Aquatic Geochemistry最新文献

{"title":"Fluid–Rock Interactions in Geothermal Reservoirs, Germany: Thermal Autoclave Experiments Using Sandstones and Natural Hydrothermal Brines","authors":"Rafael Schäffer,&nbsp;Emilia Götz,&nbsp;Nils Schlatter,&nbsp;Gabriela Schubert,&nbsp;Sebastian Weinert,&nbsp;Stefanie Schmidt,&nbsp;Ute Kolb,&nbsp;Ingo Sass","doi":"10.1007/s10498-022-09404-x","DOIUrl":"10.1007/s10498-022-09404-x","url":null,"abstract":"<div><p>As renewable energy, geothermal can contribute substantially to the energy transition. To generate electricity or to harvest heat, high-saline fluids are tapped by wells of a few kilometres and extracted from hydrothermal reservoirs. After the heat exchanger units have been passed by, these fluids are reinjected into the reservoir. Due to the pressure and temperature differences between the subsurface and the surface, as well as the cooling of the fluids in the power plant, unwanted chemical reactions can occur within the reservoir, in the borehole, and within the power plant itself. This can reduce the permeability of the reservoir as well as the output of the geothermal power plant. This study aims to simulate real subsurface reactions using batch and leaching experiments with sandstone or sandstone powder as solid phase, and deionised water or natural brine as liquid phase. It is demonstrated that fluid composition changes after only a few days. In particular, calcite, aragonite, clay minerals, and zinc phases precipitate from the natural brine. In contrast, in particular minerals containing potassium, arsenic, barium, and silica are dissolved. Due to the experimental set-up, these mineral reactions mainly took place on the surface of the samples, which is why no substantial changes in petrophysical properties could be observed. However, it is assumed that the observed reactions on the reservoir scale have a relevant influence on parameters such as permeability.</p></div>","PeriodicalId":8102,"journal":{"name":"Aquatic Geochemistry","volume":"28 2","pages":"63 - 110"},"PeriodicalIF":1.6,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10498-022-09404-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5182238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemical Proxies and Mineralogical Fingerprints of Sedimentary Processes in a Closed Shallow Lake Basin Since 1850","authors":"Paola Gravina,&nbsp;Alessandro Ludovisi,&nbsp;Beatrice Moroni,&nbsp;Riccardo Vivani,&nbsp;Roberta Selvaggi,&nbsp;Chiara Petroselli,&nbsp;David Cappelletti","doi":"10.1007/s10498-022-09403-y","DOIUrl":"10.1007/s10498-022-09403-y","url":null,"abstract":"<div><p>Lake systems are essential for the environment, the biosphere, and humans but are highly impacted by anthropogenic activities accentuated by climate change. Understanding how lake ecosystems change due to human impacts and natural forces is crucial to managing their current state and possible future restoration. The high sensitivity of shallow closed lakes to natural and anthropogenic forcing makes these lacustrine ecosystems highly prone to variations in precipitation and sedimentation processes. These variation processes, occurring in the water column, produce geochemical markers or proxies recorded in lake sedimentary archives. This study investigated specific proxies on high-resolution sedimentary archives (2–3 years resolution) of the Trasimeno lake (Central Italy). The Trasimeno lake underwent three different hydrological phases during the twentieth century due to several fluctuations induced mainly by human activities and climate change. The Trasimeno lake, a large and shallow basin located in the Mediterranean area, is a good case study to assess the effects of intense anthropogenic activity related to agriculture, tourism, industry, and climate changes during the Anthropocene. The aim is to identify the main characteristics of the main sedimentary events in the lake during the last 150 years, determining the concentrations of major and trace elements, the amount of organic matter, and the mineralogical composition of the sediments. This type of work demonstrates that studying sediment archives at high resolution is a viable method for reconstructing the lake’s history through the evolution/trends of the geochemical proxies stored in the sediment records. This effort makes it possible to assess past anthropogenic impact and, under the objectives of the European Green Deal (zero-pollution ambition for a toxic-free environment), to monitor, prevent, and remedy pollution related to soil and water compartments.