Matthias Sprenger

Lawrence Berkeley National Laboratory | LBL · Earth Sciences Division

Water stable isotopes (18O and 2H) are widely used as ideal tracers to track water through the soil and to separate evaporation from transpiration. Due to the technical developments in the last two decades, soil water stable isotope data have become easier to collect. Thus, the application of isotope methods in soils is growing rapidly. Studies tha...

Core Ideas Bulk soil water isotopes have an evaporation signal, but mobile water isotopes do not. These differences are time variant and linked to the volume and age of the mobile water. Two pore domains (fast and slow) improve simulations of soil water isotope dynamics. A new model accounts for isotopic exchange via water vapor between two pore do...

The time that water takes to travel through the terrestrial hydrological cycle and the critical zone is of great interest in Earth system sciences with broad implications for water quality and quantity. Most water age studies to date have focused on individual compartments (or sub-disciplines) of the hydrological cycle such as the unsaturated or sa...

The storage and release of water in soils is critical for sustaining plant transpiration and groundwater recharge. However, how much subsurface mixing of water occurs, and how much of the water is available for plants or otherwise percolates to streams and the groundwater is not yet understood. Based on stable isotope (2H and 18O) data, some studie...

The “Ecohydrologic separation” hypothesis challenged assumptions of translatory flow through the rooting zone. However, studies aiming to test ecohydrologic separation have largely done so with insufficient discussion of infiltration and rooting zone recharge processes, and instead have mostly focused on either isotopic differences between stream w...

About 80 % of the precipitation in the Colorado River’s headwaters is snow, and the resulting snowmelt-driven hydrograph is a crucial water source for about 40 million people. Snowmelt from alpine and subalpine snowpack contributes substantially to groundwater recharge and river flow. However, the dynamics of snowmelt progression are not well under...

In November 2021, the Artificial Intelligence for Earth System Predictability (AI4ESP) workshop was held, which involved hundreds of researchers from dozens of institutions (Hickmon et al., 2022). There were 17 sessions held at the workshop, including one on Ecohydrology. The Ecohydrology session included various break-out rooms that addressed spec...

Despite previous reports on European growing seasons lengthening due to global warming, evidence shows that this trend has been reversing in the past decade due to increased transpiration needs. To asses this, we used an innovative method along with space-based observations to determine the timing of greening and dormancy and then to determine exis...

The hydrological cycle of sub-arctic areas is dominated by the snowmelt event. Understanding the mechanisms that control water fluxes during high-volume infiltration events in sub-arctic till soils is needed to assess how future changes in the timing and magnitude of snowmelt can affect soil water storage dynamics. We conducted a tracer experiment...

The snow dominated headwaters of the Colorado River are crucial for the water supply of the south-western US. The current water crisis in the Colorado basin makes understanding runoff processes in mountainous regions more necessary than ever. We present how our observations of stable isotopes of water (2H and 18O) in the precipitation, stream-, soi...

Tracing and quantifying water fluxes in the hydrological cycle is crucial for understanding the current state of ecohydrological systems and their vulnerability to environmental change. Especially the interface between ecosystems and the atmosphere that is strongly mediated by plants is important to meaningfully describe ecohydrological system func...

Understanding the mechanisms that control seasonal groundwater recharge at local and intermediate scales is critical for understanding contaminant transport. Preferential flow accompanied with intensive and seasonal recharge allows contaminants to migrate rapidly through the unsaturated zones to underlying aquifers. In this study, we investigated t...

Water transit time is now a standard measure in catchment hydrological and ecohydrological research. The last comprehensive review of transit time modeling approaches was published 15+ years ago. But since then the field has largely expanded with new data, theory and applications. Here, we review these new developments with focus on water‐age‐balan...

Plain Language Summary Stable water isotopes are used in hydrology to track vegetation water use and stream water source. Watersheds reliant on snow alter the timing of water inputs through snow storage and melt and may produce a different isotopic input signal due to evaporation of the snowpack prior to melt. We combine a hydrologic and snowpack i...

Although it has been shown that climate warming has steadily increased the length of the growing season (LGS) in Europe, we present new evidence that this trend reversed during last decade. Warmer European winter and spring weather combined with adequate soil moisture still results in early greening, albeit at slower rates than in the past. However...

To predict hydrologic responses to inputs and perturbations, it is important to understand how precipitation is stored in catchments, released back to the atmosphere via evapotranspiration (ET), or transported to aquifers and streams. We investigated this partitioning of precipitation using stable isotopes of water (18O) at the Can Vila catchment i...

