is the leeuwin current warm or coldis the leeuwin current warm or cold

(Beagle sub-basin) in 2015 and quickly became a regional reference site for Repts., 122, Ocean Drilling Program, College Station, TX, USA, https://doi.org/10.2973/odp.proc.ir.122.1990, 1990., He, Y. and Wang, H.: Terrestrial Material Input to the Northwest Shelf of Its timing chiefly corresponds to a time of Ac., 270, 160183, https://doi.org/10.1016/j.gca.2019.11.022, 2020., Meinicke, N., Reimi, M. A., Ravelo, A. C., and Meckler, A. N.: Coupled Mg/Ca De Schepper, S., Gibbard, P. L., Salzmann, U., and Ehlers, J.: A global Cosmochim. Micropaleontol., 33, 241272. 6) and the degree of coral core replication in this study, our new proxy-based SST reconstruction probably provides the best estimates of SST for the HAI for this early instrumental period. The Leeuwin Current is one of those boundary currents, flowing southward along the Northwest Shelf of Australia (NWS), across the Carnarvon and Perth basins, ultimately rounding Cape Leeuwin to flow further east into the Great Australian Bight. Change, 161, 231243. Kaplan, A. et al. & Lough, J. M. Growth of Western Australian corals in the Anthropocene. Because of their proximity and congruous oceanographic setting, we combine proxy series from both sites to construct a Northwest Shelf of Australia end-member to compare the newly generated U1459 data with and to calculate paleoceanographic gradients along the Leeuwin Current pathway. The Leeuwin current brings warm tropical water to Western Australia, and allows spectacular coral reefs to grow much further south than they would otherwise. synthesis of the marine and terrestrial evidence for glaciation during the Two years ago chief diversity officers were some of the hottest hires into executive ranks. Dodson and Macphail, 2004; Dodson and Ramrath, 2001; He and Wang, 2021). In conclusion, the intensity of the The Leeuwin Current (LC) is an anomalous poleward-owing eastern boundary current that carries warm, low-salinitywater southward along the coast of Western Australia. Blamart, D., Burgener, L., Calmels, D., Chaduteau, C., Clog, M., De Vleeschouwer et al.(2019b) published several proxy series for Site U1459, including X-ray fluorescence (XRF)-derived element ratios, TEX86 paleotemperatures, and planktonic 18O and 13C. The southward flowing Leeuwin Current is strongest in late autumn and winter. the western Pacific warm pool, Mar. Rev., 83, 8394, https://doi.org/10.1016/j.quascirev.2013.11.003, 2014., Stuut, J.-B. We used the twentieth century reanalysis22 sea-level pressure (SLP), meridional and zonal winds from 1870 to assess the long-term relationship between WPZWS and meridional wind off WA (MWWA) with FSL and HAI SST (Fig. Indeed, none of those This is largely attributable to the LC, which bathes the islands in warm tropical water even during winter months10,11. The most recent Anderson et al.(2021) and Fiebig et al.(2021) calibrations have the advantage of covering a wide range of temperatures (0.51100C). (23.828.9C), whereas T.sacculifer 47 calcification temperatures probably echo mixed-layer temperatures at the studied Site U1459 (18.923.2C). (b)Sea surface temperature on 1January 2022 (austral summer). The 18O and 13C The West Australian Current (or the Western Australian Current) is a cool surface current of the Southern Ocean and Southern Indian Ocean . for Indian Ocean polar heat flux, Paleoceanography, PA2217, 26, https://doi.org/10.1029/2010pa001949, 2011a., Karas, C., Nrnberg, D., Tiedemann, R., and Garbe-Schnberg, D.: Indian Ocean Pliocene Paired Foraminiferal 18O and Mg/Ca Data, IGBP PAGES/World Data Center for Paleoclimatology [data set], https://www.ncei.noaa.gov/pub/data/paleo/contributions_by_author/karas2011/karas2011.txt (last access: 22May 2022), 2011b., Karatsolis, B.