Accumulation, transformation, and stabilization of organic nitrogen along a mineralogical soil gradient

Beteiligte Institutionen der FZ:GEO:

• Institut für Bodenkunde
• BGR - Bundesanstalt für Geowissenschaften und Rohstoffe

This project aims at elucidating the role of mineral−organic associations on accumulation, transformation, and stabilization of organic nitrogen (ON) in soils of a temperate rainforest chronosequence in New Zealand. The soils developed over 120,000 years upon retreat of the Franz-Josef glacier in silica-rich parent materials (schist, greywacke) giving rise to pronounced gradients in soil mineralogy and soil formation. This allows to track mineral-induced changes in ON accumulation and stabilization as well as in microbial composition and function. We will address the following aspects: (i) detailed mineralogical characterization of soils, (ii) assessment of the ON quantity held in mineral−organic associations, (iii) analyses of respective ON forms and their transformation as revealed by molecular biomarker, X-ray photoelectron and absorption spectroscopy, (iv) assessing the consequences of mineral−ON interactions for N bioavailability, and (v) investigating the interplay of the mineral−ON binding with microbial communities involved in N cycling using real-time polymerase chain reaction for 16S rRNA and functional gene quantification, and enzyme activity measurements.