188 results on '"Wutzler, Thomas"'
Search Results
2. Quantifying tree biomass carbon stocks, their changes and uncertainties using routine stand taxation inventory data
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Wutzler, Thomas, Profft, Ingolf, and Mund, Martina
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Forestry ,SD1-669.5 - Abstract
For carbon (C) trading or any other verifiable C reports, it would be reasonable to identify and quantify continuous changes in carbon stocks at regional scales without high investments into additional C-specific, time- and labor-intensive inventories. Our study demonstrates the potential of using routine stand taxation data from large scale forestry inventories for verifiable quantification of tree biomass C stocks, C stock change rates, and associated uncertainties. Empirical models, parameters, and equations of uncertainty propagation have been assembled and applied to data from a forest management unit in Central Germany (550 000 ha), using stand taxation inventories collected between 1993 and 2006. The study showed: 1) The use of stand taxation data resulted in a verifiable and sufficiently precise (cv = 7%) quantification of tree biomass carbon stocks and their changes at the level of growth-regions (1700 to 140 000Â ha). 2) The forest of the test region accumulated carbon in tree biomass at a mean annual rate of 1.8 (â0.9 to 4.5) tC/ha/yr over the studied period. 3) The taxation inventory data can reveal spatial patterns of rates of C stock changes, specifically low rates of 0.4 tC/ha/yr in the northwest and high rates of 3.0 tC/ha/yr in the south of the study region.
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- 2011
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3. Effect of the aggregation of multi-cohort mixed stands on modeling forest ecosystem carbon stocks
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Wutzler, Thomas
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Forestry ,SD1-669.5 - Abstract
Studies of the carbon sink of forest ecosystems often stratify the studied stands by the dominating species and thereby abstract from differences in the mixed-species, multi-cohort structure of many forests. This case study infers whether the aggregation of forestry data introduces a bias in the estimates of carbon stocks and their changes at the scale of individual stands and the scale of a forest district. The empirical TreeGrOSS-C model was applied to 1616 plots of a forest district in Central Germany to simulate carbon dynamics in biomass, woody debris, and soil. In a first approach each stand was explicitly simulated with all cohorts. In three other approaches the forest inventory data were aggregated in several ways, including a stratification of the stands to 110 classes according to the dominating species, age class, and site conditions. A small but significant bias was confirmed. At stand scale the initial ecosystem carbon stocks by the aggregated approach differed from that of the detailed approach by 2.3%, but at the district scale only by 0.05%. The differences in age between interspersed and dominant cohorts as well as differences in litter production were important for the differences in initial carbon stocks. The amounts of wood extracted by thinning operations were important for the differences in the projection of the carbon stocks over 100 years. Because of the smallness of bias, this case study collects evidence that the approaches, that represent stands or stratums by a single cohort, are valid at the scale of a forest district or larger.
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- 2008
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4. Models in country scale carbon accounting of forest soils
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Peltoniemi, Mikko, Thürig, Esther, Ogle, Stephen, Palosuo, Taru, Schrumpf, Marion, Wutzler, Thomas, Butterbach-Bahl, Klaus, Chertov, Oleg, Komarov, Alexander, Mikhailov, Aleksey, Gärdenäs, Annemieke, Perry, Charles, Liski, Jari, Smith, Pete, and Mäkipää, Raisa
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Forestry ,SD1-669.5 - Abstract
Countries need to assess changes in the carbon stocks of forest soils as a part of national greenhouse gas (GHG) inventories under the United Nations Framework Convention on Climate Change (UNFCCC) and the Kyoto Protocol (KP). Since measuring these changes is expensive, it is likely that many countries will use alternative methods to prepare these estimates. We reviewed seven well-known soil carbon models from the point of view of preparing country-scale soil C change estimates. We first introduced the models and explained how they incorporated the most important input variables. Second, we evaluated their applicability at regional scale considering commonly available data sources. Third, we compiled references to data that exist for evaluation of model performance in forest soils. A range of process-based soil carbon models differing in input data requirements exist, allowing some flexibility to forest soil C accounting. Simple models may be the only reasonable option to estimate soil C changes if available resources are limited. More complex models may be used as integral parts of sophisticated inventories assimilating several data sources. Currently, measurement data for model evaluation are common for agricultural soils, but less data have been collected in forest soils. Definitions of model and measured soil pools often differ, ancillary model inputs require scaling of data, and soil C measurements are uncertain. These issues complicate the preparation of model estimates and their evaluation with empirical data, at large scale. Assessment of uncertainties that accounts for the effect of model choice is important part of inventories estimating large-scale soil C changes. Joint development of models and large-scale soil measurement campaigns could reduce the inconsistencies between models and empirical data, and eventually also the uncertainties of model predictions.
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- 2007
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5. Modelling mean above and below ground litter production based on yield tables
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Wutzler, Thomas and Mund, Martina
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Forestry ,SD1-669.5 - Abstract
Estimates of litter production are a prerequisite for modeling soil carbon stocks and its changes at regional to national scale. However, the required data on biomass removal is often available only for the recent past. In this study we used yield tables as a source of probable past forest management to drive a single tree based stand growth model. Next, simulated growth and timber volume was converted to tree compartment carbon stocks and biomass turnover. The study explicitly accounted for differences in site quality between stands. In addition we performed a Monte Carlo uncertainty and sensitivity analysis. We exemplify the approach by calculating long-term means of past litter production for 10 species by using yield tables that have been applied in Central Germany during the last century. We found that litter production resulting from harvest residues was almost as large as the one from biomass turnover. Differences in site quality caused large differences in litter production. At a given site quality, the uncertainty in soil carbon inputs were 14%, 17%, and 25% for beech, spruce, and pine stands, respectively. The sensitivity analysis showed that the most influential parameters were associated with foliage biomass and turnover. We conclude that rates of mean past litter production and their uncertainties can reliably be modeled on the basis of yield tables if the model accounts for 1) full rotation length including thinning and final harvest, 2) differences in site quality, and 3) environmental dependency of foliage biomass and foliage turnover.
