scholarly journals Co-variation of silicate, carbonate and sulfide weathering drives CO2 release with erosion

2021 ◽  
Vol 14 (4) ◽  
pp. 211-216
Author(s):  
Aaron Bufe ◽  
Niels Hovius ◽  
Robert Emberson ◽  
Jeremy K. C. Rugenstein ◽  
Albert Galy ◽  
...  
Keyword(s):  
Erosion Rate ◽  
Global Climate ◽  
Stream Water ◽  
Sulfide Oxidation ◽  
Silicate Weathering ◽  
Emission Rates ◽  
Mountain Ranges ◽  
Weathering Rates ◽  
Southern Taiwan ◽  
Co2 Release

AbstractGlobal climate is thought to be modulated by the supply of minerals to Earth’s surface. Whereas silicate weathering removes carbon dioxide (CO2) from the atmosphere, weathering of accessory carbonate and sulfide minerals is a geologically relevant source of CO2. Although these weathering pathways commonly operate side by side, we lack quantitative constraints on their co-variation across erosion rate gradients. Here we use stream-water chemistry across an erosion rate gradient of three orders of magnitude in shales and sandstones of southern Taiwan, and find that sulfide and carbonate weathering rates rise with increasing erosion, while silicate weathering rates remain steady. As a result, on timescales shorter than marine sulfide compensation (approximately 106–107 years), weathering in rapidly eroding terrain leads to net CO2 emission rates that are at least twice as fast as CO2 sequestration rates in slow-eroding terrain. We propose that these weathering reactions are linked and that sulfuric acid generated from sulfide oxidation boosts carbonate solubility, whereas silicate weathering kinetics remain unaffected, possibly due to efficient buffering of the pH. We expect that these patterns are broadly applicable to many Cenozoic mountain ranges that expose marine metasediments.

Co-variation of silicate, carbonate, and sulphide weathering drives release of CO2 with erosion

2021 ◽  
Author(s):  
Aaron Bufe ◽  
Niels Hovius ◽  
Robert Emberson ◽  
Jeremy K.C. Rugenstein ◽  
Albert Galy ◽  
...  
Keyword(s):  
Atmospheric Carbon Dioxide ◽  
Erosion Rate ◽  
Global Climate ◽  
Stream Water ◽  
Sulfide Oxidation ◽  
Silicate Weathering ◽  
Emission Rates ◽  
Mountain Ranges ◽  
Order Of Magnitude ◽  
Southern Taiwan

<p>The supply of fresh minerals to Earth’s surface by erosion is thought to modulate global climate by removing atmospheric carbon dioxide (CO<sub>2</sub>) through silicate weathering. In turn, weathering of accessory carbonate and sulfide minerals is a geologically-relevant CO<sub>2</sub> source, which may dampen or reverse the effect of silicate weathering on climate. Although these weathering pathways commonly operate side by side, we lack quantitative constraints on their co-evolution across erosion-rate gradients. Using stream-water chemistry across a 3 order-of-magnitude erosion-rate gradient in shales and sandstones of southern Taiwan, here, we demonstrate that silicate, sulfide, and carbonate weathering are linked: Increasing sulfide oxidation generates sulfuric acid and boosts carbonate solubility whereas silicate weathering kinetics remain constant or even decline, perhaps due to buffering of the pH by carbonates. On timescales shorter than marine sulfide compensation, CO<sub>2</sub> emission rates from weathering in rapidly-eroding terrain are more than twice the CO<sub>2</sub> sequestration rates in slow-eroding terrain. On longer timescales, CO<sub>2</sub> emissions are compensated, but CO<sub>2</sub> sequestration rates do not increase with erosion, in contrast to assumptions in carbon cycle models. We posit that these patterns are broadly applicable to many Cenozoic mountain ranges that expose dominantly siliciclastic metasediments.</p>

scholarly journals Colluvial deposits as a possible weathering reservoir in uplifting mountains

