Articles | Volume 22, issue 8
https://doi.org/10.5194/bg-22-2097-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-22-2097-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
30 Apr 2025
Research article |
| 30 Apr 2025
| 30 Apr 2025
CO2 flux characteristics of the open savanna and its response to environmental factors in the dry–hot valley of Jinsha River, China
Chaolei Yang
Yunnan Provincial Observation and Research Station for Soil and Water Resources and Carbon Sequestration in the Alpine Gorge Area of Jinsha River, Chuxiong, 651400, China
Kunming General Survey of Natural Resources Center, China Geological Survey, Kunming, 650111, China
Technology Innovation Center for Natural Carbon Sink, Ministry of Natural Resources, Kunming, 650111, China
Key Laboratory of Coupling Process and Effect of Natural Resources Elements, Ministry of Natural Resources, Beijing, 100055, China
Yunnan Provincial Observation and Research Station for Soil and Water Resources and Carbon Sequestration in the Alpine Gorge Area of Jinsha River, Chuxiong, 651400, China
Kunming General Survey of Natural Resources Center, China Geological Survey, Kunming, 650111, China
Technology Innovation Center for Natural Carbon Sink, Ministry of Natural Resources, Kunming, 650111, China
Key Laboratory of Coupling Process and Effect of Natural Resources Elements, Ministry of Natural Resources, Beijing, 100055, China
Jingqi Cui
Institute of Space Weather, School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing, 210044, China
Guangxiong He
Tropical Eco-Agriculture Research Institute, Yunnan Academy of Agricultural Sciences, Chuxiong, 651300, China
Jingyuan Li
Institute of Space Weather, School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing, 210044, China
Canfeng Li
Yunnan Provincial Observation and Research Station for Soil and Water Resources and Carbon Sequestration in the Alpine Gorge Area of Jinsha River, Chuxiong, 651400, China
Kunming General Survey of Natural Resources Center, China Geological Survey, Kunming, 650111, China
Technology Innovation Center for Natural Carbon Sink, Ministry of Natural Resources, Kunming, 650111, China
Haichuang Duan
Kunming General Survey of Natural Resources Center, China Geological Survey, Kunming, 650111, China
Zong Wei
Yunnan Provincial Observation and Research Station for Soil and Water Resources and Carbon Sequestration in the Alpine Gorge Area of Jinsha River, Chuxiong, 651400, China
Kunming General Survey of Natural Resources Center, China Geological Survey, Kunming, 650111, China
Liu Yan
Yunnan Provincial Observation and Research Station for Soil and Water Resources and Carbon Sequestration in the Alpine Gorge Area of Jinsha River, Chuxiong, 651400, China
Kunming General Survey of Natural Resources Center, China Geological Survey, Kunming, 650111, China
Xin Xia
Yunnan Provincial Observation and Research Station for Soil and Water Resources and Carbon Sequestration in the Alpine Gorge Area of Jinsha River, Chuxiong, 651400, China
Kunming General Survey of Natural Resources Center, China Geological Survey, Kunming, 650111, China
Yong Huang
Yunnan Provincial Observation and Research Station for Soil and Water Resources and Carbon Sequestration in the Alpine Gorge Area of Jinsha River, Chuxiong, 651400, China
Kunming General Survey of Natural Resources Center, China Geological Survey, Kunming, 650111, China
Aihua Jiang
Yunnan Provincial Observation and Research Station for Soil and Water Resources and Carbon Sequestration in the Alpine Gorge Area of Jinsha River, Chuxiong, 651400, China
Kunming General Survey of Natural Resources Center, China Geological Survey, Kunming, 650111, China
Yuwen Feng
Bazhong Meteorological Office of Sichuan Province, Bazhong, 636000, China
Related subject area
Biogeochemistry: Greenhouse Gases
Rising Arctic seas and thawing permafrost: uncovering the carbon cycle impact in a thermokarst lagoon system in the outer Mackenzie Delta, Canada
Modelling decadal trends and the impact of extreme events on carbon fluxes in a temperate deciduous forest using a terrestrial biosphere model
Surface CO2 gradients challenge conventional CO2 emission quantification in lentic water bodies under calm conditions
Spatiotemporal variability of CO2, N2O and CH4 fluxes from a semi-deciduous tropical forest soil in the Congo Basin
Eddy-covariance fluxes of CO2, CH4 and N2O in a drained peatland forest after clear-cutting
Eddy covariance evaluation of ecosystem fluxes at a temperate saltmarsh in Victoria, Australia, shows large CO2 uptake
Interferences caused by the biogeochemical methane cycle in peats during the assessment of abandoned oil wells
Carbon sequestration in different urban vegetation types in Southern Finland
Proglacial methane emissions driven by meltwater and groundwater flushing in a high-Arctic glacial catchment
Seasonal and interannual variability in CO2 fluxes in southern Africa seen by GOSAT
Air temperature and precipitation constraining the modelled wetland methane emissions in a boreal region in northern Europe
Ensemble estimates of global wetland methane emissions over 2000–2020
Seasonal carbon fluxes from vegetation and soil in a Mediterranean non-tidal salt marsh
Explainable machine learning for modeling of net ecosystem exchange in boreal forests
Dynamics of CO2 and CH4 fluxes in Red Sea mangrove soils
Nitrous oxide (N2O) in Macquarie Harbour, Tasmania
Technical note: A low-cost, automatic soil–plant–atmosphere enclosure system to investigate CO2 and evapotranspiration flux dynamics
Tidal influence on carbon dioxide and methane fluxes from tree stems and soils in mangrove forests
Drought conditions disrupt atmospheric carbon uptake in a Mediterranean saline lake
Physicochemical perturbation increases nitrous oxide production from denitrification in soils and sediments
Carbon degradation and mobilisation potentials of thawing permafrost peatlands in northern Norway inferred from laboratory incubations
Seasonal dynamics and regional distribution patterns of CO2 and CH4 in the north-eastern Baltic Sea
Interannual and seasonal variability of the air–sea CO2 exchange at Utö in the coastal region of the Baltic Sea
CO2 emissions of drained coastal peatlands in the Netherlands and potential emission reduction by water infiltration systems
Intercomparison of biogenic CO2 flux models in four urban parks in the city of Zurich
Influence of wind strength and direction on diffusive methane fluxes and atmospheric methane concentrations above the North Sea
Using eddy covariance observations to determine the carbon sequestration characteristics of subalpine forests in the Qinghai–Tibet Plateau
Isotopomer labeling and oxygen dependence of hybrid nitrous oxide production
The emission of CO from tropical rainforest soils
Modelling CO2 and N2O emissions from soils in silvopastoral systems of the West African Sahelian band
A case study on topsoil removal and rewetting for paludiculture: effect on biogeochemistry and greenhouse gas emissions from Typha latifolia, Typha angustifolia, and Azolla filiculoides
Observations of methane net sinks in the Arctic tundra
Assessing improvements in global ocean pCO2 machine learning reconstructions with Southern Ocean autonomous sampling
Timescale dependence of airborne fraction and underlying climate–carbon-cycle feedbacks for weak perturbations in CMIP5 models
Technical note: Preventing CO2 overestimation from mercuric or copper(II) chloride preservation of dissolved greenhouse gases in freshwater samples
Exploring temporal and spatial variation of nitrous oxide flux using several years of peatland forest automatic chamber data
Diurnal versus spatial variability of greenhouse gas emissions from an anthropogenically modified lowland river in Germany
Regional assessment and uncertainty analysis of carbon and nitrogen balances at cropland scale using the ecosystem model LandscapeDNDC
Resolving heterogeneous fluxes from tundra halves the growing season carbon budget
Lawns and meadows in urban green space – a comparison from perspectives of greenhouse gases, drought resilience and plant functional types
Large contribution of soil N2O emission to the global warming potential of a large-scale oil palm plantation despite changing from conventional to reduced management practices
Identifying landscape hot and cold spots of soil greenhouse gas fluxes by combining field measurements and remote sensing data
Enhanced Southern Ocean CO2 outgassing as a result of stronger and poleward shifted southern hemispheric westerlies
Spatial and temporal variability of methane emissions and environmental conditions in a hyper-eutrophic fishpond
Optical and radar Earth observation data for upscaling methane emissions linked to permafrost degradation in sub-Arctic peatlands in northern Sweden
Herbivore–shrub interactions influence ecosystem respiration and biogenic volatile organic compound composition in the subarctic
Methane emissions due to reservoir flushing: a significant emission pathway?
Carbon dioxide and methane fluxes from mounds of African fungus-growing termites
Diel and seasonal methane dynamics in the shallow and turbulent Wadden Sea
Technical note: Skirt chamber – an open dynamic method for the rapid and minimally intrusive measurement of greenhouse gas emissions from peatlands
Maren Jenrich, Juliane Wolter, Susanne Liebner, Christian Knoblauch, Guido Grosse, Fiona Giebeler, Dustin Whalen, and Jens Strauss
Biogeosciences, 22, 2069–2086, https://doi.org/10.5194/bg-22-2069-2025, https://doi.org/10.5194/bg-22-2069-2025, 2025
Short summary
Short summary
Climate warming in the Arctic is causing the erosion of permafrost coasts and the transformation of permafrost lakes into lagoons. To understand how this affects greenhouse gas (GHG) emissions, we studied carbon dioxide (CO₂) and methane (CH₄) production in lagoons with varying sea connections. Younger lagoons produce more CH₄, while CO₂ increases under more marine conditions. Flooding of permafrost lowlands due to rising sea levels may lead to higher GHG emissions from Arctic coasts in future.
Tea Thum, Tuuli Miinalainen, Outi Seppälä, Holly Croft, Cheryl Rogers, Ralf Staebler, Silvia Caldararu, and Sönke Zaehle
Biogeosciences, 22, 1781–1807, https://doi.org/10.5194/bg-22-1781-2025, https://doi.org/10.5194/bg-22-1781-2025, 2025
Short summary
Short summary
Climate change has the potential to influence the carbon sequestration potential of terrestrial ecosystems, and here the nitrogen cycle is also important. We used the terrestrial biosphere model QUINCY (QUantifying Interactions between terrestrial Nutrient CYcles and the climate system) in a mixed deciduous forest in Canada. We investigated the usefulness of using the leaf area index and leaf chlorophyll content to improve the parameterization of the model. This work paves the way for using spaceborne observations in model parameterizations, also including information on the nitrogen cycle.
