Biological cycling of inorganic nutrients and metals in soils and role in soil biogeochemistry

Abstract

Microorganisms play major roles in transformations of inorganic nutrients such as phosphorus, sulfur, iron, and trace elements in terrestrial systems. The bacteria, fungi, and archaea that mediate these cycles inhabit a wide range of environmental niches in soils, varying from fully aerobic in aerated surface soils to entirely anaerobic within soil aggregates or in sediments. Important nutrient transformations include mobilization of nutrients from primary minerals through weathering, immobilization of nutrients into soil organic matter, and their mineralization from organic matter to liberate nutrients for assimilation or dissimilation as required. Mineralization mechanisms for P and S are often hydrolytic in nature, whereas key processes for metal solubilization involve chelation and redox transformations. Biological nutrient cycles for different elements are often closely integrated with each other. We present examples of these interactions in wetlands with varying water levels and during early soil development on a glacier forefield.