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Wei J, von Arx G, Fan Z, Ibrom A, Mund M, Knohl A, Peters RL, Babst F. Drought alters aboveground biomass production efficiency: Insights from two European beech forests. Sci Total Environ 2024; 919:170726. [PMID: 38331275 DOI: 10.1016/j.scitotenv.2024.170726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 02/03/2024] [Accepted: 02/03/2024] [Indexed: 02/10/2024]
Abstract
The fraction of photosynthetically assimilated carbon that trees allocate to long-lasting woody biomass pools (biomass production efficiency - BPE), is a key metric of the forest carbon balance. Its apparent simplicity belies the complex interplay between underlying processes of photosynthesis, respiration, litter and fruit production, and tree growth that respond differently to climate variability. Whereas the magnitude of BPE has been routinely quantified in ecological studies, its temporal dynamics and responses to extreme events such as drought remain less well understood. Here, we combine long-term records of aboveground carbon increment (ACI) obtained from tree rings with stand-level gross primary productivity (GPP) from eddy covariance (EC) records to empirically quantify aboveground BPE (= ACI/GPP) and its interannual variability in two European beech forests (Hainich, DE-Hai, Germany; Sorø, DK-Sor, Denmark). We found significant negative correlations between BPE and a daily-resolved drought index at both sites, indicating that woody growth is de-prioritized under water limitation. During identified extreme years, early-season drought reduced same-year BPE by 29 % (Hainich, 2011), 31 % (Sorø, 2006), and 14 % (Sorø, 2013). By contrast, the 2003 late-summer drought resulted in a 17 % reduction of post-drought year BPE at Hainich. Across the entire EC period, the daily-to-seasonal drought response of BPE resembled that of ACI, rather than that of GPP. This indicates that BPE follows sink dynamics more closely than source dynamics, which appear to be decoupled given the distinctive climate response patterns of GPP and ACI. Based on our observations, we caution against estimating the magnitude and variability of the carbon sink in European beech (and likely other temperate forests) based on carbon fluxes alone. We also encourage comparable studies at other long-term EC measurement sites from different ecosystems to further constrain the BPE response to rare climatic events.
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Affiliation(s)
- Jingshu Wei
- School of Natural Resources and the Environment, University of Arizona, 1064 E Lowell Street, Tucson, AZ 85721, USA; Swiss Federal Institute for Forest Snow and Landscape Research WSL, Zuercherstrasse 111, CH-8903 Birmensdorf, Switzerland; CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun Town, Mengla County, Yunnan Province 666303, China.
| | - Georg von Arx
- Swiss Federal Institute for Forest Snow and Landscape Research WSL, Zuercherstrasse 111, CH-8903 Birmensdorf, Switzerland; Oeschger Centre for Climate Change Research, University of Bern, Hochschulstrasse 4, CH-3012 Bern, Switzerland
| | - Zexin Fan
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun Town, Mengla County, Yunnan Province 666303, China
| | - Andreas Ibrom
- Biosystems Division, Risø National Laboratory for Sustainable Energy, Technical University of Denmark, Denmark
| | - Martina Mund
- Forestry Research and Competence Centre Gotha, Jägerstraße1, D-99867 Gotha, Germany
| | - Alexander Knohl
- Bioclimatology, University of Göttingen, Büsgenweg 2, D-37077 Göttingen, Germany
| | - Richard L Peters
- Environmental Sciences - Botany, University of Basel, Schönbeinstrasse 6, Basel CH-4056, Switzerland
| | - Flurin Babst
- School of Natural Resources and the Environment, University of Arizona, 1064 E Lowell Street, Tucson, AZ 85721, USA; Laboratory of Tree-Ring Research, University of Arizona, 1215 E Lowell Street, Tucson, AZ 85721, USA
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Schönbeck L, Arteaga M, Mirza H, Coleman M, Mitchell D, Huang X, Ortiz H, Santiago LS. Plant physiological indicators for optimizing conservation outcomes. Conserv Physiol 2023; 11:coad073. [PMID: 37711583 PMCID: PMC10498484 DOI: 10.1093/conphys/coad073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 07/20/2023] [Accepted: 08/22/2023] [Indexed: 09/16/2023]
Abstract
Plant species of concern often occupy narrow habitat ranges, making climate change an outsized potential threat to their conservation and restoration. Understanding the physiological status of a species during stress has the potential to elucidate current risk and provide an outlook on population maintenance. However, the physiological status of a plant can be difficult to interpret without a reference point, such as the capacity to tolerate stress before loss of function, or mortality. We address the application of plant physiology to conservation biology by distinguishing between two physiological approaches that together determine plant status in relation to environmental conditions and evaluate the capacity to avoid stress-induced loss of function. Plant physiological status indices, such as instantaneous rates of photosynthetic gas exchange, describe the level of physiological activity in the plant and are indicative of physiological health. When such measurements are combined with a reference point that reflects the maximum value or environmental limits of a parameter, such as the temperature at which photosynthesis begins to decline due to high temperature stress, we can better diagnose the proximity to potentially damaging thresholds. Here, we review a collection of useful plant status and reference point measurements related to photosynthesis, water relations and mineral nutrition, which can contribute to plant conservation physiology. We propose that these measurements can serve as important additional information to more commonly used phenological and morphological parameters, as the proposed parameters will reveal early warning signals before they are visible. We discuss their implications in the context of changing temperature, water and nutrient supply.
