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Extreme Monsoon Rainfall Signatures Preserved in the Invasive Terrestrial Gastropod Lissachatina fulica

Ghosh, Prosenjit and Rangarajan, Ravi and Thirumalai, Kaustubh and Naggs, Fred (2017) Extreme Monsoon Rainfall Signatures Preserved in the Invasive Terrestrial Gastropod Lissachatina fulica. In: GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS, 18 (11). pp. 3758-3770.

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Official URL: http://dx.doi.org/10.1002/2017GC007041

Abstract

Indian summer monsoon (ISM) rainfall lasts for a period of 4 months with large variations recorded in terms of rainfall intensity during its period between June and September. Proxy reconstructions of past ISM rainfall variability are required due to the paucity of long instrumental records. However, reconstructing subseasonal rainfall is extremely difficult using conventional hydroclimate proxies due to inadequate sample resolution. Here, we demonstrate the utility of the stable oxygen isotope composition of gastropod shells in reconstructing past rainfall on subseasonal timescales. We present a comparative isotopic study on present day rainwater and stable isotope ratios of precipitate found in the incremental growth bands of giant African land snail Lissachatina fulica (Bowdich) from modern day (2009) and in the historical past (1918). Isotopic signatures present in the growth bands allowed for the identification of ISM rainfall variability in terms of its active and dry spells in the modern as well as past gastropod record. Our results demonstrate the utility of gastropod growth band stable isotope ratios in semiquantitative reconstructions of seasonal rainfall patterns. High resolution climate records extracted from gastropod growth band stable isotopes (museum and archived specimens) can expand the scope for understanding past subseasonal-to-seasonal climate variability. Plain Language Summary We provide a new way to reconstruct sub-annual rainfall variability using isotope measurements on shells of the invasive Giant African Land Snails in India. We show that these records can preserve signatures of monsoon rainfall extremes. We utilize museum samples of the snails to reconstruct rainfall during 1918.

Item Type: Journal Article
Publication: GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
Publisher: 10.1002/2017GC007041
Additional Information: Copy right for this article belongs to the AMER GEOPHYSICAL UNION, 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA
Department/Centre: Division of Mechanical Sciences > Centre for Earth Sciences
Date Deposited: 12 Jan 2018 07:15
Last Modified: 12 Jan 2018 07:15
URI: http://eprints.iisc.ac.in/id/eprint/58745

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