@article {2547, title = {Long-term variations in Iceland{\textendash}Scotland overflow strength during the Holocene}, journal = {Climate of the Past}, volume = {9}, year = {2013}, month = {Jan-01-2013}, pages = {2073 - 2084}, abstract = {The overflow of deep water from the Nordic seas into the North Atlantic plays a critical role in global ocean circulation and climate. Approximately half of this overflow occurs via the Iceland{\textendash}Scotland (I{\textendash}S) overflow, yet the history of its strength throughout the Holocene (~ 0{\textendash}11 700 yr ago, ka) is poorly constrained, with previous studies presenting apparently contradictory evidence regarding its long-term variability. Here, we provide a comprehensive reconstruction of I{\textendash}S overflow strength throughout the Holocene using sediment grain size data from a depth transect of 13 cores from the Iceland Basin. Our data are consistent with the hypothesis that the main axis of the I{\textendash}S overflow on the Iceland slope was shallower during the early Holocene, deepening to its present depth by ~ 7 ka. Our results also reveal weaker I{\textendash}S overflow during the early and late Holocene, with maximum overflow strength occurring at ~ 7 ka, the time of a regional climate thermal maximum. Climate model simulations suggest a shoaling of deep convection in the Nordic seas during the early and late Holocene, consistent with our evidence for weaker I{\textendash}S overflow during these intervals. Whereas the reduction in I{\textendash}S overflow strength during the early Holocene likely resulted from melting remnant glacial ice sheets, the decline throughout the last 7000 yr was caused by an orbitally induced increase in the amount of Arctic sea ice entering the Nordic seas. Although the flux of Arctic sea ice to the Nordic seas is expected to decrease throughout the next century, model simulations predict that under high emissions scenarios, competing effects, such as warmer sea surface temperatures in the Nordic seas, will result in reduced deep convection, likely driving a weaker I{\textendash}S overflow.}, doi = {10.5194/cp-9-2073-201310.5194/cp-9-2073-2013-supplement}, url = {http://www.clim-past.net/9/2073/2013}, author = {Thornalley, D. J. R. and Blaschek, M. and Davies, F. J. and Praetorius, S. and Oppo, D. W. and McManus, J. F. and Hall, I. R. and Kleiven, H. and Renssen, H. and McCave, I. N.} } @article {2548, title = {Strengthening of the Northeast Monsoon over the Flores Sea, Indonesia, at the time of Heinrich event 1}, journal = {Geology}, volume = {40}, year = {2012}, month = {Jan-07-2012}, pages = {635 - 638}, abstract = {Paleoclimate evidence from South America and Asia has been interpreted to indicate that tropical rainfall migrated southward during the Northern Hemisphere cooling associated with Heinrich stadial 1 (HS1), an event of massive iceberg discharge to the North Atlantic ca. 18{\textendash}15 ka. Although arid conditions associated with such a shift are well documented in southern Asia, as far south as Borneo, debate still exists regarding the precipitation response in southern Indonesia and Australia during HS1. This study utilizes concentrations of the long-lived nuclide 232Th as a proxy for detrital riverine input and 230Th normalization to estimate the history of preserved fluxes reaching the seafloor in the Flores Sea, located between southern Sulawesi and the Lesser Sunda Islands, Indonesia. Because the only source of 232Th to the ocean is continental minerals, this proxy is a robust indicator of continental weathering. The 230Th normalized burial fluxes of lithogenic and biogenic matter demonstrate that both detrital and biogenic fluxes in the Flores Sea were higher during HS1 than any other period in the past 22 k.y. High detrital fluxes indicate enhanced precipitation runoff from surrounding landmasses during a period of maximum southward shift of the Intertropical Convergence Zone. This study further constrains the northern limit of enhanced rainfall associated with a southward shift of Australian monsoon-related rainfall at the time of HS1 and highlights the value of 232Th as a proxy of continental input to deep-sea sediment records.}, issn = {0091-7613}, doi = {10.1130/G32878.1}, url = {http://geology.gsapubs.org/cgi/doi/10.1130/G32878.1}, author = {Muller, J. and McManus, J. F. and Oppo, D. W. and Francois, R.} } @article {243, title = {Coordinated hydrological regimes in the Indo-Pacific region during the past two millennia}, journal = {Paleoceanography}, volume = {25}, year = {2010}, note = {id: 795; 565UW Times Cited:0 Cited References Count:42Y}, abstract = {Instrumental data suggest that major shifts in tropical Pacific atmospheric dynamics and hydrology have occurred within the past century, potentially in response to anthropogenic warming. To better understand these trends, we use the hydrogen isotopic ratios of terrestrial higher plant leaf waxes ( delta D-wax) in marine sediments from southwest Sulawesi, Indonesia, to compile a detailed reconstruction of central Indo-Pacific Warm Pool (IPWP) hydrologic variability spanning most of the last two millennia. Our paleodata are highly correlated with a monsoon reconstruction from Southeast Asia, indicating that intervals of strong East Asian summer monsoon (EASM) activity are associated with a weaker Indonesian monsoon (IM). Furthermore, the centennial-scale oscillations in our data follow known changes in Northern Hemisphere climate ( e. g., the Little Ice Age and Medieval Warm Period) implying a dynamic link between Northern Hemisphere temperatures and IPWP hydrology. The inverse relationship between the EASM and IM suggests that migrations of the Intertropical Convergence Zone and associated changes in monsoon strength caused synoptic hydrologic shifts in the IPWP throughout most of the past two millennia.}, issn = {0883-8305}, doi = {10.1029/2009pa001871}, author = {Tierney, J. E. and Oppo, D. W. and Rosenthal, Y. and Russell, J. M. and Linsley, B. K.