The EGU General Assembly 2020 will bring together geoscientists from all over the world to one meeting covering all disciplines of the Earth, planetary and space sciences. The EGU aims to provide a forum where scientists, especially early career researchers, can present their work and discuss their ideas with experts in all fields of geoscience.
Meeting website: www.egu2020.eu
Convener: Gerd Gleixner | Co-convener: Antonello Provenzale
Description: The critical zone comprises the Earth's permeable near-surface layer from the top of the canopy to the bottom of the groundwater. It is the zone where hydrosphere, atmosphere, pedosphere and geosphere interact with the biosphere. This fragile skin of our planet, which supports the life and survival of humans maintaining food production and drinking water quality, is endangered by threats such as climate change and land use change. This multidisciplinary session will bring together scientists from all disciplines that contribute to our understanding of the critical zone from the molecular to the global scale and from fast processes like electron transfer reactions to slow processes like the rock cycle. Studies that cover single-site investigations, targeted experiments, remote sensing studies, large data compilations and modelling studies are all welcome, especially if they combine multiple approaches. Cross-scale studies are especially encouraged and special attention is payed to extreme environments and events such as drylands, high-latitude and high-altitude regions and fires.
Convener: Michael Mirtl | Co-conveners: Jaana Bäck, Giorgio Matteucci, Daniel Orenstein
Description: The development and functions of ecosystems and their responses to environmental drivers are inherently long-term processes that need to be studied along gradients in time and space. Global anthropogenic drivers of change interact with natural processes, causing uncertainties, tipping points and potential crises in system behaviour Further, most ecosystem services are strongly interlinked and require a multi- and transdisciplinary approach that allows for the simultaneous analysis of multiple processes and feedbacks. The sites and platforms of the long-term ecosystem, critical zone and socio-ecological research networks and research infrastructures (ILTER, eLTER) distributed around the globe offer a unique tool for this.
This session focuses on research performed at sites and platforms implementing a whole system approach. Emphasis will be on results presenting long-term changes and responses of ecosystem and socio-ecological processes to environmental drivers, as well as observations scaling up from sites to larger regions up to the continental level.
We welcome studies linking biodiversity loss, climate change, and other anthropogenic pressures to ecosystems. We encourage contributions using interdisciplinary and multidisciplinary approaches, addressing relationships among different ecosystem compartments (vegetation, soils, waters etc.) or between ecological and social systems, as well as transdisciplinary studies that incorporate diverse forms of knowledge beyond the scientific community.
Convener: Natalie Orlowski | Co-conveners: Josie Geris, Christophe Hissler, Pilar Llorens, Matthias Sprenger
Description: Stable isotopes are powerful tools for tracing fluxes of water and associated nutrients in the soil-plant-atmosphere continuum. They are increasingly used by various disciplines to better understand the functioning of the soil-plant-atmosphere system. While new methods allow measurements at high spatial and temporal resolution, studies applying tracer methods are now tackling complex interactions between soil processes, plant physiology and ecology, and variable atmospheric drivers. As such, methodological developments and changes are happening quickly and have a strong bearing on process understanding and interpretation of findings. This session aims to address the current state of the art for methods, applications, and process interpretations using stable isotopes in the critical zone and to foster interdisciplinary exchange. We welcome experimental and modeling studies that present methodological developments and applications of isotope tracers to improve the actual knowledge of the water and nutrient exchanges at the soil-plant-atmosphere interfaces. Studies that seek to cross disciplinary boundaries and reveal new eco-hydrological process understanding are especially welcome.
Convener: Tamara Kolbe | Co-conveners: Jean Marçais, Sílvia Poblador Ibáñez
Description: Natural phenomena and human activities alter hydrological and biogeochemical cycles and challenge hydrologists and biogeochemists to represent interactions between flow and substance turnover. New tracers and innovative modeling strategies are needed to understand these complex interactions between hydrological and biogeochemical cycles within the critical zone (the heterogeneous layer between the bedrock and atmosphere, also described as the living skin of the Earth).
This session invites new advances in coupling both disciplines (hydrology and biogeochemistry) at the critical zone as a whole or within its different compartments, through field and modeling studies, to understand and predict how our planet will evolve in the Anthropocene, e.g. how water quality, water availability or ecological health will be impacted by the increasing footprint of human activities.
