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Kengdo SK, Ahrens B, Tian Y, Heinzle J, Wanek W, Schindlbacher A, Borken W. Increase in carbon input by enhanced fine root turnover in a long-term warmed forest soil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 855:158800. [PMID: 36116665 DOI: 10.1016/j.scitotenv.2022.158800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/18/2022] [Accepted: 09/12/2022] [Indexed: 06/15/2023]
Abstract
Fine root litter represents an important carbon input to soils, but the effect of global warming on fine root turnover (FRT) is hardly explored in forest ecosystems. Understanding tree fine roots' response to warming is crucial for predicting soil carbon dynamics and the functioning of forests as a sink for atmospheric carbon dioxide (CO2). We studied fine root production (FRP) with ingrowth cores and used radiocarbon signatures of first-order, second- to third-order, and bulk fine roots to estimate fine root turnover times after 8 and 14 years of soil warming (+4 °C) in a temperate forest. Fine root turnover times of the individual root fractions were estimated with a one-pool model. Soil warming strongly increased fine root production by up to 128 % within one year, but after two years, the production was less pronounced (+35 %). The first-year production was likely very high due to the rapid exploitation of the root-free ingrowth cores. The radiocarbon signatures of fine roots were overall variable among treatments and plots. Soil warming tended to decrease fine root turnover times of all the measured root fractions after 8 and 14 years of warming, and there was a tendency for trees to use older carbon reserves for fine root production in warmed plots. Furthermore, soil warming increased fine root turnover from 50 to 106 g C m-2 yr-1 (based on two different approaches). Our findings suggest that future climate warming may increase carbon input into soils by enhancing fine root turnover. If this increase may partly offset carbon losses by increased mineralization of soil organic matter in temperate forest soils is still unclear and should guide future research.
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Affiliation(s)
- Steve Kwatcho Kengdo
- Department of Soil Ecology, Bayreuth Center of Ecology and Environmental Research (BAYCEER), University of Bayreuth, Dr.-Hans-Frisch-Straße 1-3, 95448 Bayreuth, Germany.
| | - Bernhard Ahrens
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745 Jena, Germany
| | - Ye Tian
- Division of Terrestrial Ecosystem Research, Department of Microbiology and Ecosystem Science, Center of Microbiology and Environmental Systems Science, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Jakob Heinzle
- Department of Forest Ecology and Soil, Federal Research and Training Centre for Forests, Natural Hazards and Landscape-BFW, Seckendorff-Gudent Weg 8, 1131 Vienna, Austria
| | - Wolfgang Wanek
- Division of Terrestrial Ecosystem Research, Department of Microbiology and Ecosystem Science, Center of Microbiology and Environmental Systems Science, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Andreas Schindlbacher
- Department of Forest Ecology and Soil, Federal Research and Training Centre for Forests, Natural Hazards and Landscape-BFW, Seckendorff-Gudent Weg 8, 1131 Vienna, Austria
| | - Werner Borken
- Department of Soil Ecology, Bayreuth Center of Ecology and Environmental Research (BAYCEER), University of Bayreuth, Dr.-Hans-Frisch-Straße 1-3, 95448 Bayreuth, Germany
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Imada S, Tako Y. Seasonal accumulation of photoassimilated carbon relates to growth rate and use for new aboveground organs of young apple trees in following spring. TREE PHYSIOLOGY 2022; 42:2294-2305. [PMID: 35796531 PMCID: PMC9652006 DOI: 10.1093/treephys/tpac072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 06/11/2022] [Indexed: 06/15/2023]
Abstract
Deciduous trees accumulate carbon (C) in woody parts during the growth season which is subsequently used for the initial development and growth of newly formed organs in the following season; however, it is unclear which period during the growth season contributes to C accumulation. Three-year-old potted Malus domestica (apple) trees were grown in controlled growth chambers during the growth season and exposed to 13CO2 in an exposure chamber at seven different periods of the growth season, including vegetative and reproductive growth periods. Approximately half of the trees were harvested in late autumn, and the remaining trees were grown in a field in the following year. The 13C accumulation in the different organs in late autumn, and its concentration in the new aboveground growth during the following growth season, was determined. The concentration of the photoassimilated 13C in woody parts (shoots, trunk, rootstock and coarse roots) in the late autumn was higher in the trees labeled during the period of vigorous vegetative growth than in those labeled during other periods of growth. Furthermore, 13C concentration in the leaves, annual shoots, flower buds and flowers in the following early spring was also high in the trees labeled during this period. The concentration of 13C in the flower buds and flowers was positively correlated with that in the woody parts in the late autumn and old shoots in the following spring. Hence, the seasonal accumulation of photoassimilated C in woody parts in late autumn is related to growth rates during the growth season and its use for the initial development of newly formed organs in the following spring. These results suggest that under non-stressed conditions, C accumulated during the period of vigorous vegetative growth largely contributes to the C reserves that are used for the development of new organs in the following year.
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Affiliation(s)
| | - Yasuhiro Tako
- Department of Radioecology, Institute for Environmental Sciences, 1-7 Ienomae, Obuchi, Rokkasho, Kamikita, Aomori 039-3212, Japan
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3
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Freschet GT, Pagès L, Iversen CM, Comas LH, Rewald B, Roumet C, Klimešová J, Zadworny M, Poorter H, Postma JA, Adams TS, Bagniewska‐Zadworna A, Bengough AG, Blancaflor EB, Brunner I, Cornelissen JHC, Garnier E, Gessler A, Hobbie SE, Meier IC, Mommer L, Picon‐Cochard C, Rose L, Ryser P, Scherer‐Lorenzen M, Soudzilovskaia NA, Stokes A, Sun T, Valverde‐Barrantes OJ, Weemstra M, Weigelt A, Wurzburger N, York LM, Batterman SA, Gomes de Moraes M, Janeček Š, Lambers H, Salmon V, Tharayil N, McCormack ML. A starting guide to root ecology: strengthening ecological concepts and standardising root classification, sampling, processing and trait measurements. THE NEW PHYTOLOGIST 2021; 232:973-1122. [PMID: 34608637 PMCID: PMC8518129 DOI: 10.1111/nph.17572] [Citation(s) in RCA: 89] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 03/22/2021] [Indexed: 05/17/2023]
Abstract
In the context of a recent massive increase in research on plant root functions and their impact on the environment, root ecologists currently face many important challenges to keep on generating cutting-edge, meaningful and integrated knowledge. Consideration of the below-ground components in plant and ecosystem studies has been consistently called for in recent decades, but methodology is disparate and sometimes inappropriate. This handbook, based on the collective effort of a large team of experts, will improve trait comparisons across studies and integration of information across databases by providing standardised methods and controlled vocabularies. It is meant to be used not only as starting point by students and scientists who desire working on below-ground ecosystems, but also by experts for consolidating and broadening their views on multiple aspects of root ecology. Beyond the classical compilation of measurement protocols, we have synthesised recommendations from the literature to provide key background knowledge useful for: (1) defining below-ground plant entities and giving keys for their meaningful dissection, classification and naming beyond the classical fine-root vs coarse-root approach; (2) considering the specificity of root research to produce sound laboratory and field data; (3) describing typical, but overlooked steps for studying roots (e.g. root handling, cleaning and storage); and (4) gathering metadata necessary for the interpretation of results and their reuse. Most importantly, all root traits have been introduced with some degree of ecological context that will be a foundation for understanding their ecological meaning, their typical use and uncertainties, and some methodological and conceptual perspectives for future research. Considering all of this, we urge readers not to solely extract protocol recommendations for trait measurements from this work, but to take a moment to read and reflect on the extensive information contained in this broader guide to root ecology, including sections I-VII and the many introductions to each section and root trait description. Finally, it is critical to understand that a major aim of this guide is to help break down barriers between the many subdisciplines of root ecology and ecophysiology, broaden researchers' views on the multiple aspects of root study and create favourable conditions for the inception of comprehensive experiments on the role of roots in plant and ecosystem functioning.