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- 2007
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6. COSORE: A community database for continuous soil respiration and other soil‐atmosphere greenhouse gas flux data
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Bond‐Lamberty, Ben, Christianson, Danielle S, Malhotra, Avni, Pennington, Stephanie C, Sihi, Debjani, AghaKouchak, Amir, Anjileli, Hassan, Arain, M Altaf, Armesto, Juan J, Ashraf, Samaneh, Ataka, Mioko, Baldocchi, Dennis, Black, Thomas Andrew, Buchmann, Nina, Carbone, Mariah S, Chang, Shih‐Chieh, Crill, Patrick, Curtis, Peter S, Davidson, Eric A, Desai, Ankur R, Drake, John E, El‐Madany, Tarek S, Gavazzi, Michael, Görres, Carolyn‐Monika, Gough, Christopher M, Goulden, Michael, Gregg, Jillian, del Arroyo, Omar Gutiérrez, He, Jin‐Sheng, Hirano, Takashi, Hopple, Anya, Hughes, Holly, Järveoja, Järvi, Jassal, Rachhpal, Jian, Jinshi, Kan, Haiming, Kaye, Jason, Kominami, Yuji, Liang, Naishen, Lipson, David, Macdonald, Catriona A, Maseyk, Kadmiel, Mathes, Kayla, Mauritz, Marguerite, Mayes, Melanie A, McNulty, Steve, Miao, Guofang, Migliavacca, Mirco, Miller, Scott, Miniat, Chelcy F, Nietz, Jennifer G, Nilsson, Mats B, Noormets, Asko, Norouzi, Hamidreza, O’Connell, Christine S, Osborne, Bruce, Oyonarte, Cecilio, Pang, Zhuo, Peichl, Matthias, Pendall, Elise, Perez‐Quezada, Jorge F, Phillips, Claire L, Phillips, Richard P, Raich, James W, Renchon, Alexandre A, Ruehr, Nadine K, Sánchez‐Cañete, Enrique P, Saunders, Matthew, Savage, Kathleen E, Schrumpf, Marion, Scott, Russell L, Seibt, Ulli, Silver, Whendee L, Sun, Wu, Szutu, Daphne, Takagi, Kentaro, Takagi, Masahiro, Teramoto, Munemasa, Tjoelker, Mark G, Trumbore, Susan, Ueyama, Masahito, Vargas, Rodrigo, Varner, Ruth K, Verfaillie, Joseph, Vogel, Christoph, Wang, Jinsong, Winston, Greg, Wood, Tana E, Wu, Juying, Wutzler, Thomas, Zeng, Jiye, Zha, Tianshan, Zhang, Quan, and Zou, Junliang
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Climate Change Impacts and Adaptation ,Environmental Sciences ,Climate Action ,Atmosphere ,Carbon Dioxide ,Ecosystem ,Greenhouse Gases ,Methane ,Nitrous Oxide ,Reproducibility of Results ,Respiration ,Soil ,carbon dioxide ,greenhouse gases ,methane ,open data ,open science ,soil respiration ,Biological Sciences ,Ecology ,Biological sciences ,Earth sciences ,Environmental sciences - Abstract
Globally, soils store two to three times as much carbon as currently resides in the atmosphere, and it is critical to understand how soil greenhouse gas (GHG) emissions and uptake will respond to ongoing climate change. In particular, the soil-to-atmosphere CO2 flux, commonly though imprecisely termed soil respiration (RS ), is one of the largest carbon fluxes in the Earth system. An increasing number of high-frequency RS measurements (typically, from an automated system with hourly sampling) have been made over the last two decades; an increasing number of methane measurements are being made with such systems as well. Such high frequency data are an invaluable resource for understanding GHG fluxes, but lack a central database or repository. Here we describe the lightweight, open-source COSORE (COntinuous SOil REspiration) database and software, that focuses on automated, continuous and long-term GHG flux datasets, and is intended to serve as a community resource for earth sciences, climate change syntheses and model evaluation. Contributed datasets are mapped to a single, consistent standard, with metadata on contributors, geographic location, measurement conditions and ancillary data. The design emphasizes the importance of reproducibility, scientific transparency and open access to data. While being oriented towards continuously measured RS , the database design accommodates other soil-atmosphere measurements (e.g. ecosystem respiration, chamber-measured net ecosystem exchange, methane fluxes) as well as experimental treatments (heterotrophic only, etc.). We give brief examples of the types of analyses possible using this new community resource and describe its accompanying R software package.
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- 2020
7. Efficient treatment of model discrepancy by Gaussian Processes - Importance for imbalanced multiple constraint inversions
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Wutzler, Thomas
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Statistics - Computation ,49N45 (Primary), 62F15 (Secondary) ,G.3 - Abstract
Mechanistic simulation models are inverted against observations in order to gain inference on modeled processes. However, with the increasing ability to collect high resolution observations, these observations represent more patterns of detailed processes that are not part of a modeling purpose. This mismatch results in model discrepancies, i.e. systematic differences between observations and model predictions. When discrepancies are not accounted for properly, posterior uncertainty is underestimated. Furthermore parameters are inferred so that model discrepancies appear with observation data stream with few records instead of data streams corresponding to the weak model parts. This impedes the identification of weak process formulations that need to be improved. Therefore, we developed an efficient formulation to account for model discrepancy by the statistical model of Gaussian processes (GP). This paper presents a new Bayesian sampling scheme for model parameters and discrepancies, explains the effects of its application on inference by a basic example, and demonstrates applicability to a real world model-data integration study. The GP approach correctly identified model discrepancy in rich data streams. Innovations in sampling allowed successful application to observation data streams of several thousand records. Moreover, the proposed new formulation could be combined with gradient-based optimization. As a consequence, model inversion studies should acknowledge model discrepancies, especially when using multiple imbalanced data streams. To this end, studies can use the proposed GP approach to improve inference on model parameters and modeled processes., Comment: 25 pages, 10 figures
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- 2018
8. Widespread inhibition of daytime ecosystem respiration
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Keenan, Trevor F, Migliavacca, Mirco, Papale, Dario, Baldocchi, Dennis, Reichstein, Markus, Torn, Margaret, and Wutzler, Thomas
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Biological Sciences ,Ecology ,Circadian Rhythm ,Ecosystem ,Photosynthesis ,Plant Leaves ,Plant Transpiration ,Evolutionary biology ,Environmental management - Abstract
The global land surface absorbs about a third of anthropogenic emissions each year, due to the difference between two key processes: ecosystem photosynthesis and respiration. Despite the importance of these two processes, it is not possible to measure either at the ecosystem scale during the daytime. Eddy-covariance measurements are widely used as the closest 'quasi-direct' ecosystem-scale observation from which to estimate ecosystem photosynthesis and respiration. Recent research, however, suggests that current estimates may be biased by up to 25%, due to a previously unaccounted for process: the inhibition of leaf respiration in the light. Yet the extent of inhibition remains debated, and implications for estimates of ecosystem-scale respiration and photosynthesis remain unquantified. Here, we quantify an apparent inhibition of daytime ecosystem respiration across the global FLUXNET eddy-covariance network and identify a pervasive influence that varies by season and ecosystem type. We develop partitioning methods that can detect an apparent ecosystem-scale inhibition of daytime respiration and find that diurnal patterns of ecosystem respiration might be markedly different than previously thought. The results call for the re-evaluation of global terrestrial carbon cycle models and also suggest that current global estimates of photosynthesis and respiration may be biased, some on the order of magnitude of anthropogenic fossil fuel emissions.