2018 ◽  
Vol 6 (1) ◽  
pp. 217-237 ◽  
Author(s):  
Sébastien Carretier ◽  
Yves Goddéris ◽  
Javier Martinez ◽  
Martin Reich ◽  
Pierre Martinod
Keyword(s):  
Global Climate ◽  
Climatic Conditions ◽  
Silicate Weathering ◽  
Fractured Bedrock ◽  
Weathering Rates ◽  
Stochastic Transport ◽  
Below Ground ◽  
First Time ◽  
D Model

Abstract. The role of mountain uplift in the evolution of the global climate over geological times is controversial. At the heart of this debate is the capacity of rapid denudation to drive silicate weathering, which consumes CO2. Here we present the results of a 3-D model that couples erosion and weathering during mountain uplift, in which, for the first time, the weathered material is traced during its stochastic transport from the hillslopes to the mountain outlet. To explore the response of weathering fluxes to progressively cooler and drier climatic conditions, we run model simulations accounting for a decrease in temperature with or without modifications in the rainfall pattern based on a simple orographic model. At this stage, the model does not simulate the deep water circulation, the precipitation of secondary minerals, variations in the pH, below-ground pCO2, and the chemical affinity of the water in contact with minerals. Consequently, the predicted silicate weathering fluxes probably represent a maximum, although the predicted silicate weathering rates are within the range of silicate and total weathering rates estimated from field data. In all cases, the erosion rate increases during mountain uplift, which thins the regolith and produces a hump in the weathering rate evolution. This model thus predicts that the weathering outflux reaches a peak and then falls, consistent with predictions of previous 1-D models. By tracking the pathways of particles, the model can also consider how lateral river erosion drives mass wasting and the temporary storage of colluvial deposits on the valley sides. This reservoir is comprised of fresh material that has a residence time ranging from several years up to several thousand years. During this period, the weathering of colluvium appears to sustain the mountain weathering flux. The relative weathering contribution of colluvium depends on the area covered by regolith on the hillslopes. For mountains sparsely covered by regolith during cold periods, colluvium produces most of the simulated weathering flux for a large range of erosion parameters and precipitation rate patterns. In addition to other reservoirs such as deep fractured bedrock, colluvial deposits may help to maintain a substantial and constant weathering flux in rapidly uplifting mountains during cooling periods.

scholarly journals Are there signs of acidification reversal in freshwaters of the low mountain ranges in Germany?

2001 ◽  
Vol 5 (3) ◽  
pp. 367-378 ◽  
Author(s):  
C. Alewell ◽  
M. Armbruster ◽  
J. Bittersohl ◽  
C. D. Evans ◽  
H. Meesenburg ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Supply ◽  
Extreme Values ◽  
Stream Water ◽  
Base Cation ◽  
Drinking Water Supply ◽  
Mountain Ranges ◽  
Acid Neutralising Capacity ◽  
Freshwater Acidification ◽  
Low Mountain Ranges

Abstract. The reversal of freshwater acidification in the low mountain ranges of Germany is of public, political and scientific concern, because these regions are near natural ecosystems and function as an important drinking water supply. The aim of this study was to evaluate the status and trends of acidification reversal after two decades of reduced anthropogenic deposition in selected freshwaters of the low mountain ranges in the Harz, the Fichtelgebirge, the Bavarian Forest, the Spessart and the Black Forest. In response to decreased sulphate deposition, seven out of nine streams investigated had significantly decreasing sulphate concentrations (all trends were calculated with the Seasonal Kendall Test). The decrease in sulphate concentration was only minor, however, due to the release of previously stored soil sulphur. No increase was found in pH and acid neutralising capacity (defined by Reuss and Johnson, 1986). Aluminum concentrations in the streams did not decrease. Thus, no major acidification reversal can currently be noted in spite of two decades of decreased acid deposition. Nevertheless, the first signs of improvement in water quality were detected as there was a decrease in the level and frequency of extreme values of pH, acid neutralising capacity and aluminium concentrations in streams. With respect to nitrogen, no change was determined for either nitrate or ammonium concentrations in precipitation or stream water. Base cation fluxes indicate increasing net loss of base cations from all ecosystems investigated, which could be interpreted as an increase in soil acidification. The latter was due to a combination of continued high anion leaching and significant reduction of base cation deposition. No major improvement was noted in biological recovery, however, initial signs of recovery were detectable as there was re-occurrence of some single macroinvertebrate species which were formerly extinct. The results of this study have important implications for water authorities, forest managers and policy makers: the delay in acidification reversal suggests a need for ongoing intensive amelioration of waters, a careful selection of management tools to guarantee sustainable management of forests and the reduction of nitrogen deposition to prevent further acidification of soils and waters. Keywords: freshwater, acidification reversal, drinking water supply, forested catchments, Germany

