over the presence of antimony (Sb) in the environment because of chemical similarities with arsenic (As) has prompted a need to better understand its environmental behaviour and risks. The present study investigates the bioaccumulation and uptake of antimony in a highly contaminated stream near the Hillgrove antimony–gold mine in NSW, Australia, and reports high Sb (and As) concentrations in many components of the ecosystem consisting of three trophic levels, but limited uptake into aboveground parts of riparian vegetation. The data suggest that Sb can transfer into upper trophic levels of a creek ecosystem, but that direct exposure of creek fauna to creek sediment and soil, water and aquatic autotrophs are more important metalloid uptake routes than exposure via riparian vegetation. Abstract. Bioaccumulation and uptake of antimony (Sb) were investigated in a highly contaminated stream, Bakers Creek, running adjacent to mining and processing of Sb–As ores at Hillgrove Mine, NSW, Australia. Comparisons with arsenic (As) were included owing to its co-occurrence at high concentrations. Mean metalloid creek rhizome sediment concentrations were 777 ± 115 μg g–1 Sb and 60 ± 6 μg g–1 As, with water concentrations at 381 ± 23 μg L–1 Sb and 46 ± 2 μg L–1 As. Antimony and As were significantly elevated in aquatic autotrophs (96–212 μg g–1 Sb and 32–245 μg g–1 As) but Sb had a lower uptake efficiency. Both metalloids were elevated in all macroinvertebrates s led (94–316 μg g–1 Sb and 1.8–62 μg g–1 As) except Sb in gastropods. Metalloids were detected in upper trophic levels although biomagnification was not evident. Metalloid transfer to riparian vegetation leaves from roots and rhizome soil was low but rhizome soil to leaf As concentration ratios were up to 2–3 times greater than Sb concentration ratios. Direct exposure to the rhizosphere sediments and soils, water ingestion and consumption of aquatic autotrophs appear to be the major routes of Sb and As uptake for the fauna of Bakers Creek.
Tracking changes in bioavailable Fe within high-nitrate low-chlorophyll oceanic waters: A first estimate using a heterotrophic bacterial bioreporter
Publisher: American Geophysical Union (AGU)
Date: 12-2005
DOI: 10.1029/2005GB002476
Corrigendum to A solvent extraction technique for the isotopic measurement of dissolved copper in seawater [Anal. Chim. Acta 775 (2013) 106-113]
Publisher: Elsevier BV
Date: 09-2013
GEOTRACES IC1 (BATS) contamination-prone trace element isotopes Cd, Fe, Pb, Zn, Cu, and Mo intercalibration
Publisher: Wiley
Date: 09-2012
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