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Affiliation(s)
- Leonie Schönbeck
- Department of Botany & Plant Sciences, University of California, Riverside, CA 92521, USA
| | - Marc Arteaga
- Department of Botany & Plant Sciences, University of California, Riverside, CA 92521, USA
| | - Humera Mirza
- Department of Botany & Plant Sciences, University of California, Riverside, CA 92521, USA
| | - Mitchell Coleman
- Department of Botany & Plant Sciences, University of California, Riverside, CA 92521, USA
- Tejon Ranch Conservancy, Frazier Park, CA 93225, USA
| | - Denise Mitchell
- Department of Botany & Plant Sciences, University of California, Riverside, CA 92521, USA
| | - Xinyi Huang
- Department of Botany & Plant Sciences, University of California, Riverside, CA 92521, USA
| | - Haile Ortiz
- Department of Botany & Plant Sciences, University of California, Riverside, CA 92521, USA
| | - Louis S Santiago
- Department of Botany & Plant Sciences, University of California, Riverside, CA 92521, USA
- Smithsonian Tropical Research Institute, Apartado 0843-03092. Balboa, Ancon, Panama, Republic of Panama
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Zhang YL, Yang Y, Saurer M, Schaub M, Gessler A, Lehmann MM, Rigling A, Walser M, Stierli B, Hajjar N, Christen D, Li MH. Sugar infusion into trees: A novel method to study tree carbon relations and its regulations. Front Plant Sci 2023; 14:1142595. [PMID: 36909442 PMCID: PMC9996627 DOI: 10.3389/fpls.2023.1142595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 02/14/2023] [Indexed: 06/18/2023]
Abstract
Many carbon-related physiological questions in plants such as carbon (C) limitation or starvation have not yet been resolved thoroughly due to the lack of suitable experimental methodology. As a first step towards resolving these problems, we conducted infusion experiments with bonsai trees (Ficus microcarpa) and young maple trees (Acer pseudoplatanus) in greenhouse, and with adult Scots pine trees (Pinus sylvestris) in the field, that were "fed" with 13C-labelled glucose either through the phloem or the xylem. We then traced the 13C-signal in plant organic matter and respiration to test whether trees can take up and metabolize exogenous sugars infused. Ten weeks after infusion started, xylem but not phloem infusion significantly increased the δ13C values in both aboveground and belowground tissues of the bonsai trees in the greenhouse, whereas xylem infusion significantly increased xylem δ13C values and phloem infusion significantly increased phloem δ13C values of the adult pines in the field experiment, compared to the corresponding controls. The respiration measurement experiment with young maple trees showed significantly increased δ13C-values in shoot respired CO2 at the time of four weeks after xylem infusion started. Our results clearly indicate that trees do translocate and metabolize exogenous sugars infused, and because the phloem layer is too thin, and thus xylem infusion can be better operated than phloem infusion. This tree infusion method developed here opens up new avenues and has great potential to be used for research on the whole plant C balance and its regulation in response to environmental factors and extreme stress conditions.
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Affiliation(s)
- Yan-Li Zhang
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
- Department of Environmental Systems Science, Institute of Terrestrial Ecosystems, ETH Zürich, Zürich, Switzerland
| | - Yue Yang
- College of Ecology and Environment, Hainan University, Haikou, China
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Matthias Saurer
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Marcus Schaub
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Arthur Gessler
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
- Department of Environmental Systems Science, Institute of Terrestrial Ecosystems, ETH Zürich, Zürich, Switzerland
| | - Marco M. Lehmann
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Andreas Rigling
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
- Department of Environmental Systems Science, Institute of Terrestrial Ecosystems, ETH Zürich, Zürich, Switzerland
| | - Marco Walser
- Forest Soils and Biogeochemistry, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Beat Stierli
- Forest Soils and Biogeochemistry, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Noureddine Hajjar
- Forest Soils and Biogeochemistry, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Daniel Christen
- Forest Soils and Biogeochemistry, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Mai-He Li
- College of Ecology and Environment, Hainan University, Haikou, China
- Key Laboratory of Geographical Processes and Ecological Security in Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Changchun, Jilin, China
- College of Life Science, Hebei University, Baoding, Hebei, China
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Mašek J, Tumajer J, Lange J, Kaczka R, Fišer P, Treml V. Variability in Tree-ring Width and NDVI Responses to Climate at a Landscape Level. Ecosystems 2023. [DOI: 10.1007/s10021-023-00822-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
AbstractInter-annual climatically driven growth variability of above-ground biomass compartments (for example, tree stems and foliage) controls the intensity of carbon sequestration into forest ecosystems. However, understanding the differences between the climatic response of stem and foliage at the landscape level is limited. In this study, we examined the climate-growth response of stem and leaf biomass and their relationship for Pinus sylvestris (PISY) and Picea abies (PCAB) in topographically complex landscapes. We used tree-ring width chronologies and time series of the normalized difference vegetation index (NDVI) derived from high-resolution Landsat scenes as proxies for stem and leaf biomass, respectively. We then compared growth variability and climate-growth relationships of both biomass proxies between topographical categories. Our results show that the responses of tree rings to climate differ significantly from those found in NDVI, with the stronger climatic signal observed in tree rings. Topography had distinct but species-specific effects: At moisture-limited PISY stands, stem biomass (tree rings) was strongly topographically driven, and leaf biomass (NDVI) was relatively insensitive to topographic variability. In landscapes close to the climatic optimum of PCAB, the relationship between stem and leaf biomass was weak, and their correlations with climate were often inverse, with no significant effects of topography. Different climatic signals from NDVI and tree rings suggest that the response of canopy and stem growth to climate change might be decoupled. Furthermore, our results hint toward different prioritizations of biomass allocation in trees under stressful conditions which might change allometric relationships between individual tree compartments in the long term.
