1
|
San-Emeterio LM, Jiménez-Morillo NT, Pérez-Ramos IM, Domínguez MT, González-Pérez JA. Changes in soil organic matter molecular structure after five-years mimicking climate change scenarios in a Mediterranean savannah. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159288. [PMID: 36220464 DOI: 10.1016/j.scitotenv.2022.159288] [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: 07/06/2022] [Revised: 09/14/2022] [Accepted: 10/03/2022] [Indexed: 06/16/2023]
Abstract
Mediterranean savannahs (dehesas) are agro-sylvo-pastoral systems with a marked seasonality, with severe summer drought and favourable rainy spring and autumn. These conditions are forecasted to become more extreme due to the ongoing global climate change. Under such conditions, it is key to understand soil organic matter (SOM) dynamics at a molecular level. Here, analytical pyrolysis (Py-GC/MS) combined with chemometric statistical approaches was used for the molecular characterization of SOM in a five-years field manipulative experiment of single and combined rainfall exclusion (drought) and increased temperature (warming). The results indicate that SOM molecular composition in dehesas is mainly determined by the effect of the tree canopy. After only five years of the climatic experiment, the differences caused by the warming, drought and the combination of warming+drought forced climate scenarios became statistically significant with respect to the untreated controls, notably in the open pasture habitat. The climatic treatments mimicking foreseen climate changes affected mainly the lignocellulose dynamics, but also other SOM compounds (alkanes, fatty acids, isoprenoids and nitrogen compounds) pointing to accelerated humification processes and SOM degradation when soils are under warmer and dryer conditions. Therefore, it is expected that, in the short term, the foreseen climate change scenarios will exert changes in the Mediterranean savannah SOM molecular structure and in its dynamic.
Collapse
Affiliation(s)
- Layla M San-Emeterio
- Instituto de Recursos Naturales y Agrobiología de Sevilla, Consejo Superior de Investigaciones Científicas (IRNAS-CSIC), Av. Reina Mercedes 10, 41012 Sevilla, Spain; Universidad de Sevilla, MED Soil Res. Group, Dpt. Cristalografía, Mineralogía y Química Agrícola, Facultad de Química, C/Prof Garcia Gonzalez 1, 41012 Sevilla, Spain
| | - Nicasio T Jiménez-Morillo
- University of Évora, Instituto Mediterrâneo para a Agricultura, Ambiente e Desenvolvimento (MED), Núcleo da Mitra, Ap. 94, 7006-554 Évora, Portugal
| | - Ignacio M Pérez-Ramos
- Instituto de Recursos Naturales y Agrobiología de Sevilla, Consejo Superior de Investigaciones Científicas (IRNAS-CSIC), Av. Reina Mercedes 10, 41012 Sevilla, Spain
| | - María T Domínguez
- Universidad de Sevilla, MED Soil Res. Group, Dpt. Cristalografía, Mineralogía y Química Agrícola, Facultad de Química, C/Prof Garcia Gonzalez 1, 41012 Sevilla, Spain
| | - José A González-Pérez
- Instituto de Recursos Naturales y Agrobiología de Sevilla, Consejo Superior de Investigaciones Científicas (IRNAS-CSIC), Av. Reina Mercedes 10, 41012 Sevilla, Spain.
| |
Collapse
|
2
|
Rapid Permafrost Thaw Removes Nitrogen Limitation and Rises the Potential for N2O Emissions. NITROGEN 2022. [DOI: 10.3390/nitrogen3040040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ice–rich Pleistocene permafrost deposits (Yedoma) store large amounts of nitrogen (N) and are susceptible to rapid thaw. In this study, we assess whether eroding Yedoma deposits are potential sources of N and gaseous carbon (C) losses. Therefore, we determined aerobic net ammonification and nitrification, as well as anaerobic production of nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4) in laboratory incubations. Samples were collected from non-vegetated and revegetated slump floor (SF) and thaw mound (TM) soils of a retrogressive thaw slump in the Lena River Delta of Eastern Siberia. We found high nitrate concentrations (up to 110 µg N (g DW)−1) within the growing season, a faster transformation of organic N to nitrate, and high N2O production (up to 217 ng N2O-N (g DW)−1 day−1) in revegetated thaw mounds. The slump floor was low in nitrate and did not produce N2O under anaerobic conditions, but produced the most CO2 (up to 7 µg CO2-C (g DW)−1 day−1) and CH4 (up to 65 ng CH4-C (g DW)−1 day−1). Nitrate additions showed that denitrification was substrate limited in the slump floor. Nitrate limitation was rather caused by field conditions (moisture, pH) than by microbial functional limitation since nitrification rates were positive under laboratory conditions. Our results emphasize the relevance of considering landscape processes, geomorphology, and soil origin in order to identify hotspots of high N availability, as well as C and N losses. High N availability is likely to have an impact on carbon cycling, but to what extent needs further investigation.
Collapse
|
3
|
Ernakovich JG, Barbato RA, Rich VI, Schädel C, Hewitt RE, Doherty SJ, Whalen E, Abbott BW, Barta J, Biasi C, Chabot CL, Hultman J, Knoblauch C, Vetter M, Leewis M, Liebner S, Mackelprang R, Onstott TC, Richter A, Schütte U, Siljanen HMP, Taş N, Timling I, Vishnivetskaya TA, Waldrop MP, Winkel M. Microbiome assembly in thawing permafrost and its feedbacks to climate. GLOBAL CHANGE BIOLOGY 2022; 28:5007-5026. [PMID: 35722720 PMCID: PMC9541943 DOI: 10.1111/gcb.16231] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 03/24/2022] [Indexed: 05/15/2023]
Abstract
The physical and chemical changes that accompany permafrost thaw directly influence the microbial communities that mediate the decomposition of formerly frozen organic matter, leading to uncertainty in permafrost-climate feedbacks. Although changes to microbial metabolism and community structure are documented following thaw, the generality of post-thaw assembly patterns across permafrost soils of the world remains uncertain, limiting our ability to predict biogeochemistry and microbial community responses to climate change. Based on our review of the Arctic microbiome, permafrost microbiology, and community ecology, we propose that Assembly Theory provides a framework to better understand thaw-mediated microbiome changes and the implications for community function and climate feedbacks. This framework posits that the prevalence of deterministic or stochastic processes indicates whether the community is well-suited to thrive in changing environmental conditions. We predict that on a short timescale and following high-disturbance thaw (e.g., thermokarst), stochasticity dominates post-thaw microbiome assembly, suggesting that functional predictions will be aided by detailed information about the microbiome. At a longer timescale and lower-intensity disturbance (e.g., active layer deepening), deterministic processes likely dominate, making environmental parameters sufficient for predicting function. We propose that the contribution of stochastic and deterministic processes to post-thaw microbiome assembly depends on the characteristics of the thaw disturbance, as well as characteristics of the microbial community, such as the ecological and phylogenetic breadth of functional guilds, their functional redundancy, and biotic interactions. These propagate across space and time, potentially providing a means for predicting the microbial forcing of greenhouse gas feedbacks to global climate change.
