Microspectroscopy reveals dust-derived apatite grains in acidic, highly-weathered Hawaiian soils - Archive ouverte HAL Access content directly
Journal Articles Geoderma Year : 2021

Microspectroscopy reveals dust-derived apatite grains in acidic, highly-weathered Hawaiian soils

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Abstract

Dust deposition is an important source of phosphorus (P) to many ecosystems. However, there is little evidence of dust-derived P-containing minerals in soils. Here we studied P forms along a well-described climatic gradient on Hawaii, which is also a dust deposition gradient. Soil mineralogy and soil P forms from six sites along the climatic gradient were analyzed with bulk (X-ray diffraction and P K-edge X-ray absorption near edge structure) and microscale (X-ray fluorescence, P K-edge X-ray absorption near edge structure, and Raman) analysis methods. In the wettest soils, apatite grains ranging from 5 to 30 µm in size were co-located at the micro-scale with quartz, a known continental dust indicator suggesting recent atmospheric deposition. In addition to colocation with quartz, further evidence of dust-derived P included backward trajectory modeling indicating that dust particles could be brought to Hawaii from the major global dust-loading areas in central Asia and northern Africa. Although it is not certain whether the individual observed apatite grains were derived from long-distance transport of dust, or from local dust sources such as volcanic ash or windblown fertilizer, these observations offer direct evidence that P-containing minerals have reached surface layers of highly-weathered grassland soils through atmospheric deposition.
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Origin : Publication funded by an institution

Dates and versions

hal-03722798 , version 1 (13-07-2022)

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Christian Vogel, Julian Helfenstein, Michael S Massey, Ryo Sekine, Ruben Kretzschmar, et al.. Microspectroscopy reveals dust-derived apatite grains in acidic, highly-weathered Hawaiian soils. Geoderma, 2021, 381, pp.114681. ⟨10.1016/j.geoderma.2020.114681⟩. ⟨hal-03722798⟩
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