} } @article {368, title = {2,000-year-long temperature and hydrology reconstructions from the Indo-Pacific warm pool}, journal = {Nature}, volume = {460}, year = {2009}, note = {id: 860; ISI Document Delivery No.: 487YE Times Cited: 2 Cited Reference Count: 29 Cited References: *INT AT ENAG WORLD, 2006, GNIP PROGR RES *NAT RES COUNC, 2006, SURF TEMP REC LAST 2 ALDRIAN E, 2003, INT J CLIMATOL, V23, P1435, DOI 10.1002/joc.950 ANAND P, 2003, PALEOCEANOGRAPHY, V18, ARTN 1050 BARSUGLI JJ, 2002, J CLIMATE, V15, P3427 BROCCOLI AJ, 2006, GEOPHYS RES LETT, V33, ARTN L01702 CHIANG JCH, 2005, CLIM DYNAM, V25, P477, DOI 10.1007/s00382-005-0040-5 CONROY JL, 2008, QUATERNARY SCI REV, V27, P1166, DOI 10.1016/j.quascirev.2008.02.015 GORDON AL, 2003, NATURE, V425, P824, DOI 10.1038/nature02038 HAUG GH, 2001, SCIENCE, V293, P1304 JANSEN E, 2007, CLIMATE CHANGE 2007, P466 KAWAHATA H, 2002, DEEP-SEA RES PT II, V49, P2783 LEA DW, 2000, SCIENCE, V289, P1719 LOCARNINI RA, 2006, NOAA ATLAS NESDIS, V61 MANN ME, 2008, P NATL ACAD SCI USA, V105, P13252, DOI 10.1073/pnas.0805721105 MOHTADI M, 2009, PALEOCEANOGRAPHY, V24, ARTN PA1201 MOY CM, 2002, NATURE, V420, P162 NEWTON A, 2006, GEOPHYS RES LETT, V33, ARTN L19710 QU T, 2005, OCEANOGRAPHY, V18, P50 ROSENTHAL Y, 2003, GEOPHYS RES LETT, V30, DOI 10.1029/2002GL016612 SMITH TM, 2008, J CLIMATE, V21, P2283, DOI 10.1175/2007JCLI2100.1 SONTAKKE NA, 1993, J CLIMATE, V6, P1807 STOTT L, 2004, NATURE, V431, P56, DOI 10.1038/nature02903 THUNELL RC, 1984, MICROPALEONTOLOGY, V30, P243 VUILLE M, 2005, J GEOPHYS RES-ATMOS, V110, ARTN D23108 WANG YJ, 2005, SCIENCE, V308, P854, DOI 10.1126/science.1106296 XIE PP, 1996, J CLIMATE, V9, P840 YANCHEVA G, 2007, NATURE, V445, P74, DOI 10.1038/nature05431 ZHANG PZ, 2008, SCIENCE, V322, P940, DOI 10.1126/science.1163965 Oppo, Delia W. Rosenthal, Yair Linsley, Braddock K.; YY}, pages = {1113-1116}, abstract = {Northern Hemisphere surface temperature reconstructions suggest that the late twentieth century was warmer than any other time during the past 500 years and possibly any time during the past 1,300 years (refs 1, 2). These temperature reconstructions are based largely on terrestrial records from extra-tropical or high-elevation sites; however, global average surface temperature changes closely follow those of the global tropics(3), which are 75\% ocean. In particular, the tropical Indo-Pacific warm pool (IPWP) represents a major heat reservoir that both influences global atmospheric circulation(4) and responds to remote northern high-latitude forcings(5,6). Here we present a decadally resolved continuous sea surface temperature (SST) reconstruction from the IPWP that spans the past two millennia and overlaps the instrumental record, enabling both a direct comparison of proxy data to the instrumental record and an evaluation of past changes in the context of twentieth century trends. Our record from the Makassar Strait, Indonesia, exhibits trends that are similar to a recent Northern Hemisphere temperature reconstruction(2). Reconstructed SST was, however, within error of modern values from about AD 1000 to AD 1250, towards the end of the Medieval Warm Period. SSTs during the Little Ice Age ( approximately AD 1550-1850) were variable, and similar to 0.5 to 1 degrees C colder than modern values during the coldest intervals. A companion reconstruction of delta O-18 of sea water-a sea surface salinity and hydrology indicator-indicates a tight coupling with the East Asian monsoon system and remote control of IPWP hydrology on centennial-millennial timescales, rather than a dominant influence from local SST variation.}, issn = {0028-0836}, doi = {10.1038/nature08233}, author = {Oppo, D. W. and Rosenthal, Y. and Linsley, B. K.} } @article {319, title = {3500 yr record of centennial-scale climate variability from the Western Pacific Warm Pool}, journal = {Geology}, volume = {36}, year = {2008}, note = {id: 1894; ISI Document Delivery No.: 357HB Times Cited: 1 Cited Reference Count: 36 Cited References: ALDRIAN E, 2003, INT J CLIMATOL, V23, P1435, DOI 10.1002/joc.950 ALTABET MA, 1994, GLOBAL BIOGEOCHEM CY, V8, P103 ALTABET MA, 2001, LIMNOL OCEANOGR, V46, P368 ARRUDA WZ, 2003, J PHYS OCEANOGR, V33, P2815 BRANDES JA, 1998, LIMNOL OCEANOGR, V43, P1680 BRANDES JA, 2002, GLOBAL BIOGEOCHEMICA, V16 CASCIOTTI KL, 2002, ANAL CHEM, V74, P4905, DOI 10.1021/ac020113w CHRISTIAN JR, 2004, DEEP-SEA RES PT II, V51, P209, DOI 10.1016/j.dsr2.2003.06.002 DEUTSCH C, 2007, NATURE, V445, P163, DOI 10.1038/nature05392 GANESHRAM RS, 2000, PALEOCEANOGRAPHY, V15, P361 GRANGER J, 2004, EOS T AM GEOPHYS U S, V85 GRANGER J, 2004, LIMNOL OCEANOGR, V49, P1763 HAUG GH, 1998, PALEOCEANOGRAPHY, V13, P427 HAUG GH, 2001, SCIENCE, V293, P1304 HODELL DA, 2005, QUATERNARY SCI REV, V24, P1413, DOI 10.1016/j.quascirev.2004.10.013 LIU KK, 1989, LIMNOL OCEANOGR, V34, P820 MAKOU MC, 2007, ORG GEOCHEM, V38, P1680, DOI 10.1016/j.orggeochem.2007.06.003 MARIOTTI A, 1981, PLANT SOIL, V62, P413 MASUMOTO Y, 2001, GEOPHYS RES LETT, V28, P1631 MIDDELBURG JJ, 1990, GEOL ULTRIECTIN, V71, P177 MOY CM, 2002, NATURE, V420, P162 NEWTON A, 2006, GEOPHYS RES LETT, V33, ARTN L19710 REIN B, 2004, GEOPHYS RES LETT, V31, ARTN L17211 REIN B, 2005, PALEOCEANOGRAPHY, V20, ARTN PA4003 REYNOLDS RW, 1994, J CLIMATE, V7, P929 RODBELL DT, 1999, SCIENCE, V283, P516 SIGMAN DM, 2003, GEOCHEM GEOPHY GEOSY, V4, ARTN 1040 SIGMAN DM, 2005, GLOBAL BIOGEOCHEM CY, V19, ARTN GB4022 STOTT L, 2004, NATURE, V431, P56, DOI 10.1038/nature02903 STREETPERROTT FA, 1997, SCIENCE, V278, P1422 THUNELL R, 2004, GLOBAL BIOGEOCHEMICA, V18, UNSP GB3001 UEKI I, 2003, J GEOPHYS RES-OCEANS, V108, ARTN 3243 VANAKEN HMV, 1988, NETHERLANDS J SEA RE, V22, P403, DOI 10.1016/0077-7579(88)90011-7 VANDERWEIJDEN CH, 1989, NETH J SEA RES, V24, P583 VANRIEL PM, 1943, OCEANOGRAPHIC RESU 5, V2 WYRTKI K, 1961, NAGA REPORT, V2 Langton, S. J. Linsley, B. K. Robinson, R. S. Rosenthal, Y. Oppo, D. W. Eglinton, T. I. Howe, S. S. Djajadihardja, Y. S. Syamsudin, F. U.S. National Science Foundation [OCE-0502550, OCE-0502504, OCE-052960] This work was supported by the U.S. National Science Foundation (grants OCE-0502550, OCE-0502504, and OCE-052960). We thank the captain, crew, technicians, and the scientific crew who helped with sample collection on the R/V Baruna Jaya VIII. Geological soc amer, inc Boulder; YY}, pages = {795-798}, abstract = {We use geochemical data from a sediment core in the shallow-silled and intermittently dysoxic Kau Bay in Halmahera (Indonesia, lat 1 degrees N, long 127.5 degrees E) to reconstruct century-scale climate variability within the Western Pacific Warm Pool over the past similar to 3500 yr. Downcore variations in bulk sedimentary delta N-15 appear to reflect century-scale variability in basin ventilation, attributed to changes in oceanographic conditions related to century-scale fluctuations in El Nino Southern Oscillation (ENSO). We infer an increase in century-scale El Nino activity beginning ca. 1700 yr B.P. with peaks in El Nino activity ca. 1500 yr B.P., 1150 yr B.P., and ca. 700 yr B.P. The Kau Bay results suggest that there was diminished ENSO amplitude or frequency, or a departure from El Nino-like conditions during the Medieval Warm Period, and distinctive, but steadily decreasing, El Nino activity during and after the Little Ice Age.}, issn = {0091-7613}, doi = {10.1130/g24926a.1}, author = {Langton, S. J. and Linsley, B. K. and Robinson, R. S. and Rosenthal, Y. and Oppo, D. W. and Eglinton, T. I. and Howe, S. S. and Djajadihardja, Y. S. and Syamsudin, F.