Dr. Terry Quinn
Publications
Recent publications
Partin, J. W., J. Jenson, J. L. Banner, T. M. Quinn, F. W. Taylor, D. J. Sinclair, B. Hardt, M. Lander, T. Bell, B. Miklavia, J. Jocson, and D. Taboroi, Relationship between modern rainfall variability, cave dripwater and stalagmite geochemistry in Guam, USA, Geochem., Geophys., Geosyst., (in press), 2012, #2470
Delong, K. L., J. A. Flannery, C. R. Maupin, R. Z. Poore, and T. M. Quinn, A coral Sr/Ca calibration and replication study of two massive corals from the Gulf of Mexico, Palaeogeography, Palaeoclimatology, Palaeoecology, 307, 117-128, 2011, doi:10.1016/j.palaeo.2011.05.005, #2433 
This study examined the variations in the ratio of strontium-to-calcium (Sr/Ca) for two Atlantic corals (Montastraea faveolata and Siderastrea siderea) from the Dry Tortugas National Park (centered on 24.7ÃÆââ¬Å¡ÃâðN, 82.8ÃÆââ¬Å¡ÃâðW) in the Gulf of Mexico. Cores from coral colonies in close proximity (10s of meters) and with the same environmental conditions (i.e., depth and water chemistry) were micro-sampled with approximately monthly resolution and the resulting Sr/Ca variations were calibrated with local sea surface temperature (SST) records. Replication tests for coral Sr/Ca variations found high agreement between intra-colony variations and between individual colonies of S. siderea (a single M. faveolata colony was sampled). Regression analysis of monthly variations in coral Sr/Ca and local SST revealed significant correlation on monthly and inter-annual timescales. Verification of the calibration on different timescales found coral Sr/CaÃÆââââ¬Å¡Ã¬Ã¢ââ¬Ã
âSST reconstructions in S. siderea were more accurate than those from M. faveolata, especially on inter-annual timescales. Sr/CaÃÆââââ¬Å¡Ã¬Ã¢ââ¬Ã
âSST calibration equations for the two species are significantly different (cf., Sr/Ca = ÃÆâÃâ¹Ã¢â¬Â âââ‰â¢ 0.042 SST + 10.070, S. siderea; Sr/Ca = ÃÆâÃâ¹Ã¢â¬Â âââ‰â¢ 0.027 SST + 9.893, M. faveolata). Mean linear extension for M. faveolata is approximately twice that of S. siderea (4.63, 4.31, and 8.31 mm yearÃÆâÃâ¹Ã¢â¬Â âââ‰â¢1, A1, F1, and B3, respectively); however, seasonal Sr/Ca variability in M. faveolata is less than S. siderea (0.323, 0.353, and 0.254 mmol molÃÆâÃâ¹Ã¢â¬Â âââ‰â¢1, A1, F1, and B3, respectively). The reduced slope for M. faveolata is attributed to physical sampling issues associated with complex time-skeletal structure of M. faveolata, i.e., a sampling effect, and not a growth effect since the faster growing M. faveolata has the reduced Sr/Ca variability.
Hereid, K., T. M. Quinn, and F. W. Taylor, Coral record of reduced El Nino activity in the early 15th to middle 17th century, Nature Geoscience, (submitted), 2011, #2408
Kilbourne, K. H., R. P. Moyer., T. M. Quinn, and A. G. Grottoli, Testing coral-based tropical cyclone reconstructions: An example from Puerto Rico, Palaeogeography, Palaeoclimatology, Palaeoecology, 307, 90-97, 2011, doi:10.1016/j.palaeo.2011.04.027, #2432
Complimenting modern records of tropical cyclone activity with longer historical and paleoclimatological records would increase our understanding of natural tropical cyclone variability on decadal to centennial time scales. Tropical cyclones produce large amounts of precipitation with significantly lower ô18O values than normal precipitation, and hence may be geochemically identifiable as negative ô18O anomalies in marine carbonate ô18O records. This study investigates the usefulness of coral skeletal ô18O as a means of reconstructing past tropical cyclone events. Isotopic modeling of rainfall mixing with seawater shows that detecting an isotopic signal from a tropical cyclone in a coral requires a salinity of ~ 33 psu at the time of coral growth, but this threshold is dependent on the isotopic composition of both fresh and saline end-members. A comparison between coral ô18O and historical records of tropical cyclone activity, river discharge, and precipitation from multiple sites in Puerto Rico shows that tropical cyclones are not distinguishable in the coral record from normal rainfall using this approach at these sites.
