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Dou X, Hu T, Köster K, Sun A, Li G, Yue Y, Sun L, Ding Y. Temporal dynamics of soil dissolved organic carbon in temperate forest managed by prescribed burning in Northeast China. ENVIRONMENTAL RESEARCH 2023; 237:117065. [PMID: 37660872 DOI: 10.1016/j.envres.2023.117065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/29/2023] [Accepted: 08/31/2023] [Indexed: 09/05/2023]
Abstract
Dissolved organic carbon (DOC) is an important function of soil organic carbon and sensitive to environmental disturbance. Few studies have explored the variations in soil DOC dynamics and effects on soil physicochemical properties following prescribed burnings. In this study, Pinus koraiensis plantation forests in Northeast China were selected and subjected to prescribed burning in early November 2018. Soil DOC and different soil physicochemical and biological properties in the 0-10 cm and 10-20 cm soil layers were sampled six times within two years after a prescribed burning. In this study, some soil physicochemical (SOC, TN, and ST) and microbial biomass properties (MBC) recovered within two years after a prescribed burning. Compared to the unburned control stands, the post-fire soil DOC concentrations in the upper and lower soil layers increased by 16% and 12%, respectively. Soil DOC concentrations varied with sampling time, and peaked one year after the prescribed burning. Our results showed that soil chemical properties (NH4+-N and pH) rather than biological properties (microbial biomass) were the main driving factors for changes in post-fire soil DOC concentrations. Current study provides an important reference for post-fire and seasonal soil C cycling in plantation forests of Northeast China.
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Affiliation(s)
- Xu Dou
- Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, College of Forestry, Northeast Forestry University, 26 Hexing Road, 150040, Harbin, China
| | - Tongxin Hu
- Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, College of Forestry, Northeast Forestry University, 26 Hexing Road, 150040, Harbin, China
| | - Kajar Köster
- Department of Environmental and Biological Sciences, University of Eastern Finland, 80101, Joensuu, Finland
| | - Aobo Sun
- Liaoning Academy of Agricultural Sciences, 84 Dongling Road, 110161, Shenyang, China
| | - Guangxin Li
- Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, College of Forestry, Northeast Forestry University, 26 Hexing Road, 150040, Harbin, China
| | - Yang Yue
- Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, College of Forestry, Northeast Forestry University, 26 Hexing Road, 150040, Harbin, China
| | - Long Sun
- Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, College of Forestry, Northeast Forestry University, 26 Hexing Road, 150040, Harbin, China.
| | - Yiyang Ding
- Department of Forest Sciences/ Institute for Atmospheric Sciences and Earth System Research (INAR), Department of Physics, University of Helsinki, 00014 Helsinki, Finland
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2
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Vaezzadeh V, Zhong G, Zhang G. Benzene polycarboxylic acids as molecular markers of black carbon: Progresses and challenges. CHEMOSPHERE 2023; 341:140112. [PMID: 37689153 DOI: 10.1016/j.chemosphere.2023.140112] [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: 05/29/2023] [Revised: 08/29/2023] [Accepted: 09/06/2023] [Indexed: 09/11/2023]
Abstract
Black carbon (BC) is generated as a result of the pyrolysis of biomass and fossil fuels. Different approaches have been taken to analyse BC in the environment, including thermal, optical and chemical methods. The chemical approach which uses benzene polycarboxylic acids (BPCAs) as molecular markers of BC has gained popularity within the scientific community recently. These pyrogenic molecular markers can be used to reconstruct ancient fire history and human presence. Here we review the development of the BPCA protocols for the analysis of BC and the previous studies that have used these methods. Additionally, this review explores the biogeochemical factors that influence the content and composition of BPCAs, which in turn affect the sources attributed to BC. These factors include the generation temperature of char, photodegradation, biodegradation and the interference of non-pyrogenic organic matter (OM) in BPCA-BC analysis. Different combustion temperatures can yield charred BC with varying degrees of aromatic condensation throughout the BC continuum, while aged soot-BC undergoes photochemical degradation, causing the loss of its original condensed aromatic structure. Photodegradation reduces the degree of BC condensation by preferentially breaking down the most condensed forms, whereas biodegradation primarily mineralizes the smaller and more biolabile BC. Non-pyrogenic sources, such as humic acids (HAs), have been found to contribute up to 25% of BPCA-BC in soil, and their presence can lead to overestimations of BC. Future research should focus on calibrating contemporary BPCA protocols using known reference materials and investigating the role of non-pyrogenic OM in BPCA-BC analysis.