} } @article {260, title = {Deglacial variability in the surface return flow of the Atlantic meridional overturning circulation}, journal = {Paleoceanography}, volume = {23}, year = {2008}, note = {id: 838; 281YL Times Cited:4 Cited References Count:41; YY}, abstract = {[1] Benthic foraminiferal Cd/Ca from a Florida Current sediment core documents the history of the northward penetration of southern source waters within the surface return flow of the Atlantic meridional overturning circulation (AMOC). Cd seawater estimates (Cd-W) indicate that intermediate-depth southern source waters crossed the equator and contributed to the Florida Current during the Bolling-Allerod warm period of the last deglaciation, consistent with evidence of only a modest AMOC reduction compared to today. The Cd-W estimates also provide the first paleoceanographic evidence of a reduction in the influence of intermediate-depth southern source waters within the Florida Current during the Younger Dryas, a deglacial cold event characterized by a weak North Atlantic AMOC. Our results reveal a close correspondence between the northward penetration of intermediate-depth southern source waters and the influence of North Atlantic Deep Water, suggesting a possible link between intermediate-depth southern source waters and the strength of the Atlantic AMOC.}, issn = {0883-8305}, doi = {10.1029/2007pa001450}, author = {Came, R. E. and Oppo, D. W. and Curry, W. B. and Lynch-Stieglitz, J.} } @article {366, title = {Episodic reductions in bottom-water currents since the last ice age}, journal = {Nature Geoscience}, volume = {1}, year = {2008}, note = {id: 1896; ISI Document Delivery No.: 331AG Times Cited: 9 Cited Reference Count: 34 Cited References: ALLEY RB, 1997, GEOLOGY, V25, P483 BARBER DC, 1999, NATURE, V400, P344 BARD E, 1994, EARTH PLANET SC LETT, V126, P275 BIANCHI GG, 1999, NATURE, V397, P515 BIANCHI GG, 1999, SEDIMENTOLOGY, V46, P1001 BOND G, 1992, NATURE, V360, P245 BOYLE EA, 1987, NATURE, V330, P35 BROECKER WS, 1989, GEOCHIM COSMOCHIM AC, V53, P2465 BROECKER WS, 1989, NATURE, V341, P318 CAME RE, 2007, GEOLOGY, V35, P315, DOI 10.1130/G23455A.1 CURRY WB, 2005, PALEOCEANOGRAPHY, V20, ARTN PA1017 DUPLESSY JC, 1980, NATURE, V286, P479 DUPLESSY JC, 1988, PALEOCEANOGRAPHY, V3, P343 ELLISON CRW, 2006, SCIENCE, V312, P1929, DOI 10.1126/science.1127213 FIRESTONE RB, 2007, P NATL ACAD SCI USA, V104, P16016, DOI 10.1073/pnas.0706977104 GHERARDI JM, 2005, EARTH PLANET SC LETT, V240, P710, DOI 10.1016/j.epsl.2005.09.061 GROOTES PM, 1993, NATURE, V366, P552 HALL IR, 2004, QUATERNARY SCI REV, V23, P1529, DOI 10.1016/j.quascirev.2004.04.004 KENNETT JP, 2007, EOS T AGU JOINT AS S, V88, UNSP PP41A05 KROOPNICK P, 1980, EARTH PLAN, V49, P469 LEGRAND P, 1995, PALEOCEANOGRAPHY, V10, P1011 MANABE S, 1995, NATURE, V378, P165 MCCARTNEY MS, 1996, OCEANUS, V39, P19 MCCAVE IN, 1995, NATURE, V374, P149 MCCAVE IN, 1995, PALEOCEANOGRAPHY, V10, P593 MCCAVE IN, 2006, GEOCHEM GEOPHY GEOSY, V7, P37 MCMANUS JF, 2004, NATURE, V428, P824 OPPO DW, 1993, SCIENCE, V259, P1148 ROHLING EJ, 2005, NATURE, V434, P975, DOI 10.1038/nature03421 RUDDIMAN WF, 1981, PALAEOGEOGR PALAEOCL, V35, P145 SARNTHEIN M, 1994, PALEOCEANOGRAPHY, V9, P209 TARASOV L, 2005, NATURE, V435, P662, DOI 10.1038/nature03617 WORTHINGTON LV, 1976, N ATLANTIC CIRCULATI YU EF, 1996, NATURE, V379, P689 Praetorius, Summer K. McManus, Jerry F. Oppo, Delia W. Curry, William B. Nature publishing group New york; YY}, pages = {449-452}, abstract = {Past changes in the freshwater balance of the surface North Atlantic Ocean are thought to have influenced the rate of deep-water formation, and consequently climate(1,2). Although water-mass proxies are generally consistent with an impact of freshwater input on meridional overturning circulation(3), there has been little dynamic evidence to support this linkage. Here we present a 25,000 year record of variations in sediment grain size from south of Iceland, which indicates vigorous bottom-water currents during both the last glacial maximum and the Holocene period. Together with reconstructions of North Atlantic water-mass distribution, vigorous bottom currents suggest a shorter residence time of northern-source waters during the last glacial maximum, relative to the Holocene period. The most significant reductions in flow strength occur during periods that have been associated with freshening of the surface North Atlantic. The short-term deglacial oscillations in bottom current strength are closely coupled to changes in Greenland air temperature, with a minimum during the Younger Dryas cold reversal and a maximum at the time of rapid warming at the onset of the Holocene. Our results support a strong connection between ocean circulation and rapid climate change.}, issn = {1752-0894}, doi = {10.1038/ngeo227}, author = {Praetorius, S. K. and McManus, J. F. and Oppo, D. W. and Curry, W. B.} } @article {386, title = {Interpreting sea surface temperature from strontium/calcium ratios in Montastrea corals: Link with growth rate and implications for proxy reconstructions}, journal = {Paleoceanography}, volume = {23}, year = {2008}, note = {id: 864; ISI Document Delivery No.: 333MS Times Cited: 3 Cited Reference Count: 49 Cited References: *DEP CONS CULT AFF, 1986, MAR WAT QUAL MEAS CH *NAT RES COUNC, 2006, SURF TEMP REC LAST 2 BEVINGTON PR, 1969, DATA REDUCTION ERROR, P56 BLACK DE, 2004, PALEOCEANOGRAPHY, V19, ARTN PA2022 BLACK DE, 2007, PALEOCEANOGRAPHY, V22, ARTN PA4204 CARDINAL D, 2001, CHEM GEOL, V176, P213 CARRICARTGANIVET JP, 2004, J EXP MAR BIOL ECOL, V302, P249, DOI 10.1016/j.jembe.2003.10.015 CHIANG JCH, 2002, J GEOPHYS RES-ATMOS, V107, ARTN 4004 COBB KM, 2003, EARTH PLANET SC LETT, V210, P91, DOI 10.1016/S0012-821X(03)00138-9 COHEN AL, 2004, GEOPHYS RES LETT, V31, ARTN L16310 COHEN AL, 2004, MAR ECOL-PROG SER, V271, P147 COHEN AL, 2006, GEOCHEM GEOPHY GEOSY, V7, ARTN Q12004 COHEN AL, 2007, GEOPHYS RES LETT, V34, ARTN L17706 CRONIN TM, 2003, GLOBAL PLANET CHANGE, V36, P17 DEVILLIERS S, 1995, SCIENCE, V269, P1247 DEVILLIERS S, 1999, EARTH PLANET SC LETT, V171, P623 FELIS T, 2004, NATURE, V429, P164, DOI 10.1038/nature02546 GABITOV RI, 2006, GEOCHIM COSMOCHIM S, V70, A187, DOI 10.1016/j.gca.2006.06.377 GAETANI GA, 2006, GEOCHIM COSMOCHIM AC, V70, P4617, DOI 10.1016/j.gca.2006.07.008 GOODKIN NF, 2005, PALEOCEANOGRAPHY, V20, ARTN PA4016 HAASESCHRAMM A, 2003, PALEOCEANOGRAPHY, V18, ARTN 1073 HAASESCHRAMM A, 2005, PALEOCEANOGRAPHY, V20, ARTN PA4015 HAUG GH, 2001, SCIENCE, V293, P1304 HENDY EJ, 2002, SCIENCE, V295, P1511 HERNANDEZGUERRA A, 2000, GEOPHYS RES LETT, V27, P3497 HODELL DA, 2005, QUATERNARY RES, V63, P109, DOI 