Ecohydrology, i.e., the study of the interactions between water and ecosystems, is expanding rapidly as a field of research, beyond traditional discipline boundaries in terms of questions and approaches. This session aims to draw examples from this wide field, in order to portray the current diversity and common features of research frontiers in ecohydrological studies, as well as the range of methods employed. We thus encourage contributions showing novel results or methods when tackling questions related to the coupling of ecological, biogeochemical and hydrological processes, at scales ranging from the single organ or organisms to whole ecosystem/catchment. While contributions relative to all terrestrial and aquatic systems are welcome, this year we especially encourage abstracts focusing on managed ecosystems, showing how human intervention alters the interactions between water and ecosystems.

The invited speakers for the session are Prof. Amilcare Porporato (Princeton University, USA) and Dan Moore (University of British Columbia, Canada).

During the passage of precipitation through the soil-plant-atmosphere interface, water and solutes are redistributed by the plant canopy and subsurface flow and transport processes. Many of these dynamic interactions between vegetation and soil are not yet well understood. This session brings together the vibrant community addressing a better understanding of ecohydrological processes taking place between the canopy and the root zone. Innovative methods investigating throughfall, stemflow, hydraulic redistribution, and root water uptake in various environments shed light on how water and solutes are routed in the thin layer covering the terrestrial ecosystems. The session further covers open questions and new opportunities within the ecohydrological community regarding methodological developments such as the analysis of stable isotope, soil moisture, throughfall or solute dynamics.
Invited Speakers:
Christiane Werner, University of Freiburg, Germany
Alexandra Ponette-González, University of North Texas, USA

Peatlands develop in specific hydrological settings and react sensitively to changes in climatic and hydrological boundary conditions. The hydrology of peatlands is fundamental to their function and development. Soil hydrological properties can change drastically after human interventions such as drainage, causing challenges for both model parameterisation and re-wetting measures. Pristine peatlands offer and regulate a number of ecosystem services such as biodiversity, carbon storage and nutrient retention. Hydrology is a key control for a number of these services but studies on peatland hydrology are surprisingly scarce. Furthermore, the effects of peatlands (both pristine and disturbed) on flood retention and on regional climate are much debated, but there seem to be more myths than data. As hydrological and biotic processes in peatlands are strongly coupled, estimating the eco-hydrological response of peatlands under climate change and linking it to vegetation development and greenhouse gas emissions is a demanding task for modellers.
This session aims to bring together peatland scientists to focus on improved understanding of hydrological processes operating in all types of peatlands. Peatlands being considered may be pristine or disturbed and degraded and may also include rehabilitation and re-wetting interventions. Hydrological data may have been collected for other reasons (e.g. carbon flux calculations) but the session welcomes re-examination of such hydrological data in its own right or as supporting data for other studies. All aspects of peatland hydrology are welcome to boost knowledge transfer across scales and methods; from the pore to the global scale, including laboratory, field, remote sensing and modelling studies on hydrological, hydrochemical or geophysical topics, as well as ecosystem service assessments.

Public information:
Organization of the Peatland Hydrology session:

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One more note, especially addressed to young researchers! At EGU, we would meet in person after an oral presentation or in the poster hall. Don't hesitate to e-mail people and ask for a skype call as if you were live at EGU !!! Don't allow the physical distance as a hurdle for your scientific development. Our Earth faces big challenges, no need to waste time through inefficient scientific exchange!

best wishes and enjoy EGU20,
Michel Bechtold
Ullrich Dettmann
Joseph Holden
Bjørn Kløve
Marie Larocque

Groundwater-surface water interfaces (e.g., hyporheic and benthic zones and riparian corridors) are integral components of the aquifer-river or aquifer-lake continuum. Interactions between groundwater and surface water lead to strong bi-directional influences between surface waters, aquifers and interconnecting hyporheic zones. A rapidly expanding number of research projects are now investigating the implications of hyporheic exchange on the transport and transformation of nutrients and contaminants within river networks, and on controls to heat, oxygen, and organic matter budgets available to microorganisms and macroinvertebrates in streambed sediments. However, there is still a need to better understand the links between physical, biogeochemical, and ecological process dynamics in groundwater-surface water interfaces and their implications for fluvial ecology or limnology, respectively. Furthermore, it is important to consider the response of hyporheic exchange fluxes to environmental and climatic controls at different spatial and temporal scales (e.g. river channel, alluvial aquifer, regional groundwater flow). We consider up- and downscaling and the development of a general conceptual framework and improved process understanding for groundwater-surface water interfaces as among the most urgent challenges of hyporheic zone research. Consequently, we particularly welcome contributions that aim to close these knowledge gaps and solicit both experimental and modelling studies with a focus on:

- The development and application of novel experimental methods to investigate physical, biogeochemical and ecological conditions at the groundwater-surface water interface in rivers, lakes, riparian corridors, and wetlands;

- Investigations of the role of hyporheic processes for the retention and natural attenuation of nutrients and pollutants, particularly with respect to impacts on surface water and groundwater quality;

- Hydrological, biogeochemical and ecological modelling approaches (e.g. transient storage models, coupled groundwater-surface water models etc.);

- Investigations of the implications of groundwater-surface water interactions for management and risk assessment frameworks with regard to the European Water Framework Directive.

