Session GDB6

[Programme]

GDB6 | Overlooked in models?: The dynamics of terrestrial ecosystems and their coupled feedbacks on hydrology, biogeochemistry and geomorphology

Overlooked in models?: The dynamics of terrestrial ecosystems and their coupled feedbacks on hydrology, biogeochemistry and geomorphology

Convener: Martine van der Ploeg | Co-conveners: Thom Bogaard, Katherine Todd-Brown, Ilja van Meerveld

Programme

| Mon, 04 May, 10:45–12:30 (CEST)

Room E1

Earth system models and associated finer resolution models are key tools for the simulation of the feedbacks and linkages between soil, hydrological, geomorphological, and ecosystem processes, and to simulate the water and energy balance and their interactions at different scales. However, there are important coupled feedbacks on the scale of years to decades missing in many terrestrial ecosystem models. For example, water cycle patterns affect soil carbon stocks and microbial community structures, which in turn affects the hydraulic and ecophysiological response of the soil. Soil organic carbon fraction is a key determining factor for soil porosity and water holding capacity that drives soil moisture dynamics in hydrological models, and the soil moisture, in turn, drives soil organic carbon decomposition rates – creating a dynamic feedback that is often ignored in models. Another example is the coupling and feedback between hydrology and geomorphology in processes such as soil erosion and landslides and related vegetation patterns. Landscapes change and adapt to atmospheric forcing, changing climatic conditions and anthropogenic activities, leading to a changed hydrological behavior of the earth surface. These dynamics are not included in the larger scale hydrological models, nor discussed as critical. As such soil (eco)systems are often considered static in models of freshwater stocks and fluxes at catchment to global scales, and important interactions over time scales as short as a year or a decade are overlooked. While no model can include all processes, ongoing developments in computation and earth system science urge us to continue to press the boundary of model development and to include important feedback processes.
This session will contribute to the debate on which processes and stocks in the terrestrial ecosystem need to be included in modeling efforts that aim to increase our understanding of the coupled atmospheric-terrestrial water cycle. On the one hand this session aims to raise awareness of the importance of these feedbacks and that soil is more than a parameter that can be considered static for models that are run for several decades, and on the other hand provide a dialogue between contrasting opinions on what is important to include in models. In other words, the session will provide a platform to discuss when we need a detailed representation of soil-related feedback processes and when we can simplify these.

Programme: Mon, 4 May, 10:45–12:30 | Room E1

The oral presentations are given in a hybrid format supported by a Zoom meeting featuring on-site and virtual presentations. The button to access the Zoom meeting appears just before the time block starts.

Chairpersons: Martine van der Ploeg, Thom Bogaard, Ilja van Meerveld

10:45–10:50

Overlooked in models? Introduction of the debate and panellists

10:50–11:40

Perspectives across hydrology, biogeochemistry and geomorphology - presentations by panel

11:40–12:25

Audience questions and participation

12:25–12:30

Wrap-up

Speakers

James Kirchner, Retired from ETH Zurich, Switzerland
Teamrat Ghezzehei, University of California, Merced, United States of America
Stefano Manzoni, Stockholm University, Sweden
Arnaud Temme, University of Innsbruck, Austria