Our manuscript on "Measuring and Modeling Stable Isotopes of Mobile and Bulk Soil Water" was selected for the Outstanding Paper Award, 2020 by the Vadose Zone Journal Editorial Board. The "article was selected based on how it has advanced knowledge in the profession, the effectiveness of communication, methodology, originality, and impact". All ASA, CSSA, and SSSA awardees were announced in the latest CSA news that can be found here. I am personally very happy to see that our work has made some impact and was well received by the community. The presented study is a great example for a successful collaboration where data and model code have been shared openly to gain new understanding in subsurface hydrological processes. The work was done within the EU-funded VeWa project and you can find more publications and info here.

Plant water stable isotopes had not been used widely to study plant water use across Northern environments. Doerthe Tetzlaff's EU funded VeWa project addressed this research gap and an inter-site comparison of five involved sites has now been published in Hydrological Processes (open access). We show how the sampled xylem isotopes compare to precipitation, groundwater, and soil water and discuss why there is often a mismatch between the plant water and their potential sources.

Also at this year's AGU Fall Meeting, we will offer a session on "Stable Isotopes in the Critical Zone: Methods, Applications, and Process Interpretations". The last years, the session was very well attended and had lots of interesting isotope research to offer. Make sure to submit your abstract by the End of July here. The AGU Fall Meeting will be held virtually this year and you can read all about it here. This said, you will be able to attend without the usual high costs of travelling and accommodation. Further, the conference fee will be about half the usual price, due to the online form. So, it'll be a great way to keep contact with each other, despite the difficulties during the Covid crisis. You can read here about experiences some hydrologists made during the EGU General Assembly that was held as a virtual conference. I hope to see many of you again for our isotope session!

Since I met Scott in November 2017, we discussed about the concept of "ecohydrologic separation", as introduced by Renée Brooks and colleagues in a Nature Geoscience paper in 2010. In early 2019, we decided to write our thoughts down in a commentary, which was now published in the journal Water Resources Research, titled: "What ecohydrologic separation is and where we can go with it". Our main messages are:
A) Isotope ratios of plant water should differ from water flowing in soils to streams & so we need to move beyond confirming this difference
B) By focusing on dynamics of how water infiltrates into the subsurface & becomes available to plants we can better interpret past findings
C) We discuss four aspects that should be considered:

1. Soil waters seem to almost never be isotopically homogeneous, but it would be useful to identify under what conditions they are.
2. Trees do not prefer water under high tensions, but they might root in less conductive pores.
3. Concepts of plant-water availability should account for lateral heterogeneities.
4. Preferential flows should be represented to accurately model soil-water transport and plant uptake.

A paper from the current collaboration with the Surface Hydrology and Erosion Research Group at IDAEA-CSIC, Barcelona, was recently published in a special issue on "Using water age to explore hydrological processes in contrasting environments"  in Hydrological Processes. Under the lead of Francesc Gallart, we present a study on "Investigating young water fractions in a small Mediterranean mountain catchment: both precipitation forcing and sampling frequency matter" that highlights how sampling frequency and the rainfall dynamics impact estimations of the young (2-3 month) water fraction in the runoff. We found that this measure of young water fraction depends highly on the runoff dynamics with almost all runoff being young during the highest discharge events. Our findings, based on data from the Vallcebre Catchment in the Pyrenees, are for example relevant for inter-catchment comparisons based on estimated young water fractions, since the sampling design and the runoff responses should probably be considered in such approaches. A pre-print can be downloaded from researchgate and a final version can be requested via email if you do not have access to manuscripts published in Hydrological Processes.

Thanks to the support and organization by the Wassernetzwerk Baden-Württemberg, we had four full days of intensive classes and discussions with twenty graduate students and postdocs from around the world in the Black Forest on the topic of "Water Ages in the Hydrological Cylce". The classes covered current methods ranging from Ensemble Hydrograph Separation, Endmember Splitting Analysis, Age tracking in catchment-scale hydrological models, StorAge Selection functions, and  process based modeling approaches. Classes were accompanied by hands-on tutorials and in between, there was time for discussion about water age concepts, tracer hydrology, and sampling strategies. 

We are organizing an exciting workshop on studies using stable isotopes to better understand soil-plant interactions. It will take place in Hannover, Germany from 22-24 July, 2020. See info below or reach out to me in case of questions. There will be reduced registration costs for early career scientists. The workshop will be a mixture of oral and poster presentations with smaller group discussions and co-organized with support from EGU Galileo Conferences and the Volkswagenstiftung.

We offer in 2019 for the third time a session on "Stable Isotopes in the Critical Zone: Methods, Applications, and Process Interpretations" at the AGU Fall Meeting. This year our convener team will be composed by Stephen P. Good, Natalie Orlowski and Scott T. Allen. Abstract submission is open from June 12th to July 31st.
Session description:
Stable isotopes are powerful tools for tracing fluxes of water, carbon, and nutrients. They are increasingly used in various disciplines to better understand processes occurring in the soil-plant-atmosphere continuum. Furthermore, new methodological and technological developments have facilitated tracing isotopes at much finer scales, but also across larger domains. By enabling the tracing of exchanges across distinct landscape pools, stable isotopes support new interdisciplinary perspectives on critical zone processes. This session aims to address the current state of the art for methods, applications, and process interpretations using stable isotopes in the critical zone. Studies that cross disciplinary boundaries and reveal new process understanding are especially welcome. This session also encourages contributions that celebrate the AGU's Centennial, including reviews of historical data and the evolution of stable isotope tools within the critical zone, as well contributions that discuss the future direction and needs of the critical zone stable isotope community.

We are inviting applications for the new Black Forest Autumn School on "Water Ages in the Hydrological Cycle", which will be held at from October 27 to 31 in Freudenstadt, Germany. The Black Forest Autumn School will teach approaches,
methods and models to determine water fractions, water ages and transit times throughout the hydrological cycle and will foster inter-disciplinary discussions. Lectures and hands-on exercises including a small model intercomparison project will provide a stimulating learning environment. The lecturer team consists of Markus Weiler, Christine Stumpp, James Kirchner, Markus Hrachowitz, Paolo Benettin and me. The Autumn School is supported by the Water Research Network Baden-Württemberg. The course fee is 290 €, but free participation for young scientists from Baden-Württemberg. If you would like to attend, send a 1 page motivation letter and your CV to info@wassernetzwerk-bw.de by July 15 2019.
More info on this flyer.