Patrick Aurich, Uwe Spank, and Matthias Koschorreck
Biogeosciences, 22, 1697–1709, https://doi.org/10.5194/bg-22-1697-2025, https://doi.org/10.5194/bg-22-1697-2025, 2025
Short summary
Short summary
Lakes can be sources and sinks of the greenhouse gas carbon dioxide. The gas exchange between the atmosphere and the water can be measured by taking gas samples from them. However, the depth of water samples is not well defined, which may cause errors. We hypothesized that gradients of CO2 concentrations develop under the surface when wind speeds are very low. Our measurements show that such a gradient can occur on calm nights, potentially shifting lakes from a CO2 sink to a source.
Roxanne Daelman, Marijn Bauters, Matti Barthel, Emmanuel Bulonza, Lodewijk Lefevre, José Mbifo, Johan Six, Klaus Butterbach-Bahl, Benjamin Wolf, Ralf Kiese, and Pascal Boeckx
Biogeosciences, 22, 1529–1542, https://doi.org/10.5194/bg-22-1529-2025, https://doi.org/10.5194/bg-22-1529-2025, 2025
Short summary
Short summary
The increase in atmospheric concentrations of several greenhouse gases (GHGs) since 1750 is attributed to human activity. However, natural ecosystems, such as tropical forests, also contribute to GHG budgets. The Congo Basin hosts the second largest tropical forest and is understudied. In this study, measurements of soil GHG exchange were carried out during 16 months in a tropical forest in the Congo Basin. Overall, the soil acted as a major source of CO2 and N2O and a minor sink of CH4.
Olli-Pekka Tikkasalo, Olli Peltola, Pavel Alekseychik, Juha Heikkinen, Samuli Launiainen, Aleksi Lehtonen, Qian Li, Eduardo Martínez-García, Mikko Peltoniemi, Petri Salovaara, Ville Tuominen, and Raisa Mäkipää
Biogeosciences, 22, 1277–1300, https://doi.org/10.5194/bg-22-1277-2025, https://doi.org/10.5194/bg-22-1277-2025, 2025
Short summary
Short summary
The emissions of greenhouse gases (GHGs) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) were measured from a clear-cut peatland forest site. The measurements covered the whole year of 2022, which was the second growing season after the clear-cut. The site was a strong GHG source, and the highest emissions came from CO2, followed by N2O and CH4. A statistical model that included information on different surfaces at the site was developed to unravel surface-type-specific GHG fluxes.
Ruth Reef, Edoardo Daly, Tivanka Anandappa, Eboni-Jane Vienna-Hallam, Harriet Robertson, Matthew Peck, and Adrien Guyot
Biogeosciences, 22, 1149–1162, https://doi.org/10.5194/bg-22-1149-2025, https://doi.org/10.5194/bg-22-1149-2025, 2025
Short summary
Short summary
Studies show that saltmarshes excel at capturing carbon from the atmosphere. In this study, we measured CO2 flux in an Australian temperate saltmarsh on French Island. The temperate saltmarsh exhibited strong seasonality. During the warmer growing season, the saltmarsh absorbed 10.5 g CO2 m−2 on average daily from the atmosphere. Even in winter, when plants were dormant, it continued to be a CO2 sink, albeit a smaller one. Cool temperatures and high cloud cover inhibit carbon sequestration.
Sebastian F. A. Jordan, Stefan Schloemer, Martin Krüger, Tanja Heffner, Marcus A. Horn, and Martin Blumenberg
Biogeosciences, 22, 809–830, https://doi.org/10.5194/bg-22-809-2025, https://doi.org/10.5194/bg-22-809-2025, 2025
Short summary
Short summary
Using a multilayer approach, we studied the methane flux, soil gas composition, and isotopic signatures of soil methane and carbon dioxide at eight cut and buried abandoned oil wells in a peat-rich area of northern Germany. The detected methane emissions were of biogenic, peat origin and were not associated with the abandoned wells. Additional microbial analysis and methane oxidation rate measurements demonstrated a high methane emission mitigation potential in the studied peat soils.
Laura Thölix, Leif Backman, Minttu Havu, Esko Karvinen, Jesse Soininen, Justine Trémeau, Olli Nevalainen, Joyson Ahongshangbam, Leena Järvi, and Liisa Kulmala
Biogeosciences, 22, 725–749, https://doi.org/10.5194/bg-22-725-2025, https://doi.org/10.5194/bg-22-725-2025, 2025
Short summary
Short summary
Cities aim for carbon neutrality and seek to understand urban vegetation's role as a carbon sink. Direct measurements are challenging, so models are used to estimate the urban carbon cycle. We evaluated model performance at estimating carbon sequestration in lawns, park trees, and urban forests in Helsinki, Finland. Models captured seasonal and annual variations well. Trees had higher sequestration rates than lawns, and irrigation often enhanced carbon sinks.
Gabrielle E. Kleber, Leonard Magerl, Alexandra V. Turchyn, Stefan Schloemer, Mark Trimmer, Yizhu Zhu, and Andrew Hodson
Biogeosciences, 22, 659–674, https://doi.org/10.5194/bg-22-659-2025, https://doi.org/10.5194/bg-22-659-2025, 2025
Short summary
Short summary
Our research on Svalbard shows that glacier melt rivers can transport large amounts of methane, a potent greenhouse gas. By studying a glacier over one summer, we found that its river was highly concentrated in methane, suggesting that rivers could provide a significant source of methane emissions as the Arctic warms and glaciers melt. This is the first time such emissions have been measured on Svalbard, indicating a wider environmental concern as such processes are occurring across the Arctic.
Eva-Marie Metz, Sanam Noreen Vardag, Sourish Basu, Martin Jung, and André Butz
Biogeosciences, 22, 555–584, https://doi.org/10.5194/bg-22-555-2025, https://doi.org/10.5194/bg-22-555-2025, 2025
Short summary
Short summary
We estimate CO2 fluxes in semiarid southern Africa from 2009 to 2018 based on satellite CO2 measurements and atmospheric inverse modeling. By selecting process-based vegetation models, which agree with the satellite CO2 fluxes, we find that soil respiration mainly drives the seasonality, whereas photosynthesis substantially influences the interannual variability. Our study emphasizes the need for better representation of the response of semiarid ecosystems to soil rewetting in vegetation models.
Tuula Aalto, Aki Tsuruta, Jarmo Mäkelä, Jurek Müller, Maria Tenkanen, Eleanor Burke, Sarah Chadburn, Yao Gao, Vilma Mannisenaho, Thomas Kleinen, Hanna Lee, Antti Leppänen, Tiina Markkanen, Stefano Materia, Paul A. Miller, Daniele Peano, Olli Peltola, Benjamin Poulter, Maarit Raivonen, Marielle Saunois, David Wårlind, and Sönke Zaehle
Biogeosciences, 22, 323–340, https://doi.org/10.5194/bg-22-323-2025, https://doi.org/10.5194/bg-22-323-2025, 2025
Short summary
Short summary
Wetland methane responses to temperature and precipitation were studied in a boreal wetland-rich region in northern Europe using ecosystem models, atmospheric inversions, and upscaled flux observations. The ecosystem models differed in their responses to temperature and precipitation and in their seasonality. However, multi-model means, inversions, and upscaled fluxes had similar seasonality, and they suggested co-limitation by temperature and precipitation.
Zhen Zhang, Benjamin Poulter, Joe R. Melton, William J. Riley, George H. Allen, David J. Beerling, Philippe Bousquet, Josep G. Canadell, Etienne Fluet-Chouinard, Philippe Ciais, Nicola Gedney, Peter O. Hopcroft, Akihiko Ito, Robert B. Jackson, Atul K. Jain, Katherine Jensen, Fortunat Joos, Thomas Kleinen, Sara H. Knox, Tingting Li, Xin Li, Xiangyu Liu, Kyle McDonald, Gavin McNicol, Paul A. Miller, Jurek Müller, Prabir K. Patra, Changhui Peng, Shushi Peng, Zhangcai Qin, Ryan M. Riggs, Marielle Saunois, Qing Sun, Hanqin Tian, Xiaoming Xu, Yuanzhi Yao, Yi Xi, Wenxin Zhang, Qing Zhu, Qiuan Zhu, and Qianlai Zhuang
Biogeosciences, 22, 305–321, https://doi.org/10.5194/bg-22-305-2025, https://doi.org/10.5194/bg-22-305-2025, 2025
Short summary
Short summary
This study assesses global methane emissions from wetlands between 2000 and 2020 using multiple models. We found that wetland emissions increased by 6–7 Tg CH4 yr-1 in the 2010s compared to the 2000s. Rising temperatures primarily drove this increase, while changes in precipitation and CO2 levels also played roles. Our findings highlight the importance of wetlands in the global methane budget and the need for continuous monitoring to understand their impact on climate change.
Lorena Carrasco-Barea, Dolors Verdaguer, Maria Gispert, Xavier D. Quintana, Hélène Bourhis, and Laura Llorens
Biogeosciences, 22, 289–304, https://doi.org/10.5194/bg-22-289-2025, https://doi.org/10.5194/bg-22-289-2025, 2025
Short summary
Short summary
Carbon dioxide fluxes have been measured seasonally in four plant species in a Mediterranean non-tidal salt marsh, highlighting the high carbon removal potential that these species have. Carbon dioxide and methane emissions from soil showed high variability among the habitats studied, and they were generally higher than those observed in tidal salt marshes. Our results are important for making more accurate predictions regarding carbon emissions from these ecosystems.
