Student Seminar Series

29 Feb
2024
Designing Organic Molecule Sensors for Water Contaminant Detection

Name of the Speaker Vishakha Chauhan
Title of the Seminar Designing Organic Molecule Sensors for Water Contaminant Detection
Date &Time 29 February 2024 (Thursday) at 4:30 PM
Venue ICWaR Seminar Hall

Abstract:

We have come across so many research papers that show the utilization of organic molecules for sensing various hazardous contaminants present in water entities. However, how many of us truly understand the process of designing and developing these sensors to reach a stage where they can detect specific contaminants amidst a myriad of other pollutants, and do so with high sensitivity? There are a lot of distinct aspects that must be kept in mind while designing the architecture of the molecule for selective detection of any particular substance. Join to get an idea of how the aforementioned objectives can be achieved.

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19 Jan
2024
Parameter estimation with Metropolis-Hastings algorithm

Name of the Speaker Vivek Kumar Yadav
Title of the Seminar Parameter estimation with Metropolis-Hastings algorithm
Date &Time 19 January 2024 (Friday) at 4 PM
Venue ICWaR Seminar Hall

Abstract:

Hydrology still lacks physics-based equations at various spatio-temporal scales. Thus, resorting to empirical equations is inevitable.  

These equations have to represent complex processes, which are yet to be understood properly. Thus, we sometimes end up with non-linear statistical equations with parameters to be estimated. Though expert knowledge helps to estimate the range of these parameters, estimating them from a large space (let us say you have 3 parameters with parameter space of 20, 1000, and 50 respectively, that’s 1 million parameter possibilities already!) can be a daunting task. Especially if your statistical model requires lots of computational time and resources.  

In this seminar I shall present a parameter estimation technique, Metropolis-Hastings algorithm, with the particular type being Delayed Rejection Adaptive Metropolis. The algorithm is a type of Markov Chain Monte Carlo method for random sampling. It is widely used in all kinds of fields and applications. The algorithm draws samples intuitively to converge to best possible estimate in the shortest time possible. 

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01 Dec
2023
Identification of dominant hydrological processes using sensitivity analysis

Name of the Speaker Ashlin Alexander
Title of the Seminar Identification of dominant hydrological processes using sensitivity analysis
Date &Time 1 December 2023 (Friday) at 4 PM
Venue ICWaR Seminar Hall

Abstract: Recent studies indicate that hydrological models should be customized to align with distinct objectives and the basins being examined. This underscores the importance of understanding the hydrologic processes relevant to the specific objectives. In this seminar, we discuss how a sequential sensitivity analysis using the Efficient Elementary Effect (EEE) method is employed to select the sensitive parameters. The methodology is demonstrated for a highly parameterized hydrological modeling framework, SUMMA (The Structure for Unifying Multiple Modeling Alternatives). The methodology adopted not only helped to scale down the dimensionality of the problem in terms of computational demand and complexity but also allowed us to capture the dominant hydrological process of the catchment. The findings from this study align with the existing literature, thereby confirming the method’s efficacy. By giving precedence to parameters with the most substantial influence it also helps to mitigate the challenge of parameter equifinality. The potential of the method is illustrated through one of the study basins in India. The extensive model runs required are conducted through high-performance computing.

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03 Aug
2023
Glacier Tales from Ladakh: Science, Stories, and the Necessity of Fieldwork

Name of the Speaker Shairik Sengupta and Arindan Mandal
Title of the Seminar Glacier Tales from Ladakh: Science, Stories, and the Necessity of Fieldwork
Date &Time 3 August 2023 (Thursday) at 5 PM
Venue ICWaR Seminar Hall

Abstract: A field trip to the Stok Glacier in Ladakh to measure the mass balance, and to deploy weather measurement devices is discussed in the seminar. The importance of monitoring the annual changes in the mass balance and glacier climate is discussed along with the importance of the glacier meltwater as a water source for the village and local agriculture. 