-T., De Vleeschouwer, D., Groeneveld, J., Christensen, B., and Rev., 135, 83102, https://doi.org/10.1016/j.earscirev.2014.04.003, 2014., De Vleeschouwer, D.: Natural Gamma Radiation-derived K, U and Th contents of marine sediments obtained during IODP Expeditions with DV JOIDES Resolution, Version 1.0, Interdisciplinary Earth Data Alliance (IEDA) [data set], https://doi.org/10.1594/IEDA/100668, 2017., De Vleeschouwer, D., Dunlea, A. G., Auer, G., Anderson, C. H., Brumsack, H., The warming trend has significantly altered the absolute magnitude of SST extremes during La Nia and El Nio events. He, Y., Wang, H., and Liu, Z.: Development of the Leeuwin Current on the We assessed the stability of the relationship between observed FSL, reconstructed FSL and HAI SST for the past 215 years (Supplementary Fig. 1c). Ac., 74, 46394654. McCaffrey, J. C., Wallace, M. W., and Gallagher, S. J.: A Cenozoic Great Palaeogeogr. Sc. The previously published dataset exhibits positive 18O values up to 0.68 around 88mcd, which were linked to the global MIS M2 glaciation by De Vleeschouwer et al.(2019b). corresponds to lithostratigraphic Units III and IV in Gallagher et al.(2017). was supported by an Indian Ocean Marine Research Centre UWA/AIMS/CSIRO collaborative assistant professorial fellowship. The STANDS4 Network. Basin and is the southernmost site drilled in the IODP Expedition 356 Rev., 227, Google Scholar. The 18O analyses on the new HAB10A coral record was undertaken at the West Australian Biogeochemistry Centre at the University of WA following the protocol of Paul and Skrzypek34. To obtain Bohaty, S. M. and Harwood, D. M.: Southern Ocean pliocene paleotemperature Weaker southerly winds off the WA coast are associated with an offshore low SLP center (Fig. de Loach, A., Gurnis, M., Huh, Y., Ishiwa, T., Jang, K., Kominz, M. A., cycles, with individual agedepth models not exceeding one tie point every and vegetation change during the Middle Pliocene, a warm period in is also supported by the Australian Climate Change Science Programme (ACCSP). This effect has been described by B (1980), who noticed that living T.sacculifer shells collected during towing were smaller Pliocene Epoch, Earth-Sci. You are using a browser version with limited support for CSS. The Leeuwin Current generates warm-core downwelling (anticyclonic) and cold-core upwelling (cyclonic) eddies that transport coastal plankton communities westwards and help distribute heat and salt . I-CDES90C isotopic framework. A., Groeneveld, J., Petrick, B. F., Henderiks, J., Castaeda, I. S., O'Brian, E., Ellinghausen, M., Gallagher, S. J., Fulthorpe, C. S., and Plike, H.: Planktic carbon and oxygen isotopes and NGR-derived K, U and Th data, PANGAEA [data set]. Thermometer Using Carbonate Standards, Geochem. The recent strengthening of the HAI SSTLa Nia relationship suggests that the continued warming over the twenty-first century is likely to increase the magnitude of extreme Ningaloo Nios. Geosy., 20, 55655577. Veron, J. E. N. & Marsh, L. M. Hermatypic corals of Western Australia: records and annotated species list. It rounds Cape Leeuwin to enter the waters south of Australia where its influence extends as far as Tasmania . Westerhold, T., Marwan, N., Drury, A. J., Liebrand, D., Agnini, C., Anagnostou, E., Barnet, J. S. K., Bohaty, S. M., De Vleeschouwer, D., That is because such change & Meyers, G. Multidecadal variations of Freemantle sea level: Footprint of climate variability in the tropical Pacific. The mill is computer controlled (that is, speed, r.p.m. Agreement in Clumped Isotope Calibrations, Estimates of Mineral-Specific All clumped-isotope derived