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- 2019
9. Environment-sensitivity functions for gross primary productivity in light use efficiency models
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Bao, Shanning, Wutzler, Thomas, Koirala, Sujan, Cuntz, Matthias, Ibrom, Andreas, Besnard, Simon, Walther, Sophia, Šigut, Ladislav, Moreno, Alvaro, Weber, Ulrich, Wohlfahrt, Georg, Cleverly, Jamie, Migliavacca, Mirco, Woodgate, William, Merbold, Lutz, Veenendaal, Elmar, and Carvalhais, Nuno
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- 2022
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10. Drought and heatwave impacts on semi-arid ecosystems' carbon fluxes along a precipitation gradient
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El-Madany, Tarek S., Carrara, Arnaud, Martín, M. Pilar, Moreno, Gerardo, Kolle, Olaf, Pacheco-Labrador, Javier, Weber, Ulrich, Wutzler, Thomas, Reichstein, Markus, and Migliavacca, Mirco
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- 2020
11. Evergreen broadleaf greenness and its relationship with leaf flushing, aging, and water fluxes
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Luo, Yunpeng, primary, Pacheco-Labrador, Javier, additional, Richardson, Andrew, additional, Seyednasrollah, Bijan, additional, Perez-Priego, Oscar, additional, Cascon, Rosario Gonzalez, additional, Martí, M. Pilar, additional, Moreno, Gerardo, additional, Nair, Richard, additional, Wutzler, Thomas, additional, Bucher, Solveig Franziska, additional, Carrara, Arnaud, additional, Cremonese, Edoardo, additional, El-Madany, Tarek, additional, Filippa, Gianluca, additional, Galvagno, Marta, additional, Hammer, Tiana, additional, Ma, Xuanlong, additional, Martini, David, additional, Zhang, Qian, additional, Reichstein, Markus, additional, Menzel, Annette, additional, Römermann, Christine, additional, and Migliavacca, Mirco, additional
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- 2024
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12. Optimal enzyme allocation leads to the constrained enzyme hypothesis: the Soil Enzyme Steady Allocation Model (SESAM; v3.1).
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Wutzler, Thomas, Reimers, Christian, Ahrens, Bernhard, and Schrumpf, Marion
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SOIL enzymology , *NITROGEN in soils , *ENZYMES , *MICROBIAL communities , *ORGANIC compounds , *DYNAMIC models - Abstract
Describing the coupling of nitrogen (N), phosphorus (P), and carbon (C) cycles of land ecosystems requires understanding microbial element use efficiencies of soil organic matter (SOM) decomposition. These efficiencies are studied by the Soil Enzyme Steady Allocation Model (SESAM) at the decadal scale. The model assumes that the soil microbial communities and their element use efficiencies develop towards an optimum where the growth of the entire community is maximized. Specifically, SESAM approximated this growth optimization by allocating resources to several SOM-degrading enzymes proportional to the revenue of these enzymes, called the Relative approach. However, a rigorous mathematical treatment of this approximation has been lacking so far. Therefore, in this study we derive explicit formulas of enzyme allocation that maximize the total return from enzymatic processing, called the Optimal approach. Further, we derive another heuristic approach that prescribes the change of allocation without the need of deriving a formulation for the optimal allocation, called the Derivative approach. When comparing predictions across these approaches, we found that the Relative approach was a special case of the Optimal approach valid at sufficiently high microbial biomass. However, at low microbial biomass, it overestimated allocation to the enzymes having lower revenues compared to the Optimal approach. The Derivative-based allocation closely tracked the Optimal allocation. These findings increase our confidence in conclusions drawn from SESAM studies. Moreover, the new developments extend the range of conditions at which valid conclusions can be drawn. Further, based on these findings we formulated the constrained enzyme hypothesis. This hypothesis provides a complementary explanation why some substrates in soil are preserved over decades, although they are often decomposed within a few years in incubation experiments. This study shows how optimality considerations lead to simplified models, new insights, and new hypotheses. This is another step in deriving a simple representation of an adaptive microbial community, which is required for coupled stoichiometric C–N–P dynamic models that are aimed to study decadal processes beyond the ecosystem scale. [ABSTRACT FROM AUTHOR]
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- 2024
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13. Technical note: Flagging inconsistencies in flux tower data.
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Jung, Martin, Nelson, Jacob, Migliavacca, Mirco, El-Madany, Tarek, Papale, Dario, Reichstein, Markus, Walther, Sophia, and Wutzler, Thomas
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TIMESTAMPS - Abstract
Global collections of synthesized flux tower data such as FLUXNET have accelerated scientific progress beyond the eddy covariance community. However, remaining data issues in FLUXNET data pose challenges for users, particularly for multi-site synthesis and modelling activities. Here, we present complementary consistency flags (C2Fs) for flux tower data, which rely on multiple indications of inconsistency among variables, along with a methodology to detect discontinuities in time series. The C2F relates to carbon and energy fluxes, as well as to core meteorological variables, and consists of the following: (1) flags for daily data values, (2) flags for entire-site variables, and (3) flags at time stamps that mark large discontinuities in the time series. The flagging is primarily based on combining outlier scores from a set of predefined relationships among variables. The methodology to detect break points in the time series is based on a non-parametric test for the difference in distributions of model residuals. Applying C2F to the FLUXNET 2015 dataset reveals the following: (1) among the considered variables, gross primary productivity and ecosystem respiration data were flagged most frequently, in particular during rain pulses under dry and hot conditions. This information is useful for modelling and analysing ecohydrological responses. (2) There are elevated flagging frequencies for radiation variables (shortwave, photosynthetically active, and net). This information can improve the interpretation and modelling of ecosystem fluxes with respect to issues in the driver. (3) The majority of long-term sites show temporal discontinuities in the time series of latent energy, net ecosystem exchange, and radiation variables. This should be useful for carefully assessing the results in terms of interannual variations in and trends of ecosystem fluxes. The C2F methodology is flexible for customizing and allows for varying the desired strictness of consistency. We discuss the limitations of the approach that can present starting points for future developments. [ABSTRACT FROM AUTHOR]
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- 2024
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14. Comment on egusphere-2023-1492
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Wutzler, Thomas, primary
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- 2023
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15. Technical Note: Flagging inconsistencies in flux tower data
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Jung, Martin, primary, Nelson, Jacob, additional, Migliavacca, Mirco, additional, El-Madany, Tarek, additional, Papale, Dario, additional, Reichstein, Markus, additional, Walther, Sophia, additional, and Wutzler, Thomas, additional
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- 2023
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16. Optimal enzyme allocation leads to the constrained enzyme hypothesis: The Soil Enzyme Steady Allocation Model (SESAM v3.1)
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Wutzler, Thomas, primary, Reimers, Christian, additional, Ahrens, Bernhard, additional, and Schrumpf, Marion, additional
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- 2023
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17. Throughfall spatial patterns translate into spatial patterns of soil moisture dynamics – empirical evidence
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Fischer-Bedtke, Christine, primary, Metzger, Johanna Clara, additional, Demir, Gökben, additional, Wutzler, Thomas, additional, and Hildebrandt, Anke, additional
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- 2023
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18. Spatial patterns for canopy drainage translate into soil moisture dynamics – empirical evidence
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Hildebrandt, Anke, primary, Fischer-Bedtke, Christine, additional, Metzger, Johanna Clara, additional, Demir, Gökben, additional, and Wutzler, Thomas, additional
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- 2023
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19. Evaporation and Transpiration From Multiple Proximal Forests and Wetlands.
