scholarly journals Assessment of the Carbonate Weathering Carbon Sink Potential of Indian Ecosystems for the 21st Century

2021 ◽  
Author(s):  
Abhishek Chakraborty ◽  
Sekhar Muddu ◽  
Lakshminarayana Rao
Keyword(s):  
21St Century ◽  
Carbon Sink ◽  
Carbonate Weathering

scholarly journals Potential shift from a carbon sink to a source in Amazonian peatlands under a changing climate

2018 ◽  
Vol 115 (49) ◽  
pp. 12407-12412 ◽  
Author(s):  
Sirui Wang ◽  
Qianlai Zhuang ◽  
Outi Lähteenoja ◽  
Frederick C. Draper ◽  
Hinsby Cadillo-Quiroz
Keyword(s):  
21St Century ◽  
Carbon Sink ◽  
Accumulation Rate ◽  
Foreland Basin ◽  
Carbon Accumulation ◽  
Climate Conditions ◽  
Changing Climate ◽  
Soil Carbon Density ◽  
Increasing Precipitation ◽  
Aerobic And Anaerobic

Amazonian peatlands store a large amount of soil organic carbon (SOC), and its fate under a future changing climate is unknown. Here, we use a process-based peatland biogeochemistry model to quantify the carbon accumulation for peatland and nonpeatland ecosystems in the Pastaza-Marañon foreland basin (PMFB) in the Peruvian Amazon from 12,000 y before present to AD 2100. Model simulations indicate that warming accelerates peat SOC loss, while increasing precipitation accelerates peat SOC accumulation at millennial time scales. The uncertain parameters and spatial variation of climate are significant sources of uncertainty to modeled peat carbon accumulation. Under warmer and presumably wetter conditions over the 21st century, SOC accumulation rate in the PMFB slows down to 7.9 (4.3–12.2) g⋅C⋅m−2⋅y−1 from the current rate of 16.1 (9.1–23.7) g⋅C⋅m−2⋅y−1, and the region may turn into a carbon source to the atmosphere at −53.3 (−66.8 to −41.2) g⋅C⋅m−2⋅y−1 (negative indicates source), depending on the level of warming. Peatland ecosystems show a higher vulnerability than nonpeatland ecosystems, as indicated by the ratio of their soil carbon density changes (ranging from 3.9 to 5.8). This is primarily due to larger peatlands carbon stocks and more dramatic responses of their aerobic and anaerobic decompositions in comparison with nonpeatland ecosystems under future climate conditions. Peatland and nonpeatland soils in the PMFB may lose up to 0.4 (0.32–0.52) Pg⋅C by AD 2100 with the largest loss from palm swamp. The carbon-dense Amazonian peatland may switch from a current carbon sink into a source in the 21st century.

scholarly journals Reconciling Negative Soil CO2 Fluxes: Insights from a Large-Scale Experimental Hillslope

Soil Systems ◽  
2019 ◽  
Vol 3 (1) ◽  
pp. 10 ◽  
Author(s):  
Alejandro Cueva ◽  
Till H. M. Volkmann ◽  
Joost van Haren ◽  
Peter A. Troch ◽  
Laura K. Meredith
Keyword(s):  
Large Scale ◽  
Carbon Sink ◽  
Average Rate ◽  
Dominant Role ◽  
Alkaline Soils ◽  
Carbonate Weathering ◽  
Ecosystem Carbon ◽  
Environmental Controls ◽  
Source To Sink ◽  
Carbon Balances

Soil fluxes of CO2 (Fs) have long been considered unidirectional, reflecting the predominant roles of metabolic activity by microbes and roots in ecosystem carbon cycling. Nonetheless, there is a growing body of evidence that non-biological processes in soils can outcompete biological ones, pivoting soils from a net source to sink of CO2, as evident mainly in hot and cold deserts with alkaline soils. Widespread reporting of unidirectional fluxes may lead to misrepresentation of Fs in process-based models and lead to errors in estimates of local to global carbon balances. In this study, we investigate the variability and environmental controls of Fs in a large-scale, vegetation-free, and highly instrumented hillslope located within the Biosphere 2 facility, where the main carbon sink is driven by carbonate weathering. We found that the hillslope soils were persistent sinks of CO2 comparable to natural desert shrublands, with an average rate of −0.15 ± 0.06 µmol CO2 m2 s−1 and annual sink of −56.8 ± 22.7 g C m−2 y−1. Furthermore, higher uptake rates (more negative Fs) were observed at night, coinciding with strong soil–air temperature gradients and [CO2] inversions in the soil profile, consistent with carbonate weathering. Our results confirm previous studies that reported negative values of Fs in hot and cold deserts around the globe and suggest that negative Fs are more common than previously assumed. This is particularly important as negative Fs may occur widely in arid and semiarid ecosystems, which play a dominant role in the interannual variability of the terrestrial carbon cycle. This study contributes to the growing recognition of the prevalence of negative Fs as an important yet, often overlooked component of ecosystem C cycling.

scholarly journals Differences and influencing factors related to underground water carbon uptake by karsts in the Houzhai Basin, southwestern China

Solid Earth ◽  
2016 ◽  
Vol 7 (4) ◽  
pp. 1259-1268
Author(s):  
Junyi Zhang ◽  
Zihao Bian ◽  
Minghong Dai ◽  
Lachun Wang ◽  
Chunfen Zeng ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Carbon Sink ◽  
Ion Concentration ◽  
Southwestern China ◽  
Carbon Uptake ◽  
Carbonate Weathering ◽  
Concentration Data ◽  
Ion Concentrations ◽  
Run Off ◽  
The Impact