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Gong XW, Hao GY. The synergistic effect of hydraulic and thermal impairments accounts for the severe crown damage in Fraxinus mandshurica seedlings following the combined drought-heatwave stress. Sci Total Environ 2023; 856:159017. [PMID: 36167124 DOI: 10.1016/j.scitotenv.2022.159017] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 09/20/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
Drought combined with extreme heatwaves has been increasingly identified as the important trigger of worldwide tree mortality in the context of climate change; nonetheless, our understanding of the potential hydraulic and thermal impairments of hot droughts to trees and the subsequent post-recovery process remains limited. To investigate the response of tree water and carbon relations to drought, heatwave, and combined drought-heatwave stresses, three-year-old potted seedlings of Fraxinus mandshurica Rupr., a dominant tree species in temperate forests of northeast China, were grown under well-watered and drought-stressed conditions and exposed to a rapid, acute heatwave treatment. During the heatwave treatment with a maximum temperature exceeding 40 °C for two days, the leaf temperature of drought-stressed seedlings was, on average, 5 °C higher than that of well-watered counterparts due to less effective evaporative cooling, indicating that soil water availability influenced leaf thermoregulatory capacity during hot extremes. Consistently, more pronounced crown damage, as shown by 13 % irreversible leaf scorch, was found in seedlings under the drought-heatwave treatment relative to sole heatwave treatment, alongside the more severe stem xylem embolism and leaf electrolyte leakage. While the heatwave treatment accelerated the depletion of non-structural carbohydrates in drought-stressed seedlings, the increase of branch soluble sugar concentration in response to heatwave might be related to the requirement for maintaining hydraulic functioning via osmoregulation under high dehydration risk. The coordination between leaf stomatal conductance and total non-structural carbohydrate content during the post-heatwave recovery phase implied that plant-water relations and carbon physiology were closely coupled in coping with hot droughts. This study highlights that, under scenarios of aggravating drought co-occurring with heatwaves, tree seedlings could face a high risk of crown decline in relation to the synergistically increased hydraulic and thermal impairments.
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Affiliation(s)
- Xue-Wei Gong
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; Key Laboratory of Terrestrial Ecosystem Carbon Neutrality, Liaoning Province, Shenyang 110016, China; Qingyuan Forest CERN, National Observation and Research Station, Liaoning Province, Shenyang 110016, China
| | - Guang-You Hao
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; Key Laboratory of Terrestrial Ecosystem Carbon Neutrality, Liaoning Province, Shenyang 110016, China; Qingyuan Forest CERN, National Observation and Research Station, Liaoning Province, Shenyang 110016, China.
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Milligan PD, Martin TA, Pringle EG, Prior KM, Palmer TM. Symbiotic ant traits produce differential host-plant carbon and water dynamics in a multi-species mutualism. Ecology 2023; 104:e3880. [PMID: 36199213 DOI: 10.1002/ecy.3880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 06/28/2022] [Accepted: 07/28/2022] [Indexed: 02/01/2023]
Abstract
Cooperative interactions may frequently be reinforced by "partner fidelity feedback," in which high- or low-quality partners drive positive feedbacks with high or low benefits for the host, respectively. Benefits of plant-animal mutualisms for plants have been quantified almost universally in terms of growth or reproduction, but these are only two of many sinks to which a host-plant allocates its resources. By investigating how partners to host-plants impact two fundamental plant resources, carbon and water, we can better characterize plant-partner fidelity and understand how plant-partner mutualisms may be modulated by resource dynamics. In Laikipia, Kenya, four ant species compete for Acacia drepanolobium host-plants. These ants differ in multiple traits, from nectar consumption to host-plant protection. Using a 5-year ant removal experiment, we compared carbon fixation, leaf water status, and stem non-structural carbohydrate concentrations for adult ant-plants with and without ant partners. Removal treatments showed that the ants differentially mediate tree carbon and/or water resources. All three ant species known to be aggressive against herbivores were linked to benefits for host-plant resources, but only the two species that defend but do not prune the host, Crematogaster mimosae and Tetraponera penzigi, increased tree carbon fixation. Of these two species, only the nectivore C. mimosae increased tree simple sugars. Crematogaster nigriceps, which defends the tree but also castrates flowers and prunes meristems, was linked only to lower tree water stress approximated by pre-dawn leaf water potential. In contrast to those defensive ants, Crematogaster sjostedti, a poor defender that displaces other ants, was linked to lower tree carbon fixation. Comparing the effects of the four ant species across control trees suggests that differential ant occupancy drives substantial differences in carbon and water supply among host trees. Our results highlight that ant partners can positively or negatively impact carbon and/or water relations for their host-plant, and we discuss the likelihood that carbon- and water-related partner fidelity feedback loops occur across ant-plant mutualisms.
