Current chemical denudation, silicate mineral weathering and erosion in Irish catchments: reflections on the tortoise and the hare

2020 ◽  
Vol 38 (1) ◽  
pp. 15-23
Author(s):  
W. Berry Lyons ◽  
Anne E. Carey ◽  
Peter Croot ◽  
Tiernan Henry ◽  
Susan A. Welch ◽  
...  
Keyword(s):  
Mineral Weathering ◽  
Silicate Mineral

scholarly journals Palaeo-environmental evolution of Central Asia during the Cenozoic: New insights from the continental sedimentary archive of the Valley of Lakes (Mongolia)

2021 ◽  
Author(s):  
Andre Baldermann ◽  
Oliver Wasser ◽  
Elshan Abdullayev ◽  
Stefano Bernasconi ◽  
Stefan Löhr ◽  
...  
Keyword(s):  
Central Asia ◽  
Function Analysis ◽  
Global Climate ◽  
Clay Fraction ◽  
Ice Sheet ◽  
Mineral Weathering ◽  
Silicate Mineral ◽  
Arid Conditions ◽  
Soil Carbonates ◽  
Semi Arid

Abstract. The Valley of Lakes basin (Mongolia) contains a unique continental sedimentary archive, suitable for constraining the influence of tectonics and climate change on the aridification of Central Asia in the Cenozoic. We identify the sedimentary provenance, the (post)depositional environment and the palaeo-climate based on sedimentological, petrographical, mineralogical and (isotope) geochemical signatures recorded in authigenic and detrital silicates as well as soil carbonates in a sedimentary succession spanning ~34 to 21 Ma. The depositional setting was characterized by an ephemeral braided river system draining prograding alluvial fans, with episodes of lake, playa or open steppe sedimentation. Metamorphics from the northern adjacent Neoarchean to late Proterozoic hinterlands provided a continuous influx of silicate detritus to the basin, as indicated by K-Ar ages of detrital muscovite (~798-728 Ma) and discrimination function analysis. The authigenic clay fraction is dominated by illite-smectite and “hairy” illite (K-Ar ages: ~34-25 Ma), which formed during coupled petrogenesis and precipitation from hydrothermal fluids originating from major basalt flow events (~32-29 Ma and ~29-25 Ma). Changes in hydroclimate are recorded in δ18O and δ13C profiles of soil carbonates and in silicate mineral weathering patterns, indicating comparatively humid to semi-arid conditions prevailed in the late(st) Eocene, changing into arid conditions in the Oligocene and back to humid to semi-arid conditions in the early Miocene. Aridification steps are indicated at ~34-33 Ma, ~31 Ma, ~28 Ma and ~23 Ma and coincide with some episodes of high-latitude ice sheet expansion inferred from marine deep-sea sedimentary records. This suggests long-term variations of the ocean/atmosphere circulation patterns due to pCO2 fall, re-configurations of ocean gateways and ice-sheet expansion in Antarctica could have impacted the hydroclimate and weathering regime in the basin. We conclude that the aridification in Central Asia was triggered by reduced moisture influx by westerly winds driven by Cenozoic climate forcing and the exhumation of the Tian Shan and Altai mountains and modulate by global climate events.

scholarly journals Evolution of trees and mycorrhizal fungi intensifies silicate mineral weathering

2012 ◽  
Vol 8 (6) ◽  
pp. 1006-1011 ◽  
Author(s):  
Joe Quirk ◽  
David J. Beerling ◽  
Steve A. Banwart ◽  
Gabriella Kakonyi ◽  
Maria E. Romero-Gonzalez ◽  
...  
Keyword(s):  
Mycorrhizal Fungi ◽  
Atmospheric Carbon Dioxide ◽  
Field Experiments ◽  
Carbon Dioxide Concentration ◽  
Arbuscular Mycorrhizal ◽  
Mineral Weathering ◽  
Mineral Surfaces ◽  
Mature Trees ◽  
Silicate Mineral ◽  
Climate History

Forested ecosystems diversified more than 350 Ma to become major engines of continental silicate weathering, regulating the Earth's atmospheric carbon dioxide concentration by driving calcium export into ocean carbonates. Our field experiments with mature trees demonstrate intensification of this weathering engine as tree lineages diversified in concert with their symbiotic mycorrhizal fungi. Preferential hyphal colonization of the calcium silicate-bearing rock, basalt, progressively increased with advancement from arbuscular mycorrhizal (AM) to later, independently evolved ectomycorrhizal (EM) fungi, and from gymnosperm to angiosperm hosts with both fungal groups. This led to ‘trenching’ of silicate mineral surfaces by AM and EM fungi, with EM gymnosperms and angiosperms releasing calcium from basalt at twice the rate of AM gymnosperms. Our findings indicate mycorrhiza-driven weathering may have originated hundreds of millions of years earlier than previously recognized and subsequently intensified with the evolution of trees and mycorrhizas to affect the Earth's long-term CO 2 and climate history.