Ekaterina Ezhova, Topi Laanti, Anna Lintunen, Pasi Kolari, Tuomo Nieminen, Ivan Mammarella, Keijo Heljanko, and Markku Kulmala
Biogeosciences, 22, 257–288, https://doi.org/10.5194/bg-22-257-2025, https://doi.org/10.5194/bg-22-257-2025, 2025
Short summary
Short summary
Machine learning (ML) models are gaining popularity in biogeosciences. They are applied as gap-filling methods and used to upscale carbon fluxes to larger areas. Here we use explainable artificial intelligence (XAI) methods to elucidate the performance of machine learning models for carbon dioxide fluxes in boreal forests. We show that statistically equal models treat input variables differently. XAI methods can help scientists make informed decisions when applying ML models in their research.
Jessica Breavington, Alexandra Steckbauer, Chuancheng Fu, Mongi Ennasri, and Carlos M. Duarte
Biogeosciences, 22, 117–134, https://doi.org/10.5194/bg-22-117-2025, https://doi.org/10.5194/bg-22-117-2025, 2025
Short summary
Short summary
Mangrove carbon storage in the Red Sea is lower than average due to challenging growth conditions. We collected mangrove soil cores over multiple seasons to measure greenhouse gas (GHG) flux of carbon dioxide and methane. GHG emissions are a small offset to mangrove carbon storage overall but punctuated by periods of high emission. This variation is linked to environmental and soil properties, which were also measured. The findings aid understanding of GHG dynamics in arid mangrove ecosystems.
Johnathan Daniel Maxey, Neil D. Hartstein, Hermann W. Bange, and Moritz Müller
Biogeosciences, 21, 5613–5637, https://doi.org/10.5194/bg-21-5613-2024, https://doi.org/10.5194/bg-21-5613-2024, 2024
Short summary
Short summary
The distribution of N2O in fjord-like estuaries is poorly described in the Southern Hemisphere. Our study describes N2O distribution and its drivers in one such system in Macquarie Harbour, Tasmania. Water samples were collected seasonally in 2022 and 2023. Results show the system removes atmospheric N2O when river flow is high, whereas the system emits N2O when the river flow is low. N2O generated in basins is intercepted by the surface water and exported to the ocean during high river flow.
Wael Al Hamwi, Maren Dubbert, Jörg Schaller, Matthias Lück, Marten Schmidt, and Mathias Hoffmann
Biogeosciences, 21, 5639–5651, https://doi.org/10.5194/bg-21-5639-2024, https://doi.org/10.5194/bg-21-5639-2024, 2024
Short summary
Short summary
We present a fully automatic, low-cost soil–plant enclosure system to monitor CO2 and evapotranspiration fluxes within greenhouse experiments. It operates in two modes: independent, using low-cost sensors, and dependent, where multiple chambers connect to a single gas analyzer via a low-cost multiplexer. This system provides precise, accurate measurements and high temporal resolution, enabling comprehensive monitoring of plant–soil responses to various treatments and conditions.
Zhao-Jun Yong, Wei-Jen Lin, Chiao-Wen Lin, and Hsing-Juh Lin
Biogeosciences, 21, 5247–5260, https://doi.org/10.5194/bg-21-5247-2024, https://doi.org/10.5194/bg-21-5247-2024, 2024
Short summary
Short summary
We measured CO2 and CH4 fluxes from mangrove stems and soils of Avicennia marina and Kandelia obovata during tidal cycles. Both stem types served as CO2 and CH4 sources, emitting less CH4 than soils, with no difference in CO2 flux. While A. marina stems showed increased CO2 fluxes from low to high tides, they acted as a CH4 sink before flooding and as a source after ebbing. However, K. obovata stems showed no flux pattern. This study highlights the need to consider tidal influence and species.
Ihab Alfadhel, Ignacio Peralta-Maraver, Isabel Reche, Enrique P. Sánchez-Cañete, Sergio Aranda-Barranco, Eva Rodríguez-Velasco, Andrew S. Kowalski, and Penélope Serrano-Ortiz
Biogeosciences, 21, 5117–5129, https://doi.org/10.5194/bg-21-5117-2024, https://doi.org/10.5194/bg-21-5117-2024, 2024
Short summary
Short summary
Inland saline lakes are crucial in the global carbon cycle, but increased droughts may alter their carbon exchange capacity. We measured CO2 and CH4 fluxes in a Mediterranean saline lake using the eddy covariance method under dry and wet conditions. We found the lake acts as a carbon sink during wet periods but not during droughts. These results highlight the importance of saline lakes in carbon sequestration and their vulnerability to climate-change-induced droughts.
Nathaniel B. Weston, Cynthia Troy, Patrick J. Kearns, Jennifer L. Bowen, William Porubsky, Christelle Hyacinthe, Christof Meile, Philippe Van Cappellen, and Samantha B. Joye
Biogeosciences, 21, 4837–4851, https://doi.org/10.5194/bg-21-4837-2024, https://doi.org/10.5194/bg-21-4837-2024, 2024
Short summary
Short summary
Nitrous oxide (N2O) is a potent greenhouse and ozone-depleting gas produced largely from microbial nitrogen cycling processes, and human activities have resulted in increases in atmospheric N2O. We investigate the role of physical and chemical disturbances to soils and sediments in N2O production. We demonstrate that physicochemical perturbation increases N2O production, microbial community adapts over time, and initial perturbation appears to confer resilience to subsequent disturbance.
Sigrid Trier Kjær, Sebastian Westermann, Nora Nedkvitne, and Peter Dörsch
Biogeosciences, 21, 4723–4737, https://doi.org/10.5194/bg-21-4723-2024, https://doi.org/10.5194/bg-21-4723-2024, 2024
Short summary
Short summary
Permafrost peatlands are thawing due to climate change, releasing large quantities of carbon that degrades upon thawing and is released as CO2, CH4 or dissolved organic carbon (DOC). We incubated thawed Norwegian permafrost peat plateaus and thermokarst pond sediment found next to permafrost for up to 350 d to measure carbon loss. CO2 production was initially the highest, whereas CH4 production increased over time. The largest carbon loss was measured at the top of the peat plateau core as DOC.
Silvie Lainela, Erik Jacobs, Stella-Theresa Luik, Gregor Rehder, and Urmas Lips
Biogeosciences, 21, 4495–4519, https://doi.org/10.5194/bg-21-4495-2024, https://doi.org/10.5194/bg-21-4495-2024, 2024
Short summary
Short summary
We evaluate the variability of carbon dioxide and methane in the surface layer of the north-eastern basins of the Baltic Sea in 2018. We show that the shallower coastal areas have considerably higher spatial variability and seasonal amplitude of surface layer pCO2 and cCH4 than measured in the offshore areas of the Baltic Sea. Despite this high variability, caused mostly by coastal physical processes, the average annual air–sea CO2 fluxes differed only marginally between the sub-basins.
Martti Honkanen, Mika Aurela, Juha Hatakka, Lumi Haraguchi, Sami Kielosto, Timo Mäkelä, Jukka Seppälä, Simo-Matti Siiriä, Ken Stenbäck, Juha-Pekka Tuovinen, Pasi Ylöstalo, and Lauri Laakso
Biogeosciences, 21, 4341–4359, https://doi.org/10.5194/bg-21-4341-2024, https://doi.org/10.5194/bg-21-4341-2024, 2024
Short summary
Short summary
The exchange of CO2 between the sea and the atmosphere was studied in the Archipelago Sea, Baltic Sea, in 2017–2021, using an eddy covariance technique. The sea acted as a net source of CO2 with an average yearly emission of 27.1 gC m-2 yr-1, indicating that the marine ecosystem respired carbon that originated elsewhere. The yearly CO2 emission varied between 18.2–39.2 gC m-2 yr-1, mostly due to the yearly variation of ecosystem carbon uptake.
Ralf C. H. Aben, Daniël van de Craats, Jim Boonman, Stijn H. Peeters, Bart Vriend, Coline C. F. Boonman, Ype van der Velde, Gilles Erkens, and Merit van den Berg
Biogeosciences, 21, 4099–4118, https://doi.org/10.5194/bg-21-4099-2024, https://doi.org/10.5194/bg-21-4099-2024, 2024
Short summary
Short summary
Drained peatlands cause high CO2 emissions. We assessed the effectiveness of subsurface water infiltration systems (WISs) in reducing CO2 emissions related to increases in water table depth (WTD) on 12 sites for up to 4 years. Results show WISs markedly reduced emissions by 2.1 t CO2-C ha-1 yr-1. The relationship between the amount of carbon above the WTD and CO2 emission was stronger than the relationship between WTD and emission. Long-term monitoring is crucial for accurate emission estimates.
Stavros Stagakis, Dominik Brunner, Junwei Li, Leif Backman, Anni Karvonen, Lionel Constantin, Leena Järvi, Minttu Havu, Jia Chen, Sophie Emberger, and Liisa Kulmala
EGUsphere, https://doi.org/10.5194/egusphere-2024-2475, https://doi.org/10.5194/egusphere-2024-2475, 2024
Short summary
Short summary
The balance between CO2 uptake and emissions from urban green areas is still not well understood. This study evaluated for the first time the urban park CO2 exchange simulations by four different types of biosphere models by comparing them with observations. Even though some advantages and disadvantages of the different model types were identified, there was no strong evidence that more complex models performed better than simple ones.
Ingeborg Bussmann, Eric P. Achterberg, Holger Brix, Nicolas Brüggemann, Götz Flöser, Claudia Schütze, and Philipp Fischer
Biogeosciences, 21, 3819–3838, https://doi.org/10.5194/bg-21-3819-2024, https://doi.org/10.5194/bg-21-3819-2024, 2024
Short summary
Short summary
Methane (CH4) is an important greenhouse gas and contributes to climate warming. However, the input of CH4 from coastal areas to the atmosphere is not well defined. Dissolved and atmospheric CH4 was determined at high spatial resolution in or above the North Sea. The atmospheric CH4 concentration was mainly influenced by wind direction. With our detailed study on the spatial distribution of CH4 fluxes we were able to provide a detailed and more realistic estimation of coastal CH4 fluxes.
Niu Zhu, Jinniu Wang, Dongliang Luo, Xufeng Wang, Cheng Shen, and Ning Wu
Biogeosciences, 21, 3509–3522, https://doi.org/10.5194/bg-21-3509-2024, https://doi.org/10.5194/bg-21-3509-2024, 2024
Short summary
Short summary
Our study delves into the vital role of subalpine forests in the Qinghai–Tibet Plateau as carbon sinks in the context of climate change. Utilizing advanced eddy covariance systems, we uncover their significant carbon sequestration potential, observing distinct seasonal patterns influenced by temperature, humidity, and radiation. Notably, these forests exhibit robust carbon absorption, with potential implications for global carbon balance.