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Affiliation(s)
- Patrick D Milligan
- Department of Biology, University of Florida, Gainesville, Florida, USA.,Mpala Research Centre, Nanyuki, Kenya.,Department of Biology, Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, Reno, Nevada, USA
| | - Timothy A Martin
- School of Forest, Fisheries, and Geomatics Sciences, University of Florida, Gainesville, Florida, USA
| | - Elizabeth G Pringle
- Department of Biology, Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, Reno, Nevada, USA
| | - Kirsten M Prior
- Department of Biology, SUNY Binghamton, Binghamton, New York, USA
| | - Todd M Palmer
- Department of Biology, University of Florida, Gainesville, Florida, USA.,Mpala Research Centre, Nanyuki, Kenya
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Ulrich DEM, Clendinen CS, Alongi F, Mueller RC, Chu RK, Toyoda J, Gallegos-Graves LV, Goemann HM, Peyton B, Sevanto S, Dunbar J. Root exudate composition reflects drought severity gradient in blue grama (Bouteloua gracilis). Sci Rep 2022; 12:12581. [PMID: 35869127 PMCID: PMC9307599 DOI: 10.1038/s41598-022-16408-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 07/11/2022] [Indexed: 12/22/2022] Open
Abstract
Plant survival during environmental stress greatly affects ecosystem carbon (C) cycling, and plant–microbe interactions are central to plant stress survival. The release of C-rich root exudates is a key mechanism plants use to manage their microbiome, attracting beneficial microbes and/or suppressing harmful microbes to help plants withstand environmental stress. However, a critical knowledge gap is how plants alter root exudate concentration and composition under varying stress levels. In a greenhouse study, we imposed three drought treatments (control, mild, severe) on blue grama (Bouteloua gracilis Kunth Lag. Ex Griffiths), and measured plant physiology and root exudate concentration and composition using GC–MS, NMR, and FTICR. With increasing drought severity, root exudate total C and organic C increased concurrently with declining predawn leaf water potential and photosynthesis. Root exudate composition mirrored the physiological gradient of drought severity treatments. Specific compounds that are known to alter plant drought responses and the rhizosphere microbiome mirrored the drought severity-induced root exudate compositional gradient. Despite reducing C uptake, these plants actively invested C to root exudates with increasing drought severity. Patterns of plant physiology and root exudate concentration and composition co-varied along a gradient of drought severity.
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Trowbridge AM, Adams HD, Collins A, Dickman LT, Grossiord C, Hofland M, Malone S, Weaver DK, Sevanto S, Stoy PC, McDowell NG. Hotter droughts alter resource allocation to chemical defenses in piñon pine. Oecologia 2021; 197:921-38. [PMID: 34657177 DOI: 10.1007/s00442-021-05058-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 10/04/2021] [Indexed: 01/11/2023]
Abstract
Heat and drought affect plant chemical defenses and thereby plant susceptibility to pests and pathogens. Monoterpenes are of particular importance for conifers as they play critical roles in defense against bark beetles. To date, work seeking to understand the impacts of heat and drought on monoterpenes has primarily focused on young potted seedlings, leaving it unclear how older age classes that are more vulnerable to bark beetles might respond to stress. Furthermore, we lack a clear picture of what carbon resources might be prioritized to support monoterpene synthesis under drought stress. To address this, we measured needle and woody tissue monoterpene concentrations and physiological variables simultaneously from mature piñon pines (Pinus edulis) from a unique temperature and drought manipulation field experiment. While heat had no effect on total monoterpene concentrations, trees under combined heat and drought stress exhibited ~ 85% and 35% increases in needle and woody tissue, respectively, over multiple years. Plant physiological variables like maximum photosynthesis each explained less than 10% of the variation in total monoterpenes for both tissue types while starch and glucose + fructose measured 1-month prior explained ~ 45% and 60% of the variation in woody tissue total monoterpene concentrations. Although total monoterpenes increased under combined stress, some key monoterpenes with known roles in bark beetle ecology decreased. These shifts may make trees more favorable for bark beetle attack rather than well defended, which one might conclude if only considering total monoterpene concentrations. Our results point to cumulative and synergistic effects of heat and drought that may reprioritize carbon allocation of specific non-structural carbohydrates toward defense.