Spear, J. W., R. Z. Poore, and T. M. Quinn, Globorotalia truncatulinoides (dextral) Mg/Ca as a proxy for Gulf of Mexico winter mixed-layer temperature: Evidence from a sediment trap in the northern Gulf of Mexico, Marine Micropaleontology, 80, 53-61, 2011, doi:10.1016/j.marmicro.2011.05.001, #2474
Three years of weekly- to biweekly-resolved sediment-trap data show that almost 90% of the total flux of tests of the planktic foraminifer Globorotalia truncatulinoides to sediments in the northern Gulf of Mexico occurs in January and February. Comparison of 18O from tests of non-encrusted Gl. truncatulinoides in sediment-trap samples with calculated calcification depths indicates that the non-encrusted individuals secrete their test in the winter surface-mixed layer, most likely at the bottom of the surface mixed zone. Mg/Ca-temperature estimates from non-encrusted Gl. truncatulinoides in sediment-trap samples are consistent with observed temperatures at the calcification depths inferred from the 18O data. In contrast, Mg/Ca-temperature estimates from encrusted Gl. truncatulinoides in sediment-trap samples indicate the crust is formed in cooler (deeper) waters. A preliminary study in a core recovered near the sediment-trap site demonstrates that non-encrusted and encrusted forms of Gl. truncatulinoides in sediment samples show a similar offset in Mg/Ca values as observed in sediment-trap samples. A short (~ 100 years) Mg/Ca record from non-encrusted Gl. truncatulinoides indicates a warming trend that coincides with a warming trend in mean-annual sea-surface temperature recorded by Mg/Ca in Globigerinoides ruber (white) from the same core. These findings suggest Mg/Ca from non-encrusted Gl. truncatulinoides has clear potential as a proxy for past winter mixed-layer temperature.
Delong, K. L., T. M. Quinn, C.-C. Shen, and K. Lin, A snapshot of climate variability at Tahiti at 9.5 ka using a fossil coral from IODP Expedition 310, Geochem., Geophys., Geosyst., 11, Q06005, 2010, 2 citations, doi:10.1029/2009GC002758, #2203
The Integrated Ocean Drilling Program (IODP) Expedition 310 recovered drill cores from the drowned reefs around the island of Tahiti (17-40S, 149W), many of which contained samples of massive corals from the genus Porites. Herein we report on one well-preserved fossil coral sample: a 13.6 cm long Porites sp. dated by uranium series techniques at 9523 +- 33 years. Monthly 18O and Sr/Ca determinations reveal nine clear and robust annual cycles. Coral18O and Sr/Ca determinations estimate a mean temperature of 24.3C +-3.2C colder than modern) for Tahiti at 9.5 ka; however, this estimate is viewed with caution since potential sources of cold bias in coral geochemistry remain to be resolved. The interannual variability in coral 18O is similar between the 9.5 ka coral record and a modern record from nearby Moorea. The seasonal cycle in coral Sr/Ca is approximately the same or greater in the 9.5 ka coral record than in modern coral records from Tahiti. Paired analysis of coral 18O and Sr/Ca indicates cold/wet (warm/dry) interannual anomalies, opposite from those observed in the modern instrumental record.
Kilbourne, K. H., T. M. Quinn, R. S. Webb, T. P. Guilderson, J. Nyberg, and A. Winter, Coral windows onto seasonal climate variability in the northern Caribbean since 1479, Geochem., Geophys., Geosyst., 11, Q10006, 2010, 1 citation, doi:10.1029/2010GC003171, #2316
Mean surface ocean conditions in the Caribbean were up to âÃâ ü2ÃâðC cooler than today at times during the Little Ice Age. The seasonal context for such mean state changes is important for determining the mechanisms involved. We reconstructed surface ocean conditions in southwest Puerto Rico at approximately monthly resolution over eight 4âââ‰â¬Å12 year periods during the last âÃâ ü520 years to test if the seasonal cycles of temperature or salinity varied with mean state. We carried out paired analyses of Sr/Ca and Îô18O for two coral cores. The Îô18O data contained clear annual cycles and were significantly correlated to temperature during the 20th century calibration periods (1993âââ‰â¬Å2004 and 1902âââ‰â¬Å1912, r = 0.73). The Sr/Ca data contained highâââ¬ÃÂfrequency noise that obscured the seasonal cycles, although the centennial variability matched that of the coral Îô18O, indicating a common forcing that is likely temperature. The seasonal coral Îô18O amplitude averaged 0.60 Ãâñ 0.17âââ¬Ã°, with none of the periods significantly different from the most recent. The simplest explanation is that the amplitudes of seasonal seawater Îô18O and temperature variations were not different from today. Previous work in the southern Caribbean indicates that the Intertropical Convergence Zone was shifted southward or weaker during the Little Ice Age, and we speculate about how this could occur with no apparent affect on seasonality in the northern Caribbean.