calcification The raw 47 values of sample-derived CO2 were converted to the I-CDES90C scale, using the most recent values for the ETH-1, ETH-2, and ETH-3 carbonate reference materials (Bernasconi et al.,2021). On the other hand, the absolute TEX86 and clumped-isotope al.,2021). and Clumped Isotope Measurements Indicate Lack of Substantial Mixed Layer South Atlantic Western Boundary Current (warm) West Wind Drift/Antarctic Circumpolar Current. Abrolhos reef complex and Leeuwin Current. Andrae, J. W., McInerney, F. A., Polissar, P. J., Sniderman, J. M. K., We thank Kara Bogus for practical support during XRF scanning, and Aisling Dolan and Caroline Prescott for providing the Pliocene HadCM3 simulations shown in Fig.2. between both. Pacific Cold Tongue, Science, 328, 15501553. temperatures. Site U1463 stable isotope dataset is available at earlyEocene in the subsurface rather than surfaceocean, Nat. Change 3, 7882 (2012). Both paleothermometers have their pitfalls: the origin of On the contrary, the 18O data behave opposite to the expected diagenetic imprint in high-carbonate settings (e.g., Stainbank et al.,2020). latitude, shallow-water drift deposit, Earth Planet. PC1 scores for years 17951993 were used in the FSL reconstruction. framework. Pearce, A. 6). J. Mar. Notably, this interval is marked by cooler conditions Southern Hemisphere cooling, marked by the oldest tills in Argentinian likely reflects sea surface temperatures (SSTs) with a seasonal warm bias Whereas this phase transition was mostly driven by decadal variations in WPZWS25,26, considerable uncertainty exists around its linkage with long-term climate change4. Nat. Repts., 122, Ocean Drilling Program, College Station, TX, USA. Rec. Spectral peaks in panel(e) are not strongly expressed because the underlying records have been subject to conservative astronomical tuning and Dodson, J. R. and Macphail, M. K.: Palynological evidence for aridity events https://doi.org/10.1016/0016-7037(83)90232-6, 1983., Escutia, C., Brcena, M. A., Lucchi, R. G., Romero, O., Ballegeer, A. La Nia forces unprecedented Leeuwin Current warming in 2011. Lett., 48, e2021GL092745, https://doi.org/10.1029/2021GL092745, 2021., He, Y., Wang, H., and Liu, Z.: Development of the Leeuwin Current on the J. Geophys. Torrential rain swept across northern Italy on Friday, 21 July, bringing . R., and Haug, G. H.: Subpolar Link to the Emergence of the Modern Equatorial glacialinterglacial cycles, Global Planet. and Bernasconi, S. M.: Calibration and application of the clumped isotope Analyses of global sea surface temperature 1856-1991. The updated version of those calibrations can be found in Peral et al.(2022) and Meinicke et al.(2021), respectively, as well as in Table1. Change, 41, 285307. Ledges of cores HAB05B and HAB10A were milled into the outer edge of the prepared core slabs using the Zenbot Precision Mill. Sc. The 47 clumped-isotope compositions translate to Perth Basin ocean and climate modeling that can test the remaining open questions: were 356 Shipboard, S.: Quantifying K, U, and Th contents of marine sediments Their results were largely in line with earlier work by Rippert et al.(2016), who derived a T.sacculifer calcification depth of 120m in the West Pacific Warm Pool, which is at the bottom of the mixed layer or the top of the thermocline. This potential warm bias might not be negligible because of the rather steep latitudinal temperature gradient offshore southwestern Australia but is insufficient to explain temperature differences Tree-Ring Bull. Drysdale, R. N., Tyler, J. J., and Porch, N.: Pliocene reversal of late Interglacials were characterized by a stronger Leeuwin Gallagher, S. J., and Fulthorpe, C. S.: PlioPleistocene Indonesian The VOCATIO Foundation provided funding through a scholarship to David De Vleeschouwer. WAC is the West Australian Current. However, interannual variability of mean annual HAI SST is high, with La Nia years being significantly warmer (annual mean temperature in 2011 was 1.5C above the twentieth century average SST) than El Nio years10. The TEX86 temperature reconstruction was assessed as reliable in De Vleeschouwer et al.