Stable Isotopic Composition of Rice Grain Organic Matter as an Archive of Monsoonal Climate
Rice grows in saturated soil water condition and its requirement for water is highest amongst other cereal crops. In India, the southwest monsoon wind regime brings rainfall that provides a favourable environment for rice cultivation. Thus, there is significant dependency ofrice production on the so...
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ndltd-IISc-oai-etd.iisc.ernet.in-2005-39952018-08-31T03:54:59ZStable Isotopic Composition of Rice Grain Organic Matter as an Archive of Monsoonal ClimateKaushal, RitikaRice Grain - Stable Isotopic CompositionOryza sativa - Stable Isotopic CompositionPalaeoclimate RecordsPlants - IsotppesCarbon Isotope-ratio AnalysisOxygen Isotope-ratio AnalysisHydrogen isotope-ratio AnalysisRice - Palaeo-hydroclimateCentre for Earth SciencesRice grows in saturated soil water condition and its requirement for water is highest amongst other cereal crops. In India, the southwest monsoon wind regime brings rainfall that provides a favourable environment for rice cultivation. Thus, there is significant dependency ofrice production on the southwest monsoon rainfall. Being a crop that grows across diverse climatic regions in India ranging from the humid to semi-arid, it offers possibility to explore therelationship between stable isotopic compositions in the grain organic matter with the climaticfactors relevant for its growth. In this thesis, we measured the isotopic compositions of oxygen, hydrogen and carbon of several rice genotypes that were cultivated during the southwest monsoon in diverse climatic regions across the Indian landmass. These isotopic values were then compared with the seasonalaverage values of climate factors such as relative humidity and temperature. Together with thiswe also studied the dependency of the oxygen isotope composition of the grain OM (δ18OOM) onthat of the source water (δ18OSW). Upon removal of δ18OSW effect from δ18OOM, we obtained astrong and significant relationship between the 18O enrichment in grain organic matter (definedas 18OOM) with relative humidity. The gradient recorded was 0.45‰ shift in 18OOM with 1%change in the relative humidity level. This relationship can potentially be used to estimate thepast variations in relative humidity (and by extension, can provide a measure of monsoon rainfallvariations). We further validated this relationship based on experiments carried out in aglasshouse where all the physical factors were well-monitored. Together with this, carbonisotopic composition measured in the rice grain organic matter were used to infer the water useefficiency of rice grown in different climatic settings. The stable isotope approach was furtherimplemented for studying the archaeological rice grains recovered from archaeological sites. Analysis of carbon isotopic composition of archaeological rice grains from seven archaeologicalsites (Balu, Kanmer, Ojiyana, Lahuradewa, JognaKhera, Hulas and Kunal), belonging to theHarappan civilization and other contemporary cultures provided a new suit of data on quantitativeestimate of the hydroclimatic condition (specifically relative humidity) and water availabilityduring the existence of this civilization.Ghosh, Prosenjit2018-08-30T10:18:35Z2018-08-30T10:18:35Z2018-08-302015Thesishttp://etd.iisc.ernet.in/2005/3995http://etd.iisc.ernet.in/abstracts/4889/G28571-Abs.pdfen_USG28571 |
collection |
NDLTD |
language |
en_US |
sources |
NDLTD |
topic |
Rice Grain - Stable Isotopic Composition Oryza sativa - Stable Isotopic Composition Palaeoclimate Records Plants - Isotppes Carbon Isotope-ratio Analysis Oxygen Isotope-ratio Analysis Hydrogen isotope-ratio Analysis Rice - Palaeo-hydroclimate Centre for Earth Sciences |
spellingShingle |
Rice Grain - Stable Isotopic Composition Oryza sativa - Stable Isotopic Composition Palaeoclimate Records Plants - Isotppes Carbon Isotope-ratio Analysis Oxygen Isotope-ratio Analysis Hydrogen isotope-ratio Analysis Rice - Palaeo-hydroclimate Centre for Earth Sciences Kaushal, Ritika Stable Isotopic Composition of Rice Grain Organic Matter as an Archive of Monsoonal Climate |
description |
Rice grows in saturated soil water condition and its requirement for water is highest amongst other cereal crops. In India, the southwest monsoon wind regime brings rainfall that provides a favourable environment for rice cultivation. Thus, there is significant dependency ofrice production on the southwest monsoon rainfall. Being a crop that grows across diverse climatic regions in India ranging from the humid to semi-arid, it offers possibility to explore therelationship between stable isotopic compositions in the grain organic matter with the climaticfactors relevant for its growth.
In this thesis, we measured the isotopic compositions of oxygen, hydrogen and carbon of several rice genotypes that were cultivated during the southwest monsoon in diverse climatic regions across the Indian landmass. These isotopic values were then compared with the seasonalaverage values of climate factors such as relative humidity and temperature. Together with thiswe also studied the dependency of the oxygen isotope composition of the grain OM (δ18OOM) onthat of the source water (δ18OSW). Upon removal of δ18OSW effect from δ18OOM, we obtained astrong and significant relationship between the 18O enrichment in grain organic matter (definedas 18OOM) with relative humidity. The gradient recorded was 0.45‰ shift in 18OOM with 1%change in the relative humidity level. This relationship can potentially be used to estimate thepast variations in relative humidity (and by extension, can provide a measure of monsoon rainfallvariations). We further validated this relationship based on experiments carried out in aglasshouse where all the physical factors were well-monitored. Together with this, carbonisotopic composition measured in the rice grain organic matter were used to infer the water useefficiency of rice grown in different climatic settings. The stable isotope approach was furtherimplemented for studying the archaeological rice grains recovered from archaeological sites.
Analysis of carbon isotopic composition of archaeological rice grains from seven archaeologicalsites (Balu, Kanmer, Ojiyana, Lahuradewa, JognaKhera, Hulas and Kunal), belonging to theHarappan civilization and other contemporary cultures provided a new suit of data on quantitativeestimate of the hydroclimatic condition (specifically relative humidity) and water availabilityduring the existence of this civilization. |
author2 |
Ghosh, Prosenjit |
author_facet |
Ghosh, Prosenjit Kaushal, Ritika |
author |
Kaushal, Ritika |
author_sort |
Kaushal, Ritika |
title |
Stable Isotopic Composition of Rice Grain Organic Matter as an Archive of Monsoonal Climate |
title_short |
Stable Isotopic Composition of Rice Grain Organic Matter as an Archive of Monsoonal Climate |
title_full |
Stable Isotopic Composition of Rice Grain Organic Matter as an Archive of Monsoonal Climate |
title_fullStr |
Stable Isotopic Composition of Rice Grain Organic Matter as an Archive of Monsoonal Climate |
title_full_unstemmed |
Stable Isotopic Composition of Rice Grain Organic Matter as an Archive of Monsoonal Climate |
title_sort |
stable isotopic composition of rice grain organic matter as an archive of monsoonal climate |
publishDate |
2018 |
url |
http://etd.iisc.ernet.in/2005/3995 http://etd.iisc.ernet.in/abstracts/4889/G28571-Abs.pdf |
work_keys_str_mv |
AT kaushalritika stableisotopiccompositionofricegrainorganicmatterasanarchiveofmonsoonalclimate |
_version_ |
1718727597814185984 |