</p><h3>Graphical abstract</h3>\u0000 <figure><div><div><div><picture><source><img></source></picture></div></div></div></figure>\u0000 </div>","PeriodicalId":8102,"journal":{"name":"Aquatic Geochemistry","volume":"28 1","pages":"43 - 62"},"PeriodicalIF":1.6,"publicationDate":"2022-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10498-022-09403-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4825957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Late Holocene Record of Variations in the Chemical Weathering Intensity and Pedogenesis in a Lake Catchment from Southern India","authors":"Kizhur Sandeep,&nbsp;Rajasekhariah Shankar,&nbsp;Anish Kumar Warrier","doi":"10.1007/s10498-021-09402-5","DOIUrl":"10.1007/s10498-021-09402-5","url":null,"abstract":"<div><p>We investigated the detrital influx, chemical weathering intensity, provenance and pedogenesis over the past 2,500 years in the catchment of Pookot Lake, southern India. The down-core variations of metal/Al ratios (Na/Al, K/Al, Mg/Al, Ca/Al, Fe/Al, Mn/Al, Zn/Al, Ba/Al) of the Pookot sediments indicate changes in the rainfall-induced terrigenous inflow to the lake. In contrast, fluctuations in the chemical index of alteration (CIA) and Rb/Sr values denote the variability in the strength of chemical weathering in the watershed of the lake. The results show that the detrital influx, and hence rainfall, remained steady except during 1500–600 cal. years B.P. (high) and 600–300 cal. year B.P. (low) in the Pookot lake catchment. However, the periods of high/low chemical weathering intensity in the catchment do not correspond to periods of high/low detrital influx to the lake basin. The similar shale-normalized rare earth elemental curves point to a uniform provenance. The past pedogenic activity is indicated by pedogenic χ_lf and pedogenic χ_fd derived from citrate-bicarbonate-dithionite (CBD) extraction. The data indicate that the fine-grained magnetite/maghemite formed during the pedogenesis mainly contributes to the magnetic signal of sediments. The degree of pedogenesis was strong during 2500–2000 cal. years B.P. and moderate throughout 1500–600 cal. years B.P. The pedogenic intensity became stronger again during ~ 600 cal. years B.P., which weakened between 600 and 300 cal. years B.P. and remained steady thereafter. The present study indicates that detrital influx proxies like metal/Al ratios are more suitable for reconstructing past climate in tropical climate rather than chemical weathering indices.</p></div>","PeriodicalId":8102,"journal":{"name":"Aquatic Geochemistry","volume":"28 1","pages":"27 - 42"},"PeriodicalIF":1.6,"publicationDate":"2022-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4459563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Oxygen Consumption of Resuspended Sediments of the Upper Elbe Estuary: Process Identification and Prognosis","authors":"M. Spieckermann,&nbsp;A. Gröngröft,&nbsp;M. Karrasch,&nbsp;A. Neumann,&nbsp;A. Eschenbach","doi":"10.1007/s10498-021-09401-6","DOIUrl":"10.1007/s10498-021-09401-6","url":null,"abstract":"<div><p>The resuspension of sediment leads to an increased release of nutrients and organic substances into the overlying water column, which can have a negative effect on the oxygen budget. Especially in the warmer months with a lower oxygen saturation and higher biological activity, the oxygen content can reach critical thresholds in estuaries like the upper Elbe estuary. Many studies have dealt with the nutrient fluxes that occur during a resuspension event. However, the sediment properties that influence the oxygen consumption potential (OCP) and the different biochemical processes have not been examined in detail. To fill this gap, we investigated the biogeochemical composition, texture, and OCP of sediments at 21 locations as well as the temporal variability within one location for a period of 2 years (monthly sampling) in the upper Elbe estuary. The OCP of sediments during a seven-day resuspension event can be described by the processes of sulphate formation, nitrification, and mineralisation. Chlorophyll, total nitrogen (<i>N</i>_total), and total organic carbon showed the highest correlations with the OCP. Based on these correlations, we developed a prognosis model to calculate the OCP for the upper Elbe estuary with a single sediment parameter (<i>N</i>_total). The model is well suited to calculate the oxygen consumption of resuspended sediments in the Hamburg port area during the relevant warmer months and shows a normalised root mean squared error of &lt; 0.11 ± 0.13. Thus, the effect of maintenance measures such as water injection dredging and ship-induced wave on the oxygen budget of the water can be calculated.