Colette L. Kelly, Nicole M. Travis, Pascale Anabelle Baya, Claudia Frey, Xin Sun, Bess B. Ward, and Karen L. Casciotti
Biogeosciences, 21, 3215–3238, https://doi.org/10.5194/bg-21-3215-2024, https://doi.org/10.5194/bg-21-3215-2024, 2024
Short summary
Short summary
Nitrous oxide, a potent greenhouse gas, accumulates in regions of the ocean that are low in dissolved oxygen. We used a novel combination of chemical tracers to determine how nitrous oxide is produced in one of these regions, the eastern tropical North Pacific Ocean. Our experiments showed that the two most important sources of nitrous oxide under low-oxygen conditions are denitrification, an anaerobic process, and a novel “hybrid” process performed by ammonia-oxidizing archaea.
Hella van Asperen, Thorsten Warneke, Alessandro Carioca de Araújo, Bruce Forsberg, Sávio José Filgueiras Ferreira, Thomas Röckmann, Carina van der Veen, Sipko Bulthuis, Leonardo Ramos de Oliveira, Thiago de Lima Xavier, Jailson da Mata, Marta de Oliveira Sá, Paulo Ricardo Teixeira, Julie Andrews de França e Silva, Susan Trumbore, and Justus Notholt
Biogeosciences, 21, 3183–3199, https://doi.org/10.5194/bg-21-3183-2024, https://doi.org/10.5194/bg-21-3183-2024, 2024
Short summary
Short summary
Carbon monoxide (CO) is regarded as an important indirect greenhouse gas. Soils can emit and take up CO, but, until now, uncertainty remains as to which process dominates in tropical rainforests. We present the first soil CO flux measurements from a tropical rainforest. Based on our observations, we report that tropical rainforest soils are a net source of CO. In addition, we show that valley streams and inundated areas are likely additional hot spots of CO in the ecosystem.
Yélognissè Agbohessou, Claire Delon, Manuela Grippa, Eric Mougin, Daouda Ngom, Espoir Koudjo Gaglo, Ousmane Ndiaye, Paulo Salgado, and Olivier Roupsard
Biogeosciences, 21, 2811–2837, https://doi.org/10.5194/bg-21-2811-2024, https://doi.org/10.5194/bg-21-2811-2024, 2024
Short summary
Short summary
Emissions of greenhouse gases in the Sahel are not well represented because they are considered weak compared to the rest of the world. However, natural areas in the Sahel emit carbon dioxide and nitrous oxides, which need to be assessed because of extended surfaces. We propose an assessment of such emissions in Sahelian silvopastoral systems and of how they are influenced by environmental characteristics. These results are essential to inform climate change strategies in the region.
Merit van den Berg, Thomas M. Gremmen, Renske J. E. Vroom, Jacobus van Huissteden, Jim Boonman, Corine J. A. van Huissteden, Ype van der Velde, Alfons J. P. Smolders, and Bas P. van de Riet
Biogeosciences, 21, 2669–2690, https://doi.org/10.5194/bg-21-2669-2024, https://doi.org/10.5194/bg-21-2669-2024, 2024
Short summary
Short summary
Drained peatlands emit 3 % of the global greenhouse gas emissions. Paludiculture is a way to reduce CO2 emissions while at the same time generating an income for landowners. The side effect is the potentially high methane emissions. We found very high methane emissions for broadleaf cattail compared with narrowleaf cattail and water fern. The rewetting was, however, effective to stop CO2 emissions for all species. The highest potential to reduce greenhouse gas emissions had narrowleaf cattail.
Antonio Donateo, Daniela Famulari, Donato Giovannelli, Arturo Mariani, Mauro Mazzola, Stefano Decesari, and Gianluca Pappaccogli
EGUsphere, https://doi.org/10.5194/egusphere-2024-1440, https://doi.org/10.5194/egusphere-2024-1440, 2024
Short summary
Short summary
This study focuses on direct measurements of CO2 and CH4 turbulent eddy covariance fluxes in tundra ecosystems in the Svalbard Islands over a two-year period. Our results reveal dynamic interactions between climatic conditions and ecosystem activities such as photosynthesis and microbial activity. The observed net summertime methane uptake is correlated with the activation and aeration of soil microorganisms. High temperature anomalies increase CO2 and CH4 emissions.
Thea H. Heimdal, Galen A. McKinley, Adrienne J. Sutton, Amanda R. Fay, and Lucas Gloege
Biogeosciences, 21, 2159–2176, https://doi.org/10.5194/bg-21-2159-2024, https://doi.org/10.5194/bg-21-2159-2024, 2024
Short summary
Short summary
Measurements of ocean carbon are limited in time and space. Machine learning algorithms are therefore used to reconstruct ocean carbon where observations do not exist. Improving these reconstructions is important in order to accurately estimate how much carbon the ocean absorbs from the atmosphere. In this study, we find that a small addition of observations from the Southern Ocean, obtained by autonomous sampling platforms, could significantly improve the reconstructions.
Guilherme L. Torres Mendonça, Julia Pongratz, and Christian H. Reick
Biogeosciences, 21, 1923–1960, https://doi.org/10.5194/bg-21-1923-2024, https://doi.org/10.5194/bg-21-1923-2024, 2024
Short summary
Short summary
We study the timescale dependence of airborne fraction and underlying feedbacks by a theory of the climate–carbon system. Using simulations we show the predictive power of this theory and find that (1) this fraction generally decreases for increasing timescales and (2) at all timescales the total feedback is negative and the model spread in a single feedback causes the spread in the airborne fraction. Our study indicates that those are properties of the system, independently of the scenario.
François Clayer, Jan Erik Thrane, Kuria Ndungu, Andrew King, Peter Dörsch, and Thomas Rohrlack
Biogeosciences, 21, 1903–1921, https://doi.org/10.5194/bg-21-1903-2024, https://doi.org/10.5194/bg-21-1903-2024, 2024
Short summary
Short summary
Determination of dissolved greenhouse gas (GHG) in freshwater allows us to estimate GHG fluxes. Mercuric chloride (HgCl2) is used to preserve water samples prior to GHG analysis despite its environmental and health impacts and interferences with water chemistry in freshwater. Here, we tested the effects of HgCl2, two substitutes and storage time on GHG in water from two boreal lakes. Preservation with HgCl2 caused overestimation of CO2 concentration with consequences for GHG flux estimation.
Helena Rautakoski, Mika Korkiakoski, Jarmo Mäkelä, Markku Koskinen, Kari Minkkinen, Mika Aurela, Paavo Ojanen, and Annalea Lohila
Biogeosciences, 21, 1867–1886, https://doi.org/10.5194/bg-21-1867-2024, https://doi.org/10.5194/bg-21-1867-2024, 2024
Short summary
Short summary
Current and future nitrous oxide (N2O) emissions are difficult to estimate due to their high variability in space and time. Several years of N2O fluxes from drained boreal peatland forest indicate high importance of summer precipitation, winter temperature, and snow conditions in controlling annual N2O emissions. The results indicate increasing year-to-year variation in N2O emissions in changing climate with more extreme seasonal weather conditions.
Matthias Koschorreck, Norbert Kamjunke, Uta Koedel, Michael Rode, Claudia Schuetze, and Ingeborg Bussmann
Biogeosciences, 21, 1613–1628, https://doi.org/10.5194/bg-21-1613-2024, https://doi.org/10.5194/bg-21-1613-2024, 2024
Short summary
Short summary
We measured the emission of carbon dioxide (CO2) and methane (CH4) from different sites at the river Elbe in Germany over 3 days to find out what is more important for quantification: small-scale spatial variability or diurnal temporal variability. We found that CO2 emissions were very different between day and night, while CH4 emissions were more different between sites. Dried out river sediments contributed to CO2 emissions, while the side areas of the river were important CH4 sources.
Odysseas Sifounakis, Edwin Haas, Klaus Butterbach-Bahl, and Maria P. Papadopoulou
Biogeosciences, 21, 1563–1581, https://doi.org/10.5194/bg-21-1563-2024, https://doi.org/10.5194/bg-21-1563-2024, 2024
Short summary
Short summary
We performed a full assessment of the carbon and nitrogen cycles of a cropland ecosystem. An uncertainty analysis and quantification of all carbon and nitrogen fluxes were deployed. The inventory simulations include greenhouse gas emissions of N2O, NH3 volatilization and NO3 leaching from arable land cultivation in Greece. The inventory also reports changes in soil organic carbon and nitrogen stocks in arable soils.
Sarah M. Ludwig, Luke Schiferl, Jacqueline Hung, Susan M. Natali, and Roisin Commane
Biogeosciences, 21, 1301–1321, https://doi.org/10.5194/bg-21-1301-2024, https://doi.org/10.5194/bg-21-1301-2024, 2024
Short summary
Short summary
Landscapes are often assumed to be homogeneous when using eddy covariance fluxes, which can lead to biases when calculating carbon budgets. In this study we report eddy covariance carbon fluxes from heterogeneous tundra. We used the footprints of each flux observation to unmix the fluxes coming from components of the landscape. We identified and quantified hot spots of carbon emissions in the landscape. Accurately scaling with landscape heterogeneity yielded half as much regional carbon uptake.
Justine Trémeau, Beñat Olascoaga, Leif Backman, Esko Karvinen, Henriikka Vekuri, and Liisa Kulmala
Biogeosciences, 21, 949–972, https://doi.org/10.5194/bg-21-949-2024, https://doi.org/10.5194/bg-21-949-2024, 2024
Short summary
Short summary
We studied urban lawns and meadows in the Helsinki metropolitan area, Finland. We found that meadows are more resistant to drought events but that they do not increase carbon sequestration compared with lawns. Moreover, the transformation from lawns to meadows did not demonstrate any negative climate effects in terms of greenhouse gas emissions. Even though social and economic aspects also steer urban development, these results can guide planning to consider carbon-smart options.
