{"title":"Erosion modulates the effect of chemical weathering on atmospheric pCO2, Qinghai-Tibet Plateau","authors":"","doi":"10.1016/j.gloplacha.2024.104619","DOIUrl":null,"url":null,"abstract":"<div><div>Chemical weathering plays an important role in modulating Earth's climate. However, chemical weathering is usually influenced by multiple factors simultaneously (e.g., climate, topography and lithology), and it is difficult to understand how these variables modulate the effect of chemical weathering on atmospheric <em>p</em>CO<sub>2</sub>. In this study, we collected and analyzed water chemistry and multiple isotopes (δ<sup>34</sup>S<sub>SO4</sub>, δ<sup>18</sup>O<sub>SO4</sub> and δ<sup>18</sup>O<sub>H2O</sub>) in the Bailong River catchment to decipher how these variables influence chemical weathering and its effect on atmospheric <em>p</em>CO<sub>2</sub>. We used the Monte Carlo inversion model to partition the sources of major cations and <span><math><msubsup><mi>SO</mi><mn>4</mn><mrow><mn>2</mn><mo>−</mo></mrow></msubsup></math></span>, and the results reveal that carbonate weathering is the dominant source contributing cations in river. Sulfide oxidation is the most important source for <span><math><msubsup><mi>SO</mi><mn>4</mn><mrow><mn>2</mn><mo>−</mo></mrow></msubsup></math></span> and a supply-limited process that is highly dependent on slope. We thus think slope is main factor modulating the effect of chemical weathering on atmospheric <em>p</em>CO<sub>2</sub>. Steep slope increases sulfide oxidation rate by elevating erosion, resulting in chemical weathering acting as a CO<sub>2</sub> source. In contrast, gentle slope could facilitate a thick regolith that contributes long-term silicate weathering and limits sulfide oxidation, resulting in chemical weathering acting as a CO<sub>2</sub> sink. And it has been found that the influence of temperature on chemical weathering becomes progressively pronounced with increasing altitude. This study investigated sulfide weathering in eroding Qinghai-Tibet Plateau, highlighting the geomorphologically controlled CO<sub>2</sub> effects of chemical weathering.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":null,"pages":null},"PeriodicalIF":4.0000,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Global and Planetary Change","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0921818124002662","RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOGRAPHY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Chemical weathering plays an important role in modulating Earth's climate. However, chemical weathering is usually influenced by multiple factors simultaneously (e.g., climate, topography and lithology), and it is difficult to understand how these variables modulate the effect of chemical weathering on atmospheric pCO2. In this study, we collected and analyzed water chemistry and multiple isotopes (δ34SSO4, δ18OSO4 and δ18OH2O) in the Bailong River catchment to decipher how these variables influence chemical weathering and its effect on atmospheric pCO2. We used the Monte Carlo inversion model to partition the sources of major cations and , and the results reveal that carbonate weathering is the dominant source contributing cations in river. Sulfide oxidation is the most important source for and a supply-limited process that is highly dependent on slope. We thus think slope is main factor modulating the effect of chemical weathering on atmospheric pCO2. Steep slope increases sulfide oxidation rate by elevating erosion, resulting in chemical weathering acting as a CO2 source. In contrast, gentle slope could facilitate a thick regolith that contributes long-term silicate weathering and limits sulfide oxidation, resulting in chemical weathering acting as a CO2 sink. And it has been found that the influence of temperature on chemical weathering becomes progressively pronounced with increasing altitude. This study investigated sulfide weathering in eroding Qinghai-Tibet Plateau, highlighting the geomorphologically controlled CO2 effects of chemical weathering.
期刊介绍:
The objective of the journal Global and Planetary Change is to provide a multi-disciplinary overview of the processes taking place in the Earth System and involved in planetary change over time. The journal focuses on records of the past and current state of the earth system, and future scenarios , and their link to global environmental change. Regional or process-oriented studies are welcome if they discuss global implications. Topics include, but are not limited to, changes in the dynamics and composition of the atmosphere, oceans and cryosphere, as well as climate change, sea level variation, observations/modelling of Earth processes from deep to (near-)surface and their coupling, global ecology, biogeography and the resilience/thresholds in ecosystems.
Key criteria for the consideration of manuscripts are (a) the relevance for the global scientific community and/or (b) the wider implications for global scale problems, preferably combined with (c) having a significance beyond a single discipline. A clear focus on key processes associated with planetary scale change is strongly encouraged.
Manuscripts can be submitted as either research contributions or as a review article. Every effort should be made towards the presentation of research outcomes in an understandable way for a broad readership.