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Affiliation(s)
- Vahab Vaezzadeh
- State Key Laboratory of Organic Geochemistry and Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou, 510640, China.
| | - Guangcai Zhong
- State Key Laboratory of Organic Geochemistry and Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou, 510640, China.
| | - Gan Zhang
- State Key Laboratory of Organic Geochemistry and Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou, 510640, China.
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3
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Howell A, Helmkamp S, Belmont E. Stable polycyclic aromatic carbon (SPAC) formation in wildfire chars and engineered biochars. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 849:157610. [PMID: 35907547 DOI: 10.1016/j.scitotenv.2022.157610] [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: 04/26/2022] [Revised: 06/22/2022] [Accepted: 07/20/2022] [Indexed: 06/15/2023]
Abstract
Pyrogenic carbon (PyC) is an important component of wildfire chars and engineered biochars due to its potential environmental longevity, the most environmentally stable fraction of which is called stable polycyclic aromatic carbon (SPAC) and is projected to persist in global environments for >1000 yr. Rigorous characterization of SPAC, whether formed in wildfires or engineered, is essential for accurate global carbon cycle models. However, the quantification of SPAC remains challenging and methods for its direct characterization are often inaccessible and/or highly specialized. Additionally, these methods often rely on SPAC formation measured in laboratory biochars produced in inert environments, which have been shown to correlate poorly with wildfire chars and/or engineered biochars manufactured in oxidative environments. The present study investigated the relationship between SPAC formation and physicochemical metrics - mass loss and molar H:C and O:C ratios - that capture the influences of multiple formation variables, including gas environment temperature, O2 availability, and pyrolysis duration, and negates the need for these variables to be directly measured. SPAC content is measured in this study using hydrogen pyrolysis (HyPy), which is an established accurate method for characterizing that most environmentally stable PyC fraction. Results show that SPAC formation and elemental ratios correlate linearly with increased mass loss, which is reflective of increased pyrolysis severity. The relationship between these char characteristics allows for SPAC prediction based on measurement of mass loss during char formation, as well as the standardized elemental analysis method. In this study, wildfire chars exhibited relatively low SPAC contents of <30 wt% on a dry, ash-free basis, indicating that a significant fraction of PyC formed in these chars remains labile or semi-labile, while engineered biochars had a range of SPAC contents up to approximately 75 wt%. The predictive SPAC models developed in this work can improve global carbon accounting models.
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Affiliation(s)
- Alexandra Howell
- Department of Mechanical Engineering, The University of Wyoming, Laramie, WY, USA
| | - Sophia Helmkamp
- Department of Mechanical Engineering, The University of Wyoming, Laramie, WY, USA
| | - Erica Belmont
- Department of Mechanical Engineering, The University of Wyoming, Laramie, WY, USA.
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Possinger AR, Weiglein TL, Bowman MM, Gallo AC, Hatten JA, Heckman KA, Matosziuk LM, Nave LE, SanClements MD, Swanston CW, Strahm BD. Climate Effects on Subsoil Carbon Loss Mediated by Soil Chemistry. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:16224-16235. [PMID: 34813696 DOI: 10.1021/acs.est.1c04909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Subsoils store at least 50% of soil organic carbon (SOC) globally, but climate change may accelerate subsoil SOC (SOCsub) decomposition and amplify SOC-climate feedbacks. The climate sensitivity of SOCsub decomposition varies across systems, but we lack the mechanistic links needed to predict system-specific SOCsub vulnerability as a function of measurable properties at larger scales. Here, we show that soil chemical properties exert significant control over SOCsub decomposition under elevated temperature and moisture in subsoils collected across terrestrial National Ecological Observatory Network sites. Compared to a suite of soil and site-level variables, a divalent base cation-to-reactive metal gradient, linked to dominant mechanisms of SOCsub mineral protection, was the best predictor of the climate sensitivity of SOC decomposition. The response was "U"-shaped, showing higher sensitivity to temperature and moisture when either extractable base cations or reactive metals were highest. However, SOCsub in base cation-dominated subsoils was more sensitive to moisture than temperature, with the opposite relationship demonstrated in reactive metal-dominated subsoils. These observations highlight the importance of system-specific mechanisms of mineral stabilization in the prediction of SOCsub vulnerability to climate drivers. Our observations also form the basis for a spatially explicit, scalable, and mechanistically grounded tool for improved prediction of SOCsub response to climate change.