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Affiliation(s)
- Grégoire T. Freschet
- CEFEUniv Montpellier, CNRS, EPHE, IRD1919 route de MendeMontpellier34293France
- Station d’Ecologie Théorique et ExpérimentaleCNRS2 route du CNRS09200MoulisFrance
| | - Loïc Pagès
- UR 1115 PSHCentre PACA, site AgroparcINRAE84914Avignon cedex 9France
| | - Colleen M. Iversen
- Environmental Sciences Division and Climate Change Science InstituteOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Louise H. Comas
- USDA‐ARS Water Management Research Unit2150 Centre Avenue, Bldg D, Suite 320Fort CollinsCO80526USA
| | - Boris Rewald
- Department of Forest and Soil SciencesUniversity of Natural Resources and Life SciencesVienna1190Austria
| | - Catherine Roumet
- CEFEUniv Montpellier, CNRS, EPHE, IRD1919 route de MendeMontpellier34293France
| | - Jitka Klimešová
- Department of Functional EcologyInstitute of Botany CASDukelska 13537901TrebonCzech Republic
| | - Marcin Zadworny
- Institute of DendrologyPolish Academy of SciencesParkowa 562‐035KórnikPoland
| | - Hendrik Poorter
- Plant Sciences (IBG‐2)Forschungszentrum Jülich GmbHD‐52425JülichGermany
- Department of Biological SciencesMacquarie UniversityNorth RydeNSW2109Australia
| | | | - Thomas S. Adams
- Department of Plant SciencesThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Agnieszka Bagniewska‐Zadworna
- Department of General BotanyInstitute of Experimental BiologyFaculty of BiologyAdam Mickiewicz UniversityUniwersytetu Poznańskiego 661-614PoznańPoland
| | - A. Glyn Bengough
- The James Hutton InstituteInvergowrie, Dundee,DD2 5DAUK
- School of Science and EngineeringUniversity of DundeeDundee,DD1 4HNUK
| | | | - Ivano Brunner
- Forest Soils and BiogeochemistrySwiss Federal Research Institute WSLZürcherstr. 1118903BirmensdorfSwitzerland
| | - Johannes H. C. Cornelissen
- Department of Ecological ScienceFaculty of ScienceVrije Universiteit AmsterdamDe Boelelaan 1085Amsterdam1081 HVthe Netherlands
| | - Eric Garnier
- CEFEUniv Montpellier, CNRS, EPHE, IRD1919 route de MendeMontpellier34293France
| | - Arthur Gessler
- Forest DynamicsSwiss Federal Research Institute WSLZürcherstr. 1118903BirmensdorfSwitzerland
- Institute of Terrestrial EcosystemsETH Zurich8092ZurichSwitzerland
| | - Sarah E. Hobbie
- Department of Ecology, Evolution and BehaviorUniversity of MinnesotaSt PaulMN55108USA
| | - Ina C. Meier
- Functional Forest EcologyUniversity of HamburgHaidkrugsweg 122885BarsbütelGermany
| | - Liesje Mommer
- Plant Ecology and Nature Conservation GroupDepartment of Environmental SciencesWageningen University and ResearchPO Box 476700 AAWageningenthe Netherlands
| | | | - Laura Rose
- Station d’Ecologie Théorique et ExpérimentaleCNRS2 route du CNRS09200MoulisFrance
- Senckenberg Biodiversity and Climate Research Centre (BiK-F)Senckenberganlage 2560325Frankfurt am MainGermany
| | - Peter Ryser
- Laurentian University935 Ramsey Lake RoadSudburyONP3E 2C6Canada
| | | | - Nadejda A. Soudzilovskaia
- Environmental Biology DepartmentInstitute of Environmental SciencesCMLLeiden UniversityLeiden2300 RAthe Netherlands
| | - Alexia Stokes
- INRAEAMAPCIRAD, IRDCNRSUniversity of MontpellierMontpellier34000France
| | - Tao Sun
- Institute of Applied EcologyChinese Academy of SciencesShenyang110016China
| | - Oscar J. Valverde‐Barrantes
- International Center for Tropical BotanyDepartment of Biological SciencesFlorida International UniversityMiamiFL33199USA
| | - Monique Weemstra
- CEFEUniv Montpellier, CNRS, EPHE, IRD1919 route de MendeMontpellier34293France
| | - Alexandra Weigelt
- Systematic Botany and Functional BiodiversityInstitute of BiologyLeipzig UniversityJohannisallee 21-23Leipzig04103Germany
| | - Nina Wurzburger
- Odum School of EcologyUniversity of Georgia140 E. Green StreetAthensGA30602USA
| | - Larry M. York
- Biosciences Division and Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Sarah A. Batterman
- School of Geography and Priestley International Centre for ClimateUniversity of LeedsLeedsLS2 9JTUK
- Cary Institute of Ecosystem StudiesMillbrookNY12545USA
| | - Moemy Gomes de Moraes
- Department of BotanyInstitute of Biological SciencesFederal University of Goiás1974690-900Goiânia, GoiásBrazil
| | - Štěpán Janeček
- School of Biological SciencesThe University of Western Australia35 Stirling HighwayCrawley (Perth)WA 6009Australia
| | - Hans Lambers
- School of Biological SciencesThe University of Western AustraliaCrawley (Perth)WAAustralia
| | - Verity Salmon
- Environmental Sciences Division and Climate Change Science InstituteOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Nishanth Tharayil
- Department of Plant and Environmental SciencesClemson UniversityClemsonSC29634USA
| | - M. Luke McCormack
- Center for Tree ScienceMorton Arboretum, 4100 Illinois Rt. 53LisleIL60532USA
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Schwieger S, Blume-Werry G, Ciesiolka F, Anadon-Rosell A. Root biomass and root traits of Alnus glutinosa show size-dependent and opposite patterns in a drained and a rewetted forest peatland. ANNALS OF BOTANY 2021; 127:337-346. [PMID: 33211793 PMCID: PMC7872119 DOI: 10.1093/aob/mcaa195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 11/13/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND AND AIMS Forest peatlands represent 25 % of global peatlands and store large amounts of carbon (C) as peat. Traditionally they have been drained in order to increase forestry yield, which may cause large losses of C from the peat. Rewetting aims to stop these losses and to restore the initial storage function of the peatlands. As roots represent major peat-forming elements in these systems, we sampled roots with diameter <5 mm in a drained and a rewetted forest peatland in north-east Germany to evaluate differences in tree biomass investments below ground, root functional characteristics and root age. METHODS We cored soil next to Alnus glutinosa stems and sorted root biomass into <1, 1-2 and 2-5 mm diameter classes. We measured biomass distribution and specific root area (SRA) in 10-cm depth increments down to 50 cm, and estimated root age from annual growth rings. KEY RESULTS Root biomass in the rewetted site was more than double that in the drained site. This difference was mostly driven by very fine roots <1 mm, which accounted for 51 % of the total root biomass and were mostly (75 %) located in the upper 20 cm. For roots <1 mm, SRA did not differ between the sites. However, SRA of the 1-2 mm and 2-5 mm diameter roots was higher in the drained than in the rewetted site. Root age did not differ between sites. CONCLUSIONS The size-dependent opposite patterns between root biomass and their functional characteristics under contrasting water regimes indicate differences between fine and coarse roots in their response to environmental changes. Root age distribution points to similar root turnover rates between the sites, while higher root biomass in the rewetted site clearly indicates larger tree C stocks below ground under rewetting, supporting the C sink function of the ecosystem.
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Affiliation(s)
- Sarah Schwieger
- Experimental Plant Ecology, Institute of Botany and Landscape Ecology, Greifswald University, Greifswald, Germany
| | - Gesche Blume-Werry
- Experimental Plant Ecology, Institute of Botany and Landscape Ecology, Greifswald University, Greifswald, Germany
| | - Felix Ciesiolka
- Experimental Plant Ecology, Institute of Botany and Landscape Ecology, Greifswald University, Greifswald, Germany
- Landscape Ecology and Ecosystem Dynamics, Institute of Botany and Landscape Ecology, Greifswald University, Greifswald, Germany
| | - Alba Anadon-Rosell
- Landscape Ecology and Ecosystem Dynamics, Institute of Botany and Landscape Ecology, Greifswald University, Greifswald, Germany
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Cordeiro AL, Norby RJ, Andersen KM, Valverde‐Barrantes O, Fuchslueger L, Oblitas E, Hartley IP, Iversen CM, Gonçalves NB, Takeshi B, Lapola DM, Quesada CA. Fine-root dynamics vary with soil depth and precipitation in a low-nutrient tropical forest in the Central Amazonia. PLANT-ENVIRONMENT INTERACTIONS (HOBOKEN, N.J.) 2020; 1:3-16. [PMID: 37284129 PMCID: PMC10168058 DOI: 10.1002/pei3.10010] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 12/30/2019] [Accepted: 01/16/2020] [Indexed: 06/08/2023]
Abstract
A common assumption in tropical ecology is that root systems respond rapidly to climatic cues but that most of that response is limited to the uppermost layer of the soil, with relatively limited changes in deeper layers. However, this assumption has not been tested directly, preventing models from accurately predicting the response of tropical forests to environmental change.We measured seasonal dynamics of fine roots in an upper-slope plateau in Central Amazonia mature forest using minirhizotrons to 90 cm depth, which were calibrated with fine roots extracted from soil cores.Root productivity and mortality in surface soil layers were positively correlated with precipitation, whereas root standing length was greater during the dry periods at the deeper layers. Contrary to historical assumptions, a large fraction of fine-root standing biomass (46%) and productivity (41%) was found in soil layers deeper than 30 cm. Furthermore, root turnover decreased linearly with soil depth.Our findings demonstrate a relationship between fine-root dynamics and precipitation regimes in Central Amazonia. Our results also emphasize the importance of deeper roots for accurate estimates of primary productivity and the interaction between roots and carbon, water, and nutrients.
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Affiliation(s)
- Amanda L. Cordeiro
- Instituto Nacional de Pesquisas da Amazônia – INPAManausBrazil
- Colorado State University – CSUFort CollinsCOUSA
| | | | | | - Oscar Valverde‐Barrantes
- Instituto Nacional de Pesquisas da Amazônia – INPAManausBrazil
- Florida International University –MiamiMiamiFLUSA
| | - Lucia Fuchslueger
- Instituto Nacional de Pesquisas da Amazônia – INPAManausBrazil
- University of AntwerpAntwerpBelgium
| | - Erick Oblitas
- Instituto Nacional de Pesquisas da Amazônia – INPAManausBrazil
| | - Iain P. Hartley
- GeographyCollege of Life and Environmental SciencesUniversity of ExeterExeterUK
| | | | - Nathan B. Gonçalves
- Instituto Nacional de Pesquisas da Amazônia – INPAManausBrazil
- Michigan State University – MSUEast LansingMIUSA
| | - Bruno Takeshi
- Instituto Nacional de Pesquisas da Amazônia – INPAManausBrazil
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6
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Small-Scale Forest Structure Influences Spatial Variability of Belowground Carbon Fluxes in a Mature Mediterranean Beech Forest. FORESTS 2020. [DOI: 10.3390/f11030255] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [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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D'Andrea E, Rezaie N, Battistelli A, Gavrichkova O, Kuhlmann I, Matteucci G, Moscatello S, Proietti S, Scartazza A, Trumbore S, Muhr J. Winter's bite: beech trees survive complete defoliation due to spring late-frost damage by mobilizing old C reserves. THE NEW PHYTOLOGIST 2019; 224:625-631. [PMID: 31282591 DOI: 10.1111/nph.16047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 06/30/2019] [Indexed: 05/12/2023]
Abstract
Late frost can destroy the photosynthetic apparatus of trees. We hypothesized that this can alter the normal cyclic dynamics of C-reserves in the wood. We measured soluble sugar concentrations and radiocarbon signatures (Δ14 C) of soluble nonstructural carbon (NSC) in woody tissues sampled from a Mediterranean beech forest that was completely defoliated by an exceptional late frost in 2016. We used the bomb radiocarbon approach to estimate the time elapsed since fixation of mobilized soluble sugars. During the leafless period after the frost event, soluble sugar concentrations declined sharply while Δ14 C of NSC increased. This can be explained by the lack of fresh assimilate supply and a mobilization of C from reserve pools. Soluble NSC became increasingly older during the leafless period, with a maximum average age of 5 yr from samples collected 27 d before canopy recovery. Following leaf re-growth, soluble sugar concentrations increased and Δ14 C of soluble NSC decreased, indicating the allocation of new assimilates to the stem soluble sugars pool. These data highlight that beech trees rapidly mobilize reserve C to survive strong source-sink imbalances, for example due to late frost, and show that NSC is a key trait for tree resilience under global change.