We are especially inviting contributions that:
Convener: Philippe Negrel | Co-conveners: F. Chabaux, Romain Millot, Emmanuelle Petelet-Giraud
Description: The on-going evolution of the critical zone is an issue of attention of the scientific community relative to societal expectations and environmental issues. Crucial factors including ecohydrological processes, weathering and erosion rate, recharge processes and water provenance, flow paths, geochemical reactions, transit times and soils fertility are key parameters to estimate the vulnerability and the recovery-time of the critical zone to assess soil erosion rates, to plan the sustainable use of water resources, and to protect ecohydrological systems under climate or land use change. To be meaningful they must be set in the context of the wider critical zone where most of the ecosystem services are provided. This session focuses on the advancing proxies that may address pressing interdisciplinary scientific questions concerning geological, physical, chemical, and biological processes and their couplings, reactive transport modeling that may govern critical zone system dynamics, including sources, dynamics and chemistry of water, models to quantify external influences like human activities or erosion, weathering rate and water transfer in the frame of global change.
Convener: Beatrice Bechet | Co-conveners: Herve Andrieu, Cécile Delolme, Aawatif Hayar, Arjan Von Timmeren
Description: The continuous increase of world’s cities sprawl, in a context of global change, makes it urgent to promote the sustainability of these areas. But an integrated and systemic approach is required to face with simultaneous environmental, economic and social challenges. The concept of critical zone offers an adapted framework to develop integrated approach, but it needs to be adapted to the specificities of the zones where humans live and work. The critical zone is defined initially as the thin and heterogeneous and near surface environment in which occur interactions involving rock, soil, water, air, and terrestrial ecosystems. In urban areas, the critical zone is strongly transformed by the infrastructure, facilities and buildings, and impacted by human activities and usages which heavily affect the fluxes and balances of water, energy, and chemicals including pollutants….In this session, we will address the question of the biophysical processes specificities of the urban critical zone that interact with anthropic processes controlled by human activities and stakeholders. Most of the urban geophysical processes are studied are very local and small levels, it is necessary to produce interdisciplinary knowledge are more global scales.
We invite contributions of experience on urban critical zones including observations, measurements of fluxes, description of biogeochemical, physical and human resilience processes and development of models to respond to these crosscutting issues. Proposals coming from diverse urban contexts (size, growth patterns, geographical, social) at different spatial and temporal scales will be appreciated. We aim at forstering interdisciplinary dialogue to make the Urban Critical Zone a unifying concept.https://meetingorganizer.copernicus.org/EGU2020/abstractsubmission/37117
Convener: Chris McCloskey | Co-conveners: Emily Dowdeswell-Downey, Daniel Evans
Description: Soils represent a major terrestrial carbon store and are an essential component of the critical zone: the near-surface terrestrial layer extending from the bedrock through to the lower atmosphere. Carbon fluxes between soils and the atmosphere, hydrosphere, biosphere, and lithosphere are an important element of Earth system processes. Both organic and inorganic carbon plays a critical role at every soil interface at all spatial and temporal scales.
It is essential that we consider the role of carbon in all soil systems, from the microbial and aggregate scale to the catchment and the whole land surface, in order to better understand the interconnectivity between rocks, soils, plants, and the atmosphere. This is particularly important as carbon cycles are facing multiple perturbations, ranging from rapid shifts in land use and management to degradation and long-term environmental and climatic change. Alongside considering individual pools and fluxes we must also integrate them into a fuller, holistic picture of soil carbon.
This session will consider terrestrial carbon pools and dynamics and embrace a range of scales. We welcome contributions that consider carbon fluxes within and between different elements of the critical zone, alongside innovative methods of quantifying and imaging carbon stocks and fluxes. Early career researchers are strongly encouraged to apply, and we seek submissions considering empirical, modelling, or meta-analytical approaches.
Convener: Anne Verhoef | Co-conveners: Roland Baatz, Teamrat Ghezzehei, Dani Or, Pier-Luigi Vidale
Description: The parameterization of land surface processes and related properties critically determines the magnitudes and partitioning of water, energy, and carbon fluxes. Studies have shown that uncertainty in the estimates of key soil properties remain large, and that the temporal variation of soil structure (e.g., due to compaction), that has a large effect on soil properties in reality, is often not considered. These parameter uncertainties, missing processes, process descriptions that lack reality, and the assumption that soil parameters remain constant in time, adversely impact the fidelity of estimates of soil water, energy, and carbon fluxes by land surface models. For example, in recent years, highly spatially resolved global data sets of soil properties have been developed for improved parameterization of soil hydraulic properties in particular, yet lacking incorporation in Earth system models.