10.1016/j.yqres.2004.11.004 HUBBARD DK, 2005, J SEDIMENT RES, V75, P97, DOI 10.2110/jsr.2005.009 HUGHEN KA, 2004, RADIOCARBON, V46, P1059 JONES PD, 2004, REV GEOPHYS, V42, ARTN RG2002 LEDER JJ, 1996, GEOCHIM COSMOCHIM AC, V60, P2857 LOUGH JM, 2004, PALAEOGEOGR PALAEOCL, V204, P115, DOI 10.1016/S0031-0182(03)00727-2 LUND DC, 2006, PALEOCEANOGRAPHY, V21, ARTN PA2009 MEIBOM A, 2006, GEOPHYS RES LETT, V33, ARTN L11608 MOHIUDDIN MM, 2004, DEEP-SEA RES PT I, V51, P1659, DOI 10.1016/j.dsr.2004.06.002 NYBERG J, 2002, PALAEOGEOGR PALAEOCL, V183, P25 OSTERMANN DR, 2000, PALEOCEANOGRAPHY, V15, P353 PFLAUMANN U, 2003, PALEOCEANOGRAPHY, V18, ARTN 1065 REYNAUD S, 2007, GEOCHIM COSMOCHIM AC, V71, P354, DOI 10.1016/j.gca.2006.09.009 REYNOLDS RW, 1994, J CLIMATE, V7, P929 ROSENTHAL Y, 1999, ANAL CHEM, V71, P3248 SCHMIDT MW, 2006, GEOCHEM GEOPHY GEOSY, V7, ARTN Q02P10 SMITH JM, 2006, PALEOCEANOGRAPHY, V21, ARTN PA1010 SWART PK, 2002, GEOCHEM GEOPHY GEOSY, V3, ARTN 8402 THUNELL RC, 1984, MICROPALEONTOLOGY, V30, P243 VELLINGA M, 2004, J CLIMATE, V17, P4498 WATANABE T, 2001, MAR GEOL, V173, P21 WEIL E, 1994, B MAR SCI, V55, P151 WINTER A, 2000, GEOPHYS RES LETT, V27, P3365 YOO JM, 1990, J PHYS OCEANOGR, V20, P831 Saenger, Casey Cohen, Anne L. Oppo, Delia W. Hubbard, Dennis Amer geophysical union Washington; YY}, abstract = {[1] We analyzed strontium/calcium ratios (Sr/Ca) in four colonies of the Atlantic coral genus Montastrea with growth rates ranging from 2.3 to 12.6 mm a(-1). Derived Sr/Ca-sea surface temperature (SST) calibrations exhibit significant differences among the four colonies that cannot be explained by variations in SST or seawater Sr/Ca. For a single coral Sr/Ca ratio of 8.8 mmol mol(-1), the four calibrations predict SSTs ranging from 24.0 degrees to 30.9 degrees C. We find that differences in the Sr/Ca-SST relationships are correlated systematically with the average annual extension rate (ext) of each colony such that Sr/Ca ( mmol mol(-1)) = 11.82 (+/- 0.13) - 0.058 (+/- 0.004) x ext ( mm a(-1)) - 0.092 (+/- 0.005) x SST (degrees C). This observation is consistent with previous reports of a link between coral Sr/Ca and growth rate. Verification of our growth-dependent Sr/Ca - SST calibration using a coral excluded from the calibration reconstructs the mean and seasonal amplitude of the actual recorded SST to within 0.3 degrees C. Applying a traditional, nongrowth-dependent Sr/Ca - SST calibration derived from a modern Montastrea to the Sr/Ca ratios of a conspecific coral that grew during the early Little Ice Age (LIA) ( 400 years B. P.) suggests that Caribbean SSTs were > 5 degrees C cooler than today. Conversely, application of our growth-dependent Sr/Ca - SST calibration to Sr/Ca ratios derived from the LIA coral indicates that SSTs during the 5-year period analyzed were within error (+/- 1.4 degrees C) of modern values.}, issn = {0883-8305}, doi = {10.1029/2007pa001572}, author = {Saenger, C. and Cohen, A. L. and Oppo, D. W. and Hubbard, D.} } @article {318, title = {Subtropical Atlantic salinity variability and Atlantic meridional circulation during the last deglaciation}, journal = {Geology}, volume = {36}, year = {2008}, note = {id: 862; ISI Document Delivery No.: 381WN Times Cited: 5 Cited Reference Count: 32 Cited References: *CLIMAP PROJ MEMB, 1981, GEOL SOC AM MAP CHAR ANAND P, 2003, PALEOCEANOGRAPHY, V18, ARTN 1050 BENWAY HM, 2006, PALEOCEANOGRAPHY, V21, ARTN PA3008 BEVINGTON P, 2002, DATA REDUCTION ERROR BOYLE EA, 1987, NATURE, V330, P35 BROECKER WS, 1990, PALEOCEANOGRAPHY, V5, P469 CARLSON AE, 2007, P NATL ACAD SCI USA, V104, P6556, DOI 10.1073/pnas.0611313104 CLARK PU, 2004, SCIENCE, V304, P1141 GRIMM EC, 2006, QUATERNARY SCI REV, V25, P2197, DOI 10.1016/j.quascirev.2006.04.008 GROOTES PM, 1993, NATURE, V366, P552 KASPI Y, 2004, PALEOCEANOGRAPHY, V19, ARTN PA3004 KNORR G, 2003, NATURE, V424, P532, DOI 10.1038/nature01855 LEA DW, 2003, SCIENCE, V301, P1361 LEDUC G, 2007, NATURE, V445, P908, DOI 10.1038/nature05578 LEGRANDE AN, 2006, GEOPHYS RES LETT, V33, ARTN L12604 LEGRANDE AN, 2008, PALEOCEANOGRAPHY, V23, DOI 10.1029/2008PA001610 MCMANUS JF, 2004, NATURE, V428, P834, DOI 10.1038/nature02494 OPPO DW, 2007, GEOPHYS RES LETT, V34, ARTN L13701 PEETERS FJC, 2004, NATURE, V430, P661, DOI 10.1038/nature02785 PETERSON LC, 2000, SCIENCE, V290, P1947 ROBINSON LF, 2005, SCIENCE, V310, P1469, DOI 10.1126/science.1114832 RUHLEMANN C, 1999, NATURE, V402, P511 SCHMIDT GA, 2007, J GEOPHYS RES-ATMOS, V112, ARTN D10103 SCHMIDT MW, 2004, NATURE, V428, P160, DOI 10.1038/nature02346 SCHMIDT MW, 2006, NATURE, V443, P561, DOI 10.1038/nature05121 SCHMITZ WJ, 1995, REV GEOPHYS, V33, P151 SKINNER LC, 2006, QUATERNARY SCI REV, V25, P3312, DOI 10.1016/j.quascirev.2006.07.005 STOUFFER RJ, 2006, J CLIMATE, V19, P1365 THOMAS AL, 2006, EARTH PLANET SC LETT, V241, P493, DOI 10.1016/j.epsl.2005.11.031 WANG XF, 2004, NATURE, V432, P740, DOI 10.1038/nature03067 WEAVER AJ, 2003, SCIENCE, V299, P1709 WELDEAB S, 2006, EARTH PLANET SC LETT, V241, P699, DOI 10.1016/j.epsl.2005.11.012 Carlson, Anders E. Oppo, Delia W. Came, Rosemarie E. LeGrande, Allegra N. Keigwin, Lloyd D. Curry, William B. Geological soc amer, inc Boulder; YY}, pages = {991-994}, abstract = {During the last deglaciation (ca. 21-10 ka), freshening of the North Atlantic surface likely caused reductions in Atlantic meridional overturning circulation (AMOC); the mechanisms related to AMOC recovery remain poorly understood. Here we present three new deglacial surface temperature and delta O-18(seawater) (delta O-18(sw)) reconstructions from the western subtropical North and South Atlantic. Similarities to tropical Caribbean and western Atlantic delta O-18(sw) records suggest that a salty surface water mass accumulated in the western Atlantic from 27 degrees S to 33 degrees N during periods of reduced AMOC. However, delta O-18(sw) decreases led deep AMOC resumption by hundreds of years. We suggest that the northward export of salt previously trapped in the western Atlantic resulted in the early establishment of a shallow overturning circulation that eventually culminated in deep AMOC resumption, implying that AMOC may constitute a self-limiting system.}, issn = {0091-7613}, doi = {10.1130/g25080a.1}, author = {Carlson, A. E. and Oppo, D. W. and Came, R. E. and LeGrande, A. N. and Keigwin, L. D. and Curry, W. B.} } @article {1018, title = {Amplitude and timing of temperature and salinity variability in the subpolar North Atlantic over the past 10 k.y.