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Affiliation(s)
| | - Negar Rezaie
- CNR-ISAFOM, via Patacca 2, 80056, Ercolano, Italy
| | | | - Olga Gavrichkova
- CNR-IRET, via Marconi 2, 05010, Porano, Italy
- Agro-Technology Institute, Peoples Friendship University of Russia, 117198, Moscow, Russia
| | - Iris Kuhlmann
- Max-Planck-Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745, Jena, Germany
| | | | | | | | | | - Susan Trumbore
- Max-Planck-Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745, Jena, Germany
| | - Jan Muhr
- Max-Planck-Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745, Jena, Germany
- Bioclimatology, University of Göttingen, Büsgenweg 2, 37077, Göttingen, Germany
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Huo C, Cheng W. Improved root turnover assessment using field scanning rhizotrons with branch order analysis. Ecosphere 2019. [DOI: 10.1002/ecs2.2793] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Changfu Huo
- Institute of Applied Ecology Chinese Academy of Sciences Shenyang 110016 China
| | - Weixin Cheng
- Department of Environmental Studies University of California Santa Cruz California 95064 USA
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He L, Jia Z, Li Q, Feng L, Yang K. Fine-root decomposition characteristics of four typical shrubs in sandy areas of an arid and semiarid alpine region in western China. Ecol Evol 2019; 9:5407-5419. [PMID: 31110689 PMCID: PMC6509441 DOI: 10.1002/ece3.5133] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 12/26/2018] [Accepted: 03/07/2019] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND AND AIMS Research into the variability of fine-root decomposition and nutrient cycling processes in arid and semiarid ecosystems is highly significant not only for investigations of regional and global carbon and nitrogen cycling but also for offering a theoretical basis for vegetation restoration and reconstruction. In particular, information is limited on fine-root decomposition processes and nutrient releasing characteristics in the high-altitude Qinghai Gonghe basin, which has different tree species and variable fine-root diameters. MATERIALS AND METHODS Four types of Salicaceae and Caragana shrubs were selected at the Qinghai Gonghe desert ecosystem research station. The litterbag method was adopted to measure decomposition rates of fine-roots with three diameter classes (1-2 mm, 0.5-1 mm, and 0-0.5 mm). Chemical analysis was performed to determine nutrient (C, N, P, and K) concentrations of fine-root, and nutrient release rates were compared among fine-roots with different diameters during different decomposition periods. The differences in mass residual ratio and nutrient release rate among different diameter classes were studied with one-way ANOVA. RESULTS Fine-root decomposition rates were in the order Caragana intermedia > Caragana korshinskii > Salix psammophila > Salix cheilophila. Fine-root decomposition showed a trend of "fast-slow-fast" variation, and decomposition rate increased as the diameter of fine-roots increased, irrespective of tree species. During the decomposition process, the nutrients C, N, and P of fine-root were in a release state for the four shrubs with different fine-root diameters, and the corresponding release rates of Caragana shrubs were higher than those of Salicaceae shrubs. Release rates of nutrients C and N accelerated as fine-root diameter increased, whereas release rates of nutrients P and K had no observed relation with fine-root diameter. Fine-root decomposition ratio was significantly correlated with initial values of N, P, C/N, C/P, and N/P of fine-root. Fine-root mass loss ratio was significantly correlated with initial concentration of soil nutrient K, and the correlation was positive for fine-roots with diameters of 0-0.5 mm and 0.5-1 mm; however, no other significant correlation was observed between fine-root mass loss ratio and initial soil environmental factors within this study. CONCLUSIONS Our study showed that tree species and fine-root diameter strongly affected decomposition rates, whereas diameter class exerted little effect on nutrient release rates.
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Affiliation(s)
- Ling‐Xianzi He
- Institute of Desertification StudiesChinese Academy of ForestryBeijingChina
- Gonghe Desert Ecosystem Research StationQinghaiChina
| | - Zhi‐Qing Jia
- Institute of Desertification StudiesChinese Academy of ForestryBeijingChina
- Gonghe Desert Ecosystem Research StationQinghaiChina
| | - Qing‐Xue Li
- Institute of Desertification StudiesChinese Academy of ForestryBeijingChina
- Gonghe Desert Ecosystem Research StationQinghaiChina
| | - Li‐Li Feng
- Institute of Desertification StudiesChinese Academy of ForestryBeijingChina
| | - Kai‐Yue Yang
- Institute of Desertification StudiesChinese Academy of ForestryBeijingChina
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10
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The Case for Digging Deeper: Soil Organic Carbon Storage, Dynamics, and Controls in Our Changing World. SOIL SYSTEMS 2019. [DOI: 10.3390/soilsystems3020028] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Most of our terrestrial carbon (C) storage occurs in soils as organic C derived from living organisms. Therefore, the fate of soil organic C (SOC) in response to changes in climate, land use, and management is of great concern. Here we provide a unified conceptual model for SOC cycling by gathering the available information on SOC sources, dissolved organic C (DOC) dynamics, and soil biogeochemical processes. The evidence suggests that belowground C inputs (from roots and microorganisms) are the dominant source of both SOC and DOC in most ecosystems. Considering our emerging understanding of SOC protection mechanisms and long-term storage, we highlight the present need to sample (often ignored) deeper soil layers. Contrary to long-held biases, deep SOC—which contains most of the global amount and is often hundreds to thousands of years old—is susceptible to decomposition on decadal timescales when the environmental conditions under which it accumulated change. Finally, we discuss the vulnerability of SOC in different soil types and ecosystems globally, as well as identify the need for methodological standardization of SOC quality and quantity analyses. Further study of SOC protection mechanisms and the deep soil biogeochemical environment will provide valuable information about controls on SOC cycling, which in turn may help prioritize C sequestration initiatives and provide key insights into climate-carbon feedbacks.
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11
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Muhr J, Trumbore S, Higuchi N, Kunert N. Living on borrowed time - Amazonian trees use decade-old storage carbon to survive for months after complete stem girdling. THE NEW PHYTOLOGIST 2018; 220:111-120. [PMID: 30067298 PMCID: PMC6175381 DOI: 10.1111/nph.15302] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 05/11/2018] [Indexed: 05/26/2023]
Abstract
Nonstructural carbon (NSC) reserves act as buffers to sustain tree activity during periods when carbon (C) assimilation does not meet C demand, but little is known about their age and accessibility; we designed a controlled girdling experiment in the Amazon to study tree survival on NSC reserves. We used bomb-radiocarbon (14 C) to monitor the time elapsed between C fixation and release ('age' of substrates). We simultaneously monitored how the mobilization of reserve C affected δ13 CO2 . Six ungirdled control trees relied almost exclusively on recent assimilates throughout the 17 months of measurement. The Δ14 C of CO2 emitted from the six girdled stems increased significantly over time after girdling, indicating substantial remobilization of storage NSC fixed up to 13-14 yr previously. This remobilization was not accompanied by a consistent change in observed δ13 CO2 . These trees have access to storage pools integrating C accumulated over more than a decade. Remobilization follows a very clear reverse chronological mobilization with younger reserve pools being mobilized first. The lack of a shift in the δ13 CO2 might indicate a constant contribution of starch hydrolysis to the soluble sugar pool even outside pronounced stress periods (regular mixing).
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Affiliation(s)
- Jan Muhr
- Max‐Planck‐Institute for BiogeochemistryHans‐Knöll‐Str. 10Jena07745Germany
| | - Susan Trumbore
- Max‐Planck‐Institute for BiogeochemistryHans‐Knöll‐Str. 10Jena07745Germany
- Earth System ScienceUniversity of California IrvineIrvineCA92697‐3100USA
| | - Niro Higuchi
- Laboratory of Forest ManagementBrazilian National Institute for Research in the AmazonManausBrazil
| | - Norbert Kunert
- Max‐Planck‐Institute for BiogeochemistryHans‐Knöll‐Str. 10Jena07745Germany
- Conservation Ecology CenterSmithsonian Conservation Biology Institute1500 Remount Rd. MRC 5535Front RoyalVA22630USA
- Center for Tropical Forest Science‐Forest Global Earth ObservatorySmithsonian Tropical Research InstitutePanama CityPanama
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12
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Solly EF, Brunner I, Helmisaari HS, Herzog C, Leppälammi-Kujansuu J, Schöning I, Schrumpf M, Schweingruber FH, Trumbore SE, Hagedorn F. Unravelling the age of fine roots of temperate and boreal forests. Nat Commun 2018; 9:3006. [PMID: 30068916 PMCID: PMC6070616 DOI: 10.1038/s41467-018-05460-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Accepted: 07/04/2018] [Indexed: 11/30/2022] Open
Abstract
Fine roots support the water and nutrient demands of plants and supply carbon to soils. Quantifying turnover times of fine roots is crucial for modeling soil organic matter dynamics and constraining carbon cycle-climate feedbacks. Here we challenge widely used isotope-based estimates suggesting the turnover of fine roots of trees to be as slow as a decade. By recording annual growth rings of roots from woody plant species, we show that mean chronological ages of fine roots vary from <1 to 12 years in temperate, boreal and sub-arctic forests. Radiocarbon dating reveals the same roots to be constructed from 10 ± 1 year (mean ± 1 SE) older carbon. This dramatic difference provides evidence for a time lag between plant carbon assimilation and production of fine roots, most likely due to internal carbon storage. The high root turnover documented here implies greater carbon inputs into soils than previously thought which has wide-ranging implications for quantifying ecosystem carbon allocation.
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Affiliation(s)
- Emily F Solly
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903, Birmensdorf, Switzerland.
- Department of Geography, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
| | - Ivano Brunner
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903, Birmensdorf, Switzerland
| | - Heljä-Sisko Helmisaari
- Department of Forest Sciences, University of Helsinki, P.O. Box 27, 00014, Helsinki, Finland
| | - Claude Herzog
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903, Birmensdorf, Switzerland
| | | | - Ingo Schöning
- Max Planck Institute for Biogeochemistry, Hans Knöll Strasse 10, 07745, Jena, Germany
| | - Marion Schrumpf
- Max Planck Institute for Biogeochemistry, Hans Knöll Strasse 10, 07745, Jena, Germany
| | - Fritz H Schweingruber
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903, Birmensdorf, Switzerland
| | - Susan E Trumbore
- Max Planck Institute for Biogeochemistry, Hans Knöll Strasse 10, 07745, Jena, Germany
| | - Frank Hagedorn
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903, Birmensdorf, Switzerland
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13
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Xia J, Yuan W, Wang YP, Zhang Q. Adaptive Carbon Allocation by Plants Enhances the Terrestrial Carbon Sink. Sci Rep 2017; 7:3341. [PMID: 28611453 PMCID: PMC5469799 DOI: 10.1038/s41598-017-03574-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 04/28/2017] [Indexed: 11/10/2022] Open
Abstract
Carbon allocation is one of the most important physiological processes to optimize the plant growth, which exerts a strong influence on ecosystem structure and function, with potentially large implications for the global carbon budget. However, it remains unclear how the carbon allocation pattern has changed at global scale and impacted terrestrial carbon uptake. Based on the Community Atmosphere Biosphere Land Exchange (CABLE) model, this study shows the increasing partitioning ratios to leaf and wood and reducing ratio to root globally from 1979 to 2014. The results imply the plant optimizes carbon allocation and reaches its maximum growth by allocating more newly acquired photosynthate to leaves and wood tissues. Thus, terrestrial vegetation has absorbed 16% more carbon averagely between 1979 and 2014 through adjusting their carbon allocation process. Compared with the fixed carbon allocation simulation, the trend of terrestrial carbon sink from 1979 to 2014 increased by 34% in the adaptive carbon allocation simulation. Our study highlights carbon allocation, associated with climate change, needs to be mapped and incorporated into terrestrial carbon cycle estimates.
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Affiliation(s)
- Jiangzhou Xia
- Faculty of Geographical Science, State Key Laboratory of Earth Surface Processes and Resource Ecology, Zhuhai Joint Innovative Center for Climate-Environment-Ecosystem and Key Laboratory of Urban Climate and Ecodynamics, Future Earth Research Institute, Beijing Normal University, Beijing, 100875/Zhuhai, 519087, China
| | - Wenping Yuan
- Faculty of Geographical Science, State Key Laboratory of Earth Surface Processes and Resource Ecology, Zhuhai Joint Innovative Center for Climate-Environment-Ecosystem and Key Laboratory of Urban Climate and Ecodynamics, Future Earth Research Institute, Beijing Normal University, Beijing, 100875/Zhuhai, 519087, China.