Kim, W., B. W. Foulke, A. Petter, T. M. Quinn, C. Kerans, and F. W. Taylor, Sea-level rise, depth-dependent carbonate growth, and the paradox of drowned platforms, Sedimentology, (in press), 2010, #2308
Scott, R. B., C. L. Holland, and T. M. Quinn, Multidecadal trends in instrumental SST and coral proxy Sr/Ca records, J. Climate, 23, 1017-1033, 2010, doi:10.1175/2009JCLI2386.1, #2202
Historical ship observations of sea surface temperature (SST) from 1850 to present were used to compute linear 40-yr trends for all 5° latitude by 5° longitude grid cells with sufficient data. Trends from throughout the twentieth century were centered about a 7 mK yrâ1 warming trend with standard deviation 14 mK yrâ1. Although different with high statistical significance from a distribution with zero mean, the warming trends were not unusual in amplitude compared to the available nineteenth-century trends. Trends at the same grid points from the latter half of the nineteenth century were distributed about near-zero mean with standard deviation 17 mK yrâ1. The shift in mean is robust to accounting for the biases arising from differing observational methods prior to 1942. The 40-yr trends from the latter half of the twentieth century were centered about 10 ± 4 mK yrâ1 and more clearly distinct from earlier trends. Linear 40-yr trends were computed at different locations and times from all publicly available coral skeleton records of the concentration ratio of Sr to Ca. The pre-twentieth-century distribution of 40-yr trends in the Sr/Ca ratio was significantly different from the twentieth-century trends, consistent with the warming found in the instrumental SST. The interpretation of the coral Sr/Ca 40-yr trends cannot yet be reduced to a single factor. Major uncertainties were due to (i) the correlation of modern Sr/Ca records with instrumental SST being dominated by seasonal effects, with correlations on time scales longer than the annual cycle much lower, and (ii) the poor quality instrumental SST on long time scales in remote locations. Based on the NOAA extended reconstructed instrumental SST dataset since 1870 and 499 yr of Sr/Ca data from 13 different coral records, the authors found a Pearson correlation coefficient r = â0.77 for 40-yr low-pass-filtered times series. Interpreting the change in distribution of trends in Sr/Ca will require further study of the factors affecting Sr/Ca on time scales longer than seasonal.
Delong, K. L., T. M. Quinn, R. M. Mitchum, and R. Z. Poore, Evaluating highly resolved paleoclimate records in the frequency domain for multidecadal-scale climate variability, Geophys. Res. Lett., 36, L20702, 2009, doi:10.1029/2009GL039742, #2200
Do the chronological methods used in the construction of paleoclimate records influence the results of the frequency analysis applied to them? We explore this phenomenon using the Dongge Cave speleothem record (U-series chronology with variable time steps, Δt) and the El Malpais tree-ring index (cross-dating of ring-width series). Interpolation of the Dongge Cave record to a constant Δt resulted in the suppression of periodicities (<20 years) altering the red noise model used for significance testing. Frequency analysis of temporal subsets of the El Malpais tree-ring index revealed that concentrations of variance varied with the number of ring-width series. Frequency analyses of these records identified significant periodicities, some common to both (∼25 and ∼69 years). Cross-wavelet analysis, which examines periodicities in the time domain, revealed that coherency between these records occurs intermittently. We found the chronology methods can influence the ability of frequency analysis to detect periodicities and tests for coherency.
Poore, R. Z., K. L. Delong, J. N. Richey, and T. M. Quinn, Evidence of multidecadal climate variability and the Atlantic Multidecadal Oscillation from a Gulf of Mexico sea-surface temperature-proxy record, Geo-Marine Lett., 29, 477-484, 2009, 3 citations, doi:10.1007/s00367-009-0154-6, #2199
A comparison of a Mg/Ca-based sea-surface temperature (SST)-anomaly record from the northern Gulf of Mexico, a calculated index of variability in observed North Atlantic SST known as the Atlantic Multidecadal Oscillation (AMO), and a tree-ring reconstruction of the AMO contain similar patterns of variation over the last 110 years. Thus, the multidecadal variability observed in the instrumental record is present in the tree-ring and Mg/Ca proxy data. Frequency analysis of the Gulf of Mexico SST record and the tree-ring AMO reconstruction from 1550 to 1990 found similar multidecadal-scale periodicities (~30â60 years). This multidecadal periodicity is about half the observed (60â80 years) variability identified in the AMO for the 20th century. The historical records of hurricane landfalls reveal increased landfalls in the Gulf Coast region during time intervals when the AMO index is positive (warmer SST), and decreased landfalls when the AMO index is negative (cooler SST). Thus, we conclude that alternating intervals of high and low hurricane landfall occurrences may continue on multidecadal timescales along the northern Gulf Coast. However, given the short length of the instrumental record, the actual frequency and stability of the AMO are uncertain, and additional AMO proxy records are needed to establish the character of multidecadal-scale SST variability in the North Atlantic.
