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DOI | 10.1029/2023JF007255 |
Hydrologic and Landscape Controls on Rock Weathering Along a Glacial Gradient in South Central Alaska, USA | |
Munoz, S.; Jenckes, J.; Ramos, E. J.; Munk, L. A.; Ibarra, D. E. | |
发表日期 | 2024 |
ISSN | 2169-9003 |
EISSN | 2169-9011 |
起始页码 | 129 |
结束页码 | 3 |
卷号 | 129期号:3 |
英文摘要 | Rock weathering impacts atmospheric CO2 levels with silicate rock dissolution removing CO2, and carbonate dissolution, pyrite oxidation, and organic rock carbon oxidation producing CO2. Glacierization impacts the hydrology and geomorphology of catchments and glacier retreat due to warming can increase runoff and initiate landscape succession. To investigate the impact of these changes on catchment scale weathering CO2 balances, we report monthly samples of solute chemistry and continuous discharge records for a sequence of glacierized watersheds draining into Kachemak Bay, Alaska. We partition solute and acid sources and estimate inorganic weathering CO2 balances using an inverse geochemical mixing model. Furthermore, we investigated how solutes vary with discharge conditions utilizing a concentration-runoff framework. We develop an analogous fraction-runoff framework which allows us to investigate changes in weathering contributions at different flows. Fraction-runoff relationships suggest kinetic limitations on all reactions in glacierized catchments, and only silicate weathering in less glacierized catchments. Using forest cover as a proxy for landscape age and stability, multiple linear regression shows that faster reactions (pyrite oxidation) contribute less to the solute load with increasing forest cover, whereas silicate weathering (slow reaction kinetics) contributes more. Overall, in glacierized catchments, we find elevated weathering fluxes at high runoff despite significant dilution effects. This makes flux estimates that account for dilution more important in glacierized catchments. Our findings quantify how glaciers modify the inorganic weathering CO2 balance of catchments through hydrologic and geomorphic forcings, and support the previous hypothesis that deglaciation will be accompanied by a shift in inorganic weathering CO2 balances. The chemical breakdown of rocks impacts atmospheric CO2 levels and helps regulate Earth's climate. The concentration of elements in river water reflects the chemical reactions occurring across a watershed, and the number of glaciers on the landscape can impact the breakdown of rocks. To understand the influence glaciers have on the chemical breakdown of rocks and how that influences CO2 balances, we collected water monthly from 5 rivers that drain landscapes with varying number of glaciers. We utilize a mixing model to understand which reactions are taking place in each watershed, quantify the CO2 balances associated with the chemical breakdown of rocks and develop a framework for understanding how these reactions change with changing hydrologic conditions. Watersheds with more glaciers have greater chemical breakdown of rocks, even though element concentrations in rivers are lower. Accounting for this dilution is more important in watersheds with high amounts of glacier cover. Additionally, in watersheds with higher glacier cover, all rock water reactions are limited by the time water is in contact with reactive minerals. This work suggests that glacier retreat will impact the balance of CO2 in the atmosphere because of the way glaciers impact the way rocks break down. Increased runoff drives increased solute export in glacierized catchments The hydrologic and landscape changes associated with deglaciation modifies the weathering CO2 balance of catchments Weathering flux estimates that do not account for dilution overestimate contributions in glacierized catchments |
英文关键词 | weathering; hydrology; C-q relationships; carbon budget; landscape change |
语种 | 英语 |
WOS研究方向 | Geology |
WOS类目 | Geosciences, Multidisciplinary |
WOS记录号 | WOS:001176558800001 |
来源期刊 | JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE |
文献类型 | 期刊论文 |
条目标识符 | http://gcip.llas.ac.cn/handle/2XKMVOVA/306735 |
作者单位 | Brown University; Brown University; University of Alaska System; University of Alaska Anchorage; University of Alaska System; University of Alaska Fairbanks; Rice University |
推荐引用方式 GB/T 7714 | Munoz, S.,Jenckes, J.,Ramos, E. J.,et al. Hydrologic and Landscape Controls on Rock Weathering Along a Glacial Gradient in South Central Alaska, USA[J],2024,129(3). |
APA | Munoz, S.,Jenckes, J.,Ramos, E. J.,Munk, L. A.,&Ibarra, D. E..(2024).Hydrologic and Landscape Controls on Rock Weathering Along a Glacial Gradient in South Central Alaska, USA.JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE,129(3). |
MLA | Munoz, S.,et al."Hydrologic and Landscape Controls on Rock Weathering Along a Glacial Gradient in South Central Alaska, USA".JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE 129.3(2024). |
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