</p></div>","PeriodicalId":8102,"journal":{"name":"Aquatic Geochemistry","volume":"28 1","pages":"1 - 25"},"PeriodicalIF":1.6,"publicationDate":"2021-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10498-021-09401-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5164107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temporal and Spatial Variabilities of Chemical and Physical Parameters on the Heron Island Coral Reef Platform","authors":"Samuel A. H. Kekuewa,&nbsp;Travis A. Courtney,&nbsp;Tyler Cyronak,&nbsp;Theodor Kindeberg,&nbsp;Bradley D. Eyre,&nbsp;Laura Stoltenberg,&nbsp;Andreas J. Andersson","doi":"10.1007/s10498-021-09400-7","DOIUrl":"10.1007/s10498-021-09400-7","url":null,"abstract":"<div><p>Globally, coral reefs are threatened by ocean warming and acidification. The degree to which acidification will impact reefs is dependent on the local hydrodynamics, benthic community composition, and biogeochemical processes, all of which vary on different temporal and spatial scales. Characterizing the natural spatiotemporal variability of seawater carbonate chemistry across different reefs is critical for elucidating future impacts on coral reefs. To date, most studies have focused on select habitats, whereas fewer studies have focused on reef scale variability. Here, we investigate the temporal and spatial seawater physicochemical variability across the entire Heron Island coral reef platform, Great Barrier Reef, Australia, for a limited duration of six days. Autonomous sensor measurements at three sites across the platform were complemented by reef-wide boat surveys and discrete sampling of seawater carbonate chemistry during the morning and evening. Variability in both temporal and spatial physicochemical properties were predominantly driven by solar irradiance (and its effect on biological activity) and the semidiurnal tidal cycles but were influenced by the local geomorphology resulting in isolation of the platform during low tide and rapid flooding during rising tides. As a result, seawater from previous tidal cycles was sometimes trapped in different parts of the reef leading to unexpected biogeochemical trends in space and time. This study illustrates the differences and limitations of data obtained from high-frequency measurements in a few locations compared to low-frequency measurements at high spatial resolution and coverage, showing the need for a combined approach to develop predictive capability of seawater physicochemical properties on coral reefs.</p></div>","PeriodicalId":8102,"journal":{"name":"Aquatic Geochemistry","volume":"27 4","pages":"241 - 268"},"PeriodicalIF":1.6,"publicationDate":"2021-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10498-021-09400-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4184400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Organic versus Inorganic Carbon Exports from Glacier and Permafrost Watersheds in Qinghai–Tibet Plateau","authors":"Congrong Yu,&nbsp;Ying Li,&nbsp;Huijun Jin,&nbsp;Qiang Ma,&nbsp;Zhongbo Yu,&nbsp;Keliang Shi,&nbsp;Xiangying Li,&nbsp;Gang Chen","doi":"10.1007/s10498-021-09399-x","DOIUrl":"10.1007/s10498-021-09399-x","url":null,"abstract":"<div><p>In a warming climate, land-to-water carbon mobilization is increasing in glacier and permafrost area. To identify the connection between exported river carbon content and the permafrost or glacier condition in the high-altitude mountain area, we studied the dissolved organic carbon and dissolved inorganic carbon concentration in three streams of Qinghai–Tibet Plateau (QTP), which were located in the continuous permafrost, seasonal permafrost and glacial basin, respectively. It was found that the DIC and DOC concentrations were lower in the glacial rivers compared with the permafrost derived rivers; but more DOC would be exported from glacier due to the large amount of melted glacier water in the high mountainous area. DIC/DOC ratio in rivers reflected the watershed landscape types. In the permafrost area, the river recharged by seasonal permafrost had higher DIC concentration than the river in the continuous permafrost region, suggesting that increased DIC concentration could be a precursor of permafrost degradation. Research is meaningful to estimate the DOC and DIC export from high mountain area.