Richey, J. N., R. Z. Poore, B. P. Flower, T. M. Quinn, and D. J. Hollander, Regionally coherent Little Ice Age cooling in the Atlantic Warm Pool, Geophys. Res. Lett., 36, L21703, 2009, 5 citations, doi:10.1029/2009GL040445, #2201
We present 2 new decadal-resolution foraminiferal Mg/Ca-SST records covering the past 6ââ¬â8 centuries from the northern Gulf of Mexico (GOM). These records provide evidence for a Little Ice Age (LIA) cooling of 2ðC, consistent with a published Mg/Ca record from Pigmy Basin. Comparison of these 3 records with existing SST proxy records from the GOM-Caribbean region show that the magnitude of LIA cooling in the Atlantic Warm Pool (AWP) was significantly larger than the mean hemispheric cooling of <1ðC. We propose that a reduction in the intensity and spatial extent of the AWP during the LIA, combined with associated changes in atmospheric circulation may account for the regional SST patterns observed in the GOM-Caribbean region during the LIA.
Greaves, M., N. Caillon, H. Rebaubier, G. Bartoli, S. M. Bohaty, I. Cacho, L. Clarke, M. R. Cooper, C. Daunt, M. Delaney, P. De Menocal, A. Dutton, S. Eggins, Elderfield H, D. Garbe-Schoenberg, D. Green, E. Goddard, J. Groeneveld, D. Hastings, E. Hathorne, K. Kimoto, G. P. Klinkhammer, L. Labeyrie, D. W. Lea, T. Marchitto, M. A. Martinez-Boti, P. G. Mortyn, Y. Ni, D. Nuernberg, G. Paradis, L. R. Pena, T. M. Quinn, Y. Rosenthal, A. Russell, T. Sagawa, S. Sosdian, L. Stot, K. Tachikawa, E. Tappa, R. Thunell, and P. A. Wilson, Interlaboratory comparison study of calibration standards for foraminiferal Mg/Ca termometry, Geochem., Geophys., Geosyst., 9, Q08010, 2008, 28 citations, doi:10.1029/2008GC001974, #2046
An interlaboratory study of Mg/Ca and Sr/Ca ratios in three commercially available carbonate reference materials (BAM RS3, CMSI 1767, and ECRM 752-1) was performed with the participation of 25 laboratories that determine foraminiferal Mg/Ca ratios worldwide. These reference materials containing Mg/Ca in the range of foraminiferal calcite (0.8 mmol/mol to 6 mmol/mol) were circulated with a dissolution protocol for analysis. Participants were asked to make replicate dissolutions of the powdered samples and to analyze them using the instruments and calibration standards routinely used in their laboratories. Statistical analysis was performed in accordance with the International Standardization Organization standard 5725, which is based on the analysis of variance (ANOVA) technique. Repeatability (RSDr%), an indicator of intralaboratory precision, for Mg/Ca determinations in solutions after centrifuging increased with decreasing Mg/Ca, ranging from 0.78% at Mg/Ca = 5.56 mmol/mol to 1.15% at Mg/Ca = 0.79 mmol/mol. Reproducibility (RSDR%), an indicator of the interlaboratory method precision, for Mg/Ca determinations in centrifuged solutions was noticeably worse than repeatability, ranging from 4.5% at Mg/Ca = 5.56 mmol/mol to 8.7% at Mg/Ca = 0.79 mmol/mol. Results of this study show that interlaboratory variability is dominated by inconsistencies among instrument calibrations and highlight the need to improve interlaboratory compatibility. Additionally, the study confirmed the suitability of these solid standards as reference materials for foraminiferal Mg/Ca (and Sr/Ca) determinations, provided that appropriate procedures are adopted to minimize and to monitor possible contamination from silicate mineral phases.