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Huang J, Rücker A, Schmidt A, Gleixner G, Gershenzon J, Trumbore S, Hartmann H. Production of constitutive and induced secondary metabolites is coordinated with growth and storage in Norway spruce saplings. Tree Physiol 2020; 40:928-942. [PMID: 32268379 PMCID: PMC7325531 DOI: 10.1093/treephys/tpaa040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 01/17/2020] [Accepted: 03/18/2020] [Indexed: 05/12/2023]
Abstract
A mechanistic understanding of how trees balance the trade-offs between growth, storage and defense is limited but crucial for predicting tree responses to abiotic and biotic stresses. Here we investigated how trees allocate storage of non-structural carbohydrates (NSC) to growth and constitutive and induced secondary metabolites (SM). We exposed Norway spruce (Picea abies) saplings to 5 weeks of complete darkness to induce light and/or carbon limitation and then applied methyl jasmonate (MeJA) to simulate biotic attack. We measured changes in biomass, NSC (sum of soluble sugars and starches), and constitutive and induced SM (sum of phenolic compounds and terpenoids) in current-year developing and previous-year mature needles and branches, as well as volatiles emitted from the canopy. Under darkness, NSC storage was preferentially used for constitutive biosynthesis of monoterpenes rather than biosynthesis of stilbenes and growth of developing organs, while SM stored in mature organs cannot be remobilized and recycled. Furthermore, MeJA-induced production of SM was constrained by low NSC availability in developing organs but not in mature organs grown in the dark. Emissions of volatiles were suppressed in the dark but after 1 h of re-illumination, emissions of both constitutive and induced monoterpene hydrocarbons recovered rapidly, whereas emissions of linalool and sesquiterpene produced via de novo synthesis did not recover. Our results highlight that light and/or carbon limitation may constrain constitutive and JA-induced biosynthesis of SM in coordination with growth, NSC storage and mobilization.
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Affiliation(s)
- Jianbei Huang
- Department of Biogeochemical Processes, Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, Jena 07745, Germany
- Corresponding author ()
| | - Alexander Rücker
- Department of Biogeochemical Processes, Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, Jena 07745, Germany
| | - Axel Schmidt
- Department of Biochemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, Jena 07745, Germany
| | - Gerd Gleixner
- Department of Biogeochemical Processes, Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, Jena 07745, Germany
| | - Jonathan Gershenzon
- Department of Biochemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, Jena 07745, Germany
| | - Susan Trumbore
- Department of Biogeochemical Processes, Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, Jena 07745, Germany
| | - Henrik Hartmann
- Department of Biogeochemical Processes, Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, Jena 07745, Germany
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D’andrea E, Guidolotti G, Scartazza A, De Angelis P, Matteucci G. Small-Scale Forest Structure Influences Spatial Variability of Belowground Carbon Fluxes in a Mature Mediterranean Beech Forest. Forests 2020; 11:255. [DOI: 10.3390/f11030255] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The tree belowground compartment, especially fine roots, plays a relevant role in the forest ecosystem carbon (C) cycle, contributing largely to soil CO2 efflux (SR) and to net primary production (NPP). Beyond the well-known role of environmental drivers on fine root production (FRP) and SR, other determinants such as forest structure are still poorly understood. We investigated spatial variability of FRP, SR, forest structural traits, and their reciprocal interactions in a mature beech forest in the Mediterranean mountains. In the year of study, FRP resulted in the main component of NPP and explained about 70% of spatial variability of SR. Moreover, FRP was strictly driven by leaf area index (LAI) and soil water content (SWC). These results suggest a framework of close interactions between structural and functional forest features at the local scale to optimize C source–sink relationships under climate variability in a Mediterranean mature beech forest.
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Merganičová K, Merganič J, Lehtonen A, Vacchiano G, Sever MZO, Augustynczik ALD, Grote R, Kyselová I, Mäkelä A, Yousefpour R, Krejza J, Collalti A, Reyer CPO. Forest carbon allocation modelling under climate change. Tree Physiol 2019; 39:1937-1960. [PMID: 31748793 PMCID: PMC6995853 DOI: 10.1093/treephys/tpz105] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 06/03/2019] [Accepted: 09/24/2019] [Indexed: 05/19/2023]
Abstract
Carbon allocation plays a key role in ecosystem dynamics and plant adaptation to changing environmental conditions. Hence, proper description of this process in vegetation models is crucial for the simulations of the impact of climate change on carbon cycling in forests. Here we review how carbon allocation modelling is currently implemented in 31 contrasting models to identify the main gaps compared with our theoretical and empirical understanding of carbon allocation. A hybrid approach based on combining several principles and/or types of carbon allocation modelling prevailed in the examined models, while physiologically more sophisticated approaches were used less often than empirical ones. The analysis revealed that, although the number of carbon allocation studies over the past 10 years has substantially increased, some background processes are still insufficiently understood and some issues in models are frequently poorly represented, oversimplified or even omitted. Hence, current challenges for carbon allocation modelling in forest ecosystems are (i) to overcome remaining limits in process understanding, particularly regarding the impact of disturbances on carbon allocation, accumulation and utilization of nonstructural carbohydrates, and carbon use by symbionts, and (ii) to implement existing knowledge of carbon allocation into defence, regeneration and improved resource uptake in order to better account for changing environmental conditions.