Collapse
Affiliation(s)
- Jessica G. Ernakovich
- Natural Resources and the EnvironmentUniversity of New HampshireDurhamNew HampshireUSA
- Molecular, Cellular and Biomedical SciencesUniversity of New HampshireDurhamNew HampshireUSA
- EMergent Ecosystem Response to ChanGE (EMERGE) Biology Integration Institute
| | - Robyn A. Barbato
- U.S. Army Cold Regions Research and Engineering LaboratoryHanoverNew HampshireUSA
| | - Virginia I. Rich
- EMergent Ecosystem Response to ChanGE (EMERGE) Biology Integration Institute
- Microbiology DepartmentOhio State UniversityColumbusOhioUSA
- Byrd Polar and Climate Research CenterOhio State UniversityColombusOhioUSA
- Center of Microbiome ScienceOhio State UniversityColombusOhioUSA
| | - Christina Schädel
- Center for Ecosystem Science and SocietyNorthern Arizona UniversityFlagstaffArizonaUSA
| | - Rebecca E. Hewitt
- Center for Ecosystem Science and SocietyNorthern Arizona UniversityFlagstaffArizonaUSA
- Department of Environmental StudiesAmherst CollegeAmherstMassachusettsUSA
| | - Stacey J. Doherty
- Molecular, Cellular and Biomedical SciencesUniversity of New HampshireDurhamNew HampshireUSA
- U.S. Army Cold Regions Research and Engineering LaboratoryHanoverNew HampshireUSA
| | - Emily D. Whalen
- Natural Resources and the EnvironmentUniversity of New HampshireDurhamNew HampshireUSA
| | - Benjamin W. Abbott
- Department of Plant and Wildlife SciencesBrigham Young UniversityProvoUtahUSA
| | - Jiri Barta
- Centre for Polar EcologyUniversity of South BohemiaCeske BudejoviceCzech Republic
| | - Christina Biasi
- Department of Environmental and Biological SciencesUniversity of Eastern FinlandKuopioFinland
| | - Chris L. Chabot
- California State University NorthridgeNorthridgeCaliforniaUSA
| | | | - Christian Knoblauch
- Institute of Soil ScienceUniversität HamburgHamburgGermany
- Center for Earth System Research and SustainabilityUniversität HamburgHamburgGermany
| | - Maggie C. Y. Lau Vetter
- Department of GeosciencesPrinceton UniversityPrincetonNew JerseyUSA
- Laboratory of Extraterrestrial Ocean Systems (LEOS)Institute of Deep‐sea Science and EngineeringChinese Academy of SciencesSanyaChina
| | - Mary‐Cathrine Leewis
- U.S. Geological Survey, GeologyMinerals, Energy and Geophysics Science CenterMenlo ParkCaliforniaUSA
- Agriculture and Agri‐Food CanadaQuebec Research and Development CentreQuebecQuebecCanada
| | - Susanne Liebner
- GFZ German Research Centre for GeosciencesSection GeomicrobiologyPotsdamGermany
| | | | | | - Andreas Richter
- Centre for Microbiology and Environmental Systems ScienceUniversity of ViennaViennaAustria
- Austrian Polar Research InstituteViennaAustria
| | | | - Henri M. P. Siljanen
- Department of Environmental and Biological SciencesUniversity of Eastern FinlandKuopioFinland
| | - Neslihan Taş
- Lawrence Berkeley National LaboratoryBerkeleyCaliforniaUSA
| | | | - Tatiana A. Vishnivetskaya
- University of TennesseeKnoxvilleTennesseeUSA
- Institute of Physicochemical and Biological Problems of Soil SciencePushchinoRussia
| | - Mark P. Waldrop
- U.S. Geological Survey, GeologyMinerals, Energy and Geophysics Science CenterMenlo ParkCaliforniaUSA
| | - Matthias Winkel
- GFZ German Research Centre for GeosciencesInterface GeochemistryPotsdamGermany
- BfR Federal Institute for Risk AssessmentBerlinGermany
| |
Collapse
|
4
|
Wu MH, Xue K, Wei PJ, Jia YL, Zhang Y, Chen SY. Soil microbial distribution and assembly are related to vegetation biomass in the alpine permafrost regions of the Qinghai-Tibet Plateau. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 834:155259. [PMID: 35452733 DOI: 10.1016/j.scitotenv.2022.155259] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/09/2022] [Accepted: 04/09/2022] [Indexed: 06/14/2023]
Abstract
It is generally believed that there is a vegetation succession sequence from alpine marsh meadow to desert in the alpine ecosystem of the Qinghai-Tibet Plateau. However, we still have a limited understanding about distribution patterns and community assemblies of microorganisms' response to such vegetation changes. Hence, across a gradient represented by three types of alpine vegetation from swamp meadow to meadow to steppe, the soil bacterial, fungal and archaeal diversity was evaluated and then associated with their assembly processes, and glacier foreland vegetation was also surveyed as a case out of this gradient. Vegetation biomass was found to decrease significantly along the vegetation gradient. In contrast to irregular shifts in alpha diversity, bacterial and fungal beta diversities that were dominated by species replacement components (71.07-79.08%) significantly increased with the decreasing gradient in vegetation biomass (P < 0.05). These trends of increase were also found in the extent of stochastic bacterial and fungal assembly. Moreover, an increase in microbial beta diversity but a decrease in beta nearest taxon index were observed along with increased discrepancy in vegetation biomass (P < 0.001). Stepwise regression analyses and structural equation models suggested that vegetation biomass was the major variable that was related to microbial distribution and community assembly, and there might be associations between the dominance of species replacements and stochastic assembly. These findings enhanced our recognition of the relationship between vegetation and soil microorganisms and would facilitate the development of vegetation-microbe feedback models in alpine ecosystems.
Collapse
Affiliation(s)
- Ming-Hui Wu
- Cryosphere and Eco-Environment Research Station of Shule River Headwaters, National Field Science Observation and Research Station of Yulong Snow Mountain Cryosphere and Sustainable Development, State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kai Xue
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Pei-Jie Wei
- Cryosphere and Eco-Environment Research Station of Shule River Headwaters, National Field Science Observation and Research Station of Yulong Snow Mountain Cryosphere and Sustainable Development, State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ying-Lan Jia
- Cryosphere and Eco-Environment Research Station of Shule River Headwaters, National Field Science Observation and Research Station of Yulong Snow Mountain Cryosphere and Sustainable Development, State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yu Zhang
- Long-term National Scientific Research Base of the Qilian Mountain National Park, Xining, Qinghai 810000, China
| | - Sheng-Yun Chen
- Cryosphere and Eco-Environment Research Station of Shule River Headwaters, National Field Science Observation and Research Station of Yulong Snow Mountain Cryosphere and Sustainable Development, State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China; Long-term National Scientific Research Base of the Qilian Mountain National Park, Xining, Qinghai 810000, China.