Kilbourne, K. H., T. M. Quinn, T. P. Guilderson, R. S. Webb, J. Nyberg, and J. Winter, Paleoclimate proxy perspective on Caribbean climate since the year 1751: Evidence of cooler temperatures and multidecadal variability, Paleoceanography, 23, PA3220, 2008, 13 citations, doi:10.1029/2008PA001598, #2045
Annually resolved coral δ 18O and Sr/Ca records from southwestern Puerto Rico are used to investigate Caribbean climate variability between 1751 and 2004 C.E. Mean surface ocean temperatures in this region have increased steadily by about 2°C since the year 1751, with Sr/Ca data indicating 2.1 ± 0.8°C and δ 18O data indicating 2.7 ± 0.5°C. Coral geochemical records from across the tropics demonstrate that regional variability is important for understanding climate variations at centennial time scales. A strong multidecadal salinity signal in the oxygen isotope data correlates with observed multidecadal temperature variations in the Northern Hemisphere. Instrumental wind and precipitation data indicate that the most recent coral isotopic variations are caused by expansion and contraction of the steep regional salinity gradient, forced by trade wind anomalies through meridional Ekman transport. The timing of the fluctuations suggests that the multidecadal-scale wind and surface circulation anomalies might play a role in Atlantic temperature variability and meridional overturning circulation, but further work is needed to confirm this suggestion.
Maupin, C. R., T. M. Quinn, and R. B. Halley, Extracting a climate signal from the skeletal geochemistry of the Caribbean coral Siderastrea siderea, Geochem., Geophys., Geosyst., 9, Q12012, 2008, 4 citations, doi:10.1029/2008GC002106, #2047
The first bimonthly time series of paired δ 18O and Sr/Ca from the slow-growing coral Siderastrea siderea, from the Dry Tortugas, Florida, has been generated that documents that robust proxy climate records of the tropical Atlantic and IntraAmerican Seas can be produced from this massive coral. The time series contain a 20-year-long calibration window (1973â1992) for both δ 18O and Sr/Ca and a 73-year-long verification window (1900â1972) for Sr/Ca. These time series permit the quantification of the relationship between coral δ 18O-SST and Sr/Ca-SST and the assessment of the stability of the proxy relationships over time. Both coral geochemical records are highly correlated with the augmented instrumental SST record through the calibration period, and Sr/Ca remains highly correlated through the verification period both at the bimonthly (r = −0.97) and annual average resolution (r = −0.72). Coral δ 18O and Sr/Ca are highly reproducible within the same core, and Sr/Ca exhibits no extension-related vital effects. This study sets the stage for generating multicentury scale climate records from the tropical Atlantic Ocean using the skeletal geochemistry of this massive, but slow growing coral.
Shen, C.-C., K.-S. Li, K. Sieh, D. Natawidjaja, H. Cheng, X. Wang, R. L. Edwards, D. D. Lam, Y.-T. Hsieh, T.-Y. Fan, A. J. Meltzner, F. W. Taylor, T. M. Quinn, H.-W. Chiang, and K. H. Kilbourne, Variation of initial 230Th/232Th and limits of high precision U-Th dating of shallow-water corals, Geochimica et Cosmochimica Acta, 72, 4201-4223, 2008, 26 citations, doi:10.1016/j.gca.2008.06.011, #1944
One hundred eighty UâTh data, including 23 isochrons on 24 pristine modern and Holocene corals and 33 seawater samples, were analyzed using sector-field mass spectrometry to understand the variability of initial 230Th/232Th (230Th/232Th0). This dataset allows us to further assess the accuracy and precision of coral 230Th dating method. By applying quality control, including careful sampling and subsampling protocols and the use of contamination-free storage and workbench spaces, the resulting low procedural blanks give an equivalent uncertainty in age of only ±0.2â0.3 yr for 1â2 g of coral sample. Using site-specific 230Th/232Th0 values or isochron techniques, our study demonstrates that corals with an age less than 100 yrs can be 230Th-dated with precisions of ±1 yr. Six living subtidal coral samples were collected from two continental shelf sites, Nanwan off southern Taiwan in the western Pacific and Son Tra off central Vietnam in the South China Sea; one coral core was drilled from an open-ocean site, Santo Island, Vanuatu, in the western tropical Pacific; and modern and fossil intertidal coral slabs, 17 in total, were cut from six sites around the islands of Simeulue, Lago, North Pagai and South Pagai of Sumatra in the eastern Indian Ocean. The results indicate that the main source of thorium is the dissolved phase of seawater, with variation of 230Th/232Th0 depending on local hydrology. With intense input of terrestrial material, low 230Th/232Th0 atomic ratios of 4.9 à 10−6 and 3.2 à 10−6 with a 10% variation are observed in Nanwan and Son Tra, respectively. At the Santo site, we find a value of 5.6 à 10−6 at 4 horizons and one high value of 24 à 10−6 in a sample from AD 1974.6 ± 0.5, likely due to the upwelling of cold water during a La Niña event between AD 1973 and 1976. The natural dynamics of 230Th/232Th0 recorded in the intertidal corals at sites in the Sumatran islands are complicated so that this value varies significantly from 3.0 to 9.4 à 10−6. Three of the 141 modern coral 230Th ages differ from their true ages by −23 to +4, indicating the presence of detrital material with anomalous 230Th/232Th values. Duplicate measurement of coeval subsamples is therefore recommended to verify the age accuracy. This improved high precision coral 230Th dating method raises the prospects of refining the age models for band-counted and tracer-tuned chronologies and of advancing coral paleoclimate research.
