Export production in the New-Zealand region since the last glacial maximum

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dc.contributor.authorDurand, Aen_AU
dc.contributor.authorChase, Zen_AU
dc.contributor.authorNoble, TLen_AU
dc.contributor.authorBostock, HCen_AU
dc.contributor.authorJaccard, SLen_AU
dc.contributor.authorKitchener, Pen_AU
dc.contributor.authorTownsend, ATen_AU
dc.contributor.authorJansen, Nen_AU
dc.contributor.authorKinsley, Len_AU
dc.contributor.authorJacobsen, GEen_AU
dc.contributor.authorJohnson, Sen_AU
dc.contributor.authorNeil, Hen_AU
dc.date.accessioned2020-03-23T23:52:59Zen_AU
dc.date.available2020-03-23T23:52:59Zen_AU
dc.date.issued2017-07-01en_AU
dc.date.statistics2020-03-20en_AU
dc.description.abstractIncreased export production (EP) in the Subantarctic Zone (SAZ) of the Southern Ocean due to iron fertilisation has been proposed as a key mechanism for explaining carbon drawdown during the last glacial maximum (LGM). This work reconstructs marine EP since the LGM at four sites around New Zealand. For the first time in this region, 230-Thorium-normalised fluxes of biogenic opal, carbonate, excess barium, and organic carbon are presented. In Subtropical Waters and the SAZ, these flux variations show that EP has not changed markedly since the LGM. The only exception is a site currently north of the subtropical front. Here we suggest the subtropical front shifted over the core site between 18 and 12 ka, driving increased EP. To understand why EP remained mostly low and constant elsewhere, lithogenic fluxes at the four sites were measured to investigate changes in dust deposition. At all sites, lithogenic fluxes were greater during the LGM compared to the Holocene. The positive temporal correlation between the Antarctic dust record and lithogenic flux at a site in the Tasman Sea shows that regionally, increased dust deposition contributed to the high glacial lithogenic fluxes. Additionally, it is inferred that lithogenic material from erosion and glacier melting deposited on the Campbell Plateau during the deglaciation (18–12 ka). From these observations, it is proposed that even though increased glacial dust deposition may have relieved iron limitation within the SAZ around New Zealand, the availability of silicic acid limited diatom growth and thus any resultant increase in carbon export during the LGM. Therefore, silicic acid concentrations have remained low since the LGM. This result suggests that both silicic acid and iron co-limit EP in the SAZ around New Zealand, consistent with modern process studies. © 2017 Elsevier B.V.en_AU
dc.identifier.citationDurand, A., Chase, Z., Noble, T. L., Bostock, H., Jaccard, S. L., Kitchener, P., Townsend, A. T., Jansen, N., Knisley, L., Jacobsen, S., & Neil, H. (2017). Export production in the New-Zealand region since the last glacial maximum. Earth and Planetary Science Letters, 469, 110-122. doi:10.1016/j.epsl.2017.03.035en_AU
dc.identifier.govdoc8467en_AU
dc.identifier.issn0012-821Xen_AU
dc.identifier.journaltitleEarth and Planetary Science Lettersen_AU
dc.identifier.pagination110-122en_AU
dc.identifier.urihttps://doi.org/10.1016/j.epsl.2017.03.035en_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/9203en_AU
dc.identifier.volume469en_AU
dc.language.isoenen_AU
dc.publisherElsevier B. V.en_AU
dc.subjectNew Zealanden_AU
dc.subjectGlaciersen_AU
dc.subjectProductivityen_AU
dc.subjectQuaternary perioden_AU
dc.subjectCarbonen_AU
dc.subjectThoriumen_AU
dc.subjectDustsen_AU
dc.subjectCosmic ray fluxen_AU
dc.subjectSilicic aciden_AU
dc.titleExport production in the New-Zealand region since the last glacial maximumen_AU
dc.typeJournal Articleen_AU
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