}, journal = {Geology}, volume = {35}, year = {2007}, note = {id: 983}, pages = {315-318}, abstract = {Paired planktic foraminiferal δ18O and Mg/Ca data reveal trends of increasing temperatures (\~{}3 {\textdegree}C) and salinities in the subpolar North Atlantic over the course of the Holocene, which were punctuated by abrupt events. The trends likely reflect an insolation-forced northward retreat of the boundary between polar and North Atlantic subsurface waters. The superimposed variability does not appear to be periodic, but tends to recur within a broad millennial band. The records provide convincing evidence of open-ocean cooling (nearly 2 {\textdegree}C) and freshening during the 8.2 ka event, and suggest similar conditions at 9.3 ka. However, the two largest temperature oscillations in our record (\~{}2 {\textdegree}C) occurred during the past 4 k.y., suggesting a recent increase in temperature variability relative to the mid-Holocene, perhaps in response to neoglaciation, which began at about this time. }, keywords = {Bj{\"o}rn Drift, Mg/Ca, Neogloboquadrina pachyderma dextral, Ocean Drilling Program Site 984, paleotemperature}, doi = {10.1130/G23455A.1 }, author = {Came, R. E. and Oppo, D. W. and McManus, J. F.} } @article {663, title = {Paleoenvironmental change in the middle Okinawa Trough since the last deglaciation: Evidence from the sedimentation rate and planktonic foraminiferal record}, journal = {Palaeogeography Palaeoclimatology Palaeoecology}, volume = {243}, year = {2007}, note = {134kzTimes Cited:48Cited References Count:62}, month = {Jan 22}, pages = {378-393}, abstract = {Well-dated, high-resolution records of planktonic foraminifera and oxygen isotopes from two sediment cores, A7 and E017, in the middle Okinawa Trough reveal strong and rapid millennial-scale climate changes since similar to 18 to 17 thousand years before present (kyr B.P.). Sedimentation rate shows a sudden drop at similar to 11.2 cal. kyr B.P. due to a rapid rise of sea level after the Younger Dryas (YD) and consequently submergence of the large continental shelf on the East China Sea (ECS) and the retreat of the estuary providing sediment to the basin. During the last deglaciation, the relative abundance of warm and cold species of planktonic foraminifera fluctuates strongly, consistent with the timing of sea surface temperature (SST) variations determined from Mg/Ca measurements of planktonic foraminifera from one of the two cores. These fluctuations are coeval with climate variation recorded in the Greenland ice cores and North Atlantic sediments, namely Heinrich event 1 (H1), Bolling-Allerod (B/A) and YD events. At about 9.4 kyr B.P., a sudden change in the relative abundance of shallow to deep planktonic species probably indicates a sudden strengthening of the Kuroshio Current in the Okinawa Trough, which was synchronous with a rapid sea-level rise at 9.5-9.2 kyr B.P. in the ECS, Yellow Sea (YS) and South China Sea (SCS). The abundance of planktonic foraminiferal species, together with Mg/Ca based SST, exhibits millennial-scale oscillations during the Holocene, with 7 cold events (at about 1.7, 2.3-4.6, 6.2, 7.3, 8.2, 9.6, 10.6 cal. kyr BP) superimposed on a Holocene warming trend. This Holocene trend, together with centennial-scale SST variations superimposed on the last deglacial trend, suggests that both high and low latitude influences affected the climatology of the Okinawa Trough. (c) 2006 Elsevier B.V. All rights reserved.}, issn = {0031-0182}, doi = {10.1016/j.palaeo.2006.08.016}, author = {Xiang, R. and Sun, Y. B. and Li, T. G. and Oppo, D. W. and Chen, M. H. and Zheng, F.} } @article {1026, title = {Meridional overturning circulation in the South Atlantic at the last glacial maximum}, journal = {Geochemistry Geophysics Geosystems}, volume = {7}, year = {2006}, note = {092siTimes Cited:17Cited References Count:46}, month = {Oct 3}, abstract = {The geostrophic shear associated with the meridional overturning circulation is reflected in the difference in density between the eastern and western margins of the ocean basin. Here we examine how the density difference across 30 degrees S in the upper 2 km of the Atlantic Ocean ( and thus the magnitude of the shear associated with the overturning circulation) has changed between the last glacial maximum and the present. We use oxygen isotope measurements on benthic foraminifera to reconstruct density. Today, the density in upper and intermediate waters along the eastern margin in the South Atlantic is greater than along the western margin, reflecting the vertical shear associated with the northward flow of surface and intermediate waters and the southward flowing North Atlantic Deep Waters below. The greater density along the eastern margin is reflected in the higher delta(18)O values for surface sediment benthic foraminifera than those found on the western margin for the upper 2 km. For the last glacial maximum the available data indicate that the eastern margin foraminifera had similar delta(18)O to those on the western margin between 1 and 2 km and that the gradient was reversed relative to today with the higher delta(18)O values in the western margin benthic foraminifera above 1 km. If this reversal in benthic foraminifera delta(18)O gradient reflects a reversal in seawater density gradient, these data are not consistent with a vigorous but shallower overturning cell in which surface waters entering the Atlantic basin are balanced by the southward export of Glacial North Atlantic Intermediate Water.}, issn = {1525-2027}, doi = {10.1029/2005GC001226}, author = {Lynch-Stieglitz, J. and Curry, W. B. and Oppo, D. W. and Ninneman, U. S. and Charles, C. D. and Munson, J.} } @article {681, title = {Amplitude and timing of sea-surface temperature change in the northern South China Sea: Dynamic link to the East Asian monsoon}, journal = {Geology}, volume = {33}, year = {2005}, note = {969rmTimes Cited:66Cited References Count:38}, month = {Oct}, pages = {785-788}, abstract = {Magnesium/calcium (Mg/Ca) ratios of foraminiferal shells from a sediment core from the northern South China Sea, a semi-enclosed basin in the western tropical Pacific, document variations in sea-surface temperature (SST) during the past 145 k.y. Glacial SSTs were 4 degrees C colder than interglacial SSTs. During the last deglaciation, most of the warming was accomplished in a single abrupt step after continental ice-sheet decay had already begun, but warming and ice-sheet demise were nearly synchronous during the penultimate deglaciation. Abrupt SST changes of the past 15 k.y. were apparently synchronous with events in East Asian monsoon rainfall, suggesting that variations in monsoon winds and their influence on surface circulation of the western Pacific exerted a strong control on northern South China Sea SSTs. We suggest that this link persisted for the previous 130 k.y., during which time orbital-scale 2-3 degrees C SST changes and several small (<= 2 degrees C) abrupt SST events occurred in the northern South China Sea. The similar timing of northern South China Sea SST, on a benthic delta O-18 time scale, to a well-dated speleothem record from eastern China suggests that the demise of ice sheets associated with the penultimate deglaciation did not precede Northern Hemisphere summer insolation increase. Our results suggest that surface waters had higher delta O-18 values during times of strong summer monsoon than during times of weak monsoon, likely reflecting a redistribution of O-18 depleted rainfall from land during times of strong summer monsoons, to the western Pacific during times of weaker summer monsoons.