- School of Atmospheric Sciences, Sun Yat-Sen University, Guangzhou, 519082, Guangdong, China.
| | - Ying-Ping Wang
- Commonwealth Scientific and Industrial Research Organization, Oceans and Atmosphere, Private Bag 1, Aspendale, Victoria, 3195, Australia
| | - Quanguo Zhang
- Faculty of Geographical Science, State Key Laboratory of Earth Surface Processes and Resource Ecology, Zhuhai Joint Innovative Center for Climate-Environment-Ecosystem and Key Laboratory of Urban Climate and Ecodynamics, Future Earth Research Institute, Beijing Normal University, Beijing, 100875/Zhuhai, 519087, China
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14
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Bernal B, Megonigal JP, Mozdzer TJ. An invasive wetland grass primes deep soil carbon pools. GLOBAL CHANGE BIOLOGY 2017; 23:2104-2116. [PMID: 27779794 DOI: 10.1111/gcb.13539] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 09/21/2016] [Indexed: 05/25/2023]
Abstract
Understanding the processes that control deep soil carbon (C) dynamics and accumulation is of key importance, given the relevance of soil organic matter (SOM) as a vast C pool and climate change buffer. Methodological constraints of measuring SOM decomposition in the field prevent the addressing of real-time rhizosphere effects that regulate nutrient cycling and SOM decomposition. An invasive lineage of Phragmites australis roots deeper than native vegetation (Schoenoplectus americanus and Spartina patens) in coastal marshes of North America and has potential to dramatically alter C cycling and accumulation in these ecosystems. To evaluate the effect of deep rooting on SOM decomposition we designed a mesocosm experiment that differentiates between plant-derived, surface SOM-derived (0-40 cm, active root zone of native marsh vegetation), and deep SOM-derived mineralization (40-80 cm, below active root zone of native vegetation). We found invasive P. australis allocated the highest proportion of roots in deeper soils, differing significantly from the native vegetation in root : shoot ratio and belowground biomass allocation. About half of the CO2 produced came from plant tissue mineralization in invasive and native communities; the rest of the CO2 was produced from SOM mineralization (priming). Under P. australis, 35% of the CO2 was produced from deep SOM priming and 9% from surface SOM. In the native community, 9% was produced from deep SOM priming and 44% from surface SOM. SOM priming in the native community was proportional to belowground biomass, while P. australis showed much higher priming with less belowground biomass. If P. australis deep rooting favors the decomposition of deep-buried SOM accumulated under native vegetation, P. australis invasion into a wetland could fundamentally change SOM dynamics and lead to the loss of the C pool that was previously sequestered at depth under the native vegetation, thereby altering the function of a wetland as a long-term C sink.
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Affiliation(s)
- Blanca Bernal
- Smithsonian Environmental Research Center, 647 Contees Wharf Rd, Edgewater, MD, 21037, USA
| | - J Patrick Megonigal
- Smithsonian Environmental Research Center, 647 Contees Wharf Rd, Edgewater, MD, 21037, USA
| | - Thomas J Mozdzer
- Department of Biology, Bryn Mawr College, 101 N Merion Ave, Bryn Mawr, PA, 19010, USA
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15
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Urrutia‐Jalabert R, Malhi Y, Lara A. Soil respiration and mass balance estimation of fine root production in
Fitzroya cupressoides
forests of southern Chile. Ecosphere 2017. [DOI: 10.1002/ecs2.1640] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Rocio Urrutia‐Jalabert
- Laboratorio de Dendrocronología y Cambio Global Facultad de Ciencias Forestales y Recursos Naturales Instituto de Conservacion, Biodiversidad y Territorio Universidad Austral de Chile Independencia 641 Valdivia Chile
- Center for Climate and Resilience Research (CR)2 Blanco Encalada 2002 Santiago Chile
| | - Yadvinder Malhi
- School of Geography and the Environment Environmental Change Institute University of Oxford Oxford OX1 3QY UK
| | - Antonio Lara
- Laboratorio de Dendrocronología y Cambio Global Facultad de Ciencias Forestales y Recursos Naturales Instituto de Conservacion, Biodiversidad y Territorio Universidad Austral de Chile Independencia 641 Valdivia Chile
- Center for Climate and Resilience Research (CR)2 Blanco Encalada 2002 Santiago Chile
- Fundación Centro de los Bosques Nativos FORECOS Los Robles 510 interior Valdivia Chile
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16
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Hobbie EA, Rice SF, Weber NS, Smith JE. Isotopic evidence indicates saprotrophy in post-fire Morchella in Oregon and Alaska. Mycologia 2017; 108:638-45. [DOI: 10.3852/15-281] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 02/10/2016] [Indexed: 11/10/2022]
Affiliation(s)
| | - Samuel F. Rice
- Earth Systems Research Center, University of New Hampshire, Durham, New Hampshire 03824
| | - Nancy S. Weber
- Department of Forest Ecosystems and Society, Oregon State University, 2160 NW Beechwood Place, Corvallis, Oregon 97330
| | - Jane E. Smith
- US Department of Agriculture, Forest Service, Pacific Northwest Research Station, Forestry Sciences Laboratory, 3200 SW Jefferson Way, Corvallis, Oregon 97331
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17
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Schnecker J, Borken W, Schindlbacher A, Wanek W. Little effects on soil organic matter chemistry of density fractions after seven years of forest soil warming. SOIL BIOLOGY & BIOCHEMISTRY 2016; 103:300-307. [PMID: 28042178 PMCID: PMC5198888 DOI: 10.1016/j.soilbio.2016.09.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Rising temperatures enhance microbial decomposition of soil organic matter (SOM) and thereby increase the soil CO2 efflux. Elevated decomposition rates might differently affect distinct SOM pools, depending on their stability and accessibility. Soil fractions derived from density fractionation have been suggested to represent SOM pools with different turnover times and stability against microbial decomposition. To investigate the effect of soil warming on functionally different soil organic matter pools, we here investigated the chemical and isotopic composition of bulk soil and three density fractions (free particulate organic matter, fPOM; occluded particulate organic matter, oPOM; and mineral associated organic matter, MaOM) of a C-rich soil from a long-term warming experiment in a spruce forest in the Austrian Alps. At the time of sampling, the soil in this experiment had been warmed during the snow-free period for seven consecutive years. During that time no thermal adaptation of the microbial community could be identified and CO2 release from the soil continued to be elevated by the warming treatment. Our results, which included organic carbon content, total nitrogen content, δ13C, Δ14C, δ15N and the chemical composition, identified by pyrolysis-GC/MS, showed no significant differences in bulk soil between warming treatment and control. Surprisingly, the differences in the three density fractions were mostly small and the direction of warming induced change was variable with fraction and soil depth. Warming led to reduced N content in topsoil oPOM and subsoil fPOM and to reduced relative abundance of N-bearing compounds in subsoil MaOM. Further, warming increased the δ13C of MaOM at both sampling depths, reduced the relative abundance of carbohydrates while it increased the relative abundance of lignins in subsoil oPOM. As the size of the functionally different SOM pools did not significantly change, we assume that the few and small modifications in SOM chemistry result from an interplay of enhanced microbial decomposition of SOM and increased root litter input in the warmed plots. Overall, stable functional SOM pool sizes indicate that soil warming had similarly affected easily decomposable and stabilized SOM of this C-rich forest soil.
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Affiliation(s)
- Jörg Schnecker
- Department of Natural Resources and the Environment, University of
New Hampshire, Durham, NH, USA
- Department of Microbiology and Ecosystem Science, University of
Vienna, Vienna, Austria
| | - Werner Borken
- Department of Soil Ecology, University of Bayreuth, Bayreuth,
Germany
| | - Andreas Schindlbacher
- Department of Forest Ecology, Federal Research and Training Centre
for Forests, Natural Hazards and Landscape – BFW, Vienna, Austria
| | - Wolfgang Wanek
- Department of Microbiology and Ecosystem Science, University of
Vienna, Vienna, Austria
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18
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Weemstra M, Mommer L, Visser EJW, van Ruijven J, Kuyper TW, Mohren GMJ, Sterck FJ. Towards a multidimensional root trait framework: a tree root review. THE NEW PHYTOLOGIST 2016; 211:1159-69. [PMID: 27174359 DOI: 10.1111/nph.14003] [Citation(s) in RCA: 218] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 04/06/2016] [Indexed: 05/03/2023]
Abstract
Contents 1159 I. 1159 II. 1161 III. 1164 IV. 1166 1167 References 1167 SUMMARY: The search for a root economics spectrum (RES) has been sparked by recent interest in trait-based plant ecology. By analogy with the one-dimensional leaf economics spectrum (LES), fine-root traits are hypothesised to match leaf traits which are coordinated along one axis from resource acquisitive to conservative traits. However, our literature review and meta-level analysis reveal no consistent evidence of an RES mirroring an LES. Instead the RES appears to be multidimensional. We discuss three fundamental differences contributing to the discrepancy between these spectra. First, root traits are simultaneously constrained by various environmental drivers not necessarily related to resource uptake. Second, above- and belowground traits cannot be considered analogues, because they function differently and might not be related to resource uptake in a similar manner. Third, mycorrhizal interactions may offset selection for an RES. Understanding and explaining the belowground mechanisms and trade-offs that drive variation in root traits, resource acquisition and plant performance across species, thus requires a fundamentally different approach than applied aboveground. We therefore call for studies that can functionally incorporate the root traits involved in resource uptake, the complex soil environment and the various soil resource uptake mechanisms - particularly the mycorrhizal pathway - in a multidimensional root trait framework.