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13 Jul
2023
Let us explore the cool sciences

Name of the Speaker Maya Suryawanshi R
Title of the Seminar Let us explore the cool sciences.
Date &Time 13 July 2023 (Thursday) at 5 PM
Venue ICWaR Seminar Hall

Abstract: In this seminar, introductory concepts of remote sensing and polar sciences will be discussed. It will start with the familiarization of polar ice features and will continue with the display, processing, and understanding of satellite images for the same features. Also, different physical parameters obtained from satellites will be explained. Furthermore, different scientific activities carried out during the Antarctic expedition will also be discussed. The goal of this seminar is to introduce researchers to the remote sensing of polar regions and make them aware of the Indian Scientific Expedition to Antarctica.

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15 Jun
2023
My 69143rd step into the well

Name of the Speaker Balaram Shaw
Title of the Seminar My 69143rd step into the well.
Date &Time 15 June 2023 (Thursday) at 5 PM
Venue ICWaR Seminar Hall

Abstract: Droughts have far-reaching detrimental impacts on the environment, society, and economy, ranging from regional to national levels. As the drought characteristics are interrelated, multivariate analysis of those is necessary to understand the actual drought situation in a region. However, such studies are limited. Hence, this study aimed to develop a framework to investigate the meteorological and hydrological droughts using a multivariate analysis of drought characteristics in the Pennar River basin (a semi-arid region) of India, dominated by agricultural activity. Long-term observations (1980–2015) of precipitation, temperature, and streamflow were used to calculate the Standardized Precipitation Evapotranspiration Index (SPEI) and Streamflow Drought Index (SDI) at a 3-month timescale. Based on these indices, drought duration, severity, and peak were abstracted using the Run Theory. The best-fit marginal distribution was determined for every drought characteristic to establish the bivariate joint probability distribution (the copula function). Based on the best-fit copula function, the joint probabilities and the joint return periods were estimated. Results revealed that, for meteorological drought, Frank Copula and Survival Clayton copula were the best-fit copula function for the joint risk of drought duration and severity and the combination of drought duration and peak as well as drought severity and peak, respectively. The joint return period of a drought event with characteristics above the 25th percentile of the same varies between 1 and 2 years, whereas it spans between 1 and 45 years for the ­ 50th percentile. This analysis will provide vital information for water management and planning in a region to mitigate droughts.

 

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18 May
2023
Quantifying Climate and Catchment Effects on Streamflow using Budyko Framework

Name of the Speaker Pushkar Sharma
Title of the Seminar Quantifying Climate and Catchment Effects on Streamflow using Budyko Framework.
Date &Time 18 May 2023 (Thursday) at 5 PM
Venue ICWaR Seminar Hall

Abstract: Streamflow variability is affected by both climate change and direct human impacts within the catchment. Quantification of the role of these two factors has significant implications for water resources. In recent years, Budyko-based analytical methods have been widely used for such quantification due to their simplicity and efficacy. We present a comparison of such methods to attribute changes in streamflow in four Model Parameter Estimation Experiment (MOPEX) catchments in the contiguous United States. Further, a new, improved Two-stage Decomposition method to separate the role of climate and catchment changes on streamflow is proposed, considering the uncertainty in the catchment parameter that further leads to a range of evaporative index values within a catchment.

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06 Apr
2023
Monitoring and management of water pollution

Name of the Speaker Shairik Sengupta
Title of the Seminar Monitoring and management of water pollution.
Date &Time 06 April 2023 (Thursday) at 5 PM
Venue ICWaR Seminar Hall

Abstract: Charcoal-based water filtration is an effective and accessible method for purifying water. This filtration process involves activated charcoal, known for its porous structure and ability to adsorb impurities. This study was carried out with water samples collected from Kolkata and showed the simple yet effective use of charcoal-based filtration of polluted water.

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23 Mar
2023
Fate of Carbon Stocks of Indian Vegetation

Name of the Speaker Abhishek Chakraborty
Title of the Seminar Fate of Carbon Stocks of Indian Vegetation.
Date &Time 23 March 2023 (Thursday) at 5 PM
Venue ICWaR Seminar Hall