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Affiliation(s)
- Katarína Merganičová
- Czech University of Life Sciences, Prague, Faculty of Forestry and Wood Sciences, Kamýcká 129, 16500 Praha-Suchdol, Czech Republic
- Technical University Zvolen, Forestry Faculty, T. G. Masaryka 24, 96053 Zvolen, Slovakia
| | - Ján Merganič
- Technical University Zvolen, Forestry Faculty, T. G. Masaryka 24, 96053 Zvolen, Slovakia
| | - Aleksi Lehtonen
- The Finnish Forest Research Institute - Luke, PO Box 18 (Jokiniemenkuja 1), FI-01301 Vantaa, Finland
| | - Giorgio Vacchiano
- Università degli Studi di Milano, DISAA. Via Celoria 2, 20132 Milano, Italy
| | - Maša Zorana Ostrogović Sever
- Croatian Forest Research Institute, Department for forest management and forestry economics, Cvjetno naselje 41, 10450 Jastrebarsko, Croatia
| | | | - Rüdiger Grote
- Institute of Meteorology and Climate Research (IMK-IFU), Karlsruhe Institute of Technology, Garmisch-Partenkirchen, Germany
| | - Ina Kyselová
- Global Change Research Institute CAS, Bělidla 986/4a, 603 00 Brno, Czech Republic
| | - Annikki Mäkelä
- University of Helsinki, Department of Forest Science, Latokartanonkaari 7, P.O. Box 27, 00014 Helsinki, Finland
| | - Rasoul Yousefpour
- University of Freiburg, Tennenbacher Str. 4 (2. OG), D-79106 Freiburg, Germany
| | - Jan Krejza
- Global Change Research Institute CAS, Bělidla 986/4a, 603 00 Brno, Czech Republic
| | - Alessio Collalti
- National Research Council of Italy, Institute for Agriculture and Forestry Systems in the Mediterranean (CNR-ISAFOM), 87036 Rende, Italy
- Department of Innovation in Biological, Agro-food and Forest Systems, University of Tuscia, 01100 Viterbo, Italy
| | - Christopher P O Reyer
- Potsdam Institute for Climate Impact Research, Telegraphenberg, PO Box 601203, D-14473 Potsdam, Germany
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12
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Lauder JD, Moran EV, Hart SC. Fight or flight? Potential tradeoffs between drought defense and reproduction in conifers. Tree Physiol 2019; 39:1071-1085. [PMID: 30924877 DOI: 10.1093/treephys/tpz031] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 12/26/2018] [Accepted: 03/03/2019] [Indexed: 06/09/2023]
Abstract
Plants frequently exhibit tradeoffs between reproduction and growth when resources are limited, and often change these allocation patterns in response to stress. Shorter-lived plants such as annuals tend to allocate relatively more resources toward reproduction when stressed, while longer-lived plants tend to invest more heavily in survival and stress defense. However, severe stress may affect the fitness implications of allocating relatively more resources to reproduction versus stress defense. Increased drought intensity and duration have led to widespread mortality events in coniferous forests. In this review, we ask how potential tradeoffs between reproduction and survival influence the likelihood of drought-induced mortality and species persistence. We propose that trees may exhibit what we call 'fight or flight' behaviors under stress. 'Fight' behaviors involve greater resource allocation toward survival (e.g., growth, drought-resistant xylem and pest defense). 'Flight' consists of higher relative allocation of resources to reproduction, potentially increasing both offspring production and mortality risk for the adult. We hypothesize that flight behaviors increase as drought stress escalates the likelihood of mortality in a given location.