Solicited contribution: Kevin Roche, Institute of Environmental Assessment and Water Research, Spanish National Research Council (CSIC)

As confined water bodies with limited exchanges, lakes and inland seas are particularly vulnerable to climatic and human impacts accumulated over broad catchment areas. Hence, they mirror both the global change effects and
anthropogenic pressures, perhaps, stronger than any other aquatic objects. Lakes and inland seas
also play an important role in ecosystem services such as fisheries, aquaculture, tourism, and others. These multifunctional roles require careful governance measures to avoid hydrological and environmental deterioration.
Research of lakes and inland seas admits many common approaches and techniques. Oceanographic methodology and instrumentation are often applicable to limnological studies. Reciprocally, insights obtained from lakes can also be instructive with respect to marine systems. This interdisciplinary session provides a joint forum for oceanographers, limnologists, and hydrologists interested in processes governing physical, chemical, and biological regimes of various lakes and inland seas of the world, as well as their responses to climate change and anthropogenic impacts.

The last two decades have brought major technological advancements in characterisation of aquatic organic matter with spectroscopic and chromatographic methods and collection of water quality data at high spatial and temporal resolution with automated in situ instruments. The aim of this session is to demonstrate if and how this methodological advancement improves our understanding of dominant hydrochemical and ecological processes in aquatic environments controlling the fate of organic matter, nutrients and other pollutants.

Specifically, our ability to characterise different fractions of natural organic matter has increased thanks to a range of analytical methods e.g. fluorescence and absorbance spectroscopy, mass spectrometry and chromatography combined with new data mining tools (self-organising maps, PARAFAC analysis). Matching the water quality measurement interval with the timescales of hydrological responses (from minutes to hours) thanks to automated in situ wet-chemistry analysers, optical sensors and lab-on-a-chip instruments has led to discovery of new hydrochemical and biogeochemical patterns in aquatic environments e.g., concentration-discharge hysteresis and diurnal cycles. We need to understand further how hydrochemical and ecological processes control those patterns, how different biogeochemical cycles are linked in aquatic environments (e.g., carbon, phosphorus, nitrogen, sulphur and iron) and how human activities disturb those biogeochemical cycles by emitting excess amounts of nutrients to aquatic systems. In particular, there is a growing need to better characterise the origins, delivery pathways, transformations and environmental fate of organic matter and nutrients in aquatic environments along with identification of robust numerical tools for advanced data processing and modelling.

Previously in this session:
2019 https://meetingorganizer.copernicus.org/EGU2019/session/32089
2018 https://meetingorganizer.copernicus.org/EGU2018/session/26401
2017 http://meetingorganizer.copernicus.org/EGU2017/session/24958
2016 http://meetingorganizer.copernicus.org/EGU2016/session/20013
2015 http://meetingorganizer.copernicus.org/EGU2015/session/17101
2014 http://meetingorganizer.copernicus.org/EGU2014/session/15261

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.
New approaches and innovative modeling strategies are needed to understand these complex interactions between hydrological, biogeochemical cycles and human resilience processes 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, water transfer in the frame of global change and biological feedback mechanisms.
This session focuses on the advancing proxies that may address pressing interdisciplinary scientific questions in coupling various disciplines like hydrology, soil science and biogeochemistry that cover single-site investigations, targeted experiments, remote sensing studies, large data compilations and modelling. This will be illustrated in this session through studies regarding the critical zone as a whole or within its different compartments, including the different environmental processes (geological, physical, chemical, and biological), their couplings and reactive transport modeling , and exploring the cities resilience.

Shorter return period of climate and hydrological extremes has been observed in the changing climate, which affects the distribution and vitality of ecosystems. In many regions, available water is a crucial point of survival. Risk can be enhanced by the exposure and/or by the vulnerability of the affected ecosystem as well as by land use/land cover change.
The session should provide a multidisciplinary platform for sharing experiences and discussing results of local and catchment scale case studies from a wider range of relevant fields such as
• observed impacts and damage chains in natural and agricultural ecosystems induced by droughts and intense rainfall events;
• correlation between the underlying environmental factors (e.g. climate, water storage capacity of soil) and the distribution/vitality of ecosystems;
• integrated application or comparison of databases and methods for the identification and complex assessment of ecosystem responses to abiotic stress factors;
• expected tendencies of abiotic risk factors affecting and limiting the survival of the vulnerable species.
Contributions are encouraged from international experiences, ongoing research activities as well as national, regional and local initiatives.