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Shveytser, Victoria, Stoy, Paul C., Butterworth, Brian, Wiesner, Susanne, Skaggs, Todd H., Murphy, Bailey, Wutzler, Thomas, El‐Madany, Tarek S., and Desai, Ankur R.
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WETLANDS ,THROUGHFALL ,FORESTED wetlands ,DECIDUOUS forests ,HYDROLOGIC cycle ,LAND management ,VAPOR pressure ,AUTUMN - Abstract
Climate change is intensifying the hydrologic cycle and altering ecosystem function, including water flux to the atmosphere through evapotranspiration (ET). ET is made up of evaporation (E) via non‐stomatal surfaces, and transpiration (T) through plant stomata which are impacted by global changes in different ways. E and T are difficult to measure independently at the ecosystem scale, especially across multiple sites that represent different land use and land management strategies. To address this gap in understanding, we applied flux variance similarity (FVS) to quantify how E and T differ across 13 different ecosystems measured using eddy covariance in a 10 × 10 km area from the CHEESEHEAD19 experiment in northern Wisconsin, USA. The study sites included eight forests with a large deciduous broadleaf component, three evergreen needleleaf forests, and two wetlands. Average T/ET for the study period averaged nearly 52% in forested sites and 45% in wetlands, with larger values after excluding periods following rain events when evaporation from canopy interception may be expected. A dominance analysis revealed that environmental variables explained on average 69% of the variance of half‐hourly T, which decreased from summer to autumn. Deciduous and evergreen forests showed similar E trajectories over time despite differences in vegetation phenology, and vapor pressure deficit explained some 13% of the variance E in wetlands but only 5% or less in forests. Retrieval of E and T within a dense network of flux towers lends confidence that FVS is a promising approach for comparing ecosystem hydrology across multiple sites to improve our process‐based understanding of ecosystem water fluxes. Key Points: Eddy covariance‐measured evapotranspiration was partitioned to transpiration and evaporation using flux variance similarity at 14 ecosystemsNet radiation explained most of the variability in transpiration, which was lowest in wetland ecosystems and vapor pressure deficit explained more of the variability of evaporation in wetlands than forestsDaily evaporation varied little over time and amongst sites from summer to autumn [ABSTRACT FROM AUTHOR]
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- 2024
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20. Evergreen broadleaf greenness and its relationship with leaf flushing, aging, and water fluxes
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China Scholarship Council, National Science Foundation (US), German Centre for Air and Space Travel, European Commission, Ministerio de Economía y Competitividad (España), Luo, Yunpeng [0000-0001-6383-8300], Pacheco-Labrador, Javier [0000-0003-3401-7081], Richardson, Andrew D. [0000-0002-0148-6714], Seyednasrollah, Bijan [0000-0002-5195-2074], Perez-Priego, Oscar [0000-0002-3138-3177], González-Cascón, Rosario [0000-0003-3468-0967], Martín, M. Pilar [0000-0002-5563-8461], Nair, Richard [0000-0002-6293-3610], Wutzler, Thomas [0000-0003-4159-5445], Bucher, Solveig F. [0000-0002-2303-4583], Carrara, Arnaud [0000-0002-9095-8807], Cremonese, Edoardo [0000-0002-6708-8532], El-Madany, Tarek S.[0000-0002-0726-7141], Filippa, Gianluca [0000-0002-4554-6045], Galvagno, Marta [0000-0002-0827-487X], Ma, Xuanlong [0000-0003-1499-8476], Martini, David [0000-0003-2180-5126], Zhang, Qihuan [0000-0002-0860-4023], Reichstein, Markus [0000-0001-5736-1112], Menzel, A. [0000-0002-7175-2512], Römermann, Christine [0000-0003-3471-0951], Migliavacca, Mirco [0000-0003-3546-8407], Luo, Yunpeng, Pacheco-Labrador, Javier, Richardson, Andrew D., Seyednasrollah, Bijan, Pérez-Priego, Óscar, González-Cascón, Rosario, Martin, M. Pilar, Moreno, Gerardo, Nair, Richard, Wutzler, Thomas, Bucher, Solveig F., Carrara, Arnaud, Cremonese, Edoardo, El-Madany, Tarek S., Filippa, Gianluca, Galvagno, Marta, Hammer, Tiana W., Ma, Xuanlong, Martini, David, Zhang, Qihuan, Reichstein, Markus, Menzel, A., Römermann, Christine, Migliavacca, Mirco, China Scholarship Council, National Science Foundation (US), German Centre for Air and Space Travel, European Commission, Ministerio de Economía y Competitividad (España), Luo, Yunpeng [0000-0001-6383-8300], Pacheco-Labrador, Javier [0000-0003-3401-7081], Richardson, Andrew D. [0000-0002-0148-6714], Seyednasrollah, Bijan [0000-0002-5195-2074], Perez-Priego, Oscar [0000-0002-3138-3177], González-Cascón, Rosario [0000-0003-3468-0967], Martín, M. Pilar [0000-0002-5563-8461], Nair, Richard [0000-0002-6293-3610], Wutzler, Thomas [0000-0003-4159-5445], Bucher, Solveig F. [0000-0002-2303-4583], Carrara, Arnaud [0000-0002-9095-8807], Cremonese, Edoardo [0000-0002-6708-8532], El-Madany, Tarek S.[0000-0002-0726-7141], Filippa, Gianluca [0000-0002-4554-6045], Galvagno, Marta [0000-0002-0827-487X], Ma, Xuanlong [0000-0003-1499-8476], Martini, David [0000-0003-2180-5126], Zhang, Qihuan [0000-0002-0860-4023], Reichstein, Markus [0000-0001-5736-1112], Menzel, A. [0000-0002-7175-2512], Römermann, Christine [0000-0003-3471-0951], Migliavacca, Mirco [0000-0003-3546-8407], Luo, Yunpeng, Pacheco-Labrador, Javier, Richardson, Andrew D., Seyednasrollah, Bijan, Pérez-Priego, Óscar, González-Cascón, Rosario, Martin, M. Pilar, Moreno, Gerardo, Nair, Richard, Wutzler, Thomas, Bucher, Solveig F., Carrara, Arnaud, Cremonese, Edoardo, El-Madany, Tarek S., Filippa, Gianluca, Galvagno, Marta, Hammer, Tiana W., Ma, Xuanlong, Martini, David, Zhang, Qihuan, Reichstein, Markus, Menzel, A., Römermann, Christine, and Migliavacca, Mirco
- Abstract
Remote sensing capabilities to monitor evergreen broadleaved vegetation are limited by the low temporal variability in the greenness signal. With canopy greenness computed from digital repeat photography (PhenoCam), we investigated how canopy greenness related to seasonal changes in leaf age and traits as well as variation of trees’ water fluxes (characterized by sap flow and canopy conductance). The results showed that sprouting leaves are mainly responsible for the rapid increase in canopy green chromatic coordinate (GCC) in spring. We found statistically significantly differences in leaf traits and spectral properties among leaves of different leaf ages. Specifically, mean GCC of young leaves was 0.385 ± 0.010 (mean ± SD), while for mature and old leaves was 0.369 ± 0.003, and 0.376 ± 0.004, respectively. Thus, the temporal dynamics of canopy GCC can be explained by changes in leaf spectral properties and leaf age. Sap flow and canopy conductance are both well explained by a combination of environmental drivers and greenness (96% and 87% of the variance explained, respectively). In particular, air temperature and vapor pressure deficit (VPD) explained most of sap flow and canopy conductance variance, respectively. Besides, GCC is an important explanatory variable for variation of canopy conductance may because GCC can represent the leaf ontogeny information. We conclude that PhenoCam GCC can be used to identify the leaf flushing for evergreen broadleaved trees, which carries important information about leaf ontogeny and traits. Thus, it can be helpful for better estimating canopy conductance which constraints water fluxes.