| |
Collapse
|
5
|
Microbiogeochemical Traits to Identify Nitrogen Hotspots in Permafrost Regions. NITROGEN 2022. [DOI: 10.3390/nitrogen3030031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Permafrost-affected tundra soils are large carbon (C) and nitrogen (N) reservoirs. However, N is largely bound in soil organic matter (SOM), and ecosystems generally have low N availability. Therefore, microbial induced N-cycling processes and N losses were considered negligible. Recent studies show that microbial N processing rates, inorganic N availability, and lateral N losses from thawing permafrost increase when vegetation cover is disturbed, resulting in reduced N uptake or increased N input from thawing permafrost. In this review, we describe currently known N hotspots, particularly bare patches in permafrost peatland or permafrost soils affected by thermokarst, and their microbiogeochemical characteristics, and present evidence for previously unrecorded N hotspots in the tundra. We summarize the current understanding of microbial N cycling processes that promote the release of the potent greenhouse gas (GHG) nitrous oxide (N2O) and the translocation of inorganic N from terrestrial into aquatic ecosystems. We suggest that certain soil characteristics and microbial traits can be used as indicators of N availability and N losses. Identifying N hotspots in permafrost soils is key to assessing the potential for N release from permafrost-affected soils under global warming, as well as the impact of increased N availability on emissions of carbon-containing GHGs.
Collapse
|
6
|
Simulating Increased Permafrost Peatland Plant Productivity in Response to Belowground Fertilisation Using the JULES Land Surface Model. NITROGEN 2022. [DOI: 10.3390/nitrogen3020018] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Several experimental studies have shown that climate-warming-induced permafrost thaw releases previously unavailable nitrogen which can lower nitrogen limitation, increase plant productivity, and counteract some of the carbon released from thawing permafrost. The net effect of this belowground fertilisation effect remains debated and is yet to be included in Earth System models. Here, we included the impact of thaw-related nitrogen fertilisation on vegetation in the Joint UK Land Environment Simulator (JULES) land surface model for the first time. We evaluated its ability to replicate a three-year belowground fertilisation experiment in which JULES was generally able to simulate belowground fertilisation in accordance with the observations. We also ran simulations under future climate to investigate how belowground nitrogen fertilisation affects the carbon cycle. These simulations indicate an increase in plant-available inorganic nitrogen at the thaw front by the end of the century with only the productivity of deep-rooting plants increasing in response. This suggests that deep-rooting species will have a competitive advantage under future climate warming. Our results also illustrate the capacity to simulate belowground nitrogen fertilisation at the thaw front in a global land surface model, leading towards a more complete representation of coupled carbon and nitrogen dynamics in the northern high latitudes.
Collapse
|
7
|
Influences of summer warming and nutrient availability on Salix glauca L. growth in Greenland along an ice to sea gradient. Sci Rep 2022; 12:3077. [PMID: 35197470 PMCID: PMC8866482 DOI: 10.1038/s41598-022-05322-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 01/04/2022] [Indexed: 11/08/2022] Open
Abstract
The combined effects of climate change and nutrient availability on Arctic vegetation growth are poorly understood. Archaeological sites in the Arctic could represent unique nutrient hotspots for studying the long-term effect of nutrient enrichment. In this study, we analysed a time-series of ring widths of Salix glauca L. collected at nine archaeological sites and in their natural surroundings along a climate gradient in the Nuuk fjord region, Southwest Greenland, stretching from the edge of the Greenlandic Ice Sheet in the east to the open sea in the west. We assessed the temperature-growth relationship for the last four decades distinguishing between soils with past anthropogenic nutrient enrichment (PANE) and without (controls). Along the East-West gradient, the inner fjord sites showed a stronger temperature signal compared to the outermost ones. Individuals growing in PANE soils had wider ring widths than individuals growing in the control soils and a stronger climate-growth relation, especially in the inner fjord sites. Thereby, the individuals growing on the archaeological sites seem to have benefited more from the climate warming in recent decades. Our results suggest that higher nutrient availability due to past human activities plays a role in Arctic vegetation growth and should be considered when assessing both the future impact of plants on archaeological sites and the general greening in landscapes with contrasting nutrient availability.
Collapse
|
8
|
Hough M, McCabe S, Vining SR, Pickering Pedersen E, Wilson RM, Lawrence R, Chang K, Bohrer G, Riley WJ, Crill PM, Varner RK, Blazewicz SJ, Dorrepaal E, Tfaily MM, Saleska SR, Rich VI. Coupling plant litter quantity to a novel metric for litter quality explains C storage changes in a thawing permafrost peatland. GLOBAL CHANGE BIOLOGY 2022; 28:950-968. [PMID: 34727401 PMCID: PMC9298822 DOI: 10.1111/gcb.15970] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 09/30/2021] [Indexed: 06/13/2023]
Abstract
Permafrost thaw is a major potential feedback source to climate change as it can drive the increased release of greenhouse gases carbon dioxide (CO2 ) and methane (CH4 ). This carbon release from the decomposition of thawing soil organic material can be mitigated by increased net primary productivity (NPP) caused by warming, increasing atmospheric CO2 , and plant community transition. However, the net effect on C storage also depends on how these plant community changes alter plant litter quantity, quality, and decomposition rates. Predicting decomposition rates based on litter quality remains challenging, but a promising new way forward is to incorporate measures of the energetic favorability to soil microbes of plant biomass decomposition. We asked how the variation in one such measure, the nominal oxidation state of carbon (NOSC), interacts with changing quantities of plant material inputs to influence the net C balance of a thawing permafrost peatland. We found: (1) Plant productivity (NPP) increased post-thaw, but instead of contributing to increased standing biomass, it increased plant biomass turnover via increased litter inputs to soil; (2) Plant litter thermodynamic favorability (NOSC) and decomposition rate both increased post-thaw, despite limited changes in bulk C:N ratios; (3) these increases caused the higher NPP to cycle more rapidly through both plants and soil, contributing to higher CO2 and CH4 fluxes from decomposition. Thus, the increased C-storage expected from higher productivity was limited and the high global warming potential of CH4 contributed a net positive warming effect. Although post-thaw peatlands are currently C sinks due to high NPP offsetting high CO2 release, this status is very sensitive to the plant community's litter input rate and quality. Integration of novel bioavailability metrics based on litter chemistry, including NOSC, into studies of ecosystem dynamics, is needed to improve the understanding of controls on arctic C stocks under continued ecosystem transition.
