Sediment export in marly badland catchments controlled by frost cracking intensity, Draix-Bléone CZO, SE France

2021 ◽  
Author(s):  
Coline Ariagno ◽  
Caroline Le Bouteiller ◽  
Peter Van der Beek ◽  
Sébastien Klotz
Keyword(s):  
Chemical Weathering ◽  
Rainfall Variability ◽  
Critical Zone ◽  
Careful Consideration ◽  
Sediment Flux ◽  
Climate Conditions ◽  
Physical Weathering ◽  
Changing Climate ◽  
Sediment Export ◽  
Se France

<p>At the interface between the lithosphere and the atmosphere, the critical zone records the complex interactions between erosion, climate, geologic substrate and life, and can be directly monitored. The sparsely vegetated, steep marly badland catchments of the Draix-Bléone Critical Zone Observatory (CZO), SE France are characterised by high quantities of exported sediment and rapid morphologic changes. Characterizing and understanding the physical weathering processes in this area are key to predict the temporal variability of regolith production and sediment flux, as well as their evolution under changing climate conditions.</p><p>Long data records collected in the Draix-Bléone CZO allow analysing long-term regolith dynamics and climatic control on sediment export. Although widely accepted as the first order control, rainfall variability does not fully explain the observed yearly variability in sediment export, suggesting that regolith production and its controls may contribute to the observed pattern of sediment export. Within the several factors that can influence marls weathering (soil moisture, density, chemical weathering), this study focuses on continuous temperature data, recorded at different locations over multiple years, and aims to highlight the role of frost cracking in regolith production. Several proxies for frost cracking intensity have been calculated from these data and compared to the sediment export anomalies, with careful consideration of field data quality. Our initial results suggest that frost-cracking processes have a significant impact on catchment sediment response and should be taken into account when building a predictive model of sediment export from these catchments under a changing climate.</p>

scholarly journals Sediment export in marly badland catchments modulated by frost-cracking intensity, Draix-Bléone Critical Zone Observatory, SE France

2021 ◽  
Author(s):  
Coline Ariagno ◽  
Caroline Le Bouteiller ◽  
Peter van der Beek ◽  
Sébastien Klotz
Keyword(s):  
Predictive Model ◽  
Field Data ◽  
Rainfall Variability ◽  
Critical Zone ◽  
Annual Rainfall ◽  
Weathering Processes ◽  
Frost Weathering ◽  
Critical Zone Observatory ◽  
Sediment Export ◽  
Se France

Abstract. At the interface between the lithosphere and the atmosphere, the critical zone records the complex interactions between erosion, climate, geologic substrate and life, and can be directly monitored. Long data records collected in the sparsely vegetated, steep marly badland catchments of the Draix-Bléone Critical Zone Observatory (CZO), SE France, allow analysing potential climatic controls on long-term regolith dynamics and sediment export. Although widely accepted as a first-order control, rainfall variability does not fully explain the observed inter-annual variability in sediment export, suggesting that regolith production and its controls may modulate the observed pattern of sediment export. Here, we define sediment-export anomalies as the residuals from a predictive model with annual rainfall intensity above a threshold as the control. We then use continuous soil-temperature data, recorded at different locations over multiple years, to highlight the role of frost weathering in regolith production. Several proxies for different frost-weathering processes have been calculated from these data and compared to the sediment-export anomalies, with careful consideration of field data quality. Our results suggest that frost-cracking intensity (linked to ice segregation) can explain about half (47–64 %) of the sediment-export anomalies. In contrast, the number of freeze-thaw cycles (linked to volumetric expansion) has only a minor impact on catchment sediment response. The time spent below 0 °C also correlates well with the sediment-export anomalies and requires fewer field data to be calculated than the frost-cracking intensity. Thus, frost-weathering processes modulate sediment export by controlling regolith production in these catchments and should be taken into account when building a predictive model of sediment export from these badlands under a changing climate.

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 Amelioration of marine environments at the Smithian–Spathian boundary, Early Triassic

2015 ◽  
Vol 12 (5) ◽  
pp. 1597-1613 ◽  
Author(s):  
L. Zhang ◽  
L. Zhao ◽  
Z.-Q. Chen ◽  
T. J. Algeo ◽  
Y. Li ◽  
...  
Keyword(s):  
Chemical Weathering ◽  
Sulfur Isotopes ◽  
Sediment Flux ◽  
Guizhou Province ◽  
Large Igneous Province ◽  
Global Ocean ◽  
Marine Biodiversity ◽  
Early Triassic ◽  
Organic Carbon Burial ◽  
Climatic Cooling