scholarly journals Isoprene emissions from a tundra ecosystem

2013 ◽  
Vol 10 (2) ◽  
pp. 871-889 ◽  
Author(s):  
M. J. Potosnak ◽  
B. M. Baker ◽  
L. LeStourgeon ◽  
S. M. Disher ◽  
K. L. Griffin ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Global Climate ◽  
Common Species ◽  
Emission Rates ◽  
Arctic Ecosystems ◽  
Field Station ◽  
Isoprene Emission ◽  
Tundra Ecosystem ◽  
Leaf Level ◽  
Field Campaigns

Abstract. Whole-system fluxes of isoprene from a moist acidic tundra ecosystem and leaf-level emission rates of isoprene from a common species (Salix pulchra) in that same ecosystem were measured during three separate field campaigns. The field campaigns were conducted during the summers of 2005, 2010 and 2011 and took place at the Toolik Field Station (68.6° N, 149.6° W) on the north slope of the Brooks Range in Alaska, USA. The maximum rate of whole-system isoprene flux measured was over 1.2 mg C m−2 h−1 with an air temperature of 22 °C and a PAR level over 1500 μmol m−2 s−1. Leaf-level isoprene emission rates for S. pulchra averaged 12.4 nmol m−2 s−1 (27.4 μg C gdw−1 h−1) extrapolated to standard conditions (PAR = 1000 μmol m−2 s−1 and leaf temperature = 30 °C). Leaf-level isoprene emission rates were well characterized by the Guenther algorithm for temperature with published coefficients, but less so for light. Chamber measurements from a nearby moist acidic tundra ecosystem with little S. pulchra emitted significant amounts of isoprene, but at lower rates (0.45 mg C m−2 h−1) suggesting other significant isoprene emitters. Comparison of our results to predictions from a global model found broad agreement, but a detailed analysis revealed some significant discrepancies. An atmospheric chemistry box model predicts that the observed isoprene emissions have a significant impact on Arctic atmospheric chemistry, including a reduction of hydroxyl radical (OH) concentrations. Our results support the prediction that isoprene emissions from Arctic ecosystems will increase with global climate change.

scholarly journals Effects of Abiotic Factors on HIPV-Mediated Interactions between Plants and Parasitoids

2015 ◽  
Vol 2015 ◽  
pp. 1-18 ◽  
Author(s):  
Christine Becker ◽  
Nicolas Desneux ◽  
Lucie Monticelli ◽  
Xavier Fernandez ◽  
Thomas Michel ◽  
...  
Keyword(s):  
Plant Volatiles ◽  
Global Climate ◽  
Abiotic Factors ◽  
Biotic Interactions ◽  
Green Leaf Volatiles ◽  
Limited Attention ◽  
Emission Rates ◽  
Leaf Volatiles ◽  
Parasitic Hymenoptera ◽  
Growing Conditions

In contrast to constitutively emitted plant volatiles (PV), herbivore-induced plant volatiles (HIPV) are specifically emitted by plants when afflicted with herbivores. HIPV can be perceived by parasitoids and predators which parasitize or prey on the respective herbivores, including parasitic hymenoptera. HIPV act as signals and facilitate host/prey detection. They comprise a blend of compounds: main constituents are terpenoids and “green leaf volatiles.” Constitutive emission of PV is well known to be influenced by abiotic factors like temperature, light intensity, water, and nutrient availability. HIPV share biosynthetic pathways with constitutively emitted PV and might therefore likewise be affected by abiotic conditions. However, the effects of abiotic factors on HIPV-mediated biotic interactions have received only limited attention to date. HIPV being influenced by the plant’s growing conditions could have major implications for pest management. Quantitative and qualitative changes in HIPV blends may improve or impair biocontrol. Enhanced emission of HIPV may attract a larger number of natural enemies. Reduced emission rates or altered compositions, however, may render blends imperceptible to parasitoides and predators. Predicting the outcome of these changes is highly important for food production and for ecosystems affected by global climate change.