}, issn = {0091-7613}, doi = {10.1130/G21867.1}, author = {Oppo, D. W. and Sun, Y. B.} } @article {2006, title = {Glacial water mass geometry and the distribution of d 13 C of SCO 2 in the western Atlantic Ocean}, journal = {Paleoceanography}, volume = {20}, year = {2005}, note = {id: 416}, month = {2005}, author = {Curry, W. B. and Oppo, D. W.} } @article {1964, title = {Last deglaciation in the Okinawa Trough: Subtropical northwest Pacific link to Northern Hemisphere and tropical climate}, journal = {Paleoceanography}, volume = {20}, year = {2005}, note = {975ipTimes Cited:53 Cited References Count:55 }, month = {Oct 7}, abstract = {[1] Detailed deglacial and Holocene records of planktonic delta O-18 and Mg/Ca - based sea surface temperature (SST) from the Okinawa Trough suggest that at similar to 18 to 17 thousand years before present (kyr B. P.), late spring/ early summer SSTs were approximately 3 degrees C cooler than today, while surface waters were up to 1 practical salinity unit saltier. These conditions are consistent with a weaker influence of the summer East Asian Monsoon (EAM) than today. The timing of suborbital SST oscillations suggests a close link with abrupt changes in the EAM and North Atlantic climate. A tropical influence, however, may have resulted in subtle decoupling between the North Atlantic and the Okinawa Trough/EAM during the deglaciation. Okinawa Trough surface water trends in the Holocene are consistent with model simulations of an inland shift of intense EAM precipitation during the middle Holocene. Millennial-scale alternations between relatively warm, salty conditions and relatively cold, fresh conditions suggest varying influence of the Kuroshio during the Holocene.}, keywords = {cal kyr bp, deep-ocean circulation, equatorial current, kuroshio current, late pleistocene, oxygen-isotope, planktonic-foraminifera, radiocarbon age calibration, south china sea, surface-water}, isbn = {0883-8305}, doi = {10.1029/2004PA001061}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2\&SrcAuth=Alerting\&SrcApp=Alerting\&DestApp=WOS\&DestLinkType=FullRecord;UT=WOS:000232654500001}, author = {Sun, Y. B. and Oppo, D. W. and Xiang, R. and Liu, W. G. and Gao, S.} } @article {2065, title = {The amplitude and phasing of climate change during the last deglaciation in the Sulu Sea, western equatorial Pacific}, journal = {Geophysical Research Letters}, volume = {30}, year = {2003}, note = {677zxTimes Cited:122 Cited References Count:18 }, month = {Apr 22}, abstract = {[1] Variations in tropical sea surface temperature patterns and the phasing relative to climate change in higher-latitudes provide insight into the mechanisms of climate change on both orbital and shorter time-scales. Here, we present well-dated, high-resolution records of planktonic foraminiferal delta(18)O and Mg/Ca-based SST spanning the last deglaciation from the Sulu Sea, located in the western equatorial Pacific. The results indicate that the last glacial maximum was 2.3 +/- 0.5degreesC cooler than present in the Sulu Sea with a concomitant decrease in sea surface salinity. The similarity between variations in surface salinity in the Sulu Sea, the western and eastern equatorial Pacific, and the Greenland ice-core record suggests that the observed changes in salinity reflect large-scale rearrangement of atmospheric patterns, which were coherent and synchronous throughout the Northern Hemisphere. The results suggest that the glacial equatorial Pacific climate was strongly influenced by both tropical, and extra-tropical forcing, although it is not clear whether interannual (ENSO) variability is a good analogue of glacial-interglacial climate change.}, keywords = {china, enso, level, monsoon, record, surface temperature}, isbn = {0094-8276}, doi = {10.1029/2002GL016612}, author = {Rosenthal, Y. and Oppo, D. W. and Linsley, B. K.} } @inbook {1439, title = {Analog for Holocene and future Climate?}, booktitle = {Geophysical Monograph 137, Earth{\textquoteright}s Climate and Orbital Eccentricity: The Marine Isotope State 11 Questions}, year = {2003}, note = {id: 1166}, month = {2003}, pages = {69-85}, author = {McManus, J. F. and Oppo, D. W. and Cullen, J. L. and Healey, S. L.}, editor = {Droxler, A.} } @article {1016, title = {Atlantic Ocean circulation during the Younger Dryas: Insights from a new Cd/Ca record from the western subtropical South Atlantic}, journal = {Paleoceanography}, volume = {18}, year = {2003}, note = {749rtTimes Cited:30Cited References Count:39}, month = {Nov 25}, abstract = {[Benthic foraminiferal Cd/ Ca from an intermediate depth, western South Atlantic core documents the history of southward penetration of North Atlantic Intermediate Water ( NAIW). Cd seawater estimates ( Cd-W) for the last glacial are consistent with the production of NAIW and its export into the South Atlantic. At similar to 14.5 ka concurrently with the onset of the Bolling- Allerod to Younger Dryas cooling, the NAIW contribution to the South Atlantic began to decrease, marking the transition from a glacial circulation pattern to a Younger Dryas circulation. High Cd-W in both the deep North Atlantic and the intermediate South Atlantic imply reduced export of deep and intermediate water during the Younger Dryas and a significant decrease in northward oceanic heat transport. A modern circulation was achieved at similar to 9 ka, concurrently with the establishment of Holocene warmth in the North Atlantic region, further supporting a close linkage between deepwater variability and North Atlantic climate.}, issn = {0883-8305}, doi = {10.1029/2003PA000888}, author = {Came, R. E. and Oppo, D. W. and Curry, W. B.} } @article {2069, title = {Deep sea records from the southeast Labrador Ocean circulation changes and ice-rafting events during hte last 160,000 years}, journal = {Paleoceanography}, volume = {18}, year = {2003}, note = {id: 989}, month = {2003}, author = {Rasmussen, T. L. and Oppo, D. W. and Thompson, E. and Lehman, S. J.