</p></div>","PeriodicalId":8102,"journal":{"name":"Aquatic Geochemistry","volume":"27 4","pages":"283 - 296"},"PeriodicalIF":1.6,"publicationDate":"2021-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4735182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Upwelling of Deep-seated Fluid in the Sikhote-Alin Region, Far East of the Eurasian Plate","authors":"Hitomi Nakamura,&nbsp;Hikaru Iwamori,&nbsp;Noritoshi Morikawa,&nbsp;Natalia Kharitonova,&nbsp;Georgy Chelnokov,&nbsp;Ivan Bragin,&nbsp;Qing Chang","doi":"10.1007/s10498-021-09398-y","DOIUrl":"10.1007/s10498-021-09398-y","url":null,"abstract":"<div><p>Spring waters with high-pCO₂ content are widely distributed in the Sikhote-Alin region in Russia. Mukhen spa is one such spring located in the northern Sikhote-Alin region. This spa has two types of upwelling spring waters and exhibits distinct chemical signatures. One of the springs originates from a shallow aquifer and features hydrogen and oxygen isotopic ratios of meteoric water with a high ³He/⁴He ratio, whereas the other originates from a deeper aquifer and features a distinctly negative δ¹⁸O with a lower ³He/⁴He ratio. To understand this apparent discrepancy and the water circulation dynamics beneath Mukhen springs, we utilized all published data concerning the major solute elements and isotopic ratios of Mukhen spring waters and compared them with the He isotopic compositions on several springs in the far eastern region, which are newly analyzed in this study. The results show that the shallow aquifer comprises meteoric water that interacts with the crust enhanced by the gas component welling up from deep underground, while the fluid in deep aquifer fingerprinted the hydration reaction of silicate and involves a mantle component possibly delivered by a deep-seated fluid and/or gas upwelling along the tectonic fault through the western margin of the Sikhote-Alin region.</p></div>","PeriodicalId":8102,"journal":{"name":"Aquatic Geochemistry","volume":"27 4","pages":"269 - 282"},"PeriodicalIF":1.6,"publicationDate":"2021-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10498-021-09398-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4407390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Carbonate Alkalinity Enhances Triclosan Photolysis","authors":"Katie A. Albanese,&nbsp;Mrinal Chakraborty,&nbsp;Christopher M. Hadad,&nbsp;Yu-Ping Chin","doi":"10.1007/s10498-021-09397-z","DOIUrl":"10.1007/s10498-021-09397-z","url":null,"abstract":"<div><p>Triclosan (TCS) is an antimicrobial compound found in many household products used across the world. TCS is not completely removed in wastewater systems, resulting in trace-level concentrations present ubiquitously in surface waters. The direct photodegradation of TCS has been widely studied, with results indicating that TCS breaks down to chlorophenols and dioxins. To date, no studies have specifically investigated the effects of alkalinity on the photolysis of the acidic form of TCS. This study assessed the effect of carbonate/bicarbonate alkalinity, which is ubiquitous in natural waters, on the photolysis rate of TCS. Results indicate that bicarbonate enhances the photodegradation of TCS at pH values well below the p<i>K</i>_a of TCS (7.9), with direct photolysis reaction kinetics that are very slow in the absence of buffers, but significant in the presence of bicarbonate (0.711 h⁻¹ at pH 6.55). At pH values well above its p<i>K</i>_a, both unbuffered- and buffered-mediated photolysis increased dramatically (1.92 h⁻¹ for direct photolysis and 2.86 h⁻¹ in buffered water) and is attributable to the increased photoreactivity of TCS by its conjugate base. Photolysis of methyl triclosan (MeTCS), a non-acidic analog of TCS, demonstrated the importance of TCS’s acidic functionality as MeTCS did not degrade at any pH. The observed influence of alkalinity on the acidic form of TCS photolysis was attributed to both a decrease in its excited state p<i>K</i>_a, coupled with TCS deprotonation through an excited state proton transfer to a base (bicarbonate and to a lesser degree hydrogen phosphate) resulting in the more photo-labile conjugate base form of TCS.