scholarly journals Carbon Costs of Indonesian Forested Land Conversion to Oil Palm Plantations

2019 ◽  
Vol 3 (3) ◽  
Author(s):  
Sri Walyoto
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Oil Palm ◽  
Global Climate ◽  
Secondary Data ◽  
Carbon Price ◽  
Forest Conversion ◽  
Carbon Costs ◽  
Carbon Dioxide Co2 ◽  
Co2 Release

This article analyzes the loss of carbon dioxide (CO2) released in the forest conversion to oil palm plantations. This research data gathered from the relevant secondary data and relate published reports. This research finds that a loss of release of carbon dioxide (CO2) per hectare of US $ 9,800 with a carbon price of USD2 of US $ 14,000 carbon price of USD3 and US $ 19,600 in carbon price of USD4. In addition, this conversion also has a significant impact on global warming (GWP) and global climate change. Keywords: oil palm plantation, CO2 release, GWP, climate change. 

scholarly journals Mineral protection regulates the long-term global preservation of natural organic carbon

2021 ◽  
Author(s):  
Jordon Hemingway ◽  
Daniel Rothman ◽  
Katherine Grant ◽  
Sarah Rosengard ◽  
Timothy Eglinton ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Redox State ◽  
Global Climate ◽  
Atmospheric Oxygen ◽  
Atmospheric Composition ◽  
Earth Surface ◽  
Mountain Ranges ◽  
Surface Redox ◽  
Carbon Erosion

<p>The vast majority of organic carbon (OC) produced by life is respired back to carbon dioxide (CO<sub>2</sub>), but roughly 0.1% escapes and is preserved over geologic timescales. By sequestering reduced carbon from Earth’s surface, this “slow OC leak” contributes to CO<sub>2</sub> removal and promotes the accumulation of atmospheric oxygen and oxidized minerals. Countering this, OC contained within sedimentary rocks is oxidized during exhumation and erosion of mountain ranges. By respiring previously sequestered reduced carbon, erosion consumes atmospheric oxygen and produces CO<sub>2</sub>. The balance between these two processes—preservation and respiration—regulates atmospheric composition, Earth-surface redox state, and global climate. Despite this importance, the governing mechanisms remain poorly constrained. To provide new insight, we developed a method that investigates OC composition using bond-strength distributions coupled with radiocarbon ages. Here I highlight a suite of recent results using this approach, and I show that biospheric OC interacts with particles and becomes physiochemically protected during aging, thus promoting preservation. I will discuss how this mechanistic framework can help elucidate why OC preservation—and thus atmospheric composition, Earth-surface redox state, and climate—has varied throughout Earth history.</p>

Ca/Sr and Sr isotope systematics of a Himalayan glacial chronosequence: carbonate versus silicate weathering rates as a function of landscape surface age

2002 ◽  
Vol 66 (1) ◽  
pp. 13-27 ◽  
Author(s):  
Andrew D Jacobson ◽  
Joel D Blum ◽  
C.Page Chamberlain ◽  
Michael A Poage ◽  
Valerie F Sloan
Keyword(s):  
Silicate Weathering ◽  
Sr Isotope ◽  
Weathering Rates ◽  
Isotope Systematics

Thick regoliths and the geological history of climate

2020 ◽  
Author(s):  
Yves Godderis ◽  
Pierre Maffre ◽  
Yannick Donnadieu
Keyword(s):  
Response Time ◽  
Numerical Models ◽  
Global Environmental Change ◽  
Silicate Weathering ◽  
Relative Role ◽  
Mountain Building ◽  
Mountain Ranges ◽  
Colonization Event ◽  
Physical Erosion