Delong, K. L., T. M. Quinn, and F. W. Taylor, Reconstructing 20th century sea surface temperature variability in the southwest Pacific: A replication study using multiple coral Sr/Ca records from New Caledonia, Paleoceanography, 22, PA4212, 2007, 11 citations, doi:10.1029/2007PA001444, #1875
Coral-based climate reconstructions typically have not used multiple cores from a region to capture and replicate a climate signal largely because of concerns of coral conservation, analytical expense, and time constraints. Coral Sr/Ca reproducibility through the twentieth century was investigated using three intracolony and three intercolony coral records from the reefs offshore of Amédée Island, New Caledonia. Different sampling resolutions were examined in coral Sr/Ca (fortnightly and monthly) and δ 18O (fortnightly, monthly, and seasonally) as well as similar scale subsampling of the daily in situ sea surface temperature (SST) record. The mean coral Sr/Ca, δ 18O, and SST values do not change as a function of sampling resolution. The coral Sr/Ca signal is highly reproducible; the average absolute offset between coeval monthly Sr/Ca determinations between any two coral time series is 0.035 ± 0.026 mmol/mol (1σ) (∼0.65°C), which is less than twice the analytical precision of the coral Sr/Ca measurements. The stack average of the monthly coral Sr/Ca variations and monthly anomalies are significantly correlated with monthly in situ SST (1967â1992; r = −0.96 and −0.64, respectively; p < 0.05; and n = 302) and 1° grid monthly SST data product (1900â1999; r = −0.95 and −0.56, respectively; p < 0.05; and n = 1198). The coral Sr/CaâSST reconstruction exhibits interannual and decadal- timescale fluctuations that exceed those observed in the gridded SST record, which may reflect true differences between SST at a shallow reef site and those averaged over a 1° grid box or inadequacies in the methodology used to create the gridded SST product when few observations are available. A warming trend of ∼0.6°C is observed in the twentieth century coral Sr/CaâSST record.
Kilbourne, K. H., T. M. Quinn, T. P. Guilderson, R. S. Webb, and F. W. Taylor, Decadal- to interannual-scale source water variations in the Caribbean sea recorded by Puerto Rican coral radiocarbon, Climate Dynamics, 29, 51-62, 2007, 8 citations, doi:10.1007/s00382-007-0224-2, #1914
Water that forms the Florida Current, and eventually the Gulf Stream, coalesces in the Caribbean from both subtropical and equatorial sources. The equatorial sources are made up of, in part, South Atlantic water moving northward and compensating for southward flow at depth related to meridional overturning circulation. Subtropical surface water contains relatively high amounts of radiocarbon (14C), whereas equatorial waters are influenced by the upwelling of low 14C water and have relatively low concentrations of 14C. We use a 250 year record of Δ14C in a coral from southwestern Puerto Rico along with previously published coral Δ14C records as tracers of subtropical and equatorial water mixing in the northern Caribbean. Data generated in this study and from other studies indicate that the influence of either of the two water masses can change considerably on interannual to interdecadal time scales. Variability due to ocean dynamics in this region is large relative to variability caused by atmospheric 14C changes, thus masking the Suess effect at this site. A mixing model produced using coral Δ14C illustrates the time varying proportion of equatorial versus subtropical waters in the northern Caribbean between 1963 and 1983. The results of the model are consistent with linkages between multidecadal thermal variability in the North Atlantic and meridional overturning circulation. Ekman transport changes related to tradewind variability are proposed as a possible mechanism to explain the observed switches between relatively low and high Δ14C values in the coral radiocarbon records.