Collapse
Affiliation(s)
- Moira Hough
- Ecology & Evolutionary Biology DepartmentUniversity of ArizonaTucsonArizonaUSA
- Department of Environmental ScienceUniversity of ArizonaTucsonArizonaUSA
| | - Samantha McCabe
- Environmental Sciences Graduate ProgramThe Ohio State UniversityColumbusOhioUSA
| | - S. Rose Vining
- Department of Environmental ScienceUniversity of ArizonaTucsonArizonaUSA
| | - Emily Pickering Pedersen
- Department of BiologyTerrestrial EcologyUniversity of CopenhagenCopenhagenDenmark
- Center for Permafrost (CENPERM)Department of Geosciences and Natural Resource ManagementUniversity of CopenhagenCopenhagenDenmark
| | - Rachel M. Wilson
- Florida State UniversityEarth Ocean and Atmospheric SciencesTallahasseeFloridaUSA
| | - Ryan Lawrence
- Department of Earth Sciences and Institute for the Study of Earth, Oceans and SpaceUniversity of New HampshireDurhamNew HampshireUSA
| | - Kuang‐Yu Chang
- Lawrence Berkeley LaboratoryClimate and Ecosystem Sciences DivisionBerkeleyCaliforniaUSA
| | - Gil Bohrer
- Civil Environmental and Geodetic EngineeringThe Ohio State UniversityColumbusOhioUSA
| | | | - William J. Riley
- Lawrence Berkeley LaboratoryClimate and Ecosystem Sciences DivisionBerkeleyCaliforniaUSA
| | - Patrick M. Crill
- Department of Geological Sciences and Bolin Centre for Climate ResearchStockholm UniversityStockholmSweden
| | - Ruth K. Varner
- Department of Earth Sciences and Institute for the Study of Earth, Oceans and SpaceUniversity of New HampshireDurhamNew HampshireUSA
| | | | - Ellen Dorrepaal
- Climate Impacts Research Centre—Department of Ecology and Environmental SciencesUmeå UniversityAbiskoSweden
| | - Malak M. Tfaily
- Department of Environmental ScienceUniversity of ArizonaTucsonArizonaUSA
| | - Scott R. Saleska
- Ecology & Evolutionary Biology DepartmentUniversity of ArizonaTucsonArizonaUSA
| | - Virginia I. Rich
- Department of Environmental ScienceUniversity of ArizonaTucsonArizonaUSA
- Microbiology DepartmentThe Ohio State UniversityColumbusOhioUSA
- Center of Microbiome ScienceThe Ohio State UniversityColumbusOhioUSA
- The Byrd Polar and Climate Research CenterThe Ohio State UniversityColumbusOhioUSA
| |
Collapse
|
9
|
Standen KM, Baltzer JL. Permafrost condition determines plant community composition and community-level foliar functional traits in a boreal peatland. Ecol Evol 2021; 11:10133-10146. [PMID: 34367564 PMCID: PMC8328418 DOI: 10.1002/ece3.7818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 04/23/2021] [Accepted: 05/28/2021] [Indexed: 11/05/2022] Open
Abstract
Boreal peatlands are critical ecosystems globally because they house 30%-40% of terrestrial carbon (C), much of which is stored in permafrost soil vulnerable to climate warming-induced thaw. Permafrost thaw leads to thickening of the active (seasonally thawed) layer and alters nutrient and light availability. These physical changes may influence community-level plant functional traits through intraspecific trait variation and/or species turnover. As permafrost thaw is expected to cause an efflux of carbon dioxide (CO2) and methane (CH4) from the soil to the atmosphere, it is important to understand thaw-induced changes in plant community productivity to evaluate whether these changes may offset some of the anticipated increases in C emissions. To this end, we collected vascular plant community composition and foliar functional trait data along gradients in aboveground tree biomass and active layer thickness (ALT) in a rapidly thawing boreal peatland, with the expectation that changes in above- and belowground conditions are indicative of altered resource availability. We aimed to determine whether community-level traits vary across these gradients, and whether these changes are dominated by intraspecific trait variation, species turnover, or both. Our results highlight that variability in community-level traits was largely attributable to species turnover and that both community composition and traits were predominantly driven by ALT. Specifically, thicker active layers associated with permafrost-free peatlands (i.e., bogs and fens) shifted community composition from slower-growing evergreen shrubs to faster-growing graminoids and forbs with a corresponding shift toward more productive trait values. The results from this rapidly thawing peatland suggest that continued warming-induced permafrost thaw and thermokarst development alter plant community composition and community-level traits and thus ecosystem productivity. Increased productivity may help to mitigate anticipated CO2 efflux from thawing permafrost, at least in the short term, though this response may be swamped by increase CH4 release.
Collapse
|
10
|
Varsadiya M, Urich T, Hugelius G, Bárta J. Microbiome structure and functional potential in permafrost soils of the Western Canadian Arctic. FEMS Microbiol Ecol 2021; 97:6102547. [PMID: 33452882 DOI: 10.1093/femsec/fiab008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 01/13/2021] [Indexed: 01/12/2023] Open
Abstract
Substantial amounts of topsoil organic matter (OM) in Arctic Cryosols have been translocated by the process of cryoturbation into deeper soil horizons (cryoOM), reducing its decomposition. Recent Arctic warming deepens the Cryosols´ active layer, making more topsoil and cryoOM carbon accessible for microbial transformation. To quantify bacteria, archaea and selected microbial groups (methanogens - mcrA gene and diazotrophs - nifH gene) and to investigate bacterial and archaeal diversity, we collected 83 soil samples from four different soil horizons of three distinct tundra types located in Qikiqtaruk (Hershel Island, Western Canada). In general, the abundance of bacteria and diazotrophs decreased from topsoil to permafrost, but not for cryoOM. No such difference was observed for archaea and methanogens. CryoOM was enriched with oligotrophic (slow-growing microorganism) taxa capable of recalcitrant OM degradation. We found distinct microbial patterns in each tundra type: topsoil from wet-polygonal tundra had the lowest abundance of bacteria and diazotrophs, but the highest abundance of methanogens. Wet-polygonal tundra, therefore, represented a hotspot for methanogenesis. Oligotrophic and copiotrophic (fast-growing microorganism) genera of methanogens and diazotrophs were distinctly distributed in topsoil and cryoOM, resulting in different rates of nitrogen flux into these horizons affecting OM vulnerability and potential CO2 and CH4 release.