<p>The weathering of continental silicate rocks is a main sink of CO<sub>2</sub> at the geological timescale. As it is dependent on the climatic conditions (more weathering in a warmer world), the silicate weathering acts as a negative feedback on the carbon cycle, limiting the amplitude of past climatic changes.</p><p>Many contributions have shown that silicate weathering efficiency (the « weatherability ») is strongly correlated to the physical erosion. Because of this tight link, many works have focused on the role of mountain ranges in the climatic evolution, because those areas are characterized by intense physical denudation, thus potentially boosting chemical weathering. Simply speaking, periods of active mountain building are suspected to generate cold conditions.</p><p>Conversely, little attention has been paid to the role of large and flat continental areas. Due to the lack of physical erosion in those flat areas, the weathering processes will generate thick regoliths, progressively shielding the bedrock and ultimately decreasing the weatherability. Periods of limited mountain building activity might generate very high CO<sub>2</sub> level and warm climatic episodes.</p><p>However, this simple scheme, defining two extreme poles for the surficial Earth system (one mountainous and cold, the other flat and warm) raises several questions:</p><ul><li>the two modes (mountainous and flat) generally co-exist. Their relative role in the control of the climate is probably dependent on the continental configuration, and on the location of tectonically active and non-active areas in latitude and longitude.</li> <li>the dynamics of the thick regolith is not well constrained. How long does it take to generate thick regoliths? What is the response time of thick regoliths to a perturbation?</li> <li>what about the horizontal transfer of sediments? Recent works have shown that sediments are exported from mountain ranges and weathered in plains at the feet of the mountains. How can we incorporate this into numerical models? </li> </ul><p>We will explore the role of the regolith thickness with the spatially-resolved GEOCLIM model. We will focus on the consequences of the colonization of the continents by vascular land plants over the course of the Devonian. This event is suspected to have impacted the weatherability of all the continental surfaces in the same direction (increase in weatherability). We will show that the way atmospheric CO<sub>2</sub> is responding is depending on the initial state of the weathering system, prior to the colonization event. We will also explore the response time of the regolith cover to the global environmental change. We show that short glacial events can be generated in the direct vicinity of the colonization event, if the response time of the regolith layer is long and the colonization is fast. This cold overshoot disappears when the colonization time is assumed to be long (10 Myr), and the continental configuration becomes a critical factor impacting the CO<sub>2</sub> evolution.</p>

Effect of elevated CO2 concentration and vapour pressure deficit on isoprene emission from leaves of Populus deltoides during drought

2004 ◽  
Vol 31 (12) ◽  
pp. 1137 ◽  
Author(s):  
Emiliano Pegoraro ◽  
Ana Rey ◽  
Edward G. Bobich ◽  
Greg Barron-Gafford ◽  
Katherine Ann Grieve ◽  
...  
Keyword(s):  
Elevated Co2 ◽  
Vapour Pressure ◽  
Populus Deltoides ◽  
Global Climate ◽  
Stomatal Closure ◽  
Vapour Pressure Deficit ◽  
Co2 Concentration ◽  
Emission Rates ◽  
Isoprene Emission ◽  
Long Term Effect

To further our understanding of the influence of global climate change on isoprene production we studied the effect of elevated [CO2] and vapour pressure deficit (VPD) on isoprene emission rates from leaves of Populus deltoides Bartr. during drought stress. Trees, grown inside three large bays with atmospheres containing 430, 800, or 1200 μmol mol–1 CO2 at the Biosphere 2 facility, were subjected to a period of drought during which VPD was manipulated, switching between low VPD (approximately 1 kPa) and high VPD (approximately 3 kPa) for several days. When trees were not water-stressed, elevated [CO2] inhibited isoprene emission and stimulated photosynthesis. Isoprene emission was less responsive to drought than photosynthesis. As water-stress increased, the inhibition of isoprene emission disappeared, probably as a result of stomatal closure and the resulting decreases in intercellular [CO2] (Ci). This assumption was supported by increased isoprene emission under high VPD. Drought and high VPD dramatically increased the proportion of assimilated carbon lost as isoprene. When measured at the same [CO2], leaves from trees grown at ambient [CO2] always had higher isoprene emission rates than the leaves of trees grown at elevated [CO2], demonstrating that CO2 inhibition is a long-term effect.

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