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Affiliation(s)
- Monique Weemstra
- Forest Ecology and Forest Management group, Wageningen University, 6700 AA, Wageningen, the Netherlands
- Plant Ecology and Nature Conservation group, Wageningen University, 6700 AA, Wageningen, the Netherlands
| | - Liesje Mommer
- Plant Ecology and Nature Conservation group, Wageningen University, 6700 AA, Wageningen, the Netherlands
| | - Eric J W Visser
- Department of Experimental Plant Ecology, Institute for Water and Wetland Research, Radboud University Nijmegen, 6500 GL, Nijmegen, the Netherlands
| | - Jasper van Ruijven
- Plant Ecology and Nature Conservation group, Wageningen University, 6700 AA, Wageningen, the Netherlands
| | - Thomas W Kuyper
- Department of Soil Quality, Wageningen University, 6700 AA, Wageningen, the Netherlands
| | - Godefridus M J Mohren
- Forest Ecology and Forest Management group, Wageningen University, 6700 AA, Wageningen, the Netherlands
| | - Frank J Sterck
- Forest Ecology and Forest Management group, Wageningen University, 6700 AA, Wageningen, the Netherlands
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19
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Angst G, John S, Mueller CW, Kögel-Knabner I, Rethemeyer J. Tracing the sources and spatial distribution of organic carbon in subsoils using a multi-biomarker approach. Sci Rep 2016; 6:29478. [PMID: 27380728 PMCID: PMC4933938 DOI: 10.1038/srep29478] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 06/20/2016] [Indexed: 11/15/2022] Open
Abstract
Soil organic carbon (SOC) from aboveground and belowground sources has rarely been differentiated although it may drive SOC turnover and stabilization due to a presumed differing source dependent degradability. It is thus crucial to better identify the location of SOC from different sources for the parameterization of SOC models, especially in the less investigated subsoils. The aim of this study was to spatially assess contributions of organic carbon from aboveground and belowground parts of beech trees to subsoil organic carbon in a Dystric Cambisol. Different sources of SOC were distinguished by solvent-extractable and hydrolysable lipid biomarkers aided by (14)C analyses of soil compartments <63 μm. We found no effect of the distance to the trees on the investigated parameters. Instead, a vertical zonation of the subsoil was detected. A high contribution of fresh leaf- and root-derived organic carbon to the upper subsoil (leaf- and root-affected zone) indicate that supposedly fast-cycling, leaf-derived SOC may still be of considerable importance below the A-horizon. In the deeper subsoil (root-affected zone), roots were an important source of fresh SOC. Simultaneously, strongly increasing apparent (14)C ages (3860 yrs BP) indicate considerable contribution of SOC that may be inherited from the Pleistocene parent material.
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Affiliation(s)
- Gerrit Angst
- Chair of Soil Science, Technical University of Munich, Emil-Ramann-Straße 2, D-85354 Freising, Germany
| | - Stephan John
- Institute for Geology and Mineralogy, University of Cologne, Zülpicher Straße 49a, D-50674 Cologne, Germany
| | - Carsten W. Mueller
- Chair of Soil Science, Technical University of Munich, Emil-Ramann-Straße 2, D-85354 Freising, Germany
| | - Ingrid Kögel-Knabner
- Chair of Soil Science, Technical University of Munich, Emil-Ramann-Straße 2, D-85354 Freising, Germany
- Institute for Advanced Study, Technical University of Munich, Lichtenbergstraße 2a, D-85748 Garching, Germany
| | - Janet Rethemeyer
- Institute for Geology and Mineralogy, University of Cologne, Zülpicher Straße 49a, D-50674 Cologne, Germany
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20
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21
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Muhr J, Messier C, Delagrange S, Trumbore S, Xu X, Hartmann H. How fresh is maple syrup? Sugar maple trees mobilize carbon stored several years previously during early springtime sap-ascent. THE NEW PHYTOLOGIST 2016; 209:1410-1416. [PMID: 26639654 DOI: 10.1111/nph.13782] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 11/02/2015] [Indexed: 06/05/2023]
Abstract
While trees store substantial amounts of nonstructural carbon (NSC) for later use, storage regulation and mobilization of stored NSC in long-lived organisms like trees are still not well understood. At two different sites with sugar maple (Acer saccharum), we investigated ascending sap (sugar concentration, δ(13) C, Δ(14) C) as the mobilized component of stored stem NSC during early springtime. Using the bomb-spike radiocarbon approach we were able to estimate the average time elapsed since the mobilized carbon (C) was originally fixed from the atmosphere and to infer the turnover time of stem storage. Sites differed in concentration dynamics and overall δ(13) C, indicating different growing conditions. The absence of temporal trends for δ(13) C and Δ(14) C indicated sugar mobilization from a well-mixed pool with average Δ(14) C consistent with a mean turnover time (TT) of three to five years for this pool, with only minor differences between the sites. Sugar maple trees hence appear well buffered against single or even several years of negative plant C balance from environmental stress such as drought or repeated defoliation by insects. Manipulative investigations (e.g. starvation via girdling) combined with Δ(14) C measurements of this mobilized storage pool will provide further new insights into tree storage regulation and functioning.
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Affiliation(s)
- Jan Muhr
- Max-Planck-Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745, Jena, Germany
| | - Christian Messier
- Institut des Sciences de la Forêt Tempéré (ISFORT), Université du Québec en Outaouais (UQO), 58 Rue Principale, Ripon, QC, JOV 1V0, Canada
- Center for Forest Research (CEF), Université du Québec à Montréal, PO Box 8888, Centre-ville Station, Montréal, QC, H3C 3P8, Canada
| | - Sylvain Delagrange
- Center for Forest Research (CEF), Université du Québec à Montréal, PO Box 8888, Centre-ville Station, Montréal, QC, H3C 3P8, Canada
| | - Susan Trumbore
- Max-Planck-Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745, Jena, Germany
- Department of Earth System Science, University of California, Irvine, CA, 92697-3100, USA
| | - Xiaomei Xu
- Department of Earth System Science, University of California, Irvine, CA, 92697-3100, USA
| | - Henrik Hartmann
- Max-Planck-Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745, Jena, Germany
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22
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Yizhao C, Jianyang X, Zhengguo S, Jianlong L, Yiqi L, Chengcheng G, Zhaoqi W. The role of residence time in diagnostic models of global carbon storage capacity: model decomposition based on a traceable scheme. Sci Rep 2015; 5:16155. [PMID: 26541245 PMCID: PMC4635433 DOI: 10.1038/srep16155] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 09/30/2015] [Indexed: 11/09/2022] Open
Abstract
As a key factor that determines carbon storage capacity, residence time (τE) is not well constrained in terrestrial biosphere models. This factor is recognized as an important source of model uncertainty. In this study, to understand how τE influences terrestrial carbon storage prediction in diagnostic models, we introduced a model decomposition scheme in the Boreal Ecosystem Productivity Simulator (BEPS) and then compared it with a prognostic model. The result showed that τE ranged from 32.7 to 158.2 years. The baseline residence time (τ′E) was stable for each biome, ranging from 12 to 53.7 years for forest biomes and 4.2 to 5.3 years for non-forest biomes. The spatiotemporal variations in τE were mainly determined by the environmental scalar (ξ). By comparing models, we found that the BEPS uses a more detailed pool construction but rougher parameterization for carbon allocation and decomposition. With respect to ξ comparison, the global difference in the temperature scalar (ξt) averaged 0.045, whereas the moisture scalar (ξw) had a much larger variation, with an average of 0.312. We propose that further evaluations and improvements in τ′E and ξw predictions are essential to reduce the uncertainties in predicting carbon storage by the BEPS and similar diagnostic models.
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Affiliation(s)
- Chen Yizhao
- School of Life Science, Nanjing University, Nanjing, P.R. China
| | - Xia Jianyang
- Department of Microbiology and Plant Biology, University of Oklahoma, OK, USA.,School of Ecological and Environmental Sciences, East China Normal University, Shanghai, P.R. China.,Tiantong National Forest Ecosystem Observation and Research Station,School of Ecological and Environmental Sciences, East China Normal University, Shanghai, P.R. China
| | - Sun Zhengguo
- School of Life Science, Nanjing University, Nanjing, P.R. China.,College of Prataculture Science, Nanjing Agriculture University, Nanjing, P.R. China
| | - Li Jianlong
- School of Life Science, Nanjing University, Nanjing, P.R. China
| | - Luo Yiqi
- Department of Microbiology and Plant Biology, University of Oklahoma, OK, USA
| | - Gang Chengcheng
- School of Life Science, Nanjing University, Nanjing, P.R. China.,Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi, China.,Institute of Soil and Water Conservation, Chinese Academy of Science and Ministry of Water Resources, Yangling, Shaanxi, China
| | - Wang Zhaoqi
- School of Life Science, Nanjing University, Nanjing, P.R. China
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23
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Trumbore S, Czimczik CI, Sierra CA, Muhr J, Xu X. Non-structural carbon dynamics and allocation relate to growth rate and leaf habit in California oaks. TREE PHYSIOLOGY 2015; 35:1206-1222. [PMID: 26452766 DOI: 10.1093/treephys/tpv097] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Accepted: 08/17/2015] [Indexed: 06/05/2023]
Abstract
Trees contain non-structural carbon (NSC), but it is unclear for how long these reserves are stored and to what degree they are used to support plant activity. We used radiocarbon ((14)C) to show that the carbon (C) in stemwood NSC can achieve ages of several decades in California oaks. We separated NSC into two fractions: soluble (∼50% sugars) and insoluble (mostly starch) NSC. Soluble NSC contained more C than insoluble NSC, but we found no consistent trend in the amount of either pool with depth in the stem. There was no systematic difference in C age between the two fractions, although ages increased with stem depth. The C in both NSC fractions was consistently younger than the structural C from which they were extracted. Together, these results indicate considerable inward mixing of NSC within the stem and rapid exchange between soluble and insoluble pools, compared with the timescale of inward mixing. We observed similar patterns in sympatric evergreen and deciduous oaks and the largest differences among tree stems with different growth rates. The (14)C signature of carbon dioxide (CO2) emitted from tree stems was higher than expected from very recent photoassimilates, indicating that the mean age of C in respiration substrates included a contribution from C fixed years previously. A simple model that tracks NSC produced each year, followed by loss (through conversion to CO2) in subsequent years, matches our observations of inward mixing of NSC in the stem and higher (14)C signature of stem CO2 efflux. Together, these data support the idea of continuous accumulation of NSC in stemwood and that 'vigor' (growth rate) and leaf habit (deciduous vs evergreen) control NSC pool size and allocation.
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Affiliation(s)
- Susan Trumbore
- Department of Earth System Science, University of California, Irvine, Irvine, CA 92697-3100, USA Department of Biogeochemical Processes, Max-Planck-Institute for Biogeochemistry, 07701 Jena, Germany
| | - Claudia I Czimczik
- Department of Earth System Science, University of California, Irvine, Irvine, CA 92697-3100, USA
| | - Carlos A Sierra
- Department of Biogeochemical Processes, Max-Planck-Institute for Biogeochemistry, 07701 Jena, Germany
| | - Jan Muhr
- Department of Biogeochemical Processes, Max-Planck-Institute for Biogeochemistry, 07701 Jena, Germany
| | - Xiaomei Xu
- Department of Earth System Science, University of California, Irvine, Irvine, CA 92697-3100, USA
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Richter DD, Billings SA. 'One physical system': Tansley's ecosystem as Earth's critical zone. THE NEW PHYTOLOGIST 2015; 206:900-912. [PMID: 25731586 DOI: 10.1111/nph.13338] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 01/08/2015] [Indexed: 06/04/2023]
Abstract
Integrative concepts of the biosphere, ecosystem, biogeocenosis and, recently, Earth's critical zone embrace scientific disciplines that link matter, energy and organisms in a systems-level understanding of our remarkable planet. Here, we assert the congruence of Tansley's (1935) venerable ecosystem concept of 'one physical system' with Earth science's critical zone. Ecosystems and critical zones are congruent across spatial-temporal scales from vegetation-clad weathering profiles and hillslopes, small catchments, landscapes, river basins, continents, to Earth's whole terrestrial surface. What may be less obvious is congruence in the vertical dimension. We use ecosystem metabolism to argue that full accounting of photosynthetically fixed carbon includes respiratory CO₂ and carbonic acid that propagate to the base of the critical zone itself. Although a small fraction of respiration, the downward diffusion of CO₂ helps determine rates of soil formation and, ultimately, ecosystem evolution and resilience. Because life in the upper portions of terrestrial ecosystems significantly affects biogeochemistry throughout weathering profiles, the lower boundaries of most terrestrial ecosystems have been demarcated at depths too shallow to permit a complete understanding of ecosystem structure and function. Opportunities abound to explore connections between upper and lower components of critical-zone ecosystems, between soils and streams in watersheds, and between plant-derived CO₂ and deep microbial communities and mineral weathering.