Abstract. Carbon sink in karstic areas is very important at a global scale. Consequently, accurate determination of the carbon sink of karst ecosystems has become a core issue in research. We used flow and carbon ion concentration data from three stations with different environmental background conditions in the Houzhai Basin, southwestern China, to analyse the differences in carbon uptake between stations and to determine their impact factors. The results show that carbon sink discharge was mainly controlled by the flow at each site. Preliminary analysis indicated that the rapid increase in flow only had a partial dilution effect on the ion concentrations due to the high speed and stability of chemical carbonate weathering. The Land-Use and Cover-Change (LUCC) type had important effects on the bicarbonate ion concentrations; under stable run-off conditions, the influence of flow variation on the ion concentration was lower than the effects of chemical carbonate weathering on bicarbonate ion concentrations under different environmental conditions (a comparison of Laoheitan and Liugu stations showed a difference of 150 %). However, if run-off increased significantly, the impact of run-off variation on bicarbonate ions was greater than the effects of chemical carbonate weathering caused under different environmental conditions. This work provides a reference for the calculation of the karst geological carbon sink.

scholarly journals Possible decline of the carbon sink in the Mongolian Plateau during the 21st century

2009 ◽  
Vol 4 (4) ◽  
pp. 045023 ◽  
Author(s):  
Y Lu ◽  
Q Zhuang ◽  
G Zhou ◽  
A Sirin ◽  
J Melillo ◽  
...  
Keyword(s):  
21St Century ◽  
Carbon Sink ◽  
Mongolian Plateau

scholarly journals Arable Podzols Are a Substantial Carbon Sink under Current and Future Climates: Evidence from a Long-Term Experiment in the Vladimir Region, Russia

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 90
Author(s):  
Igor Ilichev ◽  
Vladimir Romanenkov ◽  
Sergei Lukin ◽  
Vera Pavlova ◽  
Stanislav Siptits ◽  
...  
Keyword(s):  
21St Century ◽  
Carbon Sink ◽  
Soil Layer ◽  
Soil Health ◽  
Climate Conditions ◽  
Central Russia ◽  
Vladimir Region ◽  
Climatic Scenarios ◽  
Long Term Experiment

Soil organic carbon (SOC) is an essential component of soil health and a potential sink for greenhouse gases. SOC dynamics in a long-term field experiment with mineral and organic fertilization on loamy sand podzol in the Vladimir Region, Russia, was traced with the dynamic carbon model RothC from 1968 until the present. During this period, C stock increased by 21%, compared to the initial level, with the application of manure, at an average annual rate of 10 t·ha−1. The model was also used to forecast SOC changes up to 2090 for two contrasting RCP4.5 and RCP8.5 climatic scenarios. Up to 2090, steady growth of SOC stocks is expected in all compared treatments for both climate scenarios. In the scenarios, this growth rate was the highest up to 2040, decreased in the period 2040–2070, and increased again in the period 2070–2090 for RCP4.5. The highest annual gain was 21–27‰ under the RCP4.5 scenario and 16–21‰ under the RCP8.5 scenario in 2020–2040 in a 0–20 cm soil layer. Under the expected climate conditions in the 21st century, the C input will increase 1.3–1.5 times under the RCP4.5 scenario and decrease by 13–20% for the same period under the RCP 8.5 scenario. Modelling demonstrated potentially more favourable conditions for SOC stability in arable podzols than in Retisols in central Russia in the 21st century.

scholarly journals Microbial decomposition processes and vulnerable arctic soil organic carbon in the 21st century

2018 ◽  
Vol 15 (18) ◽  
pp. 5621-5634 ◽  
Author(s):  
Junrong Zha ◽  
Qianlai Zhuang
Keyword(s):  
Soil Carbon ◽  
20Th Century ◽  
21St Century ◽  
Carbon Budget ◽  
Carbon Sink ◽  
The Arctic ◽  
Microbial Decomposition ◽  
New Model ◽  
Terrestrial Ecosystem Model ◽  
Rcp 8.5

Abstract. Various levels of representations of biogeochemical processes in current biogeochemistry models contribute to a large uncertainty in carbon budget quantification. Here, we present an uncertainty analysis with a process-based biogeochemistry model, the Terrestrial Ecosystem Model (TEM), into which detailed microbial mechanisms were incorporated. Ensemble regional simulations with the new model (MIC-TEM) estimated that the carbon budget of the arctic ecosystems is 76.0±114.8 Pg C during the 20th century, i.e., -3.1±61.7 Pg C under the RCP 2.6 scenario and 94.7±46 Pg C under the RCP 8.5 scenario during the 21st century. Positive values indicate the regional carbon sink while negative values are a source to the atmosphere. Compared to the estimates using a simpler soil decomposition algorithm in TEM, the new model estimated that the arctic terrestrial ecosystems stored 12 Pg less carbon over the 20th century, i.e., 19 and 30 Pg C less under the RCP 8.5 and RCP 2.6 scenarios, respectively, during the 21st century. When soil carbon within depths of 30, 100, and 300 cm was considered as initial carbon in the 21st century simulations, the region was estimated to accumulate 65.4, 88.6, and 109.8 Pg C, respectively, under the RCP 8.5 scenario. In contrast, under the RCP 2.6 scenario, the region lost 0.7, 2.2, and 3 Pg C, respectively, to the atmosphere. We conclude that the future regional carbon budget evaluation largely depends on whether or not adequate microbial activities are represented in earth system models and on the sizes of soil carbon considered in model simulations.

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