Silicate mineral weathering rate estimates: Are they precise enough to be useful when predicting the recovery of nutrient pools after harvesting?

2011 ◽  
Vol 261 (1) ◽  
pp. 1-9 ◽  
Author(s):  
J. Klaminder ◽  
R.W. Lucas ◽  
M.N. Futter ◽  
K.H. Bishop ◽  
S.J. Köhler ◽  
...  
Keyword(s):  
Mineral Weathering ◽  
Silicate Mineral ◽  
Nutrient Pools ◽  
Weathering Rate

scholarly journals Short Communication: Earth is (mostly) flat, but mountains dominate global denudation: apportionment of the continental mass flux over millennial time scales, revisited

2014 ◽  
Vol 2 (1) ◽  
pp. 1-17 ◽  
Author(s):  
J. K. Willenbring ◽  
A. T. Codilean ◽  
K. L. Ferrier ◽  
B. McElroy ◽  
J. W. Kirchner
Keyword(s):  
Mineral Weathering ◽  
Carbonate Sediments ◽  
Silicate Mineral ◽  
Erosion Rates ◽  
Denudation Rates ◽  
Methodological Errors ◽  
The Subject ◽  
Mountain Landscapes ◽  
Topographic Gradients ◽  
Continental Erosion

Abstract. Carbon dioxide consumption by silicate mineral weathering and the subsequent precipitation of carbonate sediments sequesters CO2 over geologic timescales. The rate of this carbon sequestration is coupled to rates of continental erosion, which exposes fresh minerals to weathering. Steep mountain landscapes represent a small fraction of continental surfaces but contribute disproportionately to global erosion rates. However, the relative contributions of Earth's much vaster, but more slowly eroding, plains and hills remain the subject of debate. Recently, Willenbring et al. (2013) analyzed a compilation of denudation rates and topographic gradients and concluded that low-gradient regions dominate global denudation fluxes and silicate weathering rates. Here, we show that Willenbring et al. (2003) topographic and statistical analyses were subject to methodological errors that affected their conclusions. We correct these errors, and reanalyze their denudation rate and topographic data. In contrast to the results of Willenbring et al. (2013), we find that the denudation flux from the steepest 10% of continental topography nearly equals the flux from the other 90% of the continental surface combined. This new analysis implies global denudation fluxes of ∼23 Gt yr−1, roughly five times the value reported in Willenbring et al. (2013) and closer to previous estimates found elsewhere in the literature. Although low-gradient landscapes make up a small proportion of the global fluxes, they remain important because of the human reliance, and impact, on these vast areas.

scholarly journals Hydrochemical Characterization of Groundwater Quality in Nkalagu District, Southeastern Nigeria

2021 ◽  
pp. 34-50
Author(s):  
I. M. Onwe ◽  
B. E. B. Akudinobi ◽  
C. J. Chizoba ◽  
K. A. Ifeanyichukwu
Keyword(s):  
Groundwater Quality ◽  
Major Ions ◽  
The United States ◽  
Mineral Weathering ◽  
Silicate Mineral ◽  
Southeastern Nigeria ◽  
Groundwater Samples ◽  
Hydrochemical Characterization ◽  
Drinking Purpose

Hydrochemical characterization of groundwater quality in Nkalagu District, southeastern Nigeria was carried to determine the main factors controlling the chemistry of groundwater and its suitability for drinking and irrigation purposes. Sixty (60) groundwater samples collected from boreholes and hand-dug wells in different parts of the area were analyzed for a range of physiochemical parameters and heavy metal constituents. The results show that concentration of the major ions were in the order Cl->HCO3->SO42->NO3- and Na>Ca2+>Mg2+>K+. The groundwater samples are slightly acidic with pH of 5.28 to 8.04; moderately hard with TH of 112.88 to 467.78 mg/l. The district is mainly controlled by carbonate and silicate mineral weathering based on the available result. Three main flow regimes were identified with Q-mode cluster analysis. Based on the WQIanalysis results, the groundwater quality in the district was classified, generally as ‘poor’ to ‘excellent’ for drinking purpose. Groundwater quality for drinking purpose were noted to deteriorates as one move from west towards the east of the district, while the north and south part pf the study area indicated the best quality in the district. Groundwater quality for irrigation purpose showed excellent quality based on the United States Salinity Laboratory and Wilcox diagrams. For future use of groundwater resource in the district we recommend implementation rules and guidelines in the area to enhance health and preserve groundwater sources in the district.