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- 2022
21. Stoichiometrically constrained soil microbial community adaptation modeled with SESAM
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Wutzler, Thomas, primary, Ahrens, Bernhard, additional, and Schrumpf, Marion, additional
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- 2023
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22. Improved representation of phosphorus exchange on soil mineral surfaces reduces estimates of phosphorus limitation in temperate forest ecosystems
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Yu, Lin, Caldararu, Silvia, Ahrens, Bernhard, Wutzler, Thomas, Schrumpf, Marion, Helfenstein, Julian, Pistocchi, Chiara, Zaehle, Sönke, Yu, Lin, Caldararu, Silvia, Ahrens, Bernhard, Wutzler, Thomas, Schrumpf, Marion, Helfenstein, Julian, Pistocchi, Chiara, and Zaehle, Sönke
- Abstract
Phosphorus (P) availability affects the response of terrestrial ecosystems to environmental and climate change (e.g., elevated CO2), yet the magnitude of this effect remains uncertain. This uncertainty arises mainly from a lack of quantitative understanding of the soil biological and geochemical P cycling processes, particularly the P exchange with soil mineral surfaces, which is often described by a Langmuir sorption isotherm. We first conducted a literature review on P sorption experiments and terrestrial biosphere models (TBMs) using a Langmuir isotherm. We then developed a new algorithm to describe the inorganic P exchange between soil solution and soil matrix based on the double-surface Langmuir isotherm and extracted empirical equations to calculate the sorption capacity and Langmuir coefficient. We finally tested the conventional and new models of P sorption at five beech forest sites in Germany along a soil P stock gradient using the QUINCY (QUantifying Interactions between terrestrial Nutrient CYcles and the climate system) TBM. We found that the conventional (single-surface) Langmuir isotherm approach in most TBMs largely differed from P sorption experiments regarding the sorption capacities and Langmuir coefficients, and it simulated an overly low soil P-buffering capacity. Conversely, the double-surface Langmuir isotherm approach adequately reproduced the observed patterns of soil inorganic P pools. The better representation of inorganic P cycling using the double-surface Langmuir approach also improved simulated foliar N and P concentrations as well as the patterns of gross primary production and vegetation carbon across the soil P gradient. The novel model generally reduces the estimates of P limitation compared with the conventional model, particularly at the low-P site, as the model constraint of slow inorganic P exchange on plant productivity is reduced.
- Published
- 2023
23. Technical Note: Flagging inconsistencies in flux tower data.
- Author
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Jung, Martin, Nelson, Jacob, Migliavacca, Mirco, El-Madany, Tarek, Papale, Dario, Reichstein, Markus, Walther, Sophia, and Wutzler, Thomas
- Subjects
TIMESTAMPS - Abstract
Global collections of synthesized flux tower data such as FLUXNET have accelerated scientific progress beyond the eddy covariance community. However, remaining data issues in FLUXNET data pose challenges for users, particularly for multi-site synthesis and modeling activities. Here we present complementary consistency flags (C2F) for flux tower data, which rely on multiple indications of inconsistency among variables, along with a methodology to detect discontinuities in time series. The C2F relates to carbon and energy fluxes as well as to core meteorological variables, and consists of: (1) flags for daily data values, (2) flags for entire site variables, (3) flags at time stamps that mark large discontinuities in the time series. The flagging is primarily based on combining outlier scores from a set of predefined relationships among variables. The methodology to detect break points in the time series is based on a non-parametric test for the difference of distributions of model residuals. Applying C2F to the FLUXNET 2015 dataset reveals that: (1) Among the considered variables, gross primary productivity and ecosystem respiration data were flagged most frequently, in particular during rain pulses under dry and hot conditions. This information is useful for modelling and analysing ecohydrological responses. (2) there are elevated flagging frequencies for radiation variables (shortwave, photosynthetically active, and net). This information can improve the interpretation and modelling of ecosystem fluxes with respect to issues in the driver. (3) The majority of long-term sites show temporal discontinuities in the time series of latent energy, net ecosystem exchange, and radiation variables. This should be useful for carefully assessing the results on interannual variations and trends of ecosystem fluxes. The C2F methodology is flexible for customizing, and allows for varying the desired strictness of consistency. We discuss the limitations of the approach that can present starting points for future improvements. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
24. Optimal enzyme allocation leads to the constrained enzyme hypothesis: The Soil Enzyme Steady Allocation Model (SESAM v3.1).
