Nickel Uptake by Cypress Pine (Callitris glaucophylla) in the Miandetta Area, Australia: Implications for Use in Biogeochemical Exploration

Augustine Alorbi,Kenneth G Mcqueen,Joseph A Schifano,David R Cohen

doi:10.3390/min11080808

Augustine Alorbi, Kenneth G Mcqueen + Show 2 more

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https://doi.org/10.3390/min11080808

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Abstract

The uptake of Ni and other elements by Callitris glaucophylla (white cypress pine), from weathered ultramafic rocks under varying depths of transported regolith cover, is examined at two sites in the Miandetta area, New South Wales, Australia. Results show that C. glaucophylla can accumulate elevated Ni concentrations in the needles (leaves or phyllodes) from underlying Ni-enriched regolith up to two orders of magnitude above the normal micronutrient levels required for the species. Such uptake levels occur in areas with high total Ni in the soil and regolith despite the relatively low mobility of the Ni due to its presence in a low availability form. This highlights the importance of biotic processes in extracting Ni from soil. The needles of C. glaucophylla could provide an effective and convenient sampling medium for reconnaissance biogeochemical exploration for Ni mineralisation and anomalies where transported regolith is less than ~3 m thick. The study has also demonstrated the potential for in situ analysis of Ni and other elements in the needles by portable XRF.

Highlights

Over the last twenty years, there has been resurgent interest in biogeochemical exploration methods, for potential application in the vast regolith-dominated areas of Australia [1,2,3,4,5]
Phenological studies of C. glaucophylla indicate very little growth occurs in winter months and that it is dependent on prevailing conditions at other times [10]
The current study has shown that in C. glaucophylla, Ni uptake can exceed the apparent micronutrient requirement by up to two orders of magnitude without any obvious signs of toxicity, such as stunted growth, or chlorosis and necrosis of the needles [36]

Summary

Introduction

Over the last twenty years, there has been resurgent interest in biogeochemical exploration methods, for potential application in the vast regolith-dominated areas of Australia [1,2,3,4,5]. This interest has been linked to advances in analytical methods for plant materials. Numerous case studies have documented the uptake of elements by various plant species and assessment of approaches to sampling and chemical analysis to detect geochemical dispersion patterns linked to underlying mineralisation within residual and transported regolith [6,7]. The depth of penetration of feeder roots or the existence of significant tap roots has not been documented

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