Guantao Chen, Edzo Veldkamp, Muhammad Damris, Bambang Irawan, Aiyen Tjoa, and Marife D. Corre
Biogeosciences, 21, 513–529, https://doi.org/10.5194/bg-21-513-2024, https://doi.org/10.5194/bg-21-513-2024, 2024
Short summary
Short summary
We established an oil palm management experiment in a large-scale oil palm plantation in Jambi, Indonesia. We recorded oil palm fruit yield and measured soil CO2, N2O, and CH4 fluxes. After 4 years of treatment, compared with conventional fertilization with herbicide weeding, reduced fertilization with mechanical weeding did not reduce yield and soil greenhouse gas emissions, which highlights the legacy effects of over a decade of conventional management prior to the start of the experiment.
Elizabeth Gachibu Wangari, Ricky Mwangada Mwanake, Tobias Houska, David Kraus, Gretchen Maria Gettel, Ralf Kiese, Lutz Breuer, and Klaus Butterbach-Bahl
Biogeosciences, 20, 5029–5067, https://doi.org/10.5194/bg-20-5029-2023, https://doi.org/10.5194/bg-20-5029-2023, 2023
Short summary
Short summary
Agricultural landscapes act as sinks or sources of the greenhouse gases (GHGs) CO2, CH4, or N2O. Various physicochemical and biological processes control the fluxes of these GHGs between ecosystems and the atmosphere. Therefore, fluxes depend on environmental conditions such as soil moisture, soil temperature, or soil parameters, which result in large spatial and temporal variations of GHG fluxes. Here, we describe an example of how this variation may be studied and analyzed.
Laurie C. Menviel, Paul Spence, Andrew E. Kiss, Matthew A. Chamberlain, Hakase Hayashida, Matthew H. England, and Darryn Waugh
Biogeosciences, 20, 4413–4431, https://doi.org/10.5194/bg-20-4413-2023, https://doi.org/10.5194/bg-20-4413-2023, 2023
Short summary
Short summary
As the ocean absorbs 25% of the anthropogenic emissions of carbon, it is important to understand the impact of climate change on the flux of carbon between the ocean and the atmosphere. Here, we use a very high-resolution ocean, sea-ice, carbon cycle model to show that the capability of the Southern Ocean to uptake CO2 has decreased over the last 40 years due to a strengthening and poleward shift of the southern hemispheric westerlies. This trend is expected to continue over the coming century.
Petr Znachor, Jiří Nedoma, Vojtech Kolar, and Anna Matoušů
Biogeosciences, 20, 4273–4288, https://doi.org/10.5194/bg-20-4273-2023, https://doi.org/10.5194/bg-20-4273-2023, 2023
Short summary
Short summary
We conducted intensive spatial sampling of the hypertrophic fishpond to better understand the spatial dynamics of methane fluxes and environmental heterogeneity in fishponds. The diffusive fluxes of methane accounted for only a minor fraction of the total fluxes and both varied pronouncedly within the pond and over the studied summer season. This could be explained only by the water depth. Wind substantially affected temperature, oxygen and chlorophyll a distribution in the pond.
Sofie Sjögersten, Martha Ledger, Matthias Siewert, Betsabé de la Barreda-Bautista, Andrew Sowter, David Gee, Giles Foody, and Doreen S. Boyd
Biogeosciences, 20, 4221–4239, https://doi.org/10.5194/bg-20-4221-2023, https://doi.org/10.5194/bg-20-4221-2023, 2023
Short summary
Short summary
Permafrost thaw in Arctic regions is increasing methane emissions, but quantification is difficult given the large and remote areas impacted. We show that UAV data together with satellite data can be used to extrapolate emissions across the wider landscape as well as detect areas at risk of higher emissions. A transition of currently degrading areas to fen type vegetation can increase emission by several orders of magnitude, highlighting the importance of quantifying areas at risk.
Cole G. Brachmann, Tage Vowles, Riikka Rinnan, Mats P. Björkman, Anna Ekberg, and Robert G. Björk
Biogeosciences, 20, 4069–4086, https://doi.org/10.5194/bg-20-4069-2023, https://doi.org/10.5194/bg-20-4069-2023, 2023
Short summary
Short summary
Herbivores change plant communities through grazing, altering the amount of CO2 and plant-specific chemicals (termed VOCs) emitted. We tested this effect by excluding herbivores and studying the CO2 and VOC emissions. Herbivores reduced CO2 emissions from a meadow community and altered VOC composition; however, community type had the strongest effect on the amount of CO2 and VOCs released. Herbivores can mediate greenhouse gas emissions, but the effect is marginal and community dependent.
Ole Lessmann, Jorge Encinas Fernández, Karla Martínez-Cruz, and Frank Peeters
Biogeosciences, 20, 4057–4068, https://doi.org/10.5194/bg-20-4057-2023, https://doi.org/10.5194/bg-20-4057-2023, 2023
Short summary
Short summary
Based on a large dataset of seasonally resolved methane (CH4) pore water concentrations in a reservoir's sediment, we assess the significance of CH4 emissions due to reservoir flushing. In the studied reservoir, CH4 emissions caused by one flushing operation can represent 7 %–14 % of the annual CH4 emissions and depend on the timing of the flushing operation. In reservoirs with high sediment loadings, regular flushing may substantially contribute to the overall CH4 emissions.
Matti Räsänen, Risto Vesala, Petri Rönnholm, Laura Arppe, Petra Manninen, Markus Jylhä, Jouko Rikkinen, Petri Pellikka, and Janne Rinne
Biogeosciences, 20, 4029–4042, https://doi.org/10.5194/bg-20-4029-2023, https://doi.org/10.5194/bg-20-4029-2023, 2023
Short summary
Short summary
Fungus-growing termites recycle large parts of dead plant material in African savannas and are significant sources of greenhouse gases. We measured CO2 and CH4 fluxes from their mounds and surrounding soils in open and closed habitats. The fluxes scale with mound volume. The results show that emissions from mounds of fungus-growing termites are more stable than those from other termites. The soil fluxes around the mound are affected by the termite colonies at up to 2 m distance from the mound.
Tim René de Groot, Anne Margriet Mol, Katherine Mesdag, Pierre Ramond, Rachel Ndhlovu, Julia Catherine Engelmann, Thomas Röckmann, and Helge Niemann
Biogeosciences, 20, 3857–3872, https://doi.org/10.5194/bg-20-3857-2023, https://doi.org/10.5194/bg-20-3857-2023, 2023
Short summary
Short summary
This study investigates methane dynamics in the Wadden Sea. Our measurements revealed distinct variations triggered by seasonality and tidal forcing. The methane budget was higher in warmer seasons but surprisingly high in colder seasons. Methane dynamics were amplified during low tides, flushing the majority of methane into the North Sea or releasing it to the atmosphere. Methanotrophic activity was also elevated during low tide but mitigated only a small fraction of the methane efflux.
Frederic Thalasso, Brenda Riquelme, Andrés Gómez, Roy Mackenzie, Francisco Javier Aguirre, Jorge Hoyos-Santillan, Ricardo Rozzi, and Armando Sepulveda-Jauregui
Biogeosciences, 20, 3737–3749, https://doi.org/10.5194/bg-20-3737-2023, https://doi.org/10.5194/bg-20-3737-2023, 2023
Short summary
Short summary
A robust skirt-chamber design to capture and quantify greenhouse gas emissions from peatlands is presented. Compared to standard methods, this design improves the spatial resolution of field studies in remote locations while minimizing intrusion.
Cited articles
Archibald, S. A., Kirton, A., van der Merwe, M. R., Scholes, R. J., Williams, C. A., and Hanan, N.: Drivers of inter-annual variability in Net Ecosystem Exchange in a semi-arid savanna ecosystem, South Africa, Biogeosciences, 6, 251–266, https://doi.org/10.5194/bg-6-251-2009, 2009.
Arslan, A. M., Wang, X., Liu, B. Y., Xu, Y. N., Li, L., and Gong, X. Y.: Photosynthetic resource-use efficiency trade-offs triggered by vapour pressure deficit and nitrogen supply in a C4 species, Plant Physiol. Bioch., 197, 107666, https://doi.org/10.1016/j.plaphy.2023.107666, 2023.
Bai, X. J., Wang, X. F., Liu, X. H., and Zhou, X. Q.: Dynamics and driving factors of carbon fluxes in wetland, cropland and grassland ecosystems in Heihe river basin, Remote Sens., 37, 94–107, 2022.
Bai, X. Y., Zhang, S. R., Li, C. J., Xiong, L., Song, F. J., Du, C. C., Li, M. H., Luo, Q., Xue, Y. Y., and Wang, S. J.: A carbon-neutrality-capacity index for evaluating carbon sink contributions, Environ. Sci. Ecotechnol., 15, 100237, https://doi.org/10.1016/j.ese.2023.100237, 2023.
Bureau of Statistics of Yunnan Province: Yunnan Statistical Yearbook, China Statistics Press, Beijing, China, ISBN 9787523002537, 2023.
Campbell, G. S. and Norman, J. M.: An introduction to environmental biophysics, Springer Sci. Business Media, ISBN 9781461216261, 2012.
Carey, C. J., Tang, J. W., Templer, P. H., Kroeger, K. D., Crowther, T. W., Burton, A. J., Dukes, J. S., Emmett, B., Frey, S. D., Heskel, M. A., Jiang, L. F., Machmuller, M. B., Mohan, J., Panetta, A. M., Reich, P. B., Reinsch, S., Wang, X., Allison, S. D., Bamminger, C., Bridgham, S., Collins, S. L., de Dato, G., Eddy, W. C., Enquist, B. J., Estiarte, M., Harte, J., Henderson, A., Johnson, B. R., Larsen, K. S., Luo, Y. Q., Marhan, S., Melillo, J. M., Peñuelas, J., Pfeifer-Meister, L., Poll, C., Rastetter, E., Reinmann, A. B., Reynolds, L. L., Schmidt, I. K., Shaver, G. R., Strong, A. L., Suseela, V., and Tietema, A.: Temperature response of soil respiration largely unaltered with experimental warming, P. Natl. Acad. Sci. USA, 113, 13797–13802, https://doi.org/10.1073/pnas.1605365113, 2016.