Abstract: Carbon use efficiency (CUE), defined as the ratio of the net (NPP) to gross primary productivity (GPP), is a valuable metric to examine the extent of atmospheric carbon sequestered by vegetation into biomass. Evaluating CUE is essential for policymakers to devise future carbon sequestration policies and identify hotspots of carbon storage loss. Indian ecosystems face pronounced weather variability across the year. However, the role of weather variability, spatial patterns, temporal dynamics, and resilience to hydroclimatic perturbations of CUE in Indian terrestrial ecosystems remains poorly understood, particularly at sub-annual scales. The lack of sub-annual NPP datasets hinders remote sensing-based sub-annual CUE assessments, but this study derived an 8-day scale NPP dataset through an empirical formulation performed on moderate resolution imaging spectroradiometer (MODIS) products. This study assesses CUE dynamics for India across its six homogeneous meteorological regions (HMRs) and the major biomes of each HMR, including croplands, forests, and grasslands, through a fine-scale remote sensing approach for 2000-2021. The results show pronounced variability of CUE across spatiotemporal scales governed by the water availability-temperature interplay. Distinct patterns were observed among the biomes, depending on the HMRs dictated by the land management practices of the regions. The study also derived sustainability maps of carbon stocks for India from the trend-persistence interplay of CUE, revealing alarming concerns across most HMRs. A severe loss of resilience of carbon stocks was observed, primarily driven by increased precipitation, and warming among meteorological drivers and soil and atmospheric drying among aridity drivers. Overall, this study highlights the critical role of CUE in assessing the carbon sequestration potential of Indian ecosystems and the need for a better understanding of the factors that influence it to develop effective carbon sequestration policies.

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23 Feb
2023
River water, seawater, and groundwater interaction in Hooghly River

Name of the Speaker Biswajit Panda
Title of the Seminar River water, seawater, and groundwater interaction in Hooghly River.
Date &Time 23 February 2023 (Thursday) at 5 PM
Venue ICWaR Seminar Hall

Abstract: The rivers of the Himalayas (Ganges-Brahmaputra) bring a significant amount of radiogenic Sr to the oceans. As a result, it is believed that the increase in the ratio of 87Sr to 86Sr in seawater over the past 40 million years is mainly caused by the erosion of the Himalayan region and the subsequent transport of this material by these rivers. Estuaries, which are areas where rivers meet the ocean, play a major role in carrying dissolved and solid materials from the land to the sea. In this study, we present findings on the changes in Sr concentrations and the 87Sr/86Sr ratio in water samples with different levels of saltiness collected from the Hooghly (Ganga) estuary in India, which is dominated by tidal movements.
 

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23 Aug
2022
Study to identify terrestrial Evapotranspiration response to Indian summer monsoon rainfall

Name of the Speaker Vivek Kumar
Title of the Seminar Study to identify terrestrial Evapotranspiration response to Indian summer monsoon rainfall.
Date &Time 23 August 2022 (Tuesday) at 5 PM
Venue ICWaR Seminar Hall

Abstract: Evapotranspiration (ET) is a process of mass and energy flux. Several different factors influence the ET from vapour pressure gradient, wind shear, temperature, soil type etc. The best description of this process being the Penman-Monteith equation, but it suffers from availability of poor data. This project work investigates the terrestrial ET response to rainfall during Indian summer monsoon comparing between onset & established period and established & withdrawal period using simple defined variables while deliberately ignoring temperature and other factors.

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11 Aug
2022
Application of conceptual tank model to Malaprabha catchment using Simulink

Name of the Speaker Poornima Chandralekha
Title of the Seminar Application of conceptual tank model to Malaprabha catchment using Simulink.
Date &Time 11 August 2022 (Thursday) at 5 PM
Venue ICWaR Seminar Hall

Abstract: Rainfall-runoff model using one or more Tanks as a conceptual representation of input-storage-output systems for hydrological processes is extremely popular and has been widely used in significant parts of the world, notably in Asia. The present study is focused on the development and application of the Tank model to the Malaprabha basin, which is in the semi-arid region of Karnataka State, India. The novelty of the present research is that the Tank models were developed using Simulink, an extension of MATLAB is a graphics-based model development environment for system modeling and simulation. In the present analysis, models with 1, 2, and 3 tanks were created and applied to the Malaprabha basin using rainfall and climate data as inputs. Calibration and validation of the models were performed using observed streamflow records at the outlet of the basin. Various statistics such as the Nash-Sutcliffe Efficiency (NSE), the coefficient of determination (R2), root mean square error (RMSE), and percent bias error (PBIAS) were used to evaluate the relative performances of the three model formulations in simulating total runoff at daily, monthly and annual time steps. Sensitivity analysis showed that the maximum contribution to total runoff occurred from the deepest tank, indicating the importance of groundwater contribution to runoff in the Malaprabha basin. The study demonstrates the potential for Simulink to serve as an important tool in the development and application of conceptual hydrological models.