Understanding the partitioning of snow and rain contributing to either catchment streamflow or evapotranspiration (ET) is of critical relevance for water management in response to climate change. To investigate this partitioning, we use endmember splitting and mixing analyses based on stable isotope (18 O) data from nine headwater catchments in the...

Isotopic information from 81 snowpits was collected over a 5‐year period in a large, Colorado watershed. Data spans gradients in elevation, aspect, vegetation, and seasonal climate. They are combined with overlapping campaigns for water isotopes in precipitation and snowmelt, and a land‐surface model for detailed estimates of snowfall and climate a...

To predict hydrologic responses to inputs and perturbations, it is important to understand how precipitation is stored in catchments, released back to the atmosphere via evapotranspiration (ET), or transported to aquifers and streams. We investigated this partitioning of precipitation using stable isotopes of water (2H and 18O) at the Can Vila catc...

The water present within trees when sugars and cellulose are formed is the source of hydrogen and oxygen atoms that are incorporated into tree-ring cellulose (see Chaps. 10.1007/978-3-030-92698-4_10 and 10.1007/978-3-030-92698-4_11 ). However, the isotope composition of relevant water pools is often unknown when trying to interpret δ ¹⁸ O and δ ² H...

We compared stable isotopes of water in plant stem (xylem) water and soil collected over a complete growing season from five well‐known long‐term study sites in northern/cold regions. These spanned a decreasing temperature gradient from Bruntland Burn (Scotland), Dorset (Canadian Shield), Dry Creek (USA), Krycklan (Sweden), to Wolf Creek (northern...

Investigations at the long-term experimental catchment Vallcebre in the Pyrenees revealed that rainfall-runoff dynamics are highly variable due to the Mediterranean climatic conditions affecting the storage and release of water in the subsurface. In a changing climate, to the consequences of which could lead to more variations in catchment wetness...

The proportion of water younger than 2–3 months (young water fraction, Fyw) has become increasingly investigated in catchment hydrology. Fyw is typically estimated by comparing seasonal tracer cycles in precipitation and streamflow, through water sampling. However, some open research questions remain, such as: (i) whether part of the summer precipi...

Root Water Uptake (RWU) by vegetation influences the partitioning of water between transpiration, evaporation, percolation, and surface runoff. Measurements of stable isotopes in water have facilitated estimates of the depth distribution of RWU for various tree species through methodologies based on End Member Mixing Analysis (EMMA). EMMA often ass...

Studies on the so-called ecohydrologic separation hypothesis have diverged from testing the original questions of how water infiltrates and recharges the rooting zone, and moved towards simply evaluating isotopic differences between stream water and xylem water. The isotopic composition of water in plants and streams should generally differ, so it...

How soils store and transport water affects plant's use of that water, and vice versa. Understanding such feedback between plants and soils is crucial for predicting local-to-regional water balances in changing climates. Stable isotopes of water (H and O) provide invaluable insights into the routing of water through the soil and plant water uptake....

Decisions about land use change-including the spatial distribution and extent of infrastructure for food production, energy development, and urban development-may exacerbate the consequences of human-induced climate change on water resources. Some of these consequences have implications for environmental justice. Individually, these factors affect...

Understanding the “age” of water in different times and places offers insights into how water moves through the hydrological cycle.

Understanding how water is stored in soils and either taken up by plants, evaporated, or flowing through the soil towards the streams and groundwater is crucial to address pressing water issues. We present examples that show how the information provided by depth profiles of soil water stable isotope compositions (2H and 18O) can improve our knowled...

Based on data of stable isotopes of water (2H and 18O), a lack of subsurface connectivity of mobile and tightly bound soil water was postulated to affect the recharge mechanisms in the unsaturated zone (Two Water World Hypothesis). However, the dynamics of subsurface water interaction is still poorly understood, and its investigation is usually bas...

The young water fraction, defined as the proportion of water in storage or flux that is younger than 2-3 months, was investigated in soil, ground and stream waters in the 0.56 Km2 sub-humid Can Vila catchment (Vallcebre Research Catchments). Rain water was sampled at 5-mm rainfall intervals, soil water and groundwater were sampled fortnightly, usin...

Storage and release of water in the soils is critical for sustaining plant transpiration and groundwater recharge. However, the subsurface mixing of water available for plants or quickly flowing to streams and 10 groundwater is not yet understood. Moreover, while water infiltrating into soils was shown to bypass older pore water, the mechanisms lea...

Understanding the interaction of surface water and groundwater affected by anthropogenic activities is of great importance for water resource and water quality management. The Xiong’an New Area, located in the North China Plain, has been designated a new building area by China’s government. Groundwater has been over pumped and artificial water was...