(2019b) because glycerol dialkyl glycerol tetraethers (GDGTs) were confirmed to be of marine origin, and all control parameters had values within the recommended range for reliable paleo-SST reconstructions based on TEX86. presented in Fig.5a as an assumption. Neshyba, S. J., Mooers, C. N. K., Smith, R. L., and Barber, R. T., Springer New York, New York, NY, 230254. When the SITIG index is maximum, the Hadley cell over Australia is enhanced during austral winter but weakened during summer. The Pliocene sedimentary record provides a window into Earth's climate dynamics under warmer-than-present boundary conditions. resembles alkenone-based SST reconstructions from the wider Agulhas region 3d). Henderiks, J., Christensen, B. This is a group of carbonate platforms lying ~5060km offshore the western coast of WA, and is home to the southernmost true coral reef formations in the southeastern Indian Ocean8. The new results challenge the interpretation that suggested a Hill, D. J., and Pickering, S. J.: Modelling the enigmatic Late Pliocene SSTs during El Nio events normally decrease off West Australia but even these anomalies are well above the twentieth century mean SST after 1980 (Fig. (b) 912 year, (c) 5.6 year and (d) 3.65 year frequency. The 18Osw of seawater was reconstructed by solving the Erez and Luz (1983) equation, using the clumped-isotope calcification temperature and the foraminiferal 18O. ABBREVIATIONS; ANAGRAMS; BIOGRAPHIES; CALCULATORS; CONVERSIONS; DEFINITIONS; GRAMMAR; LITERATURE; LYRICS . Cite this article. Figure8(a)Map of the South Atlantic, Indian, and Southern oceans 8). This indicates that meridional winds (through air-sea heat flux) and SLP off WA and remote forcing of the LC by WPZWS (through advection) played an important role in determining the magnitude of SST anomalies4, especially for La Nia and El Nio events. Pliocene ocean and climate variability on astronomical timescales. (Fig.5b), using the Perth Basin seawater 18O reconstruction Geosy., 19, 44874501, https://doi.org/10.1029/2018GC007908, 2018., Wyrwoll, K.-H., Greenstein, B. J., and Kendrick, G.: The palaeoceanography Meckler, A. N., Ziegler, M., Milln, M. I., Breitenbach, S. F. M., and Lauretano, V., Littler, K., Lourens, L. J., Lyle, M., Plike, H., Rhl, U., Tian, J., Wilkens, R. H., Wilson, P. A., and Zachos, J. C.: An latitude, shallow-water drift deposit, Earth Planet. Leeuwin Given their latitude, the HAIs are subject to relatively low intra-annual SST variation of ~4C. This modeling result does not match proxy results. analysis; AF and NM carried out sample preparation; MP and MM carried out USA, 114, 64746479, https://doi.org/10.1073/pnas.1700327114, 2017., Anderson, N. T., Kelson, J. R., Kele, S., Daron, M., Bonifacie, M., 5c). ETH-1, 2, and 3 define the I-CDES90C associated with Southern Hemisphere cold periods, P. Natl. Geophy. Kuroyanagi, A. and Kawahata, H.: Vertical distribution of living planktonic aeolian activity near North West Cape, Australia: inferences from grain-size Groeneveld, J., Castaeda, I. S., Reuning, L., Bogus, K., Auer, G., The 200m isobath of bottom topography is shown as solid line. Both element ratios are plotted on a logarithmic scale. Sign up for the Nature Briefing newsletter what matters in science, free to your inbox daily. (LUC), the energetic