} } @article {2084, title = {East Asian monsoon forcing of suborbital variability in the Sulu Sea during Marine Isotope Stage 3: Link to Northern Hemisphere climate}, journal = {Geochemistry Geophysics Geosystems}, volume = {4}, year = {2003}, note = {631mwTimes Cited:41 Cited References Count:53 }, month = {Jan 2}, abstract = {[1] We have generated a new high-resolution record of variations in planktonic foraminiferal oxygen isotopes (delta(18)O) and Mg/Ca from a sediment core (IMAGES 97-2141) in the Sulu Sea located in the Philippine archipelago of western tropical Pacific. This record reveals distinct, suborbital-scale delta(18)O changes, most notably during Marine Isotope Stage 3 (MIS3) (similar to30,000 to 60,000 years B.P.). The amplitudes of these delta(18)O fluctuations (0.4 to 0.7parts per thousand) exceed that which can be attributed to sea level changes and must be due to changes in sea surface conditions. In the same interval, variations in planktonic foraminifera Mg/Ca suggest that suborbital surface ocean temperature variations of 1 to 1.5degreesC in the Sulu Sea were not in phase with delta(18)O. Combined, this evidence indicates that the MIS3 millennial delta(18)O events in the Sulu Sea were primarily the result of changes in surface water salinity, which today is directly related to the East Asian Monsoon (EAM) and its influence on the balance between surface water contributions from the South China Sea and Western Pacific Warm Pool (WPWP). Within dating uncertainties the MIS3 Sulu Sea delta(18)O suborbital variability indicates that times of fresher surface conditions in the Sulu Sea coincide with similar conditions in the WPWP [Stott et al., 2002] and also with intensifications of the summer EAM as recorded in the U-Th dated Chinese (Hulu Cave) speleothem delta(18)O record [Wang et al., 2001] and thus by inference with interstadials in the Greenland Ice core records. Combined, these results indicate that pronounced suborbital variability in the summer EAM and Intertropical Convergence Zone (ITCZ) during MIS3 was tightly coupled with climate conditions in the northern high latitudes.}, keywords = {1620 global change : climate dynamics (3309), 4267 oceanography : general : paleoceanography, dissolution, equatorial pacific, eurasian snow cover, isotope stage 3, last glacial period, late pleistocene, Mg/Ca, millennial-scale climate change, oxygen isotopes, paleoceanography, planktonic-foraminifera, records, se asian monsoon, south china sea, summer monsoon, surface temperature-variations}, isbn = {1525-2027}, doi = {10.1029/2002GC000390}, author = {Dannenmann, S. and Linsley, B. K. and Oppo, D. W. and Rosenthal, Y. and Beaufort, L.} } @article {634, title = {Palaeo-oceanography: Deepwater variability in the Holocene epoch}, journal = {Nature}, volume = {422}, year = {2003}, note = {Oppo, Delia WMcManus, Jerry FCullen, James LengEngland2003/03/21 04:00Nature. 2003 Mar 20;422(6929):277.}, month = {Mar 20}, pages = {277}, issn = {0028-0836 (Linking)}, doi = {10.1038/422277b}, author = {Oppo, D. W. and McManus, J. F. and Cullen, J. L.} } @article {2224, title = {A 0.5-million-year record of millennial-scale climate variability in the north atlantic}, journal = {Science}, volume = {283}, year = {1999}, note = {McManusOppo Cullen eng 1999/02/12 03:03 Science. 1999 Feb 12;283(5404):971-5. }, month = {Feb 12}, pages = {971-5}, abstract = {Long, continuous, marine sediment records from the subpolar North Atlantic document the glacial modulation of regional climate instability throughout the past 0.5 million years. Whenever ice sheet size surpasses a critical threshold indicated by the benthic oxygen isotope (delta18O) value of 3.5 per mil during each of the past five glaciation cycles, indicators of iceberg discharge and sea-surface temperature display dramatically larger amplitudes of millennial-scale variability than when ice sheets are small. Sea-surface temperature oscillations of 1 degrees to 2 degreesC increase in size to approximately 4 degrees to 6 degreesC, and catastrophic iceberg discharges begin alternating repeatedly with brief quiescent intervals. The glacial growth associated with this amplification threshold represents a relatively small departure from the modern ice sheet configuration and sea level. Instability characterizes nearly all observed climate states, with the exception of a limited range of baseline conditions that includes the current Holocene interglacial.}, isbn = {1095-9203 (Electronic)0036-8075 (Linking)}, url = {https://www.ncbi.nlm.nih.gov/pubmed/9974387}, author = {McManus, J. F. and Oppo, D. W. and Cullen, J. L.} } @article {2222, title = {Evidence for Late Pleistocene-Holocene Intermediate-Water variability in the North Atlantic}, journal = {EOS}, volume = {80}, year = {1999}, note = {id: 172}, month = {1999}, pages = {S169}, author = {McManus, J. F. and Oppo, D. W. and Curry, W. and Marchitto, T. and Cullen, J. L.} } @article {2223, title = {Glacial modulation of rapid climate change during the last 0.5 million years}, journal = {PAGES newsletter}, volume = {7}, year = {1999}, note = {id: 168}, month = {1999}, pages = {12-13}, author = {McManus, J. F. and Oppo, D. W. and Cullen, J. L.} } @article {2241, title = {Millennial-scale climate changes in ventilation of the thermocline, intermediate and deep waters of the glacial North Atlantic}, journal = {Geophysical Monograph series}, volume = {AGU Chapman Conference volume 112}, year = {1999}, note = {id: 207}, month = {1999}, pages = {59-76}, author = {Curry, W. B. and Marchitto, T. M. and McManus, J. F. and Oppo, D. W. and L, Laarkamp K.} } @article {2225, title = {Variability in shallow- and intermediate-water hydrography during the last climate cycle of the Quaternary}, journal = {EOS}, volume = {80}, year = {1999}, note = {id: 170}, month = {1999}, pages = {F10}, author = {McManus, J. F. and Healey, S. L. and Oppo, D. W. and Curry, W. B.