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Affiliation(s)
- Daniel deB Richter
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
| | - Sharon A Billings
- Department of Ecology and Evolutionary Biology and Kansas Biological Survey, University of Kansas, Lawrence, KS, 66047, USA
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25
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Richardson AD, Carbone MS, Huggett BA, Furze ME, Czimczik CI, Walker JC, Xu X, Schaberg PG, Murakami P. Distribution and mixing of old and new nonstructural carbon in two temperate trees. THE NEW PHYTOLOGIST 2015; 206:590-7. [PMID: 25558814 PMCID: PMC4405048 DOI: 10.1111/nph.13273] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2014] [Accepted: 12/09/2014] [Indexed: 05/18/2023]
Abstract
We know surprisingly little about whole-tree nonstructural carbon (NSC; primarily sugars and starch) budgets. Even less well understood is the mixing between recent photosynthetic assimilates (new NSC) and previously stored reserves. And, NSC turnover times are poorly constrained. We characterized the distribution of NSC in the stemwood, branches, and roots of two temperate trees, and we used the continuous label offered by the radiocarbon (carbon-14, (14) C) bomb spike to estimate the mean age of NSC in different tissues. NSC in branches and the outermost stemwood growth rings had the (14) C signature of the current growing season. However, NSC in older aboveground and belowground tissues was enriched in (14) C, indicating that it was produced from older assimilates. Radial patterns of (14) C in stemwood NSC showed strong mixing of NSC across the youngest growth rings, with limited 'mixing in' of younger NSC to older rings. Sugars in the outermost five growth rings, accounting for two-thirds of the stemwood pool, had a mean age < 1 yr, whereas sugars in older growth rings had a mean age > 5 yr. Our results are thus consistent with a previously-hypothesized two-pool ('fast' and 'slow' cycling NSC) model structure. These pools appear to be physically distinct.
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Affiliation(s)
- Andrew D Richardson
- Department of Organismic and Evolutionary Biology, Harvard UniversityCambridge, MA, 02138, USA
| | - Mariah S Carbone
- Department of Organismic and Evolutionary Biology, Harvard UniversityCambridge, MA, 02138, USA
- Earth Systems Research Center, University of New HampshireDurham, NH, 03824, USA
| | - Brett A Huggett
- Department of Organismic and Evolutionary Biology, Harvard UniversityCambridge, MA, 02138, USA
- Department of Biology, Bates CollegeLewiston, ME, 04240, USA
| | - Morgan E Furze
- Department of Organismic and Evolutionary Biology, Harvard UniversityCambridge, MA, 02138, USA
| | - Claudia I Czimczik
- Department of Earth System Science, University of CaliforniaIrvine, CA, 92697-3100, USA
| | - Jennifer C Walker
- Department of Earth System Science, University of CaliforniaIrvine, CA, 92697-3100, USA
| | - Xiaomei Xu
- Department of Earth System Science, University of CaliforniaIrvine, CA, 92697-3100, USA
| | - Paul G Schaberg
- USDA Forest Service, Northern Research StationBurlington, VT, 05405, USA
| | - Paula Murakami
- USDA Forest Service, Northern Research StationBurlington, VT, 05405, USA
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Leifeld J, Meyer S, Budge K, Sebastia MT, Zimmermann M, Fuhrer J. Turnover of grassland roots in mountain ecosystems revealed by their radiocarbon signature: role of temperature and management. PLoS One 2015; 10:e0119184. [PMID: 25734640 PMCID: PMC4347979 DOI: 10.1371/journal.pone.0119184] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 01/26/2015] [Indexed: 11/18/2022] Open
Abstract
Root turnover is an important carbon flux component in grassland ecosystems because it replenishes substantial parts of carbon lost from soil via heterotrophic respiration and leaching. Among the various methods to estimate root turnover, the root's radiocarbon signature has rarely been applied to grassland soils previously, although the value of this approach is known from studies in forest soils. In this paper, we utilize the root's radiocarbon signatures, at 25 plots, in mountain grasslands of the montane to alpine zone of Europe. We place the results in context of a global data base on root turnover and discuss driving factors. Root turnover rates were similar to those of a subsample of the global data, comprising a similar temperature range, but measured with different approaches, indicating that the radiocarbon method gives reliable, plausible and comparable results. Root turnover rates (0.06-1.0 y(-1)) scaled significantly and exponentially with mean annual temperatures. Root turnover rates indicated no trend with soil depth. The temperature sensitivity was significantly higher in mountain grassland, compared to the global data set, suggesting additional factors influencing root turnover. Information on management intensity from the 25 plots reveals that root turnover may be accelerated under intensive and moderate management compared to low intensity or semi-natural conditions. Because management intensity, in the studied ecosystems, co-varied with temperature, estimates on root turnover, based on mean annual temperature alone, may be biased. A greater recognition of management as a driver for root dynamics is warranted when effects of climatic change on belowground carbon dynamics are studied in mountain grasslands.
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Affiliation(s)
- Jens Leifeld
- Agroscope, Climate/Air Pollution Group, Zurich, Switzerland
| | - Stefanie Meyer
- Institute for Geography, Friedrich Schiller Universität, Jena, Germany
| | - Karen Budge
- Independent Researcher, Kirkwall, Orkney, United Kingdom
| | - Maria Teresa Sebastia
- Forest Sciences Centre of Catalonia, Lleida, Spain
- Dept. HBJ, ETSEA, University of Lleida, Lleida, Spain
| | - Michael Zimmermann
- University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Vienna, Austria
| | - Juerg Fuhrer
- Agroscope, Climate/Air Pollution Group, Zurich, Switzerland
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Hydraulic properties and fine root mass of Larix sibirica along forest edge-interior gradients. ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY 2015. [DOI: 10.1016/j.actao.2014.11.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Mobley ML, Lajtha K, Kramer MG, Bacon AR, Heine PR, Richter DD. Surficial gains and subsoil losses of soil carbon and nitrogen during secondary forest development. GLOBAL CHANGE BIOLOGY 2015; 21:986-996. [PMID: 25155991 DOI: 10.1111/gcb.12715] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 07/22/2014] [Indexed: 06/03/2023]
Abstract
Reforestation of formerly cultivated land is widely understood to accumulate above- and belowground detrital organic matter pools, including soil organic matter. However, during 40 years of study of reforestation in the subtropical southeastern USA, repeated observations of above- and belowground carbon documented that significant gains in soil organic matter (SOM) in surface soils (0-7.5 cm) were offset by significant SOM losses in subsoils (35-60 cm). Here, we extended the observation period in this long-term experiment by an additional decade, and used soil fractionation and stable isotopes and radioisotopes to explore changes in soil organic carbon and soil nitrogen that accompanied nearly 50 years of loblolly pine secondary forest development. We observed that accumulations of mineral soil C and N from 0 to 7.5 cm were almost entirely due to accumulations of light-fraction SOM. Meanwhile, losses of soil C and N from mineral soils at 35 to 60 cm were from SOM associated with silt and clay-sized particles. Isotopic signatures showed relatively large accumulations of forest-derived carbon in surface soils, and little to no accumulation of forest-derived carbon in subsoils. We argue that the land use change from old field to secondary forest drove biogeochemical and hydrological changes throughout the soil profile that enhanced microbial activity and SOM decomposition in subsoils. However, when the pine stands aged and began to transition to mixed pines and hardwoods, demands on soil organic matter for nutrients to support aboveground growth eased due to pine mortality, and subsoil organic matter levels stabilized. This study emphasizes the importance of long-term experiments and deep measurements when characterizing soil C and N responses to land use change and the remarkable paucity of such long-term soil data deeper than 30 cm.
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Affiliation(s)
- Megan L Mobley
- University Program in Ecology, Duke University, Durham, NC, 27708, USA; Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
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Ahrens B, Hansson K, Solly EF, Schrumpf M. Reconcilable differences: a joint calibration of fine-root turnover times with radiocarbon and minirhizotrons. THE NEW PHYTOLOGIST 2014; 204:932-942. [PMID: 25196967 DOI: 10.1111/nph.12979] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 06/27/2014] [Indexed: 05/29/2023]
Abstract
We used bomb-radiocarbon and raw minirhizotron lifetimes of fine roots (< 0.5 mm in diameter) in the organic layer of Norway spruce (Picea abies) forests in southern Sweden to test if different models are able to reconcile the apparently contradicting turnover time estimates from both techniques. We present a framework based on survival functions that is able to jointly model bomb-radiocarbon and minirhizotron data. At the same time we integrate prior knowledge about biases of both techniques--the classification of dead roots in minirhizotrons and the use of carbon reserves to grow new roots. Two-pool models, either in parallel or in serial setting, were able to reconcile the bomb-radiocarbon and minirhizotron data. These models yielded a mean residence time of 3.80 ± 0.16 yr (mean ± SD). On average 60 ± 2% of fine roots turned over within 0.75 ± 0.10 yr, while the rest was turning over within 8.4 ± 0.2 yr. Bomb-radiocarbon and minirhizotron data alone give a biased estimate of fine-root turnover. The two-pool models allow a mechanistic interpretation for the coexistence of fast- and slow-cycling roots--suberization and branching for the serial-two-pool model and branching due to ectomycorrhizal fungi-root interactions for the parallel-two-pool model.
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Affiliation(s)
- Bernhard Ahrens
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07445, Jena, Germany
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31
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Roberti JA, SanClements MD, Loescher HW, Ayres E. Traceable calibration, performance metrics, and uncertainty estimates of minirhizotron digital imagery for fine-root measurements. PLoS One 2014; 9:e112362. [PMID: 25391023 PMCID: PMC4229195 DOI: 10.1371/journal.pone.0112362] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 10/10/2014] [Indexed: 11/18/2022] Open
Abstract
Even though fine-root turnover is a highly studied topic, it is often poorly understood as a result of uncertainties inherent in its sampling, e.g., quantifying spatial and temporal variability. While many methods exist to quantify fine-root turnover, use of minirhizotrons has increased over the last two decades, making sensor errors another source of uncertainty. Currently, no standardized methodology exists to test and compare minirhizotron camera capability, imagery, and performance. This paper presents a reproducible, laboratory-based method by which minirhizotron cameras can be tested and validated in a traceable manner. The performance of camera characteristics was identified and test criteria were developed: we quantified the precision of camera location for successive images, estimated the trueness and precision of each camera's ability to quantify root diameter and root color, and also assessed the influence of heat dissipation introduced by the minirhizotron cameras and electrical components. We report detailed and defensible metrology analyses that examine the performance of two commercially available minirhizotron cameras. These cameras performed differently with regard to the various test criteria and uncertainty analyses. We recommend a defensible metrology approach to quantify the performance of minirhizotron camera characteristics and determine sensor-related measurement uncertainties prior to field use. This approach is also extensible to other digital imagery technologies. In turn, these approaches facilitate a greater understanding of measurement uncertainties (signal-to-noise ratio) inherent in the camera performance and allow such uncertainties to be quantified and mitigated so that estimates of fine-root turnover can be more confidently quantified.