- Author
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Wutzler, Thomas, Reimers, Christian, Ahrens, Bernhard, and Schrumpf, Marion
- Subjects
- *
SOIL enzymology , *NITROGEN in soils , *ENZYMES , *MICROBIAL communities , *ORGANIC compounds , *DYNAMIC models - Abstract
Describing the coupling of nitrogen (N), phosphorus (P), and carbon (C) cycles of land ecosystems requires understanding microbial element use efficiencies of soil organic matter (SOM) decomposition. These efficiencies are studied by the soil enzyme steady allocation model (SESAM) at decadal scale. The model assumes that the soil microbial communities and their element use efficiencies develop towards an optimum where the growth of the entire community is maximized. Specifically, SESAM approximated this growth optimization by allocating resources to several SOM degrading enzymes pro- portional to the revenue of these enzymes, called the Relative approach. However, a rigorous mathematical treatment of this approximation has been lacking so far. Therefore, in this study we derive explicit formulas of enzyme allocation that maximize total return from enzymatic processing, called the Optimal approach. Further, we derive another heuristic approach that prescribes the change of allocation without the need of deriving a formulation for the optimal allocation, called the Derivative approach. When comparing pre- dictions across these approaches, we found that the Relative approach was a special case of the Optimal approach valid at sufficiently high microbial biomass. However, at low microbial biomass, it overestimated allocation to the enzymes having lower revenues compared to the Optimal approach. The Derivative-based allocation closely tracked the Optimal allocation. The model finding that the Relative approach was a special case of the more rigorous Optimal approach together with observing the same patterns across optimization approaches increases our confidence into conclusions drawn from SESAM studies. Moreover, the new developments extend the range of conditions at which valid conclusions can be drawn. The new model finding that a smaller set of enzyme types was expressed at low microbial biomass led us to formulate the constrained enzyme hypothesis, which provides a complementary explanation why some substrates in soil are preserved over decades although often being decomposed within a few years in incubation experiments. This study shows how optimality considerations lead to simplified models, new insights and new hypotheses. It is another step in deriving a simple representation of an adaptive micro- bial community, which is required for coupled stoichiometric CNP dynamic models that are aimed to study decadal processes beyond ecosystem scale. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
25. Supplementary material to "Throughfall spatial patterns translate into spatial patterns of soil moisture dynamics – empirical evidence"
- Author
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Fischer, Christine, primary, Metzger, Johanna Clara, additional, Demir, Goekben, additional, Wutzler, Thomas, additional, and Hildebrandt, Anke, additional
- Published
- 2023
- Full Text
- View/download PDF
26. Throughfall spatial patterns translate into spatial patterns of soil moisture dynamics – empirical evidence
- Author
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Fischer, Christine, primary, Metzger, Johanna Clara, additional, Demir, Goekben, additional, Wutzler, Thomas, additional, and Hildebrandt, Anke, additional
- Published
- 2023
- Full Text
- View/download PDF
27. Improved representation of phosphorus exchange on soil mineral surfaces reduces estimates of phosphorus limitation in temperate forest ecosystems
- Author
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Yu, Lin, primary, Caldararu, Silvia, additional, Ahrens, Bernhard, additional, Wutzler, Thomas, additional, Schrumpf, Marion, additional, Helfenstein, Julian, additional, Pistocchi, Chiara, additional, and Zaehle, Sönke, additional
- Published
- 2023
- Full Text
- View/download PDF
28. Resolving seasonal and diel dynamics of non-rainfall water inputs in a Mediterranean ecosystem using lysimeters
- Author
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Paulus, Sinikka Jasmin, primary, El-Madany, Tarek Sebastian, additional, Orth, René, additional, Hildebrandt, Anke, additional, Wutzler, Thomas, additional, Carrara, Arnaud, additional, Moreno, Gerardo, additional, Perez-Priego, Oscar, additional, Kolle, Olaf, additional, Reichstein, Markus, additional, and Migliavacca, Mirco, additional
- Published
- 2022
- Full Text
- View/download PDF
29. Simulating long-term responses of soil organic matter turnover to substrate stoichiometry by abstracting fast and small-scale microbial processes: the Soil Enzyme Steady Allocation Model (SESAM; v3.0)
- Author
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Wutzler, Thomas, primary, Yu, Lin, additional, Schrumpf, Marion, additional, and Zaehle, Sönke, additional
- Published
- 2022
- Full Text
- View/download PDF
30. Answering comments and revised version
- Author
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Wutzler, Thomas, primary
- Published
- 2022
- Full Text
- View/download PDF
31. Evergreen broadleaf greenness and its relationship with leaf flushing, aging, and water fluxes
- Author
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Luo, Yunpeng, primary, Pacheco-Labrador, Javier, additional, Richardson, Andrew D., additional, Seyednasrollah, Bijan, additional, Perez-Priego, Oscar, additional, Gonzalez-Cascon, Rosario, additional, Martín, M. Pilar, additional, Moreno, Gerardo, additional, Nair, Richard, additional, Wutzler, Thomas, additional, Bucher, Solveig Franziska, additional, Carrara, Arnaud, additional, Cremonese, Edoardo, additional, El-Madany, Tarek S., additional, Filippa, Gianluca, additional, Galvagno, Marta, additional, Hammer, Tiana, additional, Ma, Xuanlong, additional, Martini, David, additional, Zhang, Qian, additional, Reichstein, Markus, additional, Menzel, Annette, additional, Römermann, Christine, additional, and Migliavacca, Mirco, additional
- Published
- 2022
- Full Text
- View/download PDF
32. How Nitrogen and Phosphorus Availability Change Water Use Efficiency in a Mediterranean Savanna Ecosystem
- Author
