Soil compaction in forests can have severe consequences for the functioning of ecosystems, in terms of seedling establishment, root growth and overall plant development. Compaction also reduces soil porosity, affecting oxygen, water and nutrient availability to plants and microorganisms. There is limited understanding of carbon investment into the root system with different levels of soil compaction and the associated benefits in terms of root access to water and nutrients. These cost-benefit trade-offs are fundamental for plant performance and the soil carbon balance.
The objectives of FORFUS-RT1.1 are to determine how soil compaction (1) alters below-ground carbon allocation and the uptake of water and nutrients, (2) affects utilization of nutrient pools in the litter and the regolith layers in forest soils, and (3) impacts symbiosis with arbuscular mycorrhiza, an important contributor to nutrient uptake in trees.
We will set up a series of controlled experiments with young trees of different species that have been adapted to different climates and grown in soil columns divided into layers equipped with openings for water injections and extractions. Sensor foils are available to observe the CO2, O2 and pH dynamics deriving from root and mycorrhiza activity and from root exudation. Shoot gas exchange and soil respiration rates can be monitored continuously in 15 growth chambers. Isotope tracer techniques are available to track sources of nutrients (e.g. litter vs. regolith). Imaging techniques are available to record root growth dynamics and 2D fields of CO2, O2 and pH along an inclined transparent surface.
The scientific knowledge generated in this project will help us to better understand how much carbon plants need to invest below-ground under different environmental conditions in order to extract the water and nutrients they need for their growth and survival. This knowledge will help build more powerful and robust vegetation models and better understand the environmental costs of soil degradation (e.g. by compaction).
About Christophe Hissler
The curiosity that guides my research leads me to understand the processes that occur at the interfaces between the different compartments of the critical zone (CZ) and between the cycles of water, carbon and trace metals. After having worked during 15 years on trace metal pollution in the environment, I specifically study the effect of the climate change on the storage and mobility of the below ground nutrients and their fate in forest ecosystems. The main objective of this research is to better constraint the carbon balance in forests by using multidsciplinary approaches.My research is based on three pillars: observation-tracing-prediction around which I have been able to develop one interdisciplinary skill between biogeochemistry and hydrology.
Skill & Expertise
About Stanislaus Schymanski
I am a Senior Lead Research and Technology Associate at LIST, where I started a group on "Water and vegetation in a changing environment" (WAVE) in 2017, funded through an ATTRACT fellowship by the Luxembourg Research Fund (FNR). I hold a degree in Biology from the University of Freiburg (Germany) and a PhD in Environmental Engineering from the University of Western Australia. Between my PhD and current employment, I worked as a scientist at the Max Planck Instutute for Biogeochemistry in Jena (2007-2011) and the Swiss Federal Institute of Technology (ETH) in Zurich (2011-2017). Throughout my career, I have been investigating the interactions between vegetation, soil and atmosphere and the resulting hydrologic behaviour of hillslopes and catchments. In search of general laws guiding these interactions, my research focuses on physical constraints, biological adjustments and macroscopic extremum principles such as maximum net carbon profit or maximum entropy production. I combine mathematical analysis with numerical modelling to generate hypotheses and engage in lab and field observations to test these hypotheses and formulate new questions.
Being a strong advocate for Open Science, I am maintaining a Python package for reproducible and transparent mathematical modelling (https://essm.readthedocs.io) and contributing to the development of an open science platform (https://renkulab.io), which I am also using for my research. I am also editor of the open access and open-review journal Hydrology and Earth System Science (HESS).
Skill & Expertise