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Affiliation(s)
- Angela R Possinger
- Department of Forest Resources and Environmental Conservation, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Tyler L Weiglein
- Department of Forest Resources and Environmental Conservation, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Maggie M Bowman
- Environmental Studies Program, University of Colorado Boulder, Boulder, Colorado 80303, United States
- Institute of Arctic and Alpine Research (INSTAAR), University of Colorado Boulder, Boulder, Colorado 80303, United States
| | - Adrian C Gallo
- Department of Forest Engineering, Resources and Management, Oregon State University, Corvallis, Oregon 97331, United States
| | - Jeff A Hatten
- Department of Forest Engineering, Resources and Management, Oregon State University, Corvallis, Oregon 97331, United States
| | - Katherine A Heckman
- Northern Research Station, USDA Forest Service, Houghton, Michigan 49931, United States
| | - Lauren M Matosziuk
- Department of Forest Engineering, Resources and Management, Oregon State University, Corvallis, Oregon 97331, United States
| | - Lucas E Nave
- University of Michigan Biological Station, Pellston, Michigan 49769, United States
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Michael D SanClements
- Institute of Arctic and Alpine Research (INSTAAR), University of Colorado Boulder, Boulder, Colorado 80303, United States
- Battelle, National Ecological Observatory Network (NEON), Boulder, Colorado 80301, United States
| | | | - Brian D Strahm
- Department of Forest Resources and Environmental Conservation, Virginia Tech, Blacksburg, Virginia 24061, United States
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Jiménez-González MA, De la Rosa JM, Aksoy E, Jeffery S, Oliveira BRF, Verheijen FGA. Spatial distribution of pyrogenic carbon in Iberian topsoils estimated by chemometric analysis of infrared spectra. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 790:148170. [PMID: 34380273 DOI: 10.1016/j.scitotenv.2021.148170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/26/2021] [Accepted: 05/27/2021] [Indexed: 06/13/2023]
Abstract
Understanding the global carbon (C) cycle is critical to accurately model feedbacks between climate and soil. Thus, many climate change studies focused on soil organic carbon (SOC) stock changes. Pyrogenic carbon (PyC) is one of the most stable fractions of soil organic matter (SOM). Accurate maps based on measured PyC contents are required to facilitate future soil management decisions and soil-climate feedback modelling. However, consistent measurements that cover large areas are rare. Therefore, this study aimed to map the PyC content and stock of the Iberian Peninsula, which covers contrasting climatic zones and has long-term data on wildfire occurrence. A partial least square (PLS) regression using the mid-infrared spectra (1800-400 cm-1) was applied to a dataset composed of 2961 soil samples from the Iberian component of the LUCAS 2009 database. The values of PyC for LUCAS points were modelled to obtain a map of topsoil PyC by a random forest (RF) approach using 36 auxiliary variables. The results were validated through comparison with documented historical wildfire activity and anthropogenic energy production. A strong relationship was found between these sources and the distribution of PyC. Our study estimates that the accumulated PyC in Iberian Peninsula soils comprises between 3.09 and 20.39% of total organic carbon (TOC) in the topsoil. Forests have higher PyC contents than grasslands, followed by agricultural soils. The incidence of recurrent wildfires also has a notable influence on PyC contents. This study shows the potential of estimating PyC with a single, rapid, low cost, chemometric method using new or archived soil spectra, and has the ability to improve soil-climate feedback modelling. It also offers a possible tool for measuring, reporting and verifying soil C stocks, which is likely to be important moving forward if soils are used as sinks for C sequestration.
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Affiliation(s)
- M A Jiménez-González
- HERCULES Laboratory, University of Évora, Largo Marquês de Marialva, 8, 7000-809 Évora, Portugal; Department of Geology and Geochemistry, Autonomous University of Madrid, 28049 Madrid, Spain
| | - J M De la Rosa
- Instituto de Recursos Naturales y Agrobiología de Sevilla, Consejo Superior de Investigaciones Científicas (IRNAS-CSIC). Reina Mercedes Av., 10, 41012 Seville, Spain.
