Co-Evolution of Structure and Heterogeneity in Natural Permeable Media: The Emergence of Niche-Diversity and Functions During Weathering and Pedogenesis

Natural permeable media like soils, sediments, but also rocks, provide niches of different quality for the inhabitation by a diversity of organisms and communities. The locations for colonization are the microstructured, frequently hierarchic organized heterogeneous biogeochemical interfaces (BGI) that evolve during weathering and pedogenesis. These BGIs are built from a vast variety of organic and inorganic materials and organisms and become manifest as crusts or (micro)aggregates that frame the void network and connect to the liquid and gaseous phases. Microaggregates, operationally defined as composite, microporous, and themselves already heterogeneous composite structures smaller than <250µm, are supposed to be fundamental structural components, because of their stability, persistence, ubiquitous presence, and growing fraction during weathering and pedogenesis. Although research on structure development and fluid-solid interaction in permeable media is an important, exciting and competitive field of soil science, in particular the co-evolution of structure and function due to the interplay of the multitude of biochemical and biophysical processes in view of the properties, functions and resilience of soils has yet to be unravelled. By now, it is well accepted that such and endeavour requires integration of soil physical, chemical, and biological disciplines and demands the development and application of joint advanced characterization and probing techniques including molecular biology within a multi- and inter-disciplinary research approach. Within the framework of the research unit 2179 “Microaggregate development and turnover in soil” and its preceding priority research program 1315 “Biogeochemical Interfaces in Soil”, collaborative research has been put in action that aim at the systematic characterization and functional exploration of aggregates structures and the associated BGI. The presentation will give a compact introduction on the propositions, concepts, and challenges of this exciting research field that aims to contribute to a fundamental understanding of the basics of the co-evolution of architecture and function and the consequences for soil based ecosystem services, and resilience of soils.