An in-depth understanding of hydrological processes is essential especially in the context of global change, as process-poor models calibrated to past conditions are unlikely to provide correct insight into future developments. However, detailed understanding of hydrological processes at various scales can only be obtained through dedicated field w...

The time water takes to travel through the hydrological cycle is of great interest in earth system sciences because water travel times reflect how water flows through landscapes, with implications for water quality and quantity. To date, most water age studies have focused on the individual compartments of the water cycle such as the unsaturated an...

As northern environments undergo intense changes due to a warming climate and altered land use practices, there is an urgent need for improved understanding of the impact of atmospheric forcing and vegetation on water storage and flux dynamics in the critical zone. We therefore assess the age dynamics of water stored in the upper 50 cm of soil, and...

As northern environments undergo intense changes due to a warming climate and altered land use practices, there is an urgent need for improved understanding of the impact of atmospheric forcing and vegetation on water storage and flux dynamics in the critical zone. We therefore assess the age dynamics of water stored in the upper 50 cm of soil, and...

Quantifying soil water storage, mixing and release via recharge, transpiration and evaporation is essential for a better understanding of critical zone processes. Here, we integrate stable isotope (2H and 18O of soil water, precipitation, and groundwater) and hydrometric (soil moisture) data from five long-term experimental catchments along a hydro...

As the northern environments undergo intense changes due to warming climatic conditions and altered land use practices, there is a need for an improved understanding of the impact of atmospheric forcing and vegetation on water storage dynamics in the critical zone. We therefore assess the travel times of recharge and transpiration fluxes in four la...

As northern environments undergo intense respond due to a warming climate and altered land use practices, there is an urgent need for improved understanding of the impact of atmospheric forcing and vegetation on water storage and flux dynamics in the critical zone. We therefore assess the age dynamics of water stored in the upper 50 cm of soil, and...

Understanding water fluxes in the critical zone, the mixing of soil waters and the resulting transit times are crucial to assess hydrological dynamics in the soil-vegetation-atmosphere interface. To better understand how water flows and mixes in soils of northern environments with a strong seasonal climate, we studied the hydrometric conditions and...

Vegetation is fundamentally important to water partitioning and can mediate the hydrological response of catchments to climate forcing. Understanding how plants respond to environmental change and the hydrological impacts of such responses is critical for projecting future ecosystem dynamics and water availability. As part of the ERC funded “VeWa”...

Over a four-month summer period, we monitored how forest (Pinus sylvestris) and heather moorland (Calluna spp. and Erica spp.) vegetation canopies altered the volume and isotopic composition of net precipitation (NP) in a southern boreal landscape in northern Scotland. During that summer period, interception (I) losses were relatively high, and hig...

Understanding the influence of vegetation on water storage and flux in the upper soil is crucial in assessing the consequences of climate and land use change. We sampled the upper 20 cm of podzolic soils at 5 cm intervals in four sites differing in their vegetation (Scots Pine (Pinus sylvestris) and heather (Calluna sp. and Erica Sp)) and aspect. T...

The study deals with the identification and characterization of rapid subsurface flow structures through pedo- and geo-physical measurements and irrigation experiments at the point, plot and hillslope scale. Our investigation of flow-relevant structures and hydrological responses refers to the general interplay of form and function, respectively. T...

The phrase form and function was established in architecture and biology and refers to the idea that form and functionality are closely correlated, influence each other, and co-evolve. We suggest transferring this idea to hydrological systems to separate and analyze their two main characteristics: their form, which is equivalent to the spatial stru...

The authors of a recent paper in Reviews of Geophysics describe how isotope hydrology offers new insights into interactions at the interface between soil, vegetation, and the atmosphere.

Water partitioning in the unsaturated zone into groundwater recharge, plant transpiration, and evaporation is fundamental for estimating storages and travel times. How water is mixed and routed through the soil is of broad interest to understand plant available water, contamination transport and weathering rates in the critical zone. Earlier work h...

Understanding the influence of vegetation on the water storage and flux in the upper soil is crucial in assessing the consequences of climate and land use changes. We sampled the upper 20 cm of peaty podzols at 5 cm intervals in four sites differing in their vegetation (Scots Pine and heather (Calluna sp. and Erica Sp)) and aspect. The sites were l...

Sustainable water resources management needs to be based on sound process understanding. This is especially true in a changing world, where boundary conditions change and models calibrated to the status quo are no longer helpful. There is a general agreement in the hydrologic community that we are in need of a better process understanding and that...