Collapse
Affiliation(s)
- Milan Varsadiya
- Department of Ecosystems Biology, University of South Bohemia in České Budějovice, Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Tim Urich
- Institute of Microbiology, University of Greifswald, Felix-Hausdorff-Str. 8 17487 Greifswald, Germany
| | - Gustaf Hugelius
- Department of Physical Geography, Stockholm University, 106 91, Stockholm, Sweden
| | - Jiří Bárta
- Department of Ecosystems Biology, University of South Bohemia in České Budějovice, Branišovská 31, 370 05 České Budějovice, Czech Republic
| |
Collapse
|
11
|
Friggens NL, Hester AJ, Mitchell RJ, Parker TC, Subke JA, Wookey PA. Tree planting in organic soils does not result in net carbon sequestration on decadal timescales. GLOBAL CHANGE BIOLOGY 2020; 26:5178-5188. [PMID: 32662196 DOI: 10.1111/gcb.15229] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 04/24/2020] [Accepted: 06/08/2020] [Indexed: 06/11/2023]
Abstract
Tree planting is increasingly being proposed as a strategy to combat climate change through carbon (C) sequestration in tree biomass. However, total ecosystem C storage that includes soil organic C (SOC) must be considered to determine whether planting trees for climate change mitigation results in increased C storage. We show that planting two native tree species (Betula pubescens and Pinus sylvestris), of widespread Eurasian distribution, onto heather (Calluna vulgaris) moorland with podzolic and peaty podzolic soils in Scotland, did not lead to an increase in net ecosystem C stock 12 or 39 years after planting. Plots with trees had greater soil respiration and lower SOC in organic soil horizons than heather control plots. The decline in SOC cancelled out the increment in C stocks in tree biomass on decadal timescales. At all four experimental sites sampled, there was no net gain in ecosystem C stocks 12-39 years after afforestation-indeed we found a net ecosystem C loss in one of four sites with deciduous B. pubescens stands; no net gain in ecosystem C at three sites planted with B. pubescens; and no net gain at additional stands of P. sylvestris. We hypothesize that altered mycorrhizal communities and autotrophic C inputs have led to positive 'priming' of soil organic matter, resulting in SOC loss, constraining the benefits of tree planting for ecosystem C sequestration. The results are of direct relevance to current policies, which promote tree planting on the assumption that this will increase net ecosystem C storage and contribute to climate change mitigation. Ecosystem-level biogeochemistry and C fluxes must be better quantified and understood before we can be assured that large-scale tree planting in regions with considerable pre-existing SOC stocks will have the intended policy and climate change mitigation outcomes.
Collapse
Affiliation(s)
- Nina L Friggens
- Biological & Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, UK
- Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Alison J Hester
- Ecological Sciences, The James Hutton Institute, Aberdeen, UK
| | - Ruth J Mitchell
- Ecological Sciences, The James Hutton Institute, Aberdeen, UK
| | - Thomas C Parker
- Biological & Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, UK
| | - Jens-Arne Subke
- Biological & Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, UK
| | - Philip A Wookey
- Biological & Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, UK
| |
Collapse
|
12
|
Shogren AJ, Zarnetske JP, Abbott BW, Iannucci F, Frei RJ, Griffin NA, Bowden WB. Revealing biogeochemical signatures of Arctic landscapes with river chemistry. Sci Rep 2019; 9:12894. [PMID: 31501454 PMCID: PMC6733942 DOI: 10.1038/s41598-019-49296-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 08/20/2019] [Indexed: 12/14/2022] Open
Abstract
Riverine fluxes of carbon and inorganic nutrients are increasing in virtually all large permafrost-affected rivers, indicating major shifts in Arctic landscapes. However, it is currently difficult to identify what is causing these changes in nutrient processing and flux because most long-term records of Arctic river chemistry are from small, headwater catchments draining <200 km2 or from large rivers draining >100,000 km2. The interactions of nutrient sources and sinks across these scales are what ultimately control solute flux to the Arctic Ocean. In this context, we performed spatially-distributed sampling of 120 subcatchments nested within three Arctic watersheds spanning alpine, tundra, and glacial-lake landscapes in Alaska. We found that the dominant spatial scales controlling organic carbon and major nutrient concentrations was 3-30 km2, indicating a continuum of diffuse and discrete sourcing and processing dynamics. These patterns were consistent seasonally, suggesting that relatively fine-scale landscape patches drive solute generation in this region of the Arctic. These network-scale empirical frameworks could guide and benchmark future Earth system models seeking to represent lateral and longitudinal solute transport in rapidly changing Arctic landscapes.
Collapse
Affiliation(s)
- Arial J Shogren
- Michigan State University, Department of Earth and Environmental Sciences, East Lansing, Michigan, 48824, USA.
| | - Jay P Zarnetske
- Michigan State University, Department of Earth and Environmental Sciences, East Lansing, Michigan, 48824, USA
| | - Benjamin W Abbott
- Brigham Young University, Department of Plant and Wildlife Sciences, Provo, Utah, 84602, USA
| | - Frances Iannucci
- University of Vermont, Rubenstein School of Environment and Natural Resources, Burlington, Vermont, 05405, USA
| | - Rebecca J Frei
- Brigham Young University, Department of Plant and Wildlife Sciences, Provo, Utah, 84602, USA
- University of Alberta, Department of Renewable Resources, Edmonton, Alberta, T6G 2R3, Canada
| | - Natasha A Griffin
- Brigham Young University, Department of Plant and Wildlife Sciences, Provo, Utah, 84602, USA
| | - William B Bowden
- University of Vermont, Rubenstein School of Environment and Natural Resources, Burlington, Vermont, 05405, USA
| |
Collapse
|
13
|
Blume-Werry G, Milbau A, Teuber LM, Johansson M, Dorrepaal E. Dwelling in the deep - strongly increased root growth and rooting depth enhance plant interactions with thawing permafrost soil. THE NEW PHYTOLOGIST 2019; 223:1328-1339. [PMID: 31074867 DOI: 10.1111/nph.15903] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Accepted: 04/12/2019] [Indexed: 05/27/2023]
Abstract
Climate-warming-induced permafrost thaw exposes large amounts of carbon and nitrogen in soil at considerable depths, below the seasonally thawing active layer. The extent to which plant roots can reach and interact with these hitherto detached, deep carbon and nitrogen stores remains unknown. We aimed to quantify how permafrost thaw affects root dynamics across soil depths and plant functional types compared with above-ground abundance, and potential consequences for plant-soil interactions. A decade of experimental permafrost thaw strongly increased total root length and growth in the active layer, and deep roots invaded the newly thawed permafrost underneath. Root litter input to soil across all depths was 10 times greater with permafrost thaw. Root growth timing was unaffected by experimental permafrost thaw but peaked later in deeper soil, reflecting the seasonally receding thaw front. Deep-rooting species could sequester 15 N added at the base of the ambient active layer in October, which was after root growth had ceased. Deep soil organic matter that has long been locked up in permafrost is thus no longer detached from plant processes upon thaw. Whether via nutrient uptake, carbon storage, or rhizosphere priming, plant root interactions with thawing permafrost soils may feed back on our climate both positively and negatively.
