Characterization of Atmospheric Deposition as the Only Mineral Matter Input to Ombrotrophic Bog

Ombrotrophic peatlands contain a very small percentage of mineral matter that they receive exclusively from atmospheric deposition. Mineral matter deposited on the Sijec bog was characterized using scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS). We collected solid atmospheric deposition from snow, rainwater, and using passive samplers. Samples were collected at average atmospheric conditions and after two dust events. Size, morphology, and chemical composition of individual particles were determined. We distinguished four main particle groups: silicates, carbonates, organic particles, and Fe-oxyhydroxides. Silicate particles are further divided into quartz and aluminosilicates. Proportions of these groups vary between samples and between sample types. In all samples, silicate particles predominate. Samples affected by dust events are richer in solid particles. This is well observed in passive deposition samples. Carbonates and organic particles represent smaller fractions and are probably of local origin. Iron-oxyhydroxides make up a smaller, but significant part of particles and are, according to their shape and chemical composition, of both geogenic and anthropogenic origin. Estimated quantity and percentage of main groups vary throughout the year and are highly dependent on weather conditions. Dust events represent periods of increased deposition and contribute significantly to mineral matter input to peatlands.

Automated summary

This study characterized the mineral matter deposition on Ombrotrophic peatlands using scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS). Silicate particles were found to be the predominant group, followed by carbonates, organic particles, and iron-oxyhydroxides with both geogenic and anthropogenic origins. The proportions of these groups varied with sample types and weather conditions, and dust events were found to contribute significantly to mineral matter input.