interactions of the LC and LUC, and their roles in the generation of warm-core (WC) and cold-core (CC) eddies, respectively. interference in. shift, Geology, 37, 5154, 2009., Gallagher, S. J., Wallace, M. W., Hoiles, P. W., and Southwood, J. M.: . Micropaleontol., 128, 1427, https://doi.org/10.1016/j.marmicro.2016.08.004, 2016., Rohling, E. J., Yu, J., Heslop, D., Foster, G. L., Opdyke, B., and Roberts, B, A. W. H.: Gametogenic calcification in a spinose planktonic An Improved In Situ and Satellite SST Analysis for Climate, J. Past 6, 117 (2010). We also found significant correlations with ERSST (r=0.63, P<0.001) and HadSST3 (r=0.66, P<0.001) between 1960 and 2010, the period in which the observational data coverage is acceptable in this region. Reynolds, R. W. et al. Benguela upwelling system. Commun., 6, 5916, https://doi.org/10.1038/ncomms6916, 2015., Kuroyanagi, A. and Kawahata, H.: Vertical distribution of living planktonic glacial periods. Philippe Claeys acknowledges the VUB Strategic Research Program. 136, 29993017 (2008). The Leeuwin Current is the major boundary current along the west coast and as it moves southward. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/3.0/, Zinke, J., Rountrey, A., Feng, M. et al. The upwelling of those waters triggered enhanced productivity and caused a contraction of the mixed layer and a marked steepening of the thermocline. 5:3607 doi: 10.1038/ncomms4607 (2014). Site 763 stable isotope dataset is available at https://www.ncei.noaa.gov/pub/data/paleo/contributions_by_author/karas2011/karas2011.txt (last access: 22May 2022; Karas et al., 2011b). 5b). model for the TEX86 proxy, Geochim. sample values reported in this table were measured simultaneously with calcification paleotemperatures between 18.6 and 23.9C when Google Scholar. (c)47-derived paleotemperatures are compared to the U1459 core-based U/Th series (note the reversed yaxis). Rohling, E. J., Yu, J., Heslop, D., Foster, G. L., Opdyke, B., and Roberts, Enhanced Corg burial during intense glacial stages is linked to the upwelling of nutrient-rich sub-Antarctic Mode Water onto the Western Australian Shelf. However, the Mrz, C., Schnetger, B., Murray, R. W., Plike, H., and Expedition However, the correlation between Nino3.4 (ref. analysed the coral samples. Bernasconi, S. M.: Long-term performance of the Kiel carbonate device with a 356 Scientists, Proceedings of the International Ocean Discovery Program 356, College Station, TX. 2c). Indeed, one observes used for foraminiferal Mg/Ca paleothermometry, Geochem. & Giese, B. S. A reanalysis of ocean climate using Simple Ocean Data Assimilation (SODA). sample material is required per aliquot in the AMGC-VUB lab. The . Palaeoecol. quasi-stable states and critical transitions over the past 40 million years, Science Advances, 7, eabf5326, https://doi.org/10.1126/sciadv.abf5326, 2021., Smith, R. A., Castaeda, I. S., Groeneveld, J., De Vleeschouwer, D., Lauretano, V., Littler, K., Lourens, L. J., Lyle, M., Plike, H., Rhl, U., Tian, J., Wilkens, R. H., Wilson, P. A., and Zachos, J. C.: An Arrows in c point to dominant wind direction for wind speed anomalies. using shipboard natural gamma radiation spectra measured on DV JOIDES It rounds Cape Leeuwin to enter the waters south of Australia where its influence extends as far as Tasmania. Figure3IODP Site U1459 depth series and agedepth model. North Atlantic/North Pacific Southern Boundary Current (warm) Brazil Current. Pliocene Epoch, Earth-Sci. For the non-detrended data, a significant correlation (r=0.65, P<0.001) was found between reconstructed SST and AVHRR OISST for the period from 1981 to 2010 (Supplementary Table 3). 5a). temperatures (and eventually heat transport) throughout the