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13 Jun
2022
Preliminary studies on developing a sensor for dopamine

Name of the Speaker Pavithra N
Title of the Seminar Preliminary studies on developing a sensor for dopamine
Date &Time 13 June 2022 (Monday) at 5 PM
Venue Lecture Hall, ICWaR

Abstract: Dopamine is a catecholamine that is an essential neurotransmitter in the human body. Thus, even a minute variation in its concentration and metabolism leads to severe neurological damage or diseases such as Parkinson’s, Alzheimer’s, Schizophrenia, and many more. It could be prevented at some scale by early detection. Nanoparticles have a remarkable ability to be used in sensors for detection purposes. This study synthesized copper oxide nanoparticles for dopamine detection, accompanied by the enzyme tyrosinase used as a sensing material. The structural characterization of the nanoparticles and their interaction with dopamine via fluorescence spectroscopy was done to determine the sensitivity. The sensing material showed a selective response to dopamine and no response to interfering analytes like ascorbic acid, cysteine, and tyrosine. The limit of detection (LOD) of dopamine is observed to be 5 µM. This study indicates that sensing material can be a probe for detecting dopamine. This material is further used to develop electrochemical or solid-state sensors.

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17 May
2022
Assessment of the Seasonal Dynamics and Links with Environmental Change of the Carbon Use Efficiency of Indian Terrestrial Ecosystems

Name of the Speaker Abishek Chakraborty
Title of the Seminar Assessment of the Seasonal Dynamics and Links with Environmental Change of the Carbon Use Efficiency of Indian Terrestrial Ecosystems
Date &Time 17 May 2022 (Tuesday) at 5 PM
Venue Lecture Hall, ICWaR

Abstract: Global vegetation acts as a significant atmospheric carbon sink by converting atmospheric carbon dioxide to biomass. The efficiency of this conversion is termed the vegetation carbon use efficiency (CUE). It quantifies the carbon storage as useful biomass in the vegetation. It is defined as the net to gross primary productivity (NPP/GPP) ratio. CUE assessment is vital for policymakers as it helps plan future carbon sequestration strategies. Earlier studies have depicted the variation of CUE either using process-based models or satellite data for annual temporal scale (Chen and Yu, 2019, Sci Rep; El Masri et al., 2019, Sci Rep). Another study depicted the driving role of climatic factors on the CUE globally (He et al., 2018, Agr Forest Meteorol). However, the impact of meteorological, vegetation, aridity, and anthropogenic factors on the CUE of India’s terrestrial ecosystems at sub-annual (seasonal, sub-seasonal transitional, and monthly) temporal scales is seldom addressed.

This study utilizes the Moderate Resolution Imaging Spectroradiometer (MODIS) products of GPP and the net photosynthesis to produce CUE of India’s terrestrial ecosystems at the finer temporal scales (relative to annual scale), i.e., for the four seasons of India (winter, summer, monsoon, post-monsoon), the sub-seasonal transitions (wet and dry season transitions), and the twelve months. We analyze the CUE variation at the spatial scales of the country, homogeneous meteorological regions, provinces, land classes, and the Koppen climate zones from 2000 to 2021. We further discriminate the relative impacts of each environmental driver on the CUE variation of India’s terrestrial ecosystems at these spatial and temporal scales. This study demonstrates the emergent responses of the carbon storage dynamics of Indian terrestrial ecosystems to its environmental drivers and can guide policymakers in ecological restoration.