Collapse
Affiliation(s)
- Gesche Blume-Werry
- Climate Impacts Research Centre, Department of Ecology and Environmental Science, Umeå University, 981 07, Abisko, Sweden
- Experimental Plant Ecology, Institute of Botany and Landscape Ecology, Greifswald University, 17487, Greifswald, Germany
| | - Ann Milbau
- Climate Impacts Research Centre, Department of Ecology and Environmental Science, Umeå University, 981 07, Abisko, Sweden
- Research Institute for Nature and Forest INBO, Havenlaan 88, Bus 73, 1000, Brussels, Belgium
| | - Laurenz M Teuber
- Climate Impacts Research Centre, Department of Ecology and Environmental Science, Umeå University, 981 07, Abisko, Sweden
- Experimental Plant Ecology, Institute of Botany and Landscape Ecology, Greifswald University, 17487, Greifswald, Germany
| | - Margareta Johansson
- Department of Physical Geography and Ecosystem Science, Lund University, Solvegatan 12, 223 62, Lund, Sweden
| | - Ellen Dorrepaal
- Climate Impacts Research Centre, Department of Ecology and Environmental Science, Umeå University, 981 07, Abisko, Sweden
| |
Collapse
|
14
|
Chen Y, Cao J, Zhao J, Wu J, Zou X, Fu S, Zhang W. Labile C dynamics reflect soil organic carbon sequestration capacity: Understory plants drive topsoil C process in subtropical forests. Ecosphere 2019. [DOI: 10.1002/ecs2.2784] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Yuanqi Chen
- Hunan Province Key Laboratory of Coal Resources Clean‐utilization and Mine Environment Protection Hunan University of Science and Technology Xiangtan 411201 China
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems South China Botanical Garden Chinese Academy of Sciences Guangzhou 510650 China
| | - Jianbo Cao
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems South China Botanical Garden Chinese Academy of Sciences Guangzhou 510650 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Jie Zhao
- Key Laboratory of Agro‐Ecological Processes in Subtropical Region Institute of Subtropical Agriculture Chinese Academy of Sciences Changsha 410125 China
| | - Jianping Wu
- School of Ecology and Environmental Science Yunnan University Kunming 650091 China
| | - Xiaoming Zou
- Department of Environmental Sciences University of Puerto Rico P.O. Box 70377 San Juan Puerto Rico 00936‐8377 USA
| | - Shenglei Fu
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions Ministry of Education College of Environment and Planning Henan University Kaifeng 475004 China
| | - Weixin Zhang
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions Ministry of Education College of Environment and Planning Henan University Kaifeng 475004 China
| |
Collapse
|
15
|
Voigt C, Marushchak ME, Mastepanov M, Lamprecht RE, Christensen TR, Dorodnikov M, Jackowicz-Korczyński M, Lindgren A, Lohila A, Nykänen H, Oinonen M, Oksanen T, Palonen V, Treat CC, Martikainen PJ, Biasi C. Ecosystem carbon response of an Arctic peatland to simulated permafrost thaw. GLOBAL CHANGE BIOLOGY 2019; 25:1746-1764. [PMID: 30681758 DOI: 10.1111/gcb.14574] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 01/11/2019] [Indexed: 06/09/2023]
Abstract
Permafrost peatlands are biogeochemical hot spots in the Arctic as they store vast amounts of carbon. Permafrost thaw could release part of these long-term immobile carbon stocks as the greenhouse gases (GHGs) carbon dioxide (CO2 ) and methane (CH4 ) to the atmosphere, but how much, at which time-span and as which gaseous carbon species is still highly uncertain. Here we assess the effect of permafrost thaw on GHG dynamics under different moisture and vegetation scenarios in a permafrost peatland. A novel experimental approach using intact plant-soil systems (mesocosms) allowed us to simulate permafrost thaw under near-natural conditions. We monitored GHG flux dynamics via high-resolution flow-through gas measurements, combined with detailed monitoring of soil GHG concentration dynamics, yielding insights into GHG production and consumption potential of individual soil layers. Thawing the upper 10-15 cm of permafrost under dry conditions increased CO2 emissions to the atmosphere (without vegetation: 0.74 ± 0.49 vs. 0.84 ± 0.60 g CO2 -C m-2 day-1 ; with vegetation: 1.20 ± 0.50 vs. 1.32 ± 0.60 g CO2 -C m-2 day-1 , mean ± SD, pre- and post-thaw, respectively). Radiocarbon dating (14 C) of respired CO2 , supported by an independent curve-fitting approach, showed a clear contribution (9%-27%) of old carbon to this enhanced post-thaw CO2 flux. Elevated concentrations of CO2 , CH4 , and dissolved organic carbon at depth indicated not just pulse emissions during the thawing process, but sustained decomposition and GHG production from thawed permafrost. Oxidation of CH4 in the peat column, however, prevented CH4 release to the atmosphere. Importantly, we show here that, under dry conditions, peatlands strengthen the permafrost-carbon feedback by adding to the atmospheric CO2 burden post-thaw. However, as long as the water table remains low, our results reveal a strong CH4 sink capacity in these types of Arctic ecosystems pre- and post-thaw, with the potential to compensate part of the permafrost CO2 losses over longer timescales.
Collapse
Affiliation(s)
- Carolina Voigt
- Department of Geography, University of Montréal, Montréal, Québec, Canada
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
| | - Maija E Marushchak
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Mikhail Mastepanov
- Department of Bioscience, Arctic Research Centre, Aarhus University, Roskilde, Denmark
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Richard E Lamprecht
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
| | - Torben R Christensen
- Department of Bioscience, Arctic Research Centre, Aarhus University, Roskilde, Denmark
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Maxim Dorodnikov
- Department of Soil Science of Temperate Ecosystems, Georg-August-University, Göttingen, Germany
| | - Marcin Jackowicz-Korczyński
- Department of Bioscience, Arctic Research Centre, Aarhus University, Roskilde, Denmark
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Amelie Lindgren
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
- Department of Physical Geography, Stockholm University, Stockholm, Sweden
| | | | - Hannu Nykänen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
| | - Markku Oinonen
- Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland
| | - Timo Oksanen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
| | - Vesa Palonen
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Claire C Treat
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
| | - Pertti J Martikainen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
| | - Christina Biasi
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
| |
Collapse
|
16
|
Kwon MJ, Natali SM, Hicks Pries CE, Schuur EAG, Steinhof A, Crummer KG, Zimov N, Zimov SA, Heimann M, Kolle O, Göckede M. Drainage enhances modern soil carbon contribution but reduces old soil carbon contribution to ecosystem respiration in tundra ecosystems. GLOBAL CHANGE BIOLOGY 2019; 25:1315-1325. [PMID: 30681227 DOI: 10.1111/gcb.14578] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 01/15/2019] [Accepted: 01/17/2019] [Indexed: 05/06/2023]
Abstract
Warming temperatures are likely to accelerate permafrost thaw in the Arctic, potentially leading to the release of old carbon previously stored in deep frozen soil layers. Deeper thaw depths in combination with geomorphological changes due to the loss of ice structures in permafrost, may modify soil water distribution, creating wetter or drier soil conditions. Previous studies revealed higher ecosystem respiration rates under drier conditions, and this study investigated the cause of the increased ecosystem respiration rates using radiocarbon signatures of respired CO2 from two drying manipulation experiments: one in moist and the other in wet tundra. We demonstrate that higher contributions of CO2 from shallow soil layers (0-15 cm; modern soil carbon) drive the increased ecosystem respiration rates, while contributions from deeper soil (below 15 cm from surface and down to the permafrost table; old soil carbon) decreased. These changes can be attributed to more aerobic conditions in shallow soil layers, but also the soil temperature increases in shallow layers but decreases in deep layers, due to the altered thermal properties of organic soils. Decreased abundance of aerenchymatous plant species following drainage in wet tundra reduced old carbon release but increased aboveground plant biomass elevated contributions of autotrophic respiration to ecosystem respiration. The results of this study suggest that drier soils following drainage may accelerate decomposition of modern soil carbon in shallow layers but slow down decomposition of old soil carbon in deep layers, which may offset some of the old soil carbon loss from thawing permafrost.
