High-resolution palaeodust archive from subantarctic Macquarie Island

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dc.contributor.authorJohansen, Aen_AU
dc.contributor.authorStromsoe, Nen_AU
dc.contributor.authorSaunders, KMen_AU
dc.contributor.authorMarx, SKen_AU
dc.date.accessioned2023-03-31T00:43:34Zen_AU
dc.date.available2023-03-31T00:43:34Zen_AU
dc.date.issued2022-12-06en_AU
dc.date.statistics2023-03-30en_AU
dc.description.abstractMineral dust drives climate variability both during atmospheric transport and upon deposition. During transport, dust influences radiative forcing and cloud properties. Upon deposition, nutrients supplied by dust can drive primary productivity and subsequent drawdown of atmospheric carbon. Inputs of Australian dust may be especially critical in the nutrient-limited ecosystems of the South Pacific Southern Ocean and subantarctic islands. This study seeks to understand dust flux to Macquarie Island since the mid-Holocene, and the potential response of plants to changing dust inputs. Peat cores from Macquarie Island were selected to reconstruct the dust flux history as peat plants can effectively capture dust and preserve the dust signal. Peats develop in water-saturated areas where plant decomposition is slowed in the anoxic and reduced conditions. As new growth accumulates over decaying plants, some elemental components of dust are preserved in place in the peat column. We developed high-resolution age-depth models with 210Pb, 239,240Pu, and 14C analysis. We applied 210Pb dating to the top 25 cm of each core, with additional age-control from the peak concentration of anthropogenic 239,240Pu identifying the Southern Hemisphere peak from nuclear weapons testing (about 1964). These data, along with radiocarbon ages to the mid-Holocene, were used to inform the age-depth model, which indicates variability in peat accumulation rates. The quantity and quality of organic matter (OM) were indicated by loss-on-ignition and Fourier-transform infrared (FTIR) spectroscopy. The δ15N values indicated minimal animal inputs. Preliminary inductively coupled plasma mass spectrometry (ICP-MS) data indicates dust inputs by increases in the stable isotopes of Pb in the early and mid-20th century. Dust scavenges Pb during transport, and the Australian production of Pb increased with the opening of the Broken Hill mine in 1885. Work is currently in progress to confirm these findings and extend the dust record prior to the 20th century.en_AU
dc.identifier.citationJohansen, A., Stromsoe, N., Saunders, K., & Marx, S. (2022). High-resolution palaeodust archive from subantarctic Macquarie Island. Paper presented to the AQUA 2022 Conference, 6-8th December, Adelaide (pp. 120-121). Retrieved from: https://aqua.org.au/conference/aqua-2022/aqua-2022-conference-program-and-abstracts/en_AU
dc.identifier.conferenceenddate8 December 2022en_AU
dc.identifier.conferencenameAQUA 2022 Conferenceen_AU
dc.identifier.conferenceplaceAdelaideen_AU
dc.identifier.conferencestartdate6 December 2022en_AU
dc.identifier.pagination120-121en_AU
dc.identifier.urihttps://aqua.org.au/conference/aqua-2022/aqua-2022-conference-program-and-abstracts/en_AU
dc.identifier.urihttps://apo.ansto.gov.au/dspace/handle/10238/14771en_AU
dc.language.isoenen_AU
dc.publisherAustralasian Quaternary Associationen_AU
dc.subjectMineralsen_AU
dc.subjectDustsen_AU
dc.subjectClimatesen_AU
dc.subjectCarbonen_AU
dc.subjectEcosystemsen_AU
dc.subjectSeasen_AU
dc.subjectPeaten_AU
dc.subjectPlantsen_AU
dc.titleHigh-resolution palaeodust archive from subantarctic Macquarie Islanden_AU
dc.typeConference Abstracten_AU
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