Nyberg, J., B. A. Malmgren, A. Winter, M. R. Jury, K. H. Kilbourne, and T. M. Quinn, Low Atlantic hurricane activity in the 1970s and 1980s compared to the past 270 years, Nature, 447, 698-701, 2007, 57 citations, doi:10.1038/nature05895, #1924
Hurricane activity in the North Atlantic Ocean has increased significantly since 1995 (refs 1, 2). This trend has been attributed to both anthropogenically induced climate change3 and natural variability1, but the primary cause remains uncertain. Changes in the frequency and intensity of hurricanes in the past can provide insights into the factors that influence hurricane activity, but reliable observations of hurricane activity in the North Atlantic only cover the past few decades2. Here we construct a record of the frequency of major Atlantic hurricanes over the past 270 years using proxy records of vertical wind shear and sea surface temperature (the main controls on the formation of major hurricanes in this region1, 3, 4, 5) from corals and a marine sediment core. The record indicates that the average frequency of major hurricanes decreased gradually from the 1760s until the early 1990s, reaching anomalously low values during the 1970s and 1980s. Furthermore, the phase of enhanced hurricane activity since 1995 is not unusual compared to other periods of high hurricane activity in the record and thus appears to represent a recovery to normal hurricane activity, rather than a direct response to increasing sea surface temperature. Comparison of the record with a reconstruction of vertical wind shear indicates that variability in this parameter primarily controlled the frequency of major hurricanes in the Atlantic over the past 270 years, suggesting that changes in the magnitude of vertical wind shear will have a significant influence on future hurricane activity.
Quinn, T. M., and B. Schone, Corals, sclerosponges and mollusk, in Encyclopedia of Quarternary Science, edited by S. A. Elias, Elsevier, 2007, #1903
Rashid, H., B. P. Flower, R. Z. Poore, and T. M. Quinn, A ~25 ka monsoon variability record from the Andaman Sea, Quaternary Sci. Rev., 26, 2586-2597, 2007, 27 citations, doi:10.1016/j.quascirev.2007.07.002, #1925
Recent paleoclimatic work on terrestrial and marine deposits from Asia and the Indian Ocean has indicated abrupt changes in the strength of the Asian monsoon during the last deglaciation. Comparison of marine paleoclimate records that track salinity changes from Asian rivers can help evaluate the coherence of the Indian Ocean monsoon (IOM) with the larger Asian monsoon. Here we present paired Mg/Ca and δ18O data on the planktic foraminifer Globigerinoides ruber (white) from Andaman Sea core RC12-344 that provide records of sea-surface temperature (SST) and δ18O of seawater (δ18Osw) over the past 25,000 years (ka) before present (BP). Age control is based on nine accelerator mass spectrometry (AMS) dates on mixed planktic foraminifera. Mg/Ca-SST data indicate that SST was 3 ðC cooler during the last glacial maximum (LGM) than the late Holocene. Andaman Sea δ18Osw exhibited higher than present values during the Lateglacial interval ca 19ââ¬â15 ka BP and briefly during the Younger Dryas ca 12 ka BP. Lower than present δ18Osw values during the BÃËlling/AllerÃËd ca 14.5ââ¬â12.6 ka BP and during the early Holocene ca 10.8ââ¬â5.5 ka BP are interpreted to indicate lower salinity, reflect some combination of decreased evaporationââ¬âprecipitation (Eââ¬âP) over the Andaman Sea and increased Irrawaddy River outflow. Our results are consistent with the suggestion that IOM intensity was stronger than present during the BÃËlling/AllerÃËd and early Holocene, and weaker during the late glaciation, Younger Dryas, and the late Holocene. These findings support the hypothesis that rapid climate change during the last deglaciation and Holocene included substantial hydrologic changes in the IOM system that were coherent with the larger Asian monsoon.