Chen, W. N., Wang, S., Wang, J. S., Xia, J. Y., Luo, Y. Q., Yu, G. R., and Niu, S. L.: Evidence for widespread thermal optimality of ecosystem respiration, Nat. Ecol. Evol., 7, 1379–1387, https://doi.org/10.1038/s41559-023-02121-w, 2023.
Chen, Y. P., Niu, Y. Y., Li, W., Li, Y. Q., Gong, X. W., and Wang, X. Y.: Characteristics of carbon flux in sandy grassland ecosystem under natural restoration in Horqin sandy land, Plateau Meteorol., 38, 650–659, 2019.
Cui, H. C.: Challenges and approaches to crop improvement through C3-to-C4 engineering, Front. Plant Sci., 12, 715391, https://doi.org/10.3389/fpls.2021.715391, 2021.
Deng, Y.: The boundary definition and studyon the land use/cover change and landscape pattern of the dry-hot valley in Hengduan Mountains, Yunnan University, https://doi.org/10.27456/d.cnki.gyndu.2022.000408, 2022.
Dobson, A., Hopcraft, G., Mduma, S., Ogutu, J. O., Fryxell, J., Anderson, M., Archibald, S., Lehmann, C., Poole, J., Caro, T., Mulder, M. B., Holt, R. D., Berger, J., Rubenstein, D. I., Kahumbu, P., Chidumayo, E. N., Milner-Gulland, E. J., Schluter, D., Otto, S., Balmford, A., Wilcove, D., Pimm, S., Veldman, J. W., Olff, H., Noss, R., Holdo, R., Beale, C., Hempson, G., Kiwango, Y., Lindenmayer, D., Bond, W., Ritchie, M., and Sinclair, A. R. E.: Savannas are vital but overlooked carbon sinks, Science, 375, 392, https://doi.org/10.1126/science.abn4482, 2022.
Du, Q., Liu, H. Z., Feng, J. W., Wang, L., Huang, J. P., Zhang, W., and Bernhofer, C.: Carbon dioxide exchange processes over the grassland ecosystems in semiarid areas of China, Sci. China Earth Sci., 42, 711–722, https://doi.org/10.1007/s11430-011-4283-1, 2012.
Fei, X. H., Song, Q. H., Zhang, Y. P., Liu, Y. T., Sha, L. Q., Yu, G. R., Zhang, L. M., Duan, C. Q., Deng, Y., Wu, C. S., Lu, Z. Y., Luo, K., Chen, A. G., Xu, K., Liu, W. W., Huang, H., Jin, Y. Q., Zhou, R. W., Li, J., Lin, Y. X., Zhou, L. G., Fu, Y., Bai, X. L., Tang, X. H., Gao, J. B., Zhou, W. J., and Grace, J.: Carbon exchanges and their responses to temperature and precipitation in forest ecosystems in Yunnan, Southwest China, Sci. Total Environ., 616–617, 824–840, https://doi.org/10.1016/j.scitotenv.2017.10.239, 2017a.
Fei, X. H., Jin, Y. Q., Zhang, Y. P., Sha, L. Q., Liu, Y. T., Song, Q. H., Zhou, W. J., Liang, N. S., Yu, G. R., Zhang, L. M., Zhou, R. W., Li, J., Zhang, S. B., and Li, P. G.: Eddy covariance and biometric measurements show that a savanna ecosystem in Southwest China is a carbon sink, Sci. Rep.-UK, 7, 41025, https://doi.org/10.1038/srep41025, 2017b.
Grace, J., Lloyd, J., McIntyre, J., Miranda, A. C., Meir, P., Miranda, H., Moncrieff, J. M., Massheder, J., Wright, I. R., and Gash, J.: Fluxes of carbon dioxide and water vapour over an undisturbed tropical forest in south-west Amazonia, Glob. Change Biol., 1, 1–12, https://doi.org/10.1111/j.1365-2486.1995.tb00001.x, 1995.
Grace, J., José, J. S., Meir, P., Miranda, H. S., and Montes, R. A.: Productivity and carbon fluxes of tropical savannas, J. Biogeogr., 33, 387–400, https://doi.org/10.1111/j.1365-2699.2005.01448.x, 2006.
Green, J. K., Seneviratne, S. I., Berg, A. M., Findell, K. L., Hagemann, S., Lawrence, D. M., and Gentine, P.: Large influence of soil moisture on long-term terrestrial carbon uptake, Nature, 565, 476–479, https://doi.org/10.1038/s41586-018-0848-x, 2019.
Guo, W. Z., Jing, C. Q., Deng, X. J., Chen, C., Zhao, W. K., Hou, Z. X., and Wang, G. X.: Variations in carbon flux and factors influencing it on the northern slopes of the Tianshan Mountains, Acta Prataculturae Sin., 31, 1–12, https://doi.org/10.11686/cyxb2021137, 2022.
Hao, Y. B., Wang, Y. F., Sun, X. M., Huang, X. Z., Cui, X. Y., Niu, H. S., Zhang, Y. H., and Yu, G. R.: Seasonal variation in carbon exchange and its ecological analysis over Leymus chinensis steppe in Inner Mongolia, Sci. China Earth Sci., 49, 186–195, https://doi.org/10.1007/s11430-006-8186-5, 2006.
Harmon, T. C., Dierick, D., Trahan, N., Allen, M. F., Rundel, P. W., Oberbauer, S. F., Schwendenmann, L., and Zelikova, T. J.: Low-cost soil CO2 efflux and point concentration sensing systems for terrestrial ecology applications, Methods Ecol. Evol., 6, 1358–1362, https://doi.org/10.1111/2041-210X.12426, 2015.
He, B., Chen, C., Lin, S. R., Yuan, W. P., Chen, H. W., Chen, D. L., Zhang, Y. F., Guo, L. L., Zhao, X., Liu, X. B., Piao, S. L., Zhong, Z. Q., Wang, R., and Tang, R.: Worldwide impacts of atmospheric vapor pressure deficit on the interannual variability of terrestrial carbon sinks, Natl. Sci. Rev., 9, nwab150, https://doi.org/10.1093/nsr/nwab150, 2022.
He, G. X., Shi, Z. T., Fang, H. D., Shi, L. T., Wang, Y. D., Yang, H. Z., Yan, B. G., Yang, C. L., Yu, J. L., Liang, Q. L., Zhao, L., and Jiang, Q.: Climate and soil stressed elevation patterns of plant species to determine the aboveground biomass distributions in a valley-type Savanna, Front. Plant Sci., 15, 1324841, https://doi.org/10.3389/fpls.2024.1324841, 2024.
He, Y. B., Lu, P. Z., and Zhu, T.: Causes for the formation of dry-hot valleys in Hengduan Mountain-Yunnan plateau, Resour. Sci., 22, 69–72, 2000.
Hoffmann, W. A.: Seasonal flooding shapes forest–savanna transitions, P. Natl. Acad. Sci. USA, 120, e2312279120, https://doi.org/10.1073/pnas.2312279120, 2023.
Hsu, P. K., Takahashi, Y., Merilo, E., Costa, A., Zhang, L., Kernig, K., Lee, K. H., and Schroeder, J. I.: Raf-like kinases and receptor-like (pseudo) kinase GHR1 are required for stomatal vapor pressure difference response, P. Natl. Acad. Sci. USA, 118, e2107280118, https://doi.org/10.1073/pnas.2107280118, 2021.
Hu, Y., Zhu, X. P., Jia, H. T., Han, D. L., Hu, B. A., and Li, D. P.: Effects of fencing on ecosystem crabon exchange at meadow steppe in the northern slop oh the Tianshan Mountains, Chinese J. Plant Eco., 42, 372–381, https://doi.org/10.17521/cjpe.2016.0049, 2018.
Huang, M. T. and Zhai, P. M.: Impact of extreme seasonal drought on ecosystem carbon-water coupling across China, Adv. Clim. Change Res., 15, 914–923, https://doi.org/10.1016/j.accre.2024.08.001, 2024.
Hutley, L. B., Leuning, R., Beringer, J., and Cleugh, H. A.: The utility of the eddy covariance techniques as a tool in carbon accounting: tropical savanna as a case study, Aust. J. Bot., 53, 663–675, https://doi.org/10.1071/Bt04147, 2005.
IPCC (Intergovernmental Panel on Climate Change): Climate Change 2021: the Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, UK, https://doi.org/10.1017/9781009157896, 2021.
Jiang, J. M., Fei, S. M., He, Y. P., Zhang, F., and Kong, Q. H.: Study on vegetation restoration in dry-hot valleys of the Jinsha River, J. Southwest For. Univ., 27, 11–15, 2007.
Jiang, Q. Q., He, J. J., Li, Y. R., Yang, X. Y., Peng, Y., Wang, H., Yu, F., Wu, J., Gong, S. L., Che, H. Z., and Zhang, X. Y.: Analysis of the spatiotemporal changes in global land cover from 2001 to 2020, Sci. Total Environ., 908, 168354, https://doi.org/10.1016/j.scitotenv.2023.168354, 2024.
Jin, Y. Q., Li, J., Liu, C. G., Liu, Y. T., Zhang, Y. P., Song, Q. H., Sha, L. Q., Balasubramanian, D., Chen, A. G., Yang, D. X., and Li, P. G.: Precipitation reduction alters herbaceous community structure and composition in a savanna, J. Veg. Sci., 30, 821–831, https://doi.org/10.1111/jvs.12766, 2019.
Jin, Z. Z., Ou, X. K., and Zhou, Y.: The general situation of natural vegetation in dry-hot river valley of Yuanmou, Yunnan Province, Chin. J. Plant Ecol., 11, 308–317, 1987.