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Affiliation(s)
- Joshua A. Roberti
- National Ecological Observatory Network (NEON), Boulder, Colorado, United States of America
| | - Michael D. SanClements
- National Ecological Observatory Network (NEON), Boulder, Colorado, United States of America
- Institute of Arctic and Alpine Research (INSTAAR), University of Colorado, Boulder, Colorado, United States of America
| | - Henry W. Loescher
- National Ecological Observatory Network (NEON), Boulder, Colorado, United States of America
- Institute of Arctic and Alpine Research (INSTAAR), University of Colorado, Boulder, Colorado, United States of America
| | - Edward Ayres
- National Ecological Observatory Network (NEON), Boulder, Colorado, United States of America
- Institute of Arctic and Alpine Research (INSTAAR), University of Colorado, Boulder, Colorado, United States of America
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McCormack ML, Adams TS, Smithwick EAH, Eissenstat DM. Variability in root production, phenology, and turnover rate among 12 temperate tree species. Ecology 2014; 95:2224-35. [DOI: 10.1890/13-1942.1] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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33
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Herzog C, Steffen J, Graf Pannatier E, Hajdas I, Brunner I. Nine years of irrigation cause vegetation and fine root shifts in a water-limited pine forest. PLoS One 2014; 9:e96321. [PMID: 24802642 PMCID: PMC4011741 DOI: 10.1371/journal.pone.0096321] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 04/05/2014] [Indexed: 11/19/2022] Open
Abstract
Scots pines (Pinus sylvestris L.) in the inner-Alpine dry valleys of Switzerland have suffered from increased mortality during the past decades, which has been caused by longer and more frequent dry periods. In addition, a proceeding replacement of Scots pines by pubescent oaks (Quercus pubescens Willd.) has been observed. In 2003, an irrigation experiment was performed to track changes by reducing drought pressure on the natural pine forest. After nine years of irrigation, we observed major adaptations in the vegetation and shifts in Scots pine fine root abundance and structure. Irrigation permitted new plant species to assemble and promote canopy closure with a subsequent loss of herb and moss coverage. Fine root dry weight increased under irrigation and fine roots had a tendency to elongate. Structural composition of fine roots remained unaffected by irrigation, expressing preserved proportions of cellulose, lignin and phenolic substances. A shift to a more negative δ13C signal in the fine root C indicates an increased photosynthetic activity in irrigated pine trees. Using radiocarbon (14C) measurement, a reduced mean age of the fine roots in irrigated plots was revealed. The reason for this is either an increase in newly produced fine roots, supported by the increase in fine root biomass, or a reduced lifespan of fine roots which corresponds to an enhanced turnover rate. Overall, the responses belowground to irrigation are less conspicuous than the more rapid adaptations aboveground. Lagged and conservative adaptations of tree roots with decadal lifespans are challenging to detect, hence demanding for long-term surveys. Investigations concerning fine root turnover rate and degradation processes under a changing climate are crucial for a complete understanding of C cycling.
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Affiliation(s)
- Claude Herzog
- Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
- Swiss Federal Institute of Technology Zürich ETH, Zurich, Switzerland
| | - Jan Steffen
- Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | | | - Irka Hajdas
- Swiss Federal Institute of Technology Zürich ETH, Zurich, Switzerland
| | - Ivano Brunner
- Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
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Adams TS, Eissenstat DM. The continuous incorporation of carbon into existing Sassafras albidum fine roots and its implications for estimating root turnover. PLoS One 2014; 9:e95321. [PMID: 24788762 PMCID: PMC4008494 DOI: 10.1371/journal.pone.0095321] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 03/26/2014] [Indexed: 11/19/2022] Open
Abstract
Although understanding the timing of the deposition of recent photosynthate into fine roots is critical for determining root lifespan and turnover using isotopic techniques, few studies have directly examined the deposition and subsequent age of root carbon. To gain a better understanding of the timing of the deposition of root carbon, we labeled four individual Sassafras albidum trees with 99% 13C CO2. We then tracked whether the label appeared in roots that were at least two weeks old and no longer elongating, at the time of labeling. We found that not only were the non-structural carbon pools (soluble sugars and starch) of existing first-order tree roots incorporating carbon from current photosynthate, but so were the structural components of the roots, even in roots that were more than one year old at the time of labeling.Our findings imply that carbon used in root structural and nonstructural pools is not derived solely from photosynthate at root initiation and have implications regarding the determination of root age and turnover using isotopic techniques.
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Affiliation(s)
- Thomas S. Adams
- Department of Ecosystem Science and Management and the Ecology Graduate Program, the Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - David M. Eissenstat
- Department of Ecosystem Science and Management and the Ecology Graduate Program, the Pennsylvania State University, University Park, Pennsylvania, United States of America
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35
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Rytter RM. The effect of limited availability of N or water on C allocation to fine roots and annual fine root turnover in Alnus incana and Salix viminalis. TREE PHYSIOLOGY 2013; 33:924-39. [PMID: 23963409 DOI: 10.1093/treephys/tpt060] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The effect of limited nitrogen (N) or water availability on fine root growth and turnover was examined in two deciduous species, Alnus incana L. and Salix viminalis L., grown under three different regimes: (i) supply of N and water in amounts which would not hamper growth, (ii) limited N supply and (iii) limited water supply. Plants were grown outdoors during three seasons in covered and buried lysimeters placed in a stand structure and filled with quartz sand. Computer-controlled irrigation and fertilization were supplied through drip tubes. Production and turnover of fine roots were estimated by combining minirhizotron observations and core sampling, or by sequential core sampling. Annual turnover rates of fine roots <1 mm (5-6 year(-1)) and 1-2 mm (0.9-2.8 year(-1)) were not affected by changes in N or water availability. Fine root production (<1 mm) differed between Alnus and Salix, and between treatments in Salix; i.e., absolute length and biomass production increased in the order: water limited < unlimited < N limited. Few treatment effects were detected for fine roots 1-2 mm. Proportionally more C was allocated to fine roots (≤2 mm) in N or water-limited Salix; 2.7 and 2.3 times the allocation to fine roots in the unlimited regime, respectively. Estimated input to soil organic carbon increased by ca. 20% at N limitation in Salix. However, future studies on fine root decomposition under various environmental conditions are required. Fine root growth responses to N or water limitation were less pronounced in Alnus, thus indicating species differences caused by N-fixing capacity and slower initial growth in Alnus, or higher fine root plasticity in Salix. A similar seasonal growth pattern across species and treatments suggested the influence of outer stimuli, such as temperature and light.
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Affiliation(s)
- Rose-Marie Rytter
- Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden; Present address: Rytter Science, Backavägen 16, S-268 68 Röstånga, Sweden
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36
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Richardson AD, Carbone MS, Keenan TF, Czimczik CI, Hollinger DY, Murakami P, Schaberg PG, Xu X. Seasonal dynamics and age of stemwood nonstructural carbohydrates in temperate forest trees. THE NEW PHYTOLOGIST 2013. [PMID: 23190200 DOI: 10.1111/nph.12042] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Nonstructural carbohydrate reserves support tree metabolism and growth when current photosynthates are insufficient, offering resilience in times of stress. We monitored stemwood nonstructural carbohydrate (starch and sugars) concentrations of the dominant tree species at three sites in the northeastern United States. We estimated the mean age of the starch and sugars in a subset of trees using the radiocarbon ((14) C) bomb spike. With these data, we then tested different carbon (C) allocation schemes in a process-based model of forest C cycling. We found that the nonstructural carbohydrates are both highly dynamic and about a decade old. Seasonal dynamics in starch (two to four times higher in the growing season, lower in the dormant season) mirrored those of sugars. Radiocarbon-based estimates indicated that the mean age of the starch and sugars in red maple (Acer rubrum) was 7-14 yr. A two-pool (fast and slow cycling reserves) model structure gave reasonable estimates of the size and mean residence time of the total NSC pool, and greatly improved model predictions of interannual variability in woody biomass increment, compared with zero- or one-pool structures used in the majority of existing models. This highlights the importance of nonstructural carbohydrates in the context of forest ecosystem carbon cycling.
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Affiliation(s)
- Andrew D Richardson
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Mariah S Carbone
- National Center for Ecological Analysis and Synthesis, Santa Barbara, CA, 93101, USA
| | - Trevor F Keenan
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Claudia I Czimczik
- Department of Earth System Science, University of California, Irvine, CA, 92697, USA
| | - David Y Hollinger
- USDA Forest Service, Northern Research Station, Durham, NH, 03824, USA
| | - Paula Murakami
- USDA Forest Service, Northern Research Station, Burlington, VT, 05403, USA
| | - Paul G Schaberg
- USDA Forest Service, Northern Research Station, Burlington, VT, 05403, USA
| | - Xiaomei Xu
- Department of Earth System Science, University of California, Irvine, CA, 92697, USA
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37
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Koarashi J, Hockaday WC, Masiello CA, Trumbore SE. Dynamics of decadally cycling carbon in subsurface soils. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012jg002034] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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38
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Keel SG, Campbell CD, Högberg MN, Richter A, Wild B, Zhou X, Hurry V, Linder S, Näsholm T, Högberg P. Allocation of carbon to fine root compounds and their residence times in a boreal forest depend on root size class and season. THE NEW PHYTOLOGIST 2012; 194:972-981. [PMID: 22452424 DOI: 10.1111/j.1469-8137.2012.04120.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Fine roots play a key role in the forest carbon balance, but their carbon dynamics remain largely unknown. We pulse labelled 50 m(2) patches of young boreal forest by exposure to (13)CO(2) in early and late summer. Labelled photosynthates were traced into carbon compounds of < 1 and 1-3 mm diameter roots (fine roots), and into bulk tissue of these and first-order roots (root tips). Root tips were the most strongly labelled size class. Carbon allocation to all size classes was higher in late than in early summer; mean residence times (MRTs) in starch increased from 4 to 11 months. In structural compounds, MRTs were 0.8 yr in tips and 1.8 yr in fine roots. The MRT of carbon in sugars was in the range of days. Functional differences within the fine root population were indicated by carbon allocation patterns and residence times. Pronounced allocation of recent carbon and higher turnover rates in tips are associated with their role in nutrient and water acquisition. In fine roots, longer MRTs but high allocation to sugars and starch reflect their role in structural support and storage. Accounting for heterogeneity in carbon residence times will improve and most probably reduce the estimates of fine root production.