This scientific session welcomes contributions on improved parameterization of soil and critical zone processes, relevant for modelling land surface processes in the climate, hydrological, biogeosciences and critical zone sciences. This session aims to bring together scientists from the climate- and soil-biogeosciences communities and to identify key shortcomings in current land surface models that need to be tackled through research and experimentation. Specifically, we welcome contributions that are already exploring the use of existing global datasets (based on in-situ data, or derived from remote sensing) to advance soil model parameterization in land surface models, including those embedded in weather forecast or climate models.
Convener: Anika Klotzbücher | Co-conveners: Julia Cooke, Jean-Thomas Cornelis, Camille Delvigne, Jörg Schaller
Description: Silicon (Si) is crucial in numerous biochemical and geochemical processes. Earlier scientific literature on Si cycling focused on abiotic weathering processes, while in recent years, scientists have become more aware of the significant role of biotic controls. Silicon plays a key role in processes governing soil formation and soil-plant feedback interactions. Vegetation, soil organisms, including fauna, microorganisms and fungi, strongly affect Si dynamic in terrestrial ecosystems but the mechanisms are still poorly understood. In particular, Si has numerous beneficial effects on both plant structure, function as well as resilience to biotic and abiotic stresses motivating studies focusing on Si functional ecology and silica biomineralization. The global Si cycle is receiving increased attention because of its links with the carbon cycle as well as other major biogeochemical cycles and toxic elements. A better understanding of the terrestrial Si cycle is thus critical, especially as drastic and subtle changes in the terrestrial Si cycle are occurring worldwide in response to global change.
This session aims at compiling recent work focusing on biogeochemical Si cycling under global change, its functions in terrestrial ecosystems as well as its evolution in the recent past. This session bridges advances from soil sciences, ecology, plant physiology, agronomy, biogeochemistry (including isotopes studies) and paleontology. We invite studies tackling biotic and abiotic interactions at different time and spatial scales affecting the Si cycle and its interactions with other biogeochemical cycles. We encourage interdisciplinary studies as well as contributions from both field and laboratory experiments encompassing biogeochemical processes, molecular mechanisms to improve our understanding of the role of Si in ecosystem processes. Meta-analyses and paleo-environmental studies using phytoliths are also welcome.
Convener: Steffen Seitz | Co-conveners: Annegret Larsen, Carsten W. Mueller, Kirstin Übernickel
Description: The critical zone comprises a constant feedback system between climate, topography, parent material and biota. Its complex interactions not only regulate manifold ecosystems, but also shape the Earth’s surface. Soils form at this interface between atmosphere and lithosphere, sustaining terrestrial and aquatic biogeochemical cycles. Climate has a strong effect on soil properties via biological and hydrological processes, as changing water availability and thus vegetation affects soil physical and chemical properties. Topography is also an essential factor in soil formation through its influence on the redistribution of solutes and particles. Even though the underlying geology and tectonic processes have long been recognised as driving parameters for long term soil and landscape development, this is much less so for biological processes. The driving force of microorganisms, plants and animals on the formation of soils and the shape of land surfaces is still poorly understood.
Recent interdisciplinary research efforts attempt to close these scientific gaps. This session aims to bring together geoscientists, soil scientists and biologists working at different spatial and temporal scales on how soils, topography and particularly soil flora and fauna affect landscape development, erosion control and thus form the Earth’s surface. The session will cover a multitude of topics such as bio-mediated redistribution of material in the weathering zone, biotic influence on sediment fluxes and erosion, the influence of micro-biota as a driver of weathering, the depositional legacy of coupled biogenic and geological systems and/or new modelling approaches to bridge different spatial and temporal scales.
We strongly encourage early career scientists to present their research, ideas and new conceptual approaches, which will be discussed during the session.
Convener: Cecile Gautheron | Co-conveners: Julien Bouchez, Jean Braun, Emmanuelle Puceat
Description: Deep weathering covers, such as laterites, constitute a major expression of the critical zone, especially in tropical environments and participate significantly to the global geochemical budgets, weathering and erosion fluxes, and atmospheric greenhouse gas consumption. Despite their factual importance for the Earth surface, several important questions are still unanswered about their mode and timing of their formation, and their evolution in response to shifts in climatic and geodynamic forcing. We encourage all contributions addressing those questions using mineralogical studies, geochemical mass balance and isotopic signals in deep soil profiles or in rivers, dating tools at different time scales, or modeling approaches that can integrate those data to understand the evolution of deep weathering covers though time and their role in the global feedbacks between weathering and climate.
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