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Affiliation(s)
- Jeffrey D Lauder
- Quantitative and Systems Biology Graduate Group, University of California, Merced, N. Lake Road, Merced, CA, USA
| | - Emily V Moran
- Department of Life & Environmental Sciences and Sierra Nevada Research Institute, University of California, Merced, N. Lake Road, Merced, CA, USA
| | - Stephen C Hart
- Department of Life & Environmental Sciences and Sierra Nevada Research Institute, University of California, Merced, N. Lake Road, Merced, CA, USA
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13
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Churakova (Sidorova) O, Lehmann M, Saurer M, Fonti M, Siegwolf R, Bigler C. Compound-Specific Carbon Isotopes and Concentrations of Carbohydrates and Organic Acids as Indicators of Tree Decline in Mountain Pine. Forests 2018; 9:363. [DOI: 10.3390/f9060363] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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14
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Fernandez CW, Nguyen NH, Stefanski A, Han Y, Hobbie SE, Montgomery RA, Reich PB, Kennedy PG. Ectomycorrhizal fungal response to warming is linked to poor host performance at the boreal-temperate ecotone. Glob Chang Biol 2017; 23:1598-1609. [PMID: 27658686 DOI: 10.1111/gcb.13510] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 08/19/2016] [Accepted: 09/09/2016] [Indexed: 05/22/2023]
Abstract
Rising temperatures associated with climate change have been shown to negatively affect the photosynthetic rates of boreal forest tree saplings at their southern range limits. To quantify the responses of ectomycorrhizal (EM) fungal communities associated with poorly performing hosts, we sampled the roots of Betula papyrifera and Abies balsamea saplings growing in the B4Warmed (Boreal Forest Warming at an Ecotone in Danger) experiment. EM fungi on the root systems of both hosts were compared from ambient and +3.4 °C air and soil warmed plots at two sites in northern Minnesota. EM fungal communities were assessed with high-throughput sequencing along with measures of plant photosynthesis, soil temperature, moisture, and nitrogen. Warming selectively altered EM fungal community composition at both the phylum and genus levels, but had no significant effect on EM fungal operational taxonomic unit (OTU) diversity. Notably, warming strongly favored EM Ascomycetes and EM fungi with short-contact hyphal exploration types. Declining host photosynthetic rates were also significantly inversely correlated with EM Ascomycete and EM short-contact exploration type abundance, which may reflect a shift to less carbon demanding fungi due to lower photosynthetic capacity. Given the variation in EM host responses to warming, both within and between ecosystems, better understanding the link between host performance and EM fungal community structure will to clarify how climate change effects cascade belowground.
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Affiliation(s)
| | - Nhu H Nguyen
- Department of Plant Biology, University of Minnesota, St. Paul, MN, USA
- Department of Tropical Plant and Soil Sciences, University of Hawai'i at Manoa, Honolulu, HI, USA
| | - Artur Stefanski
- Department of Forest Resources, University of Minnesota, St. Paul, MN, USA
| | - Ying Han
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, China
| | - Sarah E Hobbie
- Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, MN, USA
| | | | - Peter B Reich
- Department of Forest Resources, University of Minnesota, St. Paul, MN, USA
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Peter G Kennedy
- Department of Plant Biology, University of Minnesota, St. Paul, MN, USA
- Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, MN, USA
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15
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Marias DE, Meinzer FC, Woodruff DR, McCulloh KA. Thermotolerance and heat stress responses of Douglas-fir and ponderosa pine seedling populations from contrasting climates. Tree Physiol 2017; 37:301-315. [PMID: 28008081 DOI: 10.1093/treephys/tpw117] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 11/07/2016] [Indexed: 06/06/2023]
Abstract
Temperature and the frequency and intensity of heat waves are predicted to increase throughout the 21st century. Germinant seedlings are expected to be particularly vulnerable to heat stress because they are in the boundary layer close to the soil surface where intense heating occurs in open habitats. We quantified leaf thermotolerance and whole-plant physiological responses to heat stress in first-year germinant seedlings in two populations each of Pinus ponderosa P. and C. Lawson (PIPO) and Pseudotsuga menziesii (Mirb.) Franco (PSME) from climates with contrasting precipitation and temperature regimes. Thermotolerance of detached needles was evaluated using chlorophyll fluorescence (FV/FM, FO) and electrolyte leakage. PSME was more heat tolerant than PIPO according to both independent assessments of thermotolerance. Following exposure of whole seedlings to a simulated heat wave at 45 °C for 1 h in a growth chamber, we monitored FV/FM, photosynthesis, stomatal conductance, non-structural carbohydrates (NSCs) and carbon isotope ratios (δ13C) for 14 days. Heat treatment induced significant reductions in FV/FM in both species and a transient reduction in photosynthetic gas exchange only in PIPO 1 day after treatment. Heat treatment induced an increase in glucose + fructose concurrent with a decrease in starch in both species, whereas total NSC and sucrose were not affected by heat treatment. The negative relationship between glucose + fructose and starch observed in treated plants may be due to the conversion of starch to glucose + fructose to aid recovery from heat-induced damage. Populations from drier sites displayed greater δ13C values than those from wetter sites, consistent with higher intrinsic water-use efficiency and drought resistance of populations from drier climates. Thermotolerance and heat stress responses appeared to be phenotypically plastic and representative of the environment in which plants were grown, whereas intrinsic water-use efficiency appeared to reflect ecotypic differentiation and the climate of origin.