Collapse
Affiliation(s)
- Min Jung Kwon
- Max Planck Institute for Biogeochemistry, Jena, Germany
- Korea Polar Research Institute, Incheon, South Korea
| | | | - Caitlin E Hicks Pries
- Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire
| | - Edward A G Schuur
- Center for Ecosystem Science and Society, and Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona
| | - Axel Steinhof
- Max Planck Institute for Biogeochemistry, Jena, Germany
| | - K Grace Crummer
- Department of Biology, University of Florida, Gainesville, Florida
| | - Nikita Zimov
- North-East Science Station, Pacific Institute for Geography, Far-Eastern Branch of Russian Academy of Science, Chersky, Republic of Sakha (Yakutia), Russia
| | - Sergey A Zimov
- North-East Science Station, Pacific Institute for Geography, Far-Eastern Branch of Russian Academy of Science, Chersky, Republic of Sakha (Yakutia), Russia
| | - Martin Heimann
- Max Planck Institute for Biogeochemistry, Jena, Germany
- Division of Atmospheric Sciences, Department of Physics, Helsinki University, Helsinki, Finland
| | - Olaf Kolle
- Max Planck Institute for Biogeochemistry, Jena, Germany
| | | |
Collapse
|
17
|
Nitrogen availability regulates topsoil carbon dynamics after permafrost thaw by altering microbial metabolic efficiency. Nat Commun 2018; 9:3951. [PMID: 30262803 PMCID: PMC6160441 DOI: 10.1038/s41467-018-06232-y] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 08/16/2018] [Indexed: 01/06/2023] Open
Abstract
Input of labile carbon may accelerate the decomposition of existing soil organic matter (priming effect), with the priming intensity depending on changes in soil nitrogen availability after permafrost thaw. However, experimental evidence for the linkage between the priming effect and post-thaw nitrogen availability is unavailable. Here we test the hypothesis that elevated nitrogen availability after permafrost collapse inhibits the priming effect by increasing microbial metabolic efficiency based on a combination of thermokarst-induced natural nitrogen gradient and nitrogen addition experiment. We find a negative correlation between the priming intensity and soil total dissolved nitrogen concentration along the thaw sequence. The negative effect is confirmed by the reduced priming effect after nitrogen addition. In contrast to the prevailing view, this nitrogen-regulated priming intensity is independent of extracellular enzyme activities but associated with microbial metabolic efficiency. These findings demonstrate that post-thaw nitrogen availability regulates topsoil carbon dynamics through its modification of microbial metabolic efficiency. Soil nitrogen availability may alter carbon dynamics after permafrost thaw, but experimental evidence for this carbon-nitrogen interaction is still lacking. Here the authors show that elevated post-thaw nitrogen availability inhibits soil carbon release through its enhancement in microbial metabolic efficiency.
Collapse
|
18
|
Gentsch N, Wild B, Mikutta R, Čapek P, Diáková K, Schrumpf M, Turner S, Minnich C, Schaarschmidt F, Shibistova O, Schnecker J, Urich T, Gittel A, Šantrůčková H, Bárta J, Lashchinskiy N, Fuß R, Richter A, Guggenberger G. Temperature response of permafrost soil carbon is attenuated by mineral protection. GLOBAL CHANGE BIOLOGY 2018; 24:3401-3415. [PMID: 29774972 DOI: 10.1111/gcb.14316] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 03/19/2018] [Accepted: 04/16/2018] [Indexed: 06/08/2023]
Abstract
Climate change in Arctic ecosystems fosters permafrost thaw and makes massive amounts of ancient soil organic carbon (OC) available to microbial breakdown. However, fractions of the organic matter (OM) may be protected from rapid decomposition by their association with minerals. Little is known about the effects of mineral-organic associations (MOA) on the microbial accessibility of OM in permafrost soils and it is not clear which factors control its temperature sensitivity. In order to investigate if and how permafrost soil OC turnover is affected by mineral controls, the heavy fraction (HF) representing mostly MOA was obtained by density fractionation from 27 permafrost soil profiles of the Siberian Arctic. In parallel laboratory incubations, the unfractionated soils (bulk) and their HF were comparatively incubated for 175 days at 5 and 15°C. The HF was equivalent to 70 ± 9% of the bulk CO2 respiration as compared to a share of 63 ± 1% of bulk OC that was stored in the HF. Significant reduction of OC mineralization was found in all treatments with increasing OC content of the HF (HF-OC), clay-size minerals and Fe or Al oxyhydroxides. Temperature sensitivity (Q10) decreased with increasing soil depth from 2.4 to 1.4 in the bulk soil and from 2.9 to 1.5 in the HF. A concurrent increase in the metal-to-HF-OC ratios with soil depth suggests a stronger bonding of OM to minerals in the subsoil. There, the younger 14 C signature in CO2 than that of the OC indicates a preferential decomposition of the more recent OM and the existence of a MOA fraction with limited access of OM to decomposers. These results indicate strong mineral controls on the decomposability of OM after permafrost thaw and on its temperature sensitivity. Thus, we here provide evidence that OM temperature sensitivity can be attenuated by MOA in permafrost soils.