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Ministerio de Economía y Competitividad (España), German Centre for Air and Space Travel, Junta de Extremadura, El-Madany, Tarek S. [0000-0002-0726-7141], Reichstein, Markus [0000-0001-5736-1112], Carrara, Arnaud [0000-0002-9095-8807], Martín, M. Pilar [0000-0002-5563-8461], Moreno, Gerardo [0000-0001-8053-2696], González-Cascón, Rosario [0000-0003-3468-0967], Peñuelas, Josep [0000-0002-7215-0150], Ellsworth, David S.[0000-0002-9699-2272], Burchard-Levine, Vicente [0000-0003-0222-8706], Knauer, Jürgen [0000-0002-4947-7067], Kolle, Olaf [0000-0002-7373-7519], Pacheco-Labrador, Javier [0000-0003-3401-7081], Nelson, Jacob A. [0000-0002-4663-2420], Perez-Priego, Oscar [0000-0002-3138-3177], Rolo, Victor [0000-0001-5854-9512], Wutzler, Thomas [0000-0003-4159-5445], Migliavacca, Mirco [0000-0003-3546-8407], El-Madany, Tarek S., Reichstein, Markus, Carrara, Arnaud, Martin, M. Pilar, Moreno, Gerardo, González-Cascón, Rosario, Peñuelas, Josep, Ellsworth, David S., Burchard-Levine, Vicente, Hammer, Tiana W., Knauer, Jürgen, Kolle, Olaf, Luo, Yunpeng, Pacheco-Labrador, Javier, Nelson, Jacob A., Pérez-Priego, Óscar, Rolo, Victor, Wutzler, Thomas, Migliavacca, Mirco, Ministerio de Economía y Competitividad (España), German Centre for Air and Space Travel, Junta de Extremadura, El-Madany, Tarek S. [0000-0002-0726-7141], Reichstein, Markus [0000-0001-5736-1112], Carrara, Arnaud [0000-0002-9095-8807], Martín, M. Pilar [0000-0002-5563-8461], Moreno, Gerardo [0000-0001-8053-2696], González-Cascón, Rosario [0000-0003-3468-0967], Peñuelas, Josep [0000-0002-7215-0150], Ellsworth, David S.[0000-0002-9699-2272], Burchard-Levine, Vicente [0000-0003-0222-8706], Knauer, Jürgen [0000-0002-4947-7067], Kolle, Olaf [0000-0002-7373-7519], Pacheco-Labrador, Javier [0000-0003-3401-7081], Nelson, Jacob A. [0000-0002-4663-2420], Perez-Priego, Oscar [0000-0002-3138-3177], Rolo, Victor [0000-0001-5854-9512], Wutzler, Thomas [0000-0003-4159-5445], Migliavacca, Mirco [0000-0003-3546-8407], El-Madany, Tarek S., Reichstein, Markus, Carrara, Arnaud, Martin, M. Pilar, Moreno, Gerardo, González-Cascón, Rosario, Peñuelas, Josep, Ellsworth, David S., Burchard-Levine, Vicente, Hammer, Tiana W., Knauer, Jürgen, Kolle, Olaf, Luo, Yunpeng, Pacheco-Labrador, Javier, Nelson, Jacob A., Pérez-Priego, Óscar, Rolo, Victor, Wutzler, Thomas, and Migliavacca, Mirco
- Abstract
Nutrient availability, especially of nitrogen (N) and phosphorus (P), is of major importance for every organism and at a larger scale for ecosystem functioning and productivity. Changes in nutrient availability and potential stoichiometric imbalance due to anthropogenic nitrogen deposition might lead to nutrient deficiency or alter ecosystem functioning in various ways. In this study, we present 6 years (2014–2020) of flux-, plant-, and remote sensing data from a large-scale nutrient manipulation experiment conducted in a Mediterranean savanna-type ecosystem with an emphasis on the effects of N and P treatments on ecosystem-scale water-use efficiency (WUE) and related mechanisms. Two plots were fertilized with N (NT, 16.9 Ha) and N + P (NPT, 21.5 Ha), and a third unfertilized plot served as a control (CT). Fertilization had a strong impact on leaf nutrient stoichiometry only within the herbaceous layer with increased leaf N in both fertilized treatments and increased leaf P in NPT. Following fertilization, WUE in NT and NPT increased during the peak of growing season. While gross primary productivity similarly increased in NT and NPT, transpiration and surface conductance increased more in NT than in NPT. The results show that the NPT plot with higher nutrient availability, but more balanced N:P leaf stoichiometry had the highest WUE. On average, higher N availability resulted in a 40% increased leaf area index (LAI) in both fertilized treatments in the spring. Increased LAI reduced aerodynamic conductance and thus evaporation at both fertilized plots in the spring. Despite reduced evaporation, annual evapotranspiration increased by 10% (48.6 ± 28.3 kg H2O m−2), in the NT plot, while NPT remained similar to CT (−1%, −6.7 ± 12.2 kgH2O m−2). Potential causes for increased transpiration at NT could be increased root biomass and thus higher water uptake or rhizosphere priming to increase P-mobilization through microbes. The annual net ecosystem exchange shifted from a c
- Published
- 2021
33. Carbon stock and density of northern boreal and temperate forests
- Author
-
Thurner, Martin, Beer, Christian, Santoro, Maurizio, Carvalhais, Nuno, Wutzler, Thomas, Schepaschenko, Dmitry, Shvidenko, Anatoly, Kompter, Elisabeth, Ahrens, Bernhard, Levick, Shaun R., and Schmullius, Christiane
- Published
- 2014
- Full Text
- View/download PDF
34. Evaporation and transpiration from multiple proximal forests and wetlands
- Author
-
Shveytser, Victoria, primary, Stoy, Paul Christopher, additional, Butterworth, Brian J., additional, Wiesner, Susanne, additional, Skaggs, Todd, additional, Murphy, Bailey, additional, Wutzler, Thomas, additional, El-Madany, Tarek S., additional, and Desai, Ankur Rashmikant, additional
- Published
- 2022
- Full Text
- View/download PDF
35. Upscaling microbial stoichiometric adaptability in SOM turnover: The SESAM Soil Enzyme Steady Allocation Model (v3.0)
- Author
-
Wutzler, Thomas, primary, Yu, Lin, additional, Schrumpf, Marion, additional, and Zaehle, Sönke, additional
- Published
- 2022
- Full Text
- View/download PDF
36. Improved representation of phosphorus exchange on soil mineral surfaces reduces estimates of P limitation in temperate forest ecosystems
- Author
-
Yu, Lin, primary, Caldararu, Silvia, additional, Ahrens, Bernhard, additional, Wutzler, Thomas, additional, Schrumpf, Marion, additional, Helfenstein, Julian, additional, Pistocchi, Chiara, additional, and Zaehle, Sönke, additional
- Published
- 2022
- Full Text
- View/download PDF
37. Supplementary material to "Improved representation of phosphorus exchange on soil mineral surfaces reduces estimates of P limitation in temperate forest ecosystems"
- Author
-
Yu, Lin, primary, Caldararu, Silvia, additional, Ahrens, Bernhard, additional, Wutzler, Thomas, additional, Schrumpf, Marion, additional, Helfenstein, Julian, additional, Pistocchi, Chiara, additional, and Zaehle, Sönke, additional
- Published
- 2022
- Full Text
- View/download PDF
38. Frequent water inputs to a semi-arid ecosystem at night - a lysimeter based study
- Author
-
Paulus, Sinikka J., primary, El-Manday, Tarek S., additional, Orth, René, additional, Hildebrandt, Anke, additional, Wutzler, Thomas, additional, Carrara, Arnaud, additional, Moreno, Gerardo, additional, Perez-Priego, Oscar, additional, Kolle, Olaf, additional, Reichstein, Markus, additional, and Migliavacca, Mirco, additional
- Published
- 2022
- Full Text
- View/download PDF
39. Upscaling microbial stoichiometric adaptability in SOM turnover using the SESAM model: specifics of phosphorous dynamics.
