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 co-location 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.

中文翻译：

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显微光谱揭示了酸性、高度风化的夏威夷土壤中灰尘衍生的磷灰石颗粒

摘要 沙尘沉积是许多生态系统磷（P）的重要来源。然而，几乎没有证据表明土壤中含有灰尘衍生的含磷矿物质。在这里，我们研究了沿着夏威夷描述得很好的气候梯度的 P 形式，这也是一个尘埃沉积梯度。对沿气候梯度的六个地点的土壤矿物学和土壤 P 形态进行了分析，使用了体积（X 射线衍射和 P K 边缘 X 射线吸收近边缘结构）和微观尺度（X 射线荧光、PK 边缘 X 射线吸收近边结构和拉曼）分析方法。在最潮湿的土壤中，尺寸为 5 至 30 微米的磷灰石颗粒与石英在微观尺度上共存，石英是一种已知的大陆尘埃指标，表明最近的大气沉积。除了与石英共处，来自尘埃的 P 的进一步证据包括后向轨迹模型，表明尘埃粒子可以从中亚和北非的全球主要尘埃装载区带到夏威夷。虽然不能肯定观察到的单个磷灰石颗粒是来自远距离的尘埃输送，还是来自火山灰或风吹肥料等当地尘埃源，但这些观察提供了直接证据，表明含磷矿物已到达高度地表层。 - 通过大气沉积风化草原土壤。