Collapse
Affiliation(s)
- Norman Gentsch
- Institute of Soil Science, Leibniz Universität Hannover, Hannover, Germany
| | - Birgit Wild
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
- Austrian Polar Research Institute, Vienna, Austria
- Department of Environmental Science and Analytical Chemistry, Stockholm University, Stockholm, Sweden
- Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
| | - Robert Mikutta
- Institute of Soil Science, Leibniz Universität Hannover, Hannover, Germany
- Soil Science and Soil Protection, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany
| | - Petr Čapek
- Department of Ecosystems Biology, University of South Bohemia, České Budéjovice, Czech Republic
| | - Katka Diáková
- Department of Ecosystems Biology, University of South Bohemia, České Budéjovice, Czech Republic
| | | | - Stephanie Turner
- Federal Institute for Geosciences and Natural Resources (BGR), Hannover, Germany
| | - Cynthia Minnich
- Institute of Soil Science, Leibniz Universität Hannover, Hannover, Germany
- Soil Ecology, University of Bayreuth, Bayreuth, Germany
| | | | - Olga Shibistova
- Institute of Soil Science, Leibniz Universität Hannover, Hannover, Germany
- V.N. Sukachev Institute of Forest, Siberian Branch of Russian Academy of Sciences, Krasnoyarsk, Russia
| | - Jörg Schnecker
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
- Austrian Polar Research Institute, Vienna, Austria
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, New Hampshire
| | - Tim Urich
- Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
- Institute of Microbiology, Ernst-Moritz-Arndt University, Greifswald, Germany
| | - Antje Gittel
- Department of Biology, Centre for Geobiology, University of Bergen, Bergen, Norway
- Department of Bioscience, Centre for Geomicrobiology, Aarhus, Denmark
| | - Hana Šantrůčková
- Department of Ecosystems Biology, University of South Bohemia, České Budéjovice, Czech Republic
| | - Jiři Bárta
- Department of Ecosystems Biology, University of South Bohemia, České Budéjovice, Czech Republic
| | - Nikolay Lashchinskiy
- Central Siberian Botanical Garden, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia
| | - Roland Fuß
- Thünen Institute of Climate-Smart Agriculture, Braunschweig, Germany
| | - Andreas Richter
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
- Austrian Polar Research Institute, Vienna, Austria
| | - Georg Guggenberger
- Institute of Soil Science, Leibniz Universität Hannover, Hannover, Germany
- V.N. Sukachev Institute of Forest, Siberian Branch of Russian Academy of Sciences, Krasnoyarsk, Russia
| |
Collapse
|
19
|
Monteux S, Weedon JT, Blume-Werry G, Gavazov K, Jassey VEJ, Johansson M, Keuper F, Olid C, Dorrepaal E. Long-term in situ permafrost thaw effects on bacterial communities and potential aerobic respiration. ISME JOURNAL 2018; 12:2129-2141. [PMID: 29875436 PMCID: PMC6092332 DOI: 10.1038/s41396-018-0176-z] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 03/15/2018] [Accepted: 03/28/2018] [Indexed: 12/05/2022]
Abstract
The decomposition of large stocks of soil organic carbon in thawing permafrost might depend on more than climate change-induced temperature increases: indirect effects of thawing via altered bacterial community structure (BCS) or rooting patterns are largely unexplored. We used a 10-year in situ permafrost thaw experiment and aerobic incubations to investigate alterations in BCS and potential respiration at different depths, and the extent to which they are related with each other and with root density. Active layer and permafrost BCS strongly differed, and the BCS in formerly frozen soils (below the natural thawfront) converged under induced deep thaw to strongly resemble the active layer BCS, possibly as a result of colonization by overlying microorganisms. Overall, respiration rates decreased with depth and soils showed lower potential respiration when subjected to deeper thaw, which we attributed to gradual labile carbon pool depletion. Despite deeper rooting under induced deep thaw, root density measurements did not improve soil chemistry-based models of potential respiration. However, BCS explained an additional unique portion of variation in respiration, particularly when accounting for differences in organic matter content. Our results suggest that by measuring bacterial community composition, we can improve both our understanding and the modeling of the permafrost carbon feedback.
Collapse
Affiliation(s)
- Sylvain Monteux
- Climate Impacts Research Centre (CIRC), Department of Ecology and Environmental Sciences, Umeå Universitet, 981 07, Abisko, Sweden.
| | - James T Weedon
- Systems Ecology, Department of Ecological Sciences, Vrije Universiteit Amsterdam, 1081 HV, Amsterdam, The Netherlands.,PLECO, Department of Biology, University of Antwerp, 2610, Wilrijk, Belgium
| | - Gesche Blume-Werry
- Climate Impacts Research Centre (CIRC), Department of Ecology and Environmental Sciences, Umeå Universitet, 981 07, Abisko, Sweden
| | - Konstantin Gavazov
- Climate Impacts Research Centre (CIRC), Department of Ecology and Environmental Sciences, Umeå Universitet, 981 07, Abisko, Sweden.,Federal Institute for Forest, Snow and Landscape Research WSL, CH-1015, Lausanne, Switzerland
| | - Vincent E J Jassey
- Functional Ecology and Environment Laboratory (ECOLAB), Department of Biology and Geosciences, UMR 6245 Université Toulouse III Paul Sabatier, 31062, Toulouse cedex 09, France
| | - Margareta Johansson
- Department of Physical Geography and Ecosystem Science, Lund Universitet, 223 62, Lund, Sweden
| | - Frida Keuper
- INRA, AgroImpact UR1158, Site Laon, 02000, Barenton Bugny, France
| | - Carolina Olid
- Climate Impacts Research Centre (CIRC), Department of Ecology and Environmental Sciences, Umeå Universitet, 981 07, Abisko, Sweden
| | - Ellen Dorrepaal
- Climate Impacts Research Centre (CIRC), Department of Ecology and Environmental Sciences, Umeå Universitet, 981 07, Abisko, Sweden
| |
Collapse
|
20
|
Blok D, Faucherre S, Banyasz I, Rinnan R, Michelsen A, Elberling B. Contrasting above- and belowground organic matter decomposition and carbon and nitrogen dynamics in response to warming in High Arctic tundra. GLOBAL CHANGE BIOLOGY 2018; 24:2660-2672. [PMID: 29235209 DOI: 10.1111/gcb.14017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 11/29/2017] [Indexed: 06/07/2023]
Abstract
Tundra regions are projected to warm rapidly during the coming decades. The tundra biome holds the largest terrestrial carbon pool, largely contained in frozen permafrost soils. With warming, these permafrost soils may thaw and become available for microbial decomposition, potentially providing a positive feedback to global warming. Warming may directly stimulate microbial metabolism but may also indirectly stimulate organic matter turnover through increased plant productivity by soil priming from root exudates and accelerated litter turnover rates. Here, we assess the impacts of experimental warming on turnover rates of leaf litter, active layer soil and thawed permafrost sediment in two high-arctic tundra heath sites in NE-Greenland, either dominated by evergreen or deciduous shrubs. We incubated shrub leaf litter on the surface of control and warmed plots for 1 and 2 years. Active layer soil was collected from the plots to assess the effects of 8 years of field warming on soil carbon stocks. Finally, we incubated open cores filled with newly thawed permafrost soil for 2 years in the active layer of the same plots. After field incubation, we measured basal respiration rates of recovered thawed permafrost cores in the lab. Warming significantly reduced litter mass loss by 26% after 1 year incubation, but differences in litter mass loss among treatments disappeared after 2 years incubation. Warming also reduced litter nitrogen mineralization and decreased the litter carbon to nitrogen ratio. Active layer soil carbon stocks were reduced 15% by warming, while soil dissolved nitrogen was reduced by half in warmed plots. Warming had a positive legacy effect on carbon turnover rates in thawed permafrost cores, with 10% higher respiration rates measured in cores from warmed plots. These results demonstrate that warming may have contrasting effects on above- and belowground tundra carbon turnover, possibly governed by microbial resource availability.
Collapse
Affiliation(s)
- Daan Blok
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
- Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
| | - Samuel Faucherre
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
| | - Imre Banyasz
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
| | - Riikka Rinnan
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Anders Michelsen
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Bo Elberling
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|