Buried black soils on the slopes of Mt. Kilimanjaro as a regional carbon storage hotspot
2014
Zech, Michael | Hörold, Claudia | Leiber-Sauheitl, Katharina | Kühnel, Anna | Hemp, Andreas | Zech, Wolfgang
Mt. Kilimanjaro attracts much scientific and public attention due to its dramatically shrinking ice caps, still known as “the white top” of Africa. In this mountain system forming a type of island within the surrounding savannah, a new phenomenon has recently been discovered. On the slopes of Mt. Kilimanjaro, Late Quaternary paleosol sequences, composed of dark or black buried soils, are widespread in the montane rainforest zone (1800–3000ma.s.l.). In this study we investigated in detail the soil organic carbon (SOC) content and SOC stocks in soil profiles (mostly Andosols) along two altitudinal transects, situated on both the humid southern slopes and on the drier northern slopes of the mountain.In the montane forest zone, up to 3m thick paleosol sequences are frequently found. SOC content is remarkably high, reaching values of up to more than 10%. This testifies to good preservation of soil organic matter (SOM) which may be due to such factors as rapid burial by dust, low temperatures alongside more resistant litter during glacial periods, formation of stable organo-mineral complexes and high black carbon (BC) content. The buried black soils are estimated to contain ~82kgm−2 mean SOC stocks in the montane rainforest. As compared to the SOC storage in the surrounding savannah soils of the Maasai Steppe, the buried black soils constitute a distinctive regional carbon storage hotspot.
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