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19 Apr
2022
Increased risk of low water quality, eutrophication, and fish kills under warming in a highly industrialized stretch of the Ganga River

Name of the Speaker Sneha Santy
Title of the Seminar Increased risk of low water quality, eutrophication, and fish kills under warming in a highly industrialized stretch of the Ganga River.
Date &Time 19 April 2022 (Tuesday) at 5 PM
Venue Lecture Hall, ICWaR

Abstract: Extensive industrial pollution, agricultural runoff, and disposal of untreated sewage into the river have made Kanpur the most critical water pollution hotspot of the Ganga River. This study assesses the water quality with climate change for the mid and end of the 21st century and the resulting risk of low water quality, eutrophication, and fish kill in this industrialized stretch passing through Kanpur. For this assessment, climate projections from an ensemble of 20 GCMs for the RCP 4.5 and RCP 8.5 scenarios are used to drive a hydrological model HEC-HMS coupled with the water quality model QUAL2K. The water quality parameters considered are dissolved oxygen, BOD, ammonia, nitrate, total nitrogen, organic, inorganic, total phosphorous, and faecal coliform. The simulation results show water quality degradation in the mid-21st century, improved by the end of the 21st century due to increased streamflow. The risk of eutrophication and fish kill is found to increase with climate change due to the more occurrence of low flow events.

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04 Apr
2022
CESM simulation of monsoon low-pressure systems over India and a sensitivity analysis

Name of the Speaker Tresa Mary Thomas
Title of the Seminar CESM simulation of monsoon low-pressure systems over India and a sensitivity analysis
Date &Time 04 April 2022 (Monday) at 5 PM
Venue Lecture Hall, ICWaR

Abstract: Monsoon low-pressure systems (LPS) during the summer monsoon season (June-September) over India are a lifeline for the agriculture-dependent country. We use the Community Earth System Model (CESM1.2.2) to simulate the LPS characteristics (genesis, propagation direction, tracks, intensity, and precipitation) over India and the Bay of Bengal and analyze the influence of Southeast Asian mountains (SAMs) on these characteristics. CESM reproduced most of the LPS characteristics. However, a southward latitudinal shift of about 4° is simulated in the median of the tracks, which is likely due to the weaker simulated upper tropospheric meridional temperature gradient (MTG) in the Indian region. Removal of SAMs is found to have little influence on LPS characteristics. Further, it causes only a slight reduction in mean summer monsoon precipitation (by 5%) and LPS related precipitation (from 10.7±1.0 to 10.3±0.8 mm/day) over India, as SAMs have negligible influence on in-situ westward propagating LPS which are the major contributors to LPS related precipitation. The insensitivity of LPS characteristics and precipitation over India to the removal of SAMs can be attributed to their low height and the insensitivity of MTG to the height of these mountains.

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21 Mar
2022
Coupling of hydrological and machine learning models for reservoir storage and inflow forecasting

Name of the Speaker Mr. Walter Samuel
Title of the Seminar Coupling of hydrological and machine learning models for reservoir storage and inflow forecasting
Date &Time 21 March 2022 (Monday) at 5 PM
Venue Lecture Hall, ICWaR

Abstract: Forecasting near real-time water availability in reservoirs helps in effective water resources management, flood control, hydropower generation, irrigation, and drought mitigation. The conceptual framework is built around a deep tech exercise encompassing artificial intelligence, deep-learning, water physics, hydrological science, and geoinformatics, alongside an innovative interdisciplinary approach. The predictive modelling exercise yields meaningful results when it is complemented with human understanding of the physical processes in the river basin. This is achieved by combining machine learning and hydrological modelling. Three deep learning architectures have been used – fully connected deep neural network, long short-term memory network, and WaveNets. They take inputs such as storage, inflow, outflow, and precipitation leading up to the reservoir and use these inputs to predict the inflow and storage level 30, 60 and 90 days ahead. The visualization and dissemination of the results of this exercise and other critical hydro-meteorological datasets are done through an interactive dashboard to help stakeholders make informed decisions.

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31 Oct
2019
Numerical Modelling of Ozone Transfer and Microbial Inactivation for Wastewater Treatment

Name of the Speaker Ms. Reshma Mohan
Title of the Seminar Numerical Modelling of Ozone Transfer and Microbial Inactivation for Wastewater Treatment
Date &Time 31st October 2019 – Thursday – 4.00 PM
Venue Lecture Hall, ICWaR