| | - E Aksoy
- Via Luigi Vanvitelli, 2, 00153 Rome, Italy
| | - S Jeffery
- Agriculture and Environment Department, Harper Adams University, Newport, Shropshire TF10 8NB, United Kingdom
| | - B R F Oliveira
- Earth Surface Processes Team, Centre for Environmental and Marine Studies (CESAM), Dept. Environment and Planning, University of Aveiro, 3810-193 Aveiro, Portugal
| | - F G A Verheijen
- Earth Surface Processes Team, Centre for Environmental and Marine Studies (CESAM), Dept. Environment and Planning, University of Aveiro, 3810-193 Aveiro, Portugal
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Pellegrini AFA, Caprio AC, Georgiou K, Finnegan C, Hobbie SE, Hatten JA, Jackson RB. Low-intensity frequent fires in coniferous forests transform soil organic matter in ways that may offset ecosystem carbon losses. GLOBAL CHANGE BIOLOGY 2021; 27:3810-3823. [PMID: 33884700 DOI: 10.1111/gcb.15648] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 04/07/2021] [Indexed: 06/12/2023]
Abstract
The impact of shifting disturbance regimes on soil carbon (C) storage is a key uncertainty in global change research. Wildfires in coniferous forests are becoming more frequent in many regions, potentially causing large C emissions. Repeated low-intensity prescribed fires can mitigate wildfire severity, but repeated combustion may decrease soil C unless compensatory responses stabilize soil organic matter. Here, we tested how 30 years of decadal prescribed burning affected C and nitrogen (N) in plants, detritus, and soils in coniferous forests in the Sierra Nevada mountains, USA. Tree basal area and litter stocks were resilient to fire, but fire reduced forest floor C by 77% (-36.4 Mg C/ha). In mineral soils, fire reduced C that was free from minerals by 41% (-4.4 Mg C/ha) but not C associated with minerals, and only in depths ≤ 5 cm. Fire also transformed the properties of remaining mineral soil organic matter by increasing the proportion of C in a pyrogenic form (from 3.2% to 7.5%) and associated with minerals (from 46% to 58%), suggesting the remaining soil C is more resistant to decomposition. Laboratory assays illustrated that fire reduced microbial CO2 respiration rates by 55% and the activity of eight extracellular enzymes that degrade cellulosic and aromatic compounds by 40-66%. Lower decomposition was correlated with lower inorganic N (-49%), especially ammonium, suggesting N availability is coupled with decomposition. The relative increase in forms of soil organic matter that are resistant to decay or stabilized onto mineral surfaces, and the associated decline in decomposition suggest that low-intensity fires may promote mineral soil C storage in pools with long mean residence times in coniferous forests.
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Affiliation(s)
- Adam F A Pellegrini
- Department of Earth System Science, Stanford University, Stanford, CA, USA
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
| | - Anthony C Caprio
- United States Department of the Interior, National Park Service, Sequoia and Kings Canyon National Parks, Three Rivers, CA, USA
| | - Katerina Georgiou
- Department of Earth System Science, Stanford University, Stanford, CA, USA
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Colin Finnegan
- Department of Earth System Science, Stanford University, Stanford, CA, USA
| | - Sarah E Hobbie
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN, USA
| | - Jeffery A Hatten
- Department of Forest Engineering, Resources & Management, Oregon State University, Corvallis, OR, USA
| | - Robert B Jackson
- Department of Earth System Science, Stanford University, Stanford, CA, USA
- Woods Institute for the Environment, Stanford University, Stanford, CA, USA
- Precourt Institute for Energy, Stanford University, Stanford, CA, USA
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Abstract
Prescribed burning is a tool that is frequently used for various land management objectives, mainly related to reduction of hazardous forest fuels, habitat management and ecological restoration. Given the crucial role of soil in forest ecosystem processes and functions, assessing the effects of prescribed burning on soil is particularly relevant. This study reviews research on the impacts of repeated prescribed burning on the physical, chemical and biological properties of soil. The available information shows that the effects are highly variable, rather inconsistent and generally minor for most of the soil characteristics studied, while a number of soil properties show contrasting responses. On the other hand, ecosystem characteristics, differences in fire severity, frequency of application and the cumulative effect of treatment repetition over time, have possibly made it more difficult to find a more common response in soil attributes. Our study has also revealed some limitations of previous research that may have contributed to this result, including a limited number of long-term studies, conducted at a few experimental sites, and in a limited number of forest ecosystems. Research issues concerning the effects of prescribed fire on soil are presented. The need to integrate such research into a broader interdisciplinary framework, encompassing the role of the fire regime on ecosystem functions and processes, is also highlighted.
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