ORCID Profile
0000-0002-6138-2116
Current Organisations
University of Otago
,
Oritain Global Ltd
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Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/MF03174
Abstract: Blue Lake is an abandoned, water-filled alluvial gold-mine pit in Central Otago, New Zealand. Alluvial gold mining is generally considered to be chemically benign, unless mercury is added to assist gold separation. The major element, trace metal and isotopic composition of the pit lake was compared to nearby, unaffected streams. Blue Lake was found to be enriched in the major cations, with levels that were 2–5 times higher than in unaffected streams. Furthermore, Cu, Ni and Zn concentrations exceeded 10 nmol L–1 in Blue Lake these levels were 2–30 times higher than those in nearby, unaffected streams. Processes affecting the lake’s characteristics include evaporative concentration, and the oxidation and dissolution of locally derived sulfide and sulfate minerals. Localised acidification in surface and ground waters around the lake leads to the mobilisation of Zn and Ni, resulting in lake waters being strongly enriched in these trace metals (concentrations greater than 40 nmol L–1), whereas surrounding stream waters have much lower Ni and Zn concentrations (less than 5 nmol L–1). Ongoing evaporative concentration, and the continuing mobilisation of trace metals, implies that metal enrichment in lake waters will continue to occur. The present study demonstrated that the ‘benign’ process of alluvial gold mining can have significant chemical consequences in resulting water bodies.
Publisher: Elsevier BV
Date: 08-2012
Publisher: Wiley
Date: 14-11-2007
DOI: 10.1002/JRS.1851
Publisher: Springer Science and Business Media LLC
Date: 10-2000
DOI: 10.1038/35037500
Abstract: Changes in iron supply to oceanic plankton are thought to have a significant effect on concentrations of atmospheric carbon dioxide by altering rates of carbon sequestration, a theory known as the 'iron hypothesis'. For this reason, it is important to understand the response of pelagic biota to increased iron supply. Here we report the results of a mesoscale iron fertilization experiment in the polar Southern Ocean, where the potential to sequester iron-elevated algal carbon is probably greatest. Increased iron supply led to elevated phytoplankton biomass and rates of photosynthesis in surface waters, causing a large drawdown of carbon dioxide and macronutrients, and elevated dimethyl sulphide levels after 13 days. This drawdown was mostly due to the proliferation of diatom stocks. But downward export of biogenic carbon was not increased. Moreover, satellite observations of this massive bloom 30 days later, suggest that a sufficient proportion of the added iron was retained in surface waters. Our findings demonstrate that iron supply controls phytoplankton growth and community composition during summer in these polar Southern Ocean waters, but the fate of algal carbon remains unknown and depends on the interplay between the processes controlling export, remineralisation and timescales of water mass subduction.
Publisher: Elsevier BV
Date: 09-2011
Publisher: Wiley
Date: 14-07-2016
DOI: 10.1111/AEC.12284
Publisher: American Geophysical Union (AGU)
Date: 20-06-2007
DOI: 10.1029/2006JC003748
Publisher: Springer Science and Business Media LLC
Date: 02-10-2014
Publisher: Wiley
Date: 07-2012
Publisher: Inter-Research Science Center
Date: 09-09-2014
DOI: 10.3354/MEPS10923
Publisher: Elsevier BV
Date: 09-2014
Publisher: Inter-Research Science Center
Date: 08-04-2013
DOI: 10.3354/MEPS10327
Publisher: Elsevier BV
Date: 09-2012
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/MFV71N3_ED
Publisher: Springer Science and Business Media LLC
Date: 12-03-2015
Publisher: American Geophysical Union (AGU)
Date: 12-2005
DOI: 10.1029/2005GB002494
Publisher: Wiley
Date: 19-09-2011
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.
Publisher: Wiley
Date: 26-03-2017
DOI: 10.1002/LNO.10524
No related grants have been discovered for Russell Frew.