</p></div>","PeriodicalId":8102,"journal":{"name":"Aquatic Geochemistry","volume":"27 3","pages":"159 - 171"},"PeriodicalIF":1.6,"publicationDate":"2021-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s10498-021-09397-z","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4252103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Abiotic Nitrite Oxidation by Ligand-Bound Manganese (III): The Chemical Mechanism","authors":"George W. Luther III,&nbsp;Jennifer S. Karolewski,&nbsp;Kevin M. Sutherland,&nbsp;Colleen M. Hansel,&nbsp;Scott D. Wankel","doi":"10.1007/s10498-021-09396-0","DOIUrl":"10.1007/s10498-021-09396-0","url":null,"abstract":"<div><p>Given their environmental abundances, it has been long hypothesized that geochemical interactions between reactive forms of manganese and nitrogen may play important roles in the cycling of these elements. Indeed, recent studies have begun shedding light on the possible role of soluble, ligand-bound Mn(III) in promoting abiotic transformations under environmentally relevant conditions. Here, using the kinetic data of Karolewski et al. (Geochim Cosmochim Acta 293:365–378, 2021), we provide the chemical mechanism for the abiotic oxidation of nitrite (NO₂⁻) by Mn(III)-pyrophosphate, Mn^IIIPP, to form nitrate (NO₃⁻). Nitrous acid (HNO₂), not NO₂⁻, is the reductant in the reaction, based on thermodynamic and kinetic considerations. As soluble Mn(III) complexes react in a one-electron transfer reaction, two one-electron transfer steps must occur. In step one, HNO₂ is first oxidized to nitrogen dioxide, ·NO₂, a free radical via a hydrogen atom transfer (HAT) reaction. We show that this inner sphere reaction process is the rate-limiting step in the reaction sequence. In step two, ·NO₂ reacts with a second Mn^IIIPP complex to form the nitronium ion (NO₂⁺), which is isoelectronic with CO₂. Unlike the poor electron-accepting capability of CO₂, NO₂⁺ is an excellent electron acceptor for both OH⁻ and H₂O, so NO₂⁺ reacts quickly with water to form the end-product NO₃⁻ (step 3 in the reaction sequence). Thus, water provides the O atom in this nitrification reaction in accordance with the O-isotope data. This work provides mechanistic perspective on a potentially important interaction between Mn and nitrogen species, thereby offering a framework in which to interpret kinetic and isotopic data and to further investigate the relevance of this reaction under environmental conditions.</p></div>","PeriodicalId":8102,"journal":{"name":"Aquatic Geochemistry","volume":"27 3","pages":"207 - 220"},"PeriodicalIF":1.6,"publicationDate":"2021-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s10498-021-09396-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5185219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chemical weathering and carbon dioxide consumption in a small tropical river catchment, southwestern India","authors":"Baby Krishnan Nisha,&nbsp;Keshava Balakrishna,&nbsp;Harikripa Narayana Udayashankar,&nbsp;Busnur Rachotappa Manjunatha","doi":"10.1007/s10498-021-09394-2","DOIUrl":"10.1007/s10498-021-09394-2","url":null,"abstract":"<div><p>Studies done on small tropical west-flowing river catchments located in the Western Ghats in southwestern India have suggested very intense chemical weathering rates and associated CO₂ consumption. Very less studies are reported from these catchments notwithstanding their importance as potential sinks of atmospheric CO₂ at the global scale. A total of 156 samples were collected from a small river catchment in the southwestern India, the Payaswini–Chandragiri river Basin, during pre-monsoon, monsoon and post-monsoon seasons in 2016 and 2017, respectively. This river system comprises two small rivers originating at an elevation of 1350 m in the Western Ghats in peninsular India. The catchment area is dominated by biotite sillimanite gneiss. Sodium is the dominant cation, contributing ~ 50% of the total cations, whereas HCO₃⁻ contributes ~ 75% of total anions. The average anion concentration in the samples varied in the range HCO₃⁻ &gt; Cl⁻ &gt; SO₄²⁻ &gt; NO₃⁻ &gt; F⁻, whereas major cation concentration varied in the range Na⁺  &gt; Ca²⁺  &gt; Mg²⁺  &gt; K⁺. The average silicate weathering rate (SWR) was 42 t km⁻² y⁻¹ in the year 2016 and 36 t km⁻² y⁻¹ in 2017. The average annual carbon dioxide consumption rate (CCR) due to silicate rock weathering was 9.6 × 10⁵ mol km⁻²y⁻¹ and 8.3 × 10⁵ mol km⁻² y⁻¹ for 2016 and 2017, respectively. The CCR in the study area is higher than other large tropical river catchments like Amazon, Congo-Zaire, Orinoco, Parana and Indus because of its unique topography, hot and humid climate and intense rainfall.</p></div>","PeriodicalId":8102,"journal":{"name":"Aquatic Geochemistry","volume":"27 3","pages":"173 - 206"},"PeriodicalIF":1.6,"publicationDate":"2021-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s10498-021-09394-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5518241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}