Abstract: Ozonation is currently considered as one of the most effective microbial disinfection technologies due to its powerful disinfection capacity. The solubility of ozone gas in water is limited, once dissolved, aqueous ozone engages in complex chemistry that includes auto-decomposition reaction with various constituents in water, in addition to reaction with microorganisms. The two widely accepted mechanism of aqueous ozone chemistry include Hoigne, Staeholin and Bader mechanisms and Gordan, Tomiyasn and Fukuton mechanisms. In efforts to meet drinking water regulations and to be cost-effective, it is required to optimize ozone dosage for disinfection. Therefore, there is a need to develop a robust and flexible tool to accurately describe ozone disinfection processes which can aid in design and operation. Computational fluid dynamics (CFD) has come into use recently for evaluating disinfection systems. A multiphase CFD model is developed to analyze the efficiency of ozone disinfection technology used in treatment of greywater in Berambadi primary school located in Berambadi village (rural Karnataka). The mass transfer of ozone species from gas into water is modeled using the Two-Film theory developed by Lewis and Whitman (1924). While the microbial inactivation kinetics by ozone reaction is modeled using the Hom-Haas Model. Transport equations for ozone mass transfer and reactions are incorporated to the multiphase CFD model (with the grey water as the primary phase and ozone as secondary phase). The developed multiphase CFD model is planned to be validated by comparing the numerical and experimental local ozone residual concentrations.

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31 Jul
2019
Influence of Irrigation on Soil Carbon Fluxes for a Semi-arid Agro-ecosystem of India

Name of the Speaker Mr. Abhishek Chakraborty
Title of the Seminar Influence of Irrigation on Soil Carbon Fluxes for a Semi-arid Agro-ecosystem of India
Date &Time 31st July 2019 – Monday – 4.00 PM
Venue Lecture Hall, ICWaR

Abstract: With the increasing population of India, not only is there a growing stress on the water resources of the country but also there is a need to increase the crop yield throughout the nation. Due to these reasons, there is a pressing need to switch to water-saving irrigation practices in the water-stressed climates of semi-arid dryland ecosystems of India. The transformation from flood irrigation to drip and sprinkler irrigation is one such method by which the water- use efficiency of irrigation systems has increased. Also, to cater to the needs of increasing population, there is a requirement to increase the crop yield by either intensifying irrigation or switching to high yielding varieties of crops. These transformations are expected to play a huge part in change in carbon fluxes from soils of these regions. Soil is the largest terrestrial carbon sink and plays an important role in carbon sequestration. Crop production through irrigation and fertilization results in the greenhouse gas emission from the soil to atmosphere. It is expected that a drip or sprinkler irrigation system would have a greater carbon footprint than a conventional flood irrigation system. This is partially attributed to the carbon emission during their manufacturing and partially to the heterogeneous and under saturated state of soil. There is a definite gap in understanding the soil carbon fluxes from the irrigation fields of semi-arid ecosystems in India. In this seminar, I wish to discuss a few methods by which the soil carbon fluxes from a heterogeneous agro-ecosystem of India present in the semi-arid climate can be addressed.

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07 Jul
2019
Authigenic clay mineral formation by reverse weathering: Impact on global climate and heavy metal cycling in large water bodies

Name of the Speaker Mr. Biswajit Panda
Title of the Seminar Authigenic clay mineral formation by reverse weathering: Impact on global climate and heavy metal cycling in large water bodies
Date &Time 7th July 2019 – Monday – 4.15 PM
Venue Lecture Hall, ICWaR

Abstract: Weathering of continental silicate rock consumes  and supply cation to oceans and thereby modulating both climate and sea water chemistry (Raymo et. al., 1988). A series of secondary reactions dominate the transport of these cation from the weathering site to their point of release in oceans. These secondary reactions which lead to the formation of authigenic clay minerals thus acts as a controller of cation flux to the oceans (Misra and Froelich, 2012). The neoformed clays within the fluvial and oceanic system act as a sink for the soluble cation, thus playing a significant role in the global riverine and oceanic elemental budgets. The release of  due to clay mineral formation is in contrast to silicate weathering that acts as a net sink of  and is hence, termed Reverse weathering (Mackenzie and Garrels, 1966). Reverse weathering not only plays a critical role in the geochemical cycling of elements it also modulates the global carbon cycle. In this seminar I am going to discuss some aspects of reverse weathering and the ways to study the same in Indian riverine systems where in recent years heavy metal concentration have been on the rise because of anthropogenic activity.

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Interdisciplinary Centre for Water Research (ICWaR) - IISc Bangalore