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Affiliation(s)
- Danielle E Marias
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA
| | - Frederick C Meinzer
- USDA Forest Service, Pacific Northwest Research Station, 3200 SW Jefferson Way, Corvallis, OR 97331, USA
| | - David R Woodruff
- USDA Forest Service, Pacific Northwest Research Station, 3200 SW Jefferson Way, Corvallis, OR 97331, USA
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16
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Marias DE, Meinzer FC, Still C. Impacts of leaf age and heat stress duration on photosynthetic gas exchange and foliar nonstructural carbohydrates in Coffea arabica. Ecol Evol 2017; 7:1297-1310. [PMID: 28303198 PMCID: PMC5306013 DOI: 10.1002/ece3.2681] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 10/28/2016] [Accepted: 11/27/2016] [Indexed: 01/04/2023] Open
Abstract
Given future climate predictions of increased temperature, and frequency and intensity of heat waves in the tropics, suitable habitat to grow ecologically, economically, and socially valuable Coffea arabica is severely threatened. We investigated how leaf age and heat stress duration impact recovery from heat stress in C. arabica. Treated plants were heated in a growth chamber at 49°C for 45 or 90 min. Physiological recovery was monitored in situ using gas exchange, chlorophyll fluorescence (the ratio of variable to maximum fluorescence, FV/FM), and leaf nonstructural carbohydrate (NSC) on mature and expanding leaves before and 2, 15, 25, and 50 days after treatment. Regardless of leaf age, the 90-min treatment resulted in greater FV/FM reduction 2 days after treatment and slower recovery than the 45-min treatment. In both treatments, photosynthesis of expanding leaves recovered more slowly than in mature leaves. Stomatal conductance (gs) decreased in expanding leaves but did not change in mature leaves. These responses led to reduced intrinsic water-use efficiency with increasing heat stress duration in both age classes. Based on a leaf energy balance model, aftereffects of heat stress would be exacerbated by increases in leaf temperature at low gs under full sunlight where C. arabica is often grown, but also under partial sunlight. Starch and total NSC content of the 45-min group significantly decreased 2 days after treatment and then accumulated 15 and 25 days after treatment coinciding with recovery of photosynthesis and FV/FM. In contrast, sucrose of the 90-min group accumulated at day 2 suggesting that phloem transport was inhibited. Both treatment group responses contrasted with control plant total NSC and starch, which declined with time associated with subsequent flower and fruit production. No treated plants produced flowers or fruits, suggesting that short duration heat stress can lead to crop failure.
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Affiliation(s)
- Danielle E. Marias
- Department of Forest Ecosystems and SocietyOregon State UniversityCorvallisORUSA
| | | | - Christopher Still
- Department of Forest Ecosystems and SocietyOregon State UniversityCorvallisORUSA
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17
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Mystakidis S, Davin EL, Gruber N, Seneviratne SI. Constraining future terrestrial carbon cycle projections using observation-based water and carbon flux estimates. Glob Chang Biol 2016; 22:2198-215. [PMID: 26732346 DOI: 10.1111/gcb.13217] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 10/20/2015] [Accepted: 11/12/2015] [Indexed: 05/15/2023]
Abstract
The terrestrial biosphere is currently acting as a sink for about a third of the total anthropogenic CO2 emissions. However, the future fate of this sink in the coming decades is very uncertain, as current earth system models (ESMs) simulate diverging responses of the terrestrial carbon cycle to upcoming climate change. Here, we use observation-based constraints of water and carbon fluxes to reduce uncertainties in the projected terrestrial carbon cycle response derived from simulations of ESMs conducted as part of the 5th phase of the Coupled Model Intercomparison Project (CMIP5). We find in the ESMs a clear linear relationship between present-day evapotranspiration (ET) and gross primary productivity (GPP), as well as between these present-day fluxes and projected changes in GPP, thus providing an emergent constraint on projected GPP. Constraining the ESMs based on their ability to simulate present-day ET and GPP leads to a substantial decrease in the projected GPP and to a ca. 50% reduction in the associated model spread in GPP by the end of the century. Given the strong correlation between projected changes in GPP and in NBP in the ESMs, applying the constraints on net biome productivity (NBP) reduces the model spread in the projected land sink by more than 30% by 2100. Moreover, the projected decline in the land sink is at least doubled in the constrained ensembles and the probability that the terrestrial biosphere is turned into a net carbon source by the end of the century is strongly increased. This indicates that the decline in the future land carbon uptake might be stronger than previously thought, which would have important implications for the rate of increase in the atmospheric CO2 concentration and for future climate change.
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Affiliation(s)
- Stefanos Mystakidis
- Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, 8092, Switzerland
- Center for Climate Systems Modeling, ETH Zurich, Universitätstrasse 16, Zurich, 8092, Switzerland
| | - Edouard L Davin
- Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, 8092, Switzerland
| | - Nicolas Gruber
- Center for Climate Systems Modeling, ETH Zurich, Universitätstrasse 16, Zurich, 8092, Switzerland
- Environmental Physics, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitätstrasse 16, Zurich, 8092, Switzerland
| | - Sonia I Seneviratne
- Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, 8092, Switzerland
- Center for Climate Systems Modeling, ETH Zurich, Universitätstrasse 16, Zurich, 8092, Switzerland
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