} } @article {762, title = {Millennial-scale changes in North Atlantic circulation since the last glaciation}, journal = {Nature}, volume = {393}, year = {1998}, note = {Zt988Times Cited:106Cited References Count:30}, month = {Jun 11}, pages = {557-561}, abstract = {Ocean circulation is closely linked to climate change on glacial-interglacial and shorter timescales. Extensive reorganizations in the circulation of deep and intermediate-depth waters in the Atlantic Ocean have been hypothesized for both the last glaciation(1-6) and the subsequent Younger Dryas cold interval(3,6-10), but there has been little palaeoceanographic study of the subtropical gyres(11-13). These gyres are the dominant oceanic features of wind-driven circulation, and as such they reflect changes in climate and are a significant control on nutrient cycling and, possible, atmospheric CO2 concentrations. Here we present Cd/Ca ratios in the shells of benthic foraminifera from the Bahama banks that confirm previous suggestions(11,12) that nutrient concentrations in the North Atlantic subtropical gyre were much lower during the Last Glacial Maximum than they are today (up to 50\% lower according to our data). These contrasting nutrient burdens imply much shorter residence times for waters within the thermocline of the Last Glacial Maximum. Below the glacial thermocline, nutrient concentrations were reduced owing to the presence of Glacial North Atlantic Intermediate Water. A high-resolution Cd/Ca record from an intermediate depth indicates decreased nutrient concentrations during the Younger Dryas interval as well, mirroring opposite changes at a nearby deep site(3,9). Together, these observations suggest that the formation of deep and intermediate waters-North Atlantic Deep Water and Glacial North Atlantic Intermediate Water, respectively-wax and wane alternately on both orbital and millennial timescales.}, issn = {0028-0836}, doi = {10.1038/31197}, author = {Marchitto, T. M. and Curry, W. B. and Oppo, D. W.} } @article {779, title = {Synchronous, high-frequency oscillations in tropical sea surface temperatures and North Atlantic Deep Water production during the last glacial cycle}, journal = {Paleoceanography}, volume = {12}, year = {1997}, note = {Wd891Times Cited:109Cited References Count:63}, month = {Feb}, pages = {1-14}, abstract = {Stable isotopic measurements of G. sacculifer and C. wuellerstorfi in a core from the western equatorial Atlantic imply that there are parallel, suborbital oscillations in surface water hydrography and deep water circulation occurring during oxygen isotope stages 2 and 3. Low values of G. sacculifer delta(18)O accompany high values of C. wuellerstorfi delta(13)C, linking warmer sea surface temperatures (SSTs) in the tropics with increased production of lower North Atlantic Deep Water (NADW). The amplitude of the delta(18)O oscillations is 0.6 parts per thousand (or 2 degrees-3 degrees C), which is superimposed on a glacial/interglacial amplitude of about 2.1 parts per thousand,. Using the G. sacculifer delta(18)O data, we calculate that surface waters were colder during stage 2 than calculated by CLIMAP [1976, 1981]. The longer-period (> 2 kyr) oscillations in air temperature recorded in the Greenland and Antarctic ice cores appear to correlate with oscillations in sea surface temperature in the equatorial Atlantic. The magnitude of these oscillations in tropical SST is too large to have resulted from changes in meridional heat transport caused by the global conveyor alone. The apparent synchroneity of equatorial SST and polar air temperature changes, as well as the amplitude of the SST changes at the equator, are consistent with the climate effects expected from changes in the atmosphere{\textquoteright}s greenhouse gas content (H(2)0(vapor), CO2, and CH4).}, issn = {0883-8305}, doi = {10.1029/96pa02413}, author = {Curry, W. B. and Oppo, D. W.} } @article {2303, title = {Western South Atlantic deepwater hydrography derived from benthic Cd/Ca and stable isotope data}, journal = {Supplement to EOS}, volume = {17}, year = {1997}, note = {id: 1269}, month = {1997}, pages = {185}, author = {Horowitz, M. and Oppo, D. W.} } @article {2314, title = {East Asian monsoon variations; linkage to northern hemisphere millenniallll-scale climate oscillations}, journal = {Supplement to EOS}, volume = {77}, year = {1996}, note = {id: 56}, month = {1996}, pages = {19}, author = {Oppo, D. W. and Deiner, L. and Curry, W. B. and Norris, R. D.} } @article {2347, title = {North Atlantic Deep Water variability during stage 3}, journal = {Eos, Transactions, American Geophysical Union}, volume = {76}, year = {1995}, note = {id: 58}, month = {1995}, pages = {171-172}, author = {Oppo, D. W. and Lehman, S. J. and Curry, J. and Lynch, Stieglitz and Fairbanks, R. G.} } @article {784, title = {Suborbital Timescale Variability of North-Atlantic Deep-Water during the Past 200,000 Years}, journal = {Paleoceanography}, volume = {10}, year = {1995}, note = {Rx409Times Cited:145Cited References Count:39}, month = {Oct}, pages = {901-910}, abstract = {We generated similar to 200-kyr-long proxy records of surface and deepwater variability from a subpolar North Atlantic core (V29-202), enabling us to assess the linkage between surface and deepwater changes on suborbital timescales. In particular, we used a benthic delta(13)C record to evaluate the deep water response to Dansgaard-Oeschger temperature oscillations and to Heinrich events, times of massive iceberg delivery to the North Atlantic. We found that the reduction of North Atlantic Deep Water (NADW) production was generally associated with cold or dropping sea surface temperatures (SSTs) as indicated by planktonic foraminiferal assemblages. The NADW contribution to the site did not drop appreciably during Heinrich events H4 through H2, probably because these events followed intervals of prolonged surface cooling already characterized by low rates of NADW production. By contrast NADW reduction appears to have been synchronous with H5. SST rise associated with both Dansgaard-Oeschger oscillations and Heinrich events was usually accompanied by increasing NADW strength. In a few cases the NADW recovery appeared to lag the SST rise; however, the apparent delay is most likely an artefact of the sedimentary record (low concentrations of benthic foraminifera). As a result of low benthic foraminiferal abundances during stage 6, the stage 6 benthic foraminiferal delta(13)C record is of lower resolution than the younger part of the record. The stage 6 proxy records for surface hydrography nevertheless reveal millennial-scale oscillations similar to those seen in stage 3. The available delta(13)C data suggest that NADW weakened in association with the cold portions of stage 6 SST oscillations. We also sought to confirm a recent study which concluded that there was little NADW variability during the peak of the last interglaciation, marine oxygen isotope substage 5e (Eemian). Isotope stage 5 was marked by a trend of increasing benthic delta(13)C in V29-202. Rising delta(13)C through isotope stage 5 is also seen in tropical surface water records and at some deep Atlantic sites and may reflect the common derivation of these water masses. Variations of greater than or equal to 0.5 parts per thousand superimposed on this rising delta(13)C trend within substage 5e in V29-202 are so far not evident in tropical feed waters and may therefore indicate that NADW production was weaker during the late than mid-Eemian.}, issn = {0883-8305}, doi = {10.1029/95pa02089}, author = {Oppo, D. W. and Lehman, S. J.} }