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Affiliation(s)
- Sonja G Keel
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden
- Present address: Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - Catherine D Campbell
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, SE-901 87 Umeå, Sweden
| | - Mona N Högberg
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden
| | - Andreas Richter
- Department of Terrestrial Ecosystem Research, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, AT-1090 Vienna, Austria
| | - Birgit Wild
- Department of Terrestrial Ecosystem Research, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, AT-1090 Vienna, Austria
| | - Xuhui Zhou
- Research Institute for the Changing Global Environment, Fudan University, Shanghai 200433 China
- Department of Botany and Microbiology, University of Oklahoma, Norman, OK 73019, USA
| | - Vaughan Hurry
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, SE-901 87 Umeå, Sweden
| | - Sune Linder
- Southern Swedish Forest Research Centre, SLU, PO Box 49, SE-230 53 Alnarp, Sweden
| | - Torgny Näsholm
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden
| | - Peter Högberg
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden
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39
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Finér L, Ohashi M, Noguchi K, Hirano Y. Fine root production and turnover in forest ecosystems in relation to stand and environmental characteristics. FOREST ECOLOGY AND MANAGEMENT 2011; 262:2008-2023. [PMID: 0 DOI: 10.1016/j.foreco.2011.08.042] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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Powers EM, Marshall JD. Pulse labeling of dissolved (13) C-carbonate into tree xylem: developing a new method to determine the fate of recently fixed photosynthate. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2011; 25:33-40. [PMID: 21154652 DOI: 10.1002/rcm.4829] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Stable carbon isotopes are often employed as tracers in plant and soil systems to study the fate and transformations of carbon as is it assimilated by the forest canopies and then translocated into the soil matrix and soil microorganisms. This experiment tested a new method of (13) C-labeling. We dissolved (13) C-carbonate into 12 mL of water and injected it into the xylem of a 6-cm diameter tree. The isotopic composition of foliage, stem CO(2) , and phloem contents were measured before the experiment and up to two weeks after the pulse label. Isotopic enrichments of 6.1‰ and 7.7‰ were observed in stem CO(2) and phloem contents, respectively. No enrichment in bulk foliage was observed. The pulse came through the phloem five days after the label was injected, consistent with expectations based on transport rates through the tree. The application of this xylem pulse-labeling method may provide new insights into labile carbon sequestration in trees, perhaps even in much larger trees. Furthermore, the method could be applied under experimental treatments that would elucidate the mechanisms controlling the fate and transformation of recently fixed photosynthate in forests.
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Affiliation(s)
- Elizabeth M Powers
- Idaho Stable Isotopes Laboratory, University of Idaho, College of Natural Resources, Moscow, ID 83844, USA.
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Dawson TE, Simonin KA. The Roles of Stable Isotopes in Forest Hydrology and Biogeochemistry. FOREST HYDROLOGY AND BIOGEOCHEMISTRY 2011. [DOI: 10.1007/978-94-007-1363-5_7] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Kitajima K, Anderson KE, Allen MF. Effect of soil temperature and soil water content on fine root turnover rate in a California mixed conifer ecosystem. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jg001210] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
Historically, ephemeral roots have been equated with 'fine roots' (i.e. all roots of less than an arbitrary diameter, such as 2 mm), but evidence shows that 'fine roots' in woody species are complex branching systems with both rapid-cycling and slow-cycling components. A precise definition of ephemeral roots is therefore needed. Using a branch-order classification, a rhizotron method and sequential sampling of a root cohort, we tested the hypothesis that ephemeral root modules exist within the branching Fraxinus mandshurica (Manchurian ash) root system as distal nonwoody lateral branches, which show anatomical, nutritional and physiological patterns distinct from their woody mother roots. Our results showed that in F. mandshurica, distal nonwoody root branch orders die rapidly as intact lateral branches (or modules). These nonwoody branch orders exhibited highly synchronous changes in tissue nitrogen concentrations and respiration, dominated root turnover, nutrient flux and root respiration, and never underwent secondary development. The ephemeral root modules proposed here may provide a functional basis for differentiating and sampling short-lived absorptive roots in woody plants, and represent a conceptual leap over the traditional coarse-fine root dichotomies based on arbitrary size classes.
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Affiliation(s)
- Mengxue Xia
- Department of Ecology, College of Urban and Environmental Sciences and Key Laboratory for Earth Surface Processes of Ministry of Education, Peking University, Beijing 100871, China
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Endrulat T, Saurer M, Buchmann N, Brunner I. Incorporation and remobilization of ¹³C within the fine-root systems of individual Abies alba trees in a temperate coniferous stand. TREE PHYSIOLOGY 2010; 30:1515-1527. [PMID: 21076129 DOI: 10.1093/treephys/tpq090] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Forest ecosystems have a large carbon (C) storage capacity, which depends on their productivity and the residence time of C. Therefore, the time interval between C assimilation and its return to the atmosphere is an important parameter for determining C storage. Especially fine roots (≤2 mm in diameter) undergo constant replacement and provide a large biomass input to the soil. In this study, we aimed to determine the residence time of C in living fine roots and the decomposition rates of dead fine roots. Therefore, we pulse-labelled nine 20-year-old individual silver fir trees (Abies alba Miller; ∼70 cm tall) with ¹³CO₂ in situ to trace the assimilated C over time into the fine-root systems. Whole trees were harvested at different time points after labelling in autumn, biomass was determined and cellulose and starch of fine roots were extracted. Moreover, soil cores were taken and ingrowth cores installed, in which fine roots were genetically identified, to assess incorporation and remobilization of ¹³C in the fine roots of silver fir trees; litterbags were used to determine fine-root decomposition rates. The ¹³C label was incorporated in the fine-root system as cellulose within 3 days, with highest values after 30 days, before reaching background levels after 1 year. The highest δ¹³C values were found in starch throughout the experiment. ¹³C recovery and carbon mean residence times did not differ significantly among fine-root diameter classes, indicating size-independent C turnover times in fine roots of A. alba trees of ∼219 days. Furthermore, carbon was remobilized from starch into newly grown fine roots in the next spring after our autumn labelling. One year after installation, litterbags with fine roots revealed a decrease of biomass of ∼40% with relative ¹³C content in fine-root bulk biomass and cellulose of ∼50%, indicating a faster loss of ¹³C-labelled compounds compared with bulk biomass. Our results also suggest that genetic analysis of fine-root fragments found in soil and ingrowth cores is advisable when working in mixed forest stands with trees of similar fine-root morphology. Only then can one avoid dilution of the labelling signal by mistake, due to analysis of non-labelled non-target species roots.
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Affiliation(s)
- Tina Endrulat
- Swiss Federal Research Institute WSL, Zuercherstrasse 111, 8903 Birmensdorf, Switzerland
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Very fine roots respond to soil depth: biomass allocation, morphology, and physiology in a broad-leaved temperate forest. Ecol Res 2010. [DOI: 10.1007/s11284-010-0764-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Li A, Guo D, Wang Z, Liu H. Nitrogen and phosphorus allocation in leaves, twigs, and fine roots across 49 temperate, subtropical and tropical tree species: a hierarchical pattern. Funct Ecol 2010. [DOI: 10.1111/j.1365-2435.2009.01603.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Milchunas DG. Estimating Root Production: Comparison of 11 Methods in Shortgrass Steppe and Review of Biases. Ecosystems 2009. [DOI: 10.1007/s10021-009-9295-8] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Finlay R, Wallander H, Smits M, Holmstrom S, van Hees P, Lian B, Rosling A. The role of fungi in biogenic weathering in boreal forest soils. FUNGAL BIOL REV 2009. [DOI: 10.1016/j.fbr.2010.03.002] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Riley WJ, Gaudinski JB, Torn MS, Joslin JD, Hanson PJ. Fine-root mortality rates in a temperate forest: estimates using radiocarbon data and numerical modeling. THE NEW PHYTOLOGIST 2009; 184:387-398. [PMID: 19694965 DOI: 10.1111/j.1469-8137.2009.02980.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
* We used an inadvertent whole-ecosystem 14C label at a temperate forest in Oak Ridge, Tennessee, USA to develop a model (Radix1.0) of fine-root dynamics. Radix simulates two live-root pools, two dead-root pools, non-normally distributed root mortality turnover times, a stored carbon (C) pool, and seasonal growth and respiration patterns. * We applied Radix to analyze measurements from two root size classes (< 0.5 and 0.5-2.0 mm diameter) and three soil-depth increments (O horizon, 0-15 cm and 30-60 cm). * Predicted live-root turnover times were < 1 yr and approximately 10 yr for short- and long-lived pools, respectively. Dead-root pools had decomposition turnover times of approximately 2 yr and approximately 10 yr. Realistic characterization of C flows through fine roots requires a model with two live fine-root populations, two dead fine-root pools, and root respiration. These are the first fine-root turnover time estimates that take into account respiration, storage, seasonal growth patterns, and non-normal turnover time distributions. * The presence of a root population with decadal turnover times implies a lower amount of belowground net primary production used to grow fine-root tissue than is currently predicted by models with a single annual turnover pool.
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Affiliation(s)
- W J Riley
- Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - J B Gaudinski
- Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Environmental Studies, University of California, Santa Cruz, CA, USA
- Department of Integrative Biology, University of California, Berkeley, CA, USA
| | - M S Torn
- Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Energy and Resources Group, University of California, Berkeley, CA, USA
| | - J D Joslin
- Belowground Forest Research, Apartado 104-5655, Santa Elena de Monteverde, Puntarenas, Costa Rica
| | - P J Hanson
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
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Vargas R. On the fate of old stored carbon after large-infrequent disturbances in plants. PLANT SIGNALING & BEHAVIOR 2009; 4:617-9. [PMID: 19820352 PMCID: PMC2710554 DOI: 10.4161/psb.4.7.8906] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Accepted: 05/01/2009] [Indexed: 05/28/2023]
Abstract
Plants have the capacity to store and reallocate stored nonstructural C, but little is known about the age and ecological roles of these pools. It was thought that plants allocate recently assimilated C to produce new fine roots. However, there is recent evidence that plants can allocate old stored C for the production of fine roots following a large-infrequent disturbance (LID) providing a new dimension of the fate and the implied role of stored C in plants. Here, I explore other possible adaptations of plants to allocate stored C reserves, and provide a series of open questions on the fate of old stored C in plants. Specifically, I propose that another metabolic function of old stored C may be for supporting mycorrhizal fungi colonization after a large-infrequent disturbance, because the production of hyphae may be more economical in terms of C to the plant under stressful conditions. Finally, in order to better understand plant resilience to LIDs it is critical to understand the mechanisms that regulate the fate of old stored C in plants.
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Affiliation(s)
- Rodrigo Vargas
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, USA.
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