Johnston, A. S. A., Meade, A., Ardö, J., Arriga, N., Black, A., Blanken, P. D., Bonalo, D., Brümmer, C., Cescatti, A., Dušeko, J., Grafo, A., Gioli, B., Godedo, I., Gougho, C. M., Ikawa, H., Jassalo, R., Kobayashi, H., Magliulo, V., Mancao, G., Montagnani, L., Moyano, F. E., Olesen, J. E., Sachs, T., Shao, C. L., Tagesson, T., Wohlfahrt, G., Wolfo, S., Woodgate, W., Varlagin, A., and Venditti, C.: Temperature thresholds of ecosystem respiration at a global scale, Nat. Ecol. Evol., 5, 487–494, https://doi.org/10.1038/s41559-021-01398-z, 2021.
Kannenberg, S. A., Anderegg, W. R. L., Barnes, M. L., Dannenberg, M. P., and Knapp, A. K.: Dominant role of soil moisture in mediating carbon and water fluxes in dryland ecosystems, Nat. Geosci., 17, 38–43, https://doi.org/10.1038/s41561-023-01351-8, 2024.
Knapp, A., Fay, P. A., Blair, J. M., Collins, S., Smith, M. D., Carlisle, J. D., Harpper, C. W., Danner, B. T., Lett, M. S., and Mccarron, J.: Rainfall variability, carbon cycling, and plant species diversity in a mesic grassland, Science, 298, 2202–2205, https://doi.org/10.1126/science.1076347, 2002.
Lee, E., Kumar, P., Barron-Gafford, G. A., Hendryx, S. M., Sanchez-Cañete, E. P., Minor, R. L., Colella, T., and Scott, R. L.: Impact of hydraulic redistribution on multispecies vegetation water use in a semiarid savanna ecosystem: an experimental and modeling synthesis, Water Resour. Res., 54, 4009–4027, https://doi.org/10.1029/2017WR021006, 2018.
Li, G. Y., Han, H. Y., Du, Y., Hui, D. F., Xia, J. Y., Niu, S. L., Li, X. N., and Wan, S. Q.: Effects of warming and increased precipitation on net ecosystem productivity: a long-term manipulative experiment in a semiarid grassland, Agr. Forest Meteorol., 232, 359–366, https://doi.org/10.1016/j.agrformet.2016.09.004, 2017.
Li, J. X., Zeng, H., Zhu, J. T., Zhang, Y. J., Chen, N., and Liu, Y. J.: Responses of different experimental warming on ecosystem respiration in Tibetan alpine meadow, Ecol. Environ. Sci., 25, 1612–1620, https://doi.org/10.16258/j.cnki.1674-5906.2016.10.004, 2016.
Liu, D., Li, Y., Wang, T., Peylin, P., MacBean, N., Ciais, P., Jia, G., Ma, M. G., Ma, Y. M., Shen, M. G., Zhang, X. Z., and Piao, S. L.: Contrasting responses of grassland water and carbon exchanges to climate change between Tibetan Plateau and InnerMongolia, Agr. Forest Meteorol., 249, 163–175, https://doi.org/10.1016/j.agrformet.2017.11.034, 2018.
Liu, J. X., Wang, Z., Duan, Y. F., Li, X. R., Zhang, M. Y., Liu, H. Y., Xue, P., Gong, H. B., Wang, X., Chen, Y., and Geng, Y. N.: Effects of land use patterns on the interannual variations of carbon sinks of terrestrial ecosystems in China, Ecol. Indic., 146, 109914, https://doi.org/10.1016/j.ecolind.2023.109914, 2023.
Liu, Z. G., Chen, Z., Yang, M., Hao, T. X., Yu, G. R., Zhu, X. J., Zhang, W. K., Ma, L. X., Dou, X. J., Lin, Y., Luo, W. X., Han, L., Sun, M. Y., Chen, S. P., Dong, G., Gao, Y. H., Hao, Y. B., Jiang, S. C., Li, Y. N., Li, Y. Z., Liu, S. M., Shi, P. L., Tang, Y. K., Xin, X. P., Zhang, F. W., Zhang, Y. J., Zhao, L., Zhou, L., and Zhu, Z. L.: Precipitation consistently promotes, but temperature oppositely drives carbon fluxes in temperate and alpine grasslands in China, Agr. Forest Meteorol., 344, 109811, https://doi.org/10.1016/j.agrformet.2023.109811, 2024.
Livesley, S. J., Grover, S., Hutley, L. B., Jamali, H., Butterbach-Bahl, K., Fest, B., and Arndt, S. K.: Seasonal variation and fire effects on CH4, N2O and CO2 exchange in savanna soils of northern Australia, Agr. Forest Meteorol., 151, 1440–1452, https://doi.org/10.1016/j.agrformet.2011.02.001, 2011.
McDowell, N. G. and Allen, C. D.: Darcy's law predicts widespread forest mortality under climate warming, Nat. Clim. Change, 5, 669–672, https://doi.org/10.1038/nclimate2641, 2015.
Millard, P., Midwood, A. J., Hunt, J. E., Whitehead, D., and Boutton, T. W.: Partitioning soil surface CO2 efflux into autotrophic and heterotrophic components, using natural gradients in soil δ13C in an undisturbed savannah soil, Soil Biol. Biochem., 40, 1575–1582, https://doi.org/10.1016/j.soilbio.2008.01.011, 2008.
Niu, S. L., Wu, M. Y., Han, Y., Xia, J. Y., Li, L. H., and Wan, S. Q.: Water-mediated responses of ecosystem carbon fluxes to climatic change in a temperate steppe, New Phytol., 177, 209–219, https://doi.org/10.1111/j.1469-8137.2007.02237.x, 2008.
Niu, Y. Y., Li, Y. Q., Wang, X. Y., Gong, X. W., Luo, Y. Q., and Tian, D. Y.: Characteristics of annual variation in net carbon dioxide flux in a sandy grassland ecosystem during dry years, Acta Prataculturae Sin., 27, 215–221, https://doi.org/10.11686/cyxb2017231, 2018.
Novick, K. A., Miniat, C. F., and Vose, J. M.: Drought limitations to leaf-level gas exchange: results from a model linking stomatal optimization and cohesion–tension theory, Plant Cell Environ., 39, 583–96, https://doi.org/10.1111/pce.12657, 2016.
Pan, S. F., Yang, J., Tian, H. Q., Shi, H., Chang, J. F., Ciais, P., Francois, L., Frieler, K., Fu, B. J., Hickler, T., Ito, A., Nishina, K., Ostberg, S., Reyer, C. P. O., Schaphoff, S., Steinkamp, J., and Zhao, F.: Climate extreme versus carbon extreme: responses of terrestrial carbon fluxes to temperature and precipitation, J. Geophys. Res.-Biogeo., 125, e2019JG005252, https://doi.org/10.1029/2019JG005252, 2020.
Peel, M. C., Finlayson, B. L., and McMahon, T. A.: Updated world map of the Köppen-Geiger climate classification, Hydrol. Earth Syst. Sci., 11, 1633–1644, https://doi.org/10.5194/hess-11-1633-2007, 2007.
Peng, J. L., Tang, J. W., Xie, S. D., Wang, Y. H., Liao, J. Q., Chen, C., Sun, C. L., Mao, J. H., Zhou, Q. P., and Niu, S. L.: Evidence for the acclimation of ecosystem photosynthesis to soil moisture, Nat. Commun., 15, 9795, https://doi.org/10.1038/s41467-024-54156-7, 2024.
Piao, S. L., Huang, M. T., Liu, Z., Wang, X. H., Ciais, P., Canadell, J. G., Wang, K., Bastos, A., Friedlingstei, P., Houghto, R. A., Quéré, C. L., Liu, Y. W., Myneni, R. B., Peng, S. S., Pongratz, J., Sitch, S., Yan, T., Wang, Y. L., Zhu, Z. C., Wu, D. H., and Wang, T.: Lower land-use emissions responsible for increased net land carbon sink during the slow warming period, Nat. Geosci., 11, 739–743, https://doi.org/10.1038/s41561-018-0204-7, 2018.
Quansah, E., Mauder, M., Balogun, A. A., Amekudz, L. K., Hingerl, L., Bliefernicht, J., and Kunstmann, H.: Carbon dioxide fluxes from contrasting ecosystems in the Sudanian savanna in West Africa, Carbon Balance Manage., 10, 1, https://doi.org/10.1186/s13021-014-0011-4, 2015.
Ruimy, A., Jarvis, P. G., Baldocchi, D. D., and Saugier, B.: CO2 fluxes over plant canopies and solar radiation: a review, Adv. Ecol. Res., 26, 1–68, https://doi.org/10.1016/s0065-2504(08)60063-x, 1995.
Sha, Z. Y., Bai, Y. F., Li, R. R., Lan, H., Zhang, X. L., Li, J., Liu, X. F., Chang, S. J., and Xie, Y. C.: The global carbon sink potential of terrestrial vegetation can be increased substantially by optimal land management, Commun. Earth Environ., 3, 8, https://doi.org/10.1038/s43247-021-00333-1, 2022.
Shen, R., Zhang, J. L., He, B., Li, F., Zhang, Z. M., Zhou, R., and Ou, X. K.: The structure characteristic and analysis on similarity of grassland community in dry-hot valley of Yuanjiang, Ecol. Environ. Sci., 19, 2821–2825, https://doi.org/10.16258/j.cnki.1674-5906.2010.12.011, 2010.
Sulman, B. N., Roman, D. T., Yi, K., Wang, L. X., Phillips, R. P., and Novick, K. A.: High atmospheric demand for water can limit forest carbon uptake and transpiration as severely as dry soil, Geophys. Res. Lett., 43, 9686–9695, https://doi.org/10.1002/2016GL069416, 2016.
Tang, J. W., Niu, B., Hu, Z. G., and Zhang, X. Z.: Increasing susceptibility and shortening response time of vegetation productivity to drought from 2001 to 2021, Agr. Forest Meteorol., 352, 110025, https://doi.org/10.1016/j.agrformet.2024.110025, 2024.
Tarin, T., Nolan, R. H., Eamus, D., and Cleverly, J.: Carbon and water fluxes in two adjacent Australian semi-arid ecosystems, Agr. Forest Meteorol., 281, 107853, https://doi.org/10.1016/j.agrformet.2019.107853, 2020.