Abstract. The protracted recovery of marine ecosystems following the Permian–Triassic mass extinction may have been caused, in part, by episodic environmental and climatic crises during the Early Triassic, among which the Smithian–Spathian boundary (SSB) event is conspicuous. Here, we investigate the SSB event in the Shitouzhai section, Guizhou Province, South China, using a combination of carbonate carbon (δ13Ccarb) and carbonate-associated sulfate sulfur isotopes (δ34SCAS), rare earth elements, and elemental paleoredox and paleoproductivity proxies. The SSB at Shitouzhai is characterized by a +4‰ shift in δ13Ccarb and a −10 to −15‰ shift in δ34SCAS, recording negative covariation that diverges from the positive δ13Ccarb−δ34SCAS covariation that characterizes most of the Early Triassic. This pattern is inferred to reflect an increase in organic carbon burial (e.g., due to elevated marine productivity) concurrently with the oxidation of isotopically light H2S, as the result of enhanced vertical advection of nutrient- and sulfide-rich deep waters to the ocean-surface layer. Enhanced upwelling was likely a response to climatic cooling and the reinvigoration of global-ocean overturning circulation at the SSB. Coeval decreases in chemical weathering intensity and detrital sediment flux at Shitouzhai are also consistent with climatic cooling. A decline in marine biodiversity was probably associated with the late Smithian thermal maximum (LSTM) rather than with the SSB per se. The SSB thus marked the termination of the extreme hothouse conditions of the Griesbachian–Smithian substages of the Early Triassic and is significant as a record of accompanying climatic, environmental, and biotic changes. The ultimate cause of the SSB event is uncertain but may have been related to a reduction in intrusive magmatic activity in the Siberian Traps large igneous province.

scholarly journals Potential impacts to freshwater ecosystems caused by flow regime alteration under changing climate conditions in Taiwan

2008 ◽  
Vol 5 (6) ◽  
pp. 3005-3032 ◽  
Author(s):  
J.-P. Suen
Keyword(s):  
Climate Change ◽  
Flow Regime ◽  
River Flow ◽  
Aquatic Organisms ◽  
Freshwater Ecosystems ◽  
Climate Conditions ◽  
Regime Changes ◽  
Changing Climate ◽  
Extreme Flood ◽  
Precautionary Measures

Abstract. Observed increases in the Earth's surface temperature bring with them associated changes in precipitation and atmospheric moisture that consequentially alter river flow regimes. This paper uses the Indicators of Hydrologic Alteration approach to examine climate-induced flow regime changes that can potentially affect freshwater ecosystems. Analyses of the annual extreme water conditions at 23 gauging stations throughout Taiwan reveal large alterations in recent years; extreme flood and drought events were more frequent in the period after 1991 than from 1961–1990, and the frequency and duration of the flood and drought events also show high fluctuation. Climate change forecasts suggest that such flow regime alterations are going to continue into the foreseeable future. Aquatic organisms not only feel the effects of anthropogenic damage to river systems, but they also face on-going threats of thermal and flow regime alterations associated with climate change. This paper calls attention to the issue, so that water resources managers can take precautionary measures that reduce the cumulative effects from anthropogenic influence and changing climate conditions.

scholarly journals Effect of Graphene Nanoplatelet on the Carbonation Depth of Concrete under Changing Climate Conditions

2021 ◽  
Vol 11 (19) ◽  
pp. 9265
Author(s):  
Yingzi Zhang ◽  
Yanze Wang ◽  
Mingqian Yang ◽  
Huatao Wang ◽  
Guofang Chen ◽  
...  
Keyword(s):  
Control Sample ◽  
Co2 Concentration ◽  
Favorable Effect ◽  
Carbonation Depth ◽  
Graphene Nanoplatelet ◽  
Carbonation Reaction ◽  
Climate Conditions ◽  
Ordinary Concrete ◽  
Changing Climate ◽  
Carbon Dioxide Co2

Climate change has been unprecedented in the past decades or even thousands of years, which has had an adverse impact on the mechanical properties of concrete structures. Many researchers have begun to study new concrete materials. Graphene nanoplatelet (GNP) is an attractive nanomaterial that can change the crystal structure of concrete and improve durability. The aim of the present study was to investigate the effect of GNP (0.05%wt) on the carbonation depth of concrete under simulated changing climate conditions (varying temperature, relative humidity, and carbon dioxide (CO2) concentration), and compare it with ordinary concrete. When the concentration of CO2 is variable, the carbonation depth of graphene concrete is 10% to 20% lower than that of ordinary concrete. When the temperature is lower than 33 °C, the carbonation depth of graphene concrete is less than that of the control sample; however, above 33 °C, the thermal conductivity of GNP increases the carbonation reaction rate of concrete. When the humidity is a variable, the carbonation depth of graphene concrete is less than 15% to 30% of ordinary concrete, and when the humidity is higher than 78%, the difference in the carbonation depth between the ordinary concrete and the graphene concrete decreases gradually. The overall results indicated that GNP has a favorable effect on anti-carbonation performance under changing climate conditions.

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