A Combination of Genomics, Transcriptomics, and Genetics Provides Insights into the Mineral Weathering Phenotype of Pseudomonas azotoformans F77

2021 ◽  
Author(s):  
Yuan-Li Wang ◽  
Wen Dong ◽  
Kai-Xiang Xiang ◽  
Qi Wang ◽  
Lin-Yan He ◽  
...  
Keyword(s):  
Metabolic Pathways ◽  
Gluconic Acid ◽  
Acid Production ◽  
Molecular Mechanisms ◽  
Acid Metabolism ◽  
Reducing Power ◽  
Acid Tolerance ◽  
Mineral Weathering ◽  
Silicate Mineral ◽  
Flagellar Assembly

Silicate mineral weathering (dissolution) plays important roles in soil formation and global biogeochemical cycling. In this study, a combination of genomics, transcriptomics, and genetics was used to identify the molecular basis of mineral weathering activity and acid tolerance in Pseudomonas azotoformans F77. Biotite was chosen as a silicate mineral to investigate mineral weathering. The genome of strain F77 was sequenced, and the genes significantly upregulated when grown in the presence of biotite included mineral weathering-related genes associated with gluconic acid metabolism, flagellar assembly, and pilus biosynthesis and acid tolerance-related genes associated with neutralizing component production, reducing power, and proton efflux. Then, the biotite-weathering behaviors of strain F77 and its mutants that were created by deleting the tkt , tal , gntP , potF , nuoF , and gdtO genes, which are involved in gluconic acid metabolism and acid tolerance, respectively, were determined. The Fe and Al concentrations in the strain F77-inoculated medium increased 2.2- to 13.7-fold compared to the controls. The cell numbers of strain F77 increased over time, while the pH values in the medium ranged from 3.75 to 3.90 between 20 and 36 h of incubation. The release of Al and Fe was significantly reduced in the mutants F77Δ tal , F77Δ gntP , F77Δ potF , and F77Δ nuoF . Bacterial growth was significantly reduced in the presence of biotite in the mutants F77Δ potF and F77Δ nuoF . Our results demonstrated the acid tolerance of strain F77 and suggested that multiple genes and metabolic pathways in strain F77 are involved in biotite weathering and acid tolerance during the mineral weathering process. IMPORTANCE Acid production and tolerance play important roles in effective and persistent mineral weathering in bacteria, although the molecular mechanisms governing acid production and acid tolerance in bacteria have not been fully elucidated. In this study, the molecular mechanisms underlying biotite (as a silicate mineral) weathering (dissolution) and acid tolerance of P. azotoformans F77 were characterized using genomics, transcriptomics, and genetics analyses. Our results showed that the genes and metabolic pathways for gluconic acid metabolism, flagellar assembly, and pilus biosynthesis may play important roles in mineral weathering by strain F77. Notably, the genes associated with neutralizing component production, reducing power, and proton efflux may be related to acid tolerance in strain F77. The expression of these acid production- and acid tolerance-related genes was observed to be increased by biotite in strain F77. Our findings may help to elucidate the molecular mechanisms governing mineral weathering and, especially, acid tolerance in mineral-weathering bacteria.

Characterization ofRhizobiumsp. Q32 Isolated from Weathered Rocks and its Role in Silicate Mineral Weathering

2013 ◽  
Vol 30 (7) ◽  
pp. 616-622 ◽  
Author(s):  
Fei Zhao ◽  
Gang Qiu ◽  
Zhi Huang ◽  
Linyan He ◽  
Xiafang Sheng
Keyword(s):  
Mineral Weathering ◽  
Silicate Mineral ◽  
Weathered Rocks

scholarly journals Climatic and landscape controls on water transit times and silicate mineral weathering in the critical zone

2015 ◽  
Vol 51 (8) ◽  
pp. 6036-6051 ◽  
Author(s):  
Xavier Zapata-Rios ◽  
Jennifer McIntosh ◽  
Laura Rademacher ◽  
Peter A. Troch ◽  
Paul D. Brooks ◽  
...  
Keyword(s):  
Critical Zone ◽  
Mineral Weathering ◽  
Silicate Mineral ◽  
Transit Times
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