EarthShape

Connecting the green and the grey world – an experimental approach to separating climate, vegetation and geochemical effects on nutrient cycling along a climate gradient

This project is part of the DFG Priority Programme ‘EarthShape’. Which tries to investigate the importance of biological control over geological processes using a climate gradient in Chile.

The objective of our project is to combine plant ecological with biogeochemical expertise and methodology for investigating how the relative importance of geochemical and biological processes for geo-biosphere feedbacks change in response to climatic conditions. Therefore, we combine a space-for-time approach with mechanistically orientated field experiments that directly manipulate environmental conditions along the EarthShape climatic gradient in Chile.

With our approach, we aim to address the following overarching questions: Can space substitute for time, and which temporal processes can be better described by a space-for-time approach than others? What is the role of biotic processes in determining the predictability of bio-geo dynamics? Under which circumstances can spatial climate gradients, i.e. the result of long-term climatic impact on the earth surface, serve as proxy for short- to medium term temporal climatic changes? As a side effect, our study will be the first in Chile to investigate the impact of concurrent climate change on ecosystem processes by means of large-scale field experiments.

By moving subsets of the site-specific systems to a different climate and comparing ecosystem processes, we adopt a novel experimental approach to address the question whether and to what extent space can really substitute for time. Furthermore, we study how the relationship between plants, soil and parent rock is mediated by climatic variables. Finally, mechanistic information about bio-geo feedback with climate will be generated by implementing permanent rainout shelters at two dryland sites.