Reading the tea-tree leaves: Melaleuca quinquenervia leaves as a palaeoclimate proxy

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dc.contributor.authorGeer, Jen_AU
dc.contributor.authorMcInerney, Fen_AU
dc.contributor.authorTibby, Jen_AU
dc.contributor.authorHua, Qen_AU
dc.contributor.authorSchulz, Cen_AU
dc.contributor.authorBarr, Cen_AU
dc.contributor.authorMarshall, Jen_AU
dc.contributor.authorMcGregor, Gen_AU
dc.date.accessioned2023-06-15T01:09:22Zen_AU
dc.date.available2023-06-15T01:09:22Zen_AU
dc.date.issued2019-07-30en_AU
dc.date.statistics2023-03-24en_AU
dc.description.abstractThe analysis of organic material preserved in sedimentary records is a useful tool in reconstructing past climatic conditions. It has been suggested that the carbon isotope discrimination (Δ) calculated from the bulk leaf δ13C of the modern Melaleuca quinquenervia tree responds to local precipitation in south-east Queensland, Australia [1]. The preservation of these leaves in lake sediments on Minjerribah (North Stradbroke Island) dating to the mid-Holocene presents the opportunity to produce species-specific stable isotope-based records of precipitation. Here, we test the potential for M. quinquenervia to be used as a palaeoclimate proxy by examining the preservation of the bulk leaf δ13C over time and the relationship of Δ values to historical records of precipitation. Due to the varying rates of degradation of the different chemical constituents of plant matter, it is possible δ13C ratios to be altered by early diagenetic processes before, or during, the incorporation of leaves into the sediment. Therefore, modern studies are needed to establish what factors influence the discrimination derived precipitation record. Focusing on the M. quinquenervia growing at Swallow Lagoon on Minjerribah, we studied the changes to the bulk leaf δ13C ratios of exposed leaves over an eighteen-month field study. We then applied our findings to the measured δ13C ratios of bulk leaf material retrieved from a core taken from the lagoon. The Δ values calculated based on these measurements were then compared to instrumental rainfall data from the past century to test the established relationship with modern precipitation through time. By bisecting each leaf used in this study, we were able to compare the experimentally degraded leaves directly to their corresponding control halves. We observed that decay causes an approximate decrease of 1 ‰ in δ13C, as the leaves become more 13C depleted relative to the control leaf halves that were dried immediately. Quantifying this offset enables adjustment of values to be comparable to the calibration equation established using natural fall leaves from modern M. quinquenervia. Comparing the adjusted Δ values for lake core leaves from the last century to corresponding rainfall data the relationship to local precipitation seems to be preserved. Understanding exactly how early diagenesis changes the stable isotope composition of M. quinquenervia leaf material over time allows us to adjust for the offset between modern and sub-fossil bulk leaf δ13C and advances the potential to use this species as a reliable climate proxy in the future. © The authors.en_AU
dc.identifier.citationGreer, J., McInerney, F., Tibby, J., Hua, Q., Chulz, C., Barr, C., Marchall, J., & McGregor, G. (2019). Reading the tea-tree leaves: Melaleuca quinquenervia leaves as a palaeoclimate proxy. Poster presented to the 20th INQUA Congress 25th - 31st July 2019, Dublin, Ireland. Retrieved from: https://virtual.oxfordabstracts.com/#/event/public/574/submission/890en_AU
dc.identifier.conferenceenddate31 July 2019en_AU
dc.identifier.conferencename20th INQUA Congressen_AU
dc.identifier.conferenceplaceDublin, Irelanden_AU
dc.identifier.conferencestartdate25 July 2019en_AU
dc.identifier.urihttps://virtual.oxfordabstracts.com/#/event/public/574/submission/890en_AU
dc.identifier.urihttps://apo.ansto.gov.au/handle/10238/15057en_AU
dc.language.isoenen_AU
dc.publisherInternational Union for Quaternary Research (INQUA)en_AU
dc.subjectLeavesen_AU
dc.subjectTreesen_AU
dc.subjectPrecipitationen_AU
dc.subjectClimatesen_AU
dc.subjectQueenslanden_AU
dc.subjectAustraliaen_AU
dc.subjectCarbon isotopesen_AU
dc.subjectQuaternary perioden_AU
dc.subjectRainen_AU
dc.titleReading the tea-tree leaves: Melaleuca quinquenervia leaves as a palaeoclimate proxyen_AU
dc.typeConference Posteren_AU
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