Taylor, P. G., Cleveland, C. C., Wieder, W. R., Sullivan, B. W., Doughty, C. E., Dobrowski, S. Z., and Townsend, A. R.: Temperature and rainfall interact to control carbon cycling in tropical forests, Ecol. Lett., 20, 779–788, https://doi.org/10.1111/ele.12765, 2017.
Wang, F., Harindintwali, J. D., Wei, K., Shan, Y. L., Mi, Z. F., Costello, M. J., Grunwald, S., Feng, Z. Z., Wang, F. M., Guo, Y. M., Wu, X., Kumar, P., Kästner, M., Feng, X. J., Kang, S. C., Liu, Z., Fu, Y. H., Zhao, W., Ouyang, C. J., Shen, J. L., Wang, H. J., Chang, S. X., Evans, D. L., Wang, R., Zhu, C. W., Xiang, L. L., Rinklebe, J., Du, M. M., Huang, L., Bai, Z. H., Li, S., Lal, R., Elsner, M., Wigneron, J. P., Florindo, F., Jiang, X., Shaheen, S. M., Zhong, X. Y., Bol, R., Vasques, G. M., Li, X. F., Pfautsch, S., Wang, M. G., He, X., Agathokleous, E., Du, H. B., Kengara, F. O., Brahushi, F., Long, X. E., Pereira, P., Ok, Y. S., Rillig, M. C., Jeppesen, E., Barceló, D., Yan, X. Y., Jiao, N. Z., Han, B. X., Schäffer, A., Chen, J. M., Zhu, Y. G., Cheng, H., Amelung, W., Spötl, C., Zhu, J. K., and Tiedje, J. M.: Climate change: Strategies for mitigation and adaptation, The Innovation Geosci., 1, 100015, https://doi.org/10.59717/j.xinn-geo.2023.100015, 2023.
Wang, N., Quesada, B., Xia, L. L., Butterbach-Bahl, K., Goodale, C. L., and Kiese, R.: Effects of climate warming on carbon fluxes in grasslands – a global meta-analysis, Glob. Change Biol., 25, 1839–1851, https://doi.org/10.1111/gcb.14603, 2019.
Wang, W. Y., Guo, J. X., Wang, Y. S., and Wu, K.: Observing characteristics of CO2 flux and its influencing factors over Xilinhot grassland, J. Meteorol. Sci., 35, 100–107, https://doi.org/10.3969/2013jms.0065, 2015.
Wang, Y. Y., Xiao, J. F., Ma, Y. M., Luo, Y. Q., Hu, Z. Y., Li, F., Li, Y. N., Gu, L. L., Li, Z. G., and Yuan, L.: Carbon fluxes and environmental controls across different alpine grassland types on the Tibetan Plateau, Agr. Forest Meteorol., 311, 1–14, https://doi.org/10.1016/j.agrformet.2021.108694, 2021.
Wang, Z. K., Chen, W., Piao, J. L., Cai, Q. Y., Chen, S. F., Xue, X., and Ma, T. J.: Synergistic effects of high atmospheric and soil dryness on record-breaking decreases in vegetation productivity over Southwest China in 2023, npj Clim. Atmos. Sci., 8, 6, https://doi.org/10.1038/s41612-025-00895-3, 2025.
Weltzin, J. F., Loik, M. E., Schwinning, S., Williams, D. G., Fay, P. A., Haddad, B. M., Harte, J., Huxman, T. E., Knapp, A. K., Lin, G. H., Pockman, W. T., Shaw, R. M., Small, E. E., Smith, M. D., Smith, S. D., Tissue, D. T., and Zak, J. C.: Assessing the response of terrestrial ecosystems to potential changes in precipitation, BioScience, 53, 941–952, https://doi.org/10.1641/0006-3568(2003)053[0941:ATROTE]2.0.CO;2, 2003.
Wen, X. F., Sun, X. M., Liu, Y. F., and Li, X. B.: Effect of linear and exponential fitting on the initial rate of change in CO2 concentration across the soil surface, Chin. J. Plant Ecol., 31, 380–385, https://doi.org/10.17521/cjpe.2007.0046, 2007.
Williams, A. P., Allen, C. D., Macalady, A. K., Griffin, D., Woodhouse, C. A., Meko, D. M., Swetnam, T. W., Rauscher, S. A., Seager, R., Grissino-Mayer, H. D., Dean, J. S., Cook, E. R., Gangodagamage, C., Cai, M., and McDowell, N. G.: Temperature as a potent driver of regional forest drought stress and tree mortality, Nat. Clim. Change, 3, 292–297, https://doi.org/10.1038/nclimate1693, 2013.
Williamson, G. J., Tng, D. Y. P., and Bowman, D. M. J. S.: Climate, fire, and anthropogenic disturbance determine the current global distribution of tropical forest and savanna, Environ. Res. Lett., 19, 024032, https://doi.org/10.1088/1748-9326/ad20ac, 2024.
Xiang, Y. B., Zhou, S. X., Xiao, Y. X., Hu, T. X., Tu, L. H., and Huang, C. D.: Effects of precipitation variations on soil respiration in an evergreen broad-leaved forest during dry and wet seasons, Acta Ecol. Sin., 37, 4734–4742, 2017.
Xu, X. L.: China watershed and river network datasets based on DEM extraction, Resource and Environmental Science Data Registration and Publishing System [data set], https://doi.org/10.12078/2018060101, 2018.
Xu, X. L.: China's multi-year provincial administrative division boundary data, Resource and Environmental Science Data Registration and Publishing System [data set], https://doi.org/10.12078/2023010103, 2023a.
Xu, X. L.: China's multi-year county administrative division boundary data, Resource and Environmental Science Data Registration and Publishing System [data set], https://doi.org/10.12078/2023010101, 2023b.
Yang, K. Y., Gong, H. D., Li, J., Liu, Y. T., Sha, L. Q., Song, Q. H., Jin, Y. Q., Yang, D. X., Li, P. G., Wen, G. J., Chen, A. G., Pang, Z. Q., and Zhang, Y. P.: Dynamic characteristics of soil respiration of savanna ecosystem in dry hot valley of Yuanjiang, J. Zhejiang Agric. For. Univ., 37, 849–859, https://doi.org/10.11833/j.issn.2095-0756.20190647, 2020.
Yang, Z. P. and Chang, Y.: Ecological problems of primary dry valleys is southwest China and advances in the researches into them, Agric. Res. Arid Areas, 25, 90–93, 2007.
Yu, K. and D'Odorico, P.: Hydraulic lift as a determinant of tree–grass coexistence on savannas, New Phytol., 207, 1038–1051, https://doi.org/10.1111/nph.13431, 2015.
Yuan, W. P., Zheng, Y., Piao, S. L., Ciais, P., Lombardozzi, D., Wang, Y. P., Ryu, Y., Chen, G. X., Dong, W. J., Hu, Z. M., Jain, A. K., Jiang, C. Y., Kato, E., Li, S. H., Lienert, S., Liu, S. G., Nabel, J. E. M. S., Qin, Z. C., Quine, T., Sitch, S., Smith, W. K., Wang, F., Wu, C. Y., Xiao, Z. Q., and Yang, S.: Increased atmospheric vapor pressure deficit reduces global vegetation growth, Sci. Adv., 5, eaax1396, https://doi.org/10.1126/sciadv.aax1396, 2019.
Zeng, Z. Q., Wu, W. X., Li, Y. M., Huang, C., Zhang, X. Q., Peñuelas, J., Zhang, Y., Gentine, P., Li, Z. L., Wang, X. Y., Huang, H., Ren, X. S., and Ge, Q. S.: Increasing meteorological drought under climate change reduces terrestrial ecosystem productivity and carbon storage, One Earth, 6, 1326–1339, https://doi.org/10.1016/j.oneear.2023.09.007, 2023.
Zhang, R., Zhao, X. Y., Zuo, X. A., Qu, H., Degen, A. A., Luo, Y. Y., Ma, X. J., Chen, M., Liu, L. X., and Chen, J. L.: Impacts of precipitation on ecosystem carbon fluxes in desert-grasslands in Inner Mongolia, China, J. Geophys. Res.-Atmos., 124, 1266–1276, https://doi.org/10.1029/2018JD028419, 2019a.
Zhang, R. Z.: The dry valley of the Henduan Mountains region, Beijing Sci. Press, ISBN 703002916X, 1992.
Zhang, W. M., Brandt, M., Penuelas, J., Guichard, F., Tong, X., Tian, F., and Fensholt, R.: Ecosystem structural changes controlled by altered rainfall climatology in tropical savannas, Nat. Commun., 10, 671, https://doi.org/10.1038/s41467-019-08602-6, 2019b.
Zhang, Y. J., Qiu, L. P., Gao, H. L., Liu, J., Wei, X. R., and Zhang, X. C.: Responses of ecosystem CO2 exchange to clipping in a semi-arid typical grassland on the Loess Plateau, Acta Ecol. Sin., 40, 336–344, https://doi.org/10.5846/stxb201810172244, 2020.
Zhao, H. C., Jia, G. S., Wang, H. S., Zhang, A. Z., and Xu, X. Y.: Diurnal variations of the carbon fluxes of semiarid meadow steppe and typical steppe in China, Clim. Environ. Res., 25, 172–184, 2020.
Zhao, L., Gu, S., Xu, S. X., Zhao, X. Q., and Li, Y. N.: Carbon flux and controlling process of alpine meadow on Qinghai-Tibetan plateau, Acta Botan. Boreali-Occidentalia Sin., 27, 1054–1060, 2007.
Zou, H., Gao, G. Y., and Fu, B. J.: The relationship between grassland ecosystem and soil water in arid and semi-arid areas: a review, Acta Ecol. Sin., 36, 3127–3136, 2016.
Short summary
Due to the influence of extreme-drought events in southwest China, the carbon sequestration capacity of the open savanna in the dry–hot valley of the Jinsha River has been significantly diminished, with soil water content being the key environmental factor governing CO2 flux. Under the climate scenario where the frequency and severity of extreme droughts are expected to continue increasing, the CO2 emissions from the open savanna are also anticipated to rise persistently.
Due to the influence of extreme-drought events in southwest China, the carbon sequestration...
Altmetrics
Final-revised paper
Preprint