- Author
-
Wutzler, Thomas, primary, Yu, Lin, additional, Zaehle, Sönke, additional, Schrumpf, Marion, additional, Ahrens, Bernhard, additional, and Reichstein, Markus, additional
- Published
- 2022
- Full Text
- View/download PDF
40. Submit to statistical journal
- Author
-
Wutzler, Thomas, primary
- Published
- 2022
- Full Text
- View/download PDF
41. Lysimeter based evaporation and condensation dynamics in a Mediterranean ecosystem
- Author
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Paulus, Sinikka, primary, El-Madany, Tarek S., additional, Orth, René, additional, Hildebrandt, Anke, additional, Wutzler, Thomas, additional, Carrara, Arnaud, additional, Moreno, Gerardo, additional, Perez-Priego, Oscar, additional, Kolle, Olaf, additional, Reichstein, Markus, additional, and Migliavacca, Mirco, additional
- Published
- 2021
- Full Text
- View/download PDF
42. Setting priorities for land management to mitigate climate change
- Author
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Böttcher, Hannes, Freibauer, Annette, Scholz, Yvonne, Gitz, Vincent, Ciais, Philippe, Mund, Martina, Wutzler, Thomas, and Schulze, Ernst-Detlef
- Published
- 2012
- Full Text
- View/download PDF
43. Defend the conclusions despite the large posterior uncertainty.
- Author
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Wutzler, Thomas, primary
- Published
- 2021
- Full Text
- View/download PDF
44. How Nitrogen and Phosphorus Availability Change Water Use Efficiency in a Mediterranean Savanna Ecosystem
- Author
-
El‐Madany, Tarek S., primary, Reichstein, Markus, additional, Carrara, Arnaud, additional, Martín, M. Pilar, additional, Moreno, Gerardo, additional, Gonzalez‐Cascon, Rosario, additional, Peñuelas, Josep, additional, Ellsworth, David S., additional, Burchard‐Levine, Vicente, additional, Hammer, Tiana W., additional, Knauer, Jürgen, additional, Kolle, Olaf, additional, Luo, Yunpeng, additional, Pacheco‐Labrador, Javier, additional, Nelson, Jacob A., additional, Perez‐Priego, Oscar, additional, Rolo, Victor, additional, Wutzler, Thomas, additional, and Migliavacca, Mirco, additional
- Published
- 2021
- Full Text
- View/download PDF
45. Upscaling microbial stoichiometric adaptability in SOM turnover: The SESAM Soil Enzyme Steady Allocation Model (v3.0).
- Author
-
Wutzler, Thomas, Lin Yu, Schrumpf, Marion, and Zaehle, Sönke
- Subjects
- *
SOIL enzymology , *EXTRACELLULAR enzymes , *MICROBIAL communities , *ORGANIC compounds , *RESOURCE allocation - Abstract
Understanding the coupling of nitrogen (N) and carbon (C) cycles of land ecosystems, requires understanding microbial element use efficiencies of soil organic matter (SOM) decomposition. Whereas important controls of those efficiencies by microbial community adaptations have been shown at the scale of a soil pore, a simplified representation of those controls is needed at the ecosystem scale. However, without abstracting from the many details, models are not identifiable, i.e. can not be fitted without ambiguities to observations. There is a need to find, implement, and validate abstract simplified formulations of theses processes. Therefore, we developed the SESAM model as an abstraction of the more detailed soil enzyme allocation model (SEAM) model and tested, whether it can provide the same decadal-term predictions. SEAM explicitly models community adaptation strategies of resource allocation to extracellular enzymes and enzyme limitations on SOM decomposition. It thus provides a scaling from representing several microbial functional groups to a single holistic microbial community. Here we further abstracted the model using quasi-steady-state assumption for extracellular enzyme pools to derive the SESAM model. SESAM reproduced the priming effect, the SOM banking mechanism, and the damping of fluctuations of carbon use efficiency with microbial competition as predicted by SEAM and other more detailed models. This development is an important step towards more parsimonious representation of soil microbial effects in global land surface models. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
46. Improved representation of phosphorus exchange on soil mineral surfaces reduces estimates of P limitation in temperate forest ecosystems.
- Author
-
Yu, Lin, Caldararu, Silvia, Ahrens, Bernhard, Wutzler, Thomas, Schrumpf, Marion, Helfenstein, Julian, Pistocchi, Chiara, and Zaehle, Sönke
- Subjects
TEMPERATE forest ecology ,SOIL mineralogy ,PHOSPHORUS in soils ,LANGMUIR isotherms ,NUTRIENT cycles - Abstract
Phosphorus (P) availability affects the response of terrestrial ecosystems to environmental and climate change (e.g. elevated CO
2 ), yet the magnitude of this effect remains uncertain. This uncertainty arises mainly from a lack of quantitative understanding of the soil biological and geochemical P cycling processes, particularly the P exchange with soil mineral surfaces, which is often described by a Langmuir sorption isotherm. We first conducted a literature review on P sorption experiments and terrestrial biosphere models (TBMs) using Langmuir isotherm. We then developed a new algorithm to describe the inorganic P exchange between soil solution and soil matrix based on the double-surface Langmuir isotherm and extracted empirical equations to calculate the sorption capacity and Langmuir coefficient. We finally tested the conventional and new models of P sorption at five beech forest sites in Germany along a soil P stock gradient using the QUINCY (Quantifying Interactions between terrestrial Nutrient CYcles and the climate system) TBM. We found that the conventional (single-surface) Langmuir isotherm approach in most TBMs largely differed from P sorption experiments regarding the sorption capacities and Langmuir coefficients, and simulated a too low soil P buffering capacity. Conversely, the double-surface Langmuir isotherm approach adequately reproduced the observed patterns of soil inorganic P pools. The better representation of inorganic P cycling using the double Langmuir approach also improved simulated foliar N and P concentrations, and the patterns of gross primary production and vegetation carbon across the soil P gradient. The novel model generally reduces the estimates of P limitation compared to the conventional model, particularly at the low-P site, as the model constraint of slow inorganic P exchange on plant productivity is reduced. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
47. How do spatial throughfall patterns reflect in soil moisture patterns?
- Author
-
Fischer, Christine, primary, Lark, Murray, additional, Metzger, Johanna C., additional, Wutzler, Thomas, additional, and Hildebrandt, Anke, additional
- Published
- 2021
- Full Text
- View/download PDF
48. A tool for evaluation of target area homogeneity at ecosystem stations employing eddy covariance method
- Author
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Šigut, Ladislav, primary, Wutzler, Thomas, additional, El-Madany, Tarek, additional, Fischer, Milan, additional, and Migliavacca, Mirco, additional
- Published
- 2021
- Full Text
- View/download PDF
49. N:P imbalance effects on the seasonal C cycle in a Mediterranean Tree-Grass Ecosystem
- Author
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Nair, Richard, primary, El-Madany, Tarek, additional, Carrara, Arnaud, additional, Luo, Yunpeng, additional, Kolle, Olaf, additional, Moreno, Gerardo, additional, Reichstein, Markus, additional, Schrumpf, Marion, additional, Wutzler, Thomas, additional, and Migliavacca, Mirco, additional
- Published
- 2021
- Full Text
- View/download PDF
50. Generic biomass functions for Common beech (Fagus sylvatica) in Central Europe: predictions and components of uncertainty
- Author
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Wutzler, Thomas, Wirth, Christian, and Schumacher, Jens
- Subjects
Plant biomass -- Research -- Physiological aspects ,Beech -- Physiological aspects -- Research ,Forestry research -- Physiological aspects -- Research ,Earth sciences ,Physiological aspects ,Research - Abstract
Abstract: This study provides a comprehensive set of functions for predicting biomass for Common beech (Fagus sylvatica L.) in Central Europe for all major tree compartments. The equations are based [...]
- Published
- 2008
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