Richey, J. N., R. Z. Poore, B. P. Flower, and T. M. Quinn, A 1400 yr multiproxy record of climate variability from the northern Gulf of Mexico, Geology, 35, 423-426, 2007, 27 citations, doi:10.1130/G23507A.1, #1910
A continuous decadal-scale resolution record of climate variability over the past 1400 yr in the northern Gulf of Mexico was constructed from a box core recovered in the Pigmy Basin, northern Gulf of Mexico. Proxies include paired analyses of Mg/Ca and δ18O in the white variety of the planktic foraminifer Globigerinoides ruber and relative abundance variations of G. sacculifer in the foraminifer assemblages. Two multi-decadal intervals of sustained high Mg/Ca indicate that Gulf of Mexico sea surface temperatures (SSTs) were as warm or warmer than near-modern conditions between 1000 and 1400 yr B.P. Foraminiferal Mg/Ca during the coolest interval of the Little Ice Age (ca. 250 yr B.P.) indicate that SST was 2â2.5 °C below modern SST. Four minima in the Mg/Ca record between 900 and 250 yr B.P. correspond with the Maunder, Spörer, Wolf, and Oort sunspot minima, suggesting a link between changes in solar insolation and SST variability in the Gulf of Mexico. An abrupt shift recorded in both δ18Ocalcite and relative abundance of G. sacculifer occurred ca. 600 yr B.P. The shift in the Pigmy Basin record corresponds with a shift in the sea-salt-sodium (ssNa) record from the Greenland Ice Sheet Project 2 ice core, linking changes in high-latitude atmospheric circulation with the subtropical Atlantic Ocean.
Eakin, C. M., P. K. Swart, T. M. Quinn, K. P. Helme, J. M. Smith, and R. E. Dodge, Application of paleoclimatology to coral reef monitoring and management, Proc. 10th Int. Coral Reef. Symp., 588-596, 2006, #1943
Hill, H. W., B. P. Flower, T. M. Quinn, D. J. Hollander, and T. P. Guilderson, Laurentide ice sheet meltwater and abrupt climate change during the last glaciation, Paleoceanography, 21, PA1006, 2006, 7 citations, doi:10.1029/2005PA001186, #1904
A leading hypothesis to explain abrupt climate change during the last glacial cycle calls on fluctuations in the margin of the North American Laurentide Ice Sheet (LIS), which may have routed fresh water between the Gulf of Mexico (GOM) and the North Atlantic, affecting North Atlantic Deep Water variability and regional climate. Paired measurements of δ18O and Mg/Ca of foraminiferal calcite from GOM sediments reveal five episodes of LIS meltwater input from 28 to 45 thousand years ago (ka) that do not match the millennial-scale Dansgaard-Oeschger warmings recorded in Greenland ice. We suggest that summer melting of the LIS may occur during Antarctic warming and likely contributed to sea level variability during marine isotope stage 3.
Iryu, Y., H. Matsuda, H. Machiyama, W. E. Piller, T. M. Quinn, and M. Mutti, Introductory perspective on the COREF project, Island Arc, 15, 393-406, 2006, 6 citations, doi:10.1111/j.1440-1738.2006.00537.x, #1908
Coral reefs are tropic to subtropic, coastal ecosystems comprising very diverse organisms. Late Quaternary reef deposits are fossil archives of environmental, tectonic and eustatic variations that can be used to reconstruct the paleoclimatic and paleoceanographic history of the tropic surface oceans. Reefs located at the latitudinal limits of coral-reef ecosystems (i.e. those at coral-reef fronts) are particularly sensitive to environmental changes ÃÆââââ¬Å¡Ã¬Ã¢ââ¬Ã
â especially those associated with glacialÃÆââââ¬Å¡Ã¬Ã¢ââ¬Ã
âinterglacial changes in climate and sealevel. We propose a land and ocean scientific drilling campaign in the Ryukyu Islands (the Ryukyus) in the northwestern Pacific Ocean to investigate the dynamic response of the corals and coral-reef ecosystems in this region to Late Quaternary climate and sealevel change. Such a drilling campaign, which we call the COREF (coral-reef front) Project, will allow the following three major questions to be evaluated: (i) What are the nature, magnitude and driving mechanisms of coral-reef front migration in the Ryukyus? (ii) What is the ecosystem response of coral reefs in the Ryukyus to Quaternary climate changes? (iii) What is the role of coral reefs in the global carbon cycle? Subsidiary objectives include (i) the timing of coral-reef initiation in the Ryukyus and its causes; (ii) the position of the Kuroshio current during glacial periods and its effects on coral-reef formation; and (iii) early carbonate diagenetic responses as a function of compounded variations in climate, eustacy and depositional mineralogies (subtropic aragonitic to warm-temperate calcitic). The geographic, climatic and oceanographic settings of the Ryukyu Islands provide an ideal natural laboratory to address each of these research questions.
LoDico, J. M., B. P. Flower, and T. M. Quinn, Subcentennial-scale climatic and hydrologic variability in the Gulf of Mexico during the early Holocene, Paleoceanography, 21, PA3015, 2006, 9 citations, doi:10.1029/2005PA001243, #1906
An early Holocene record from the Gulf of Mexico (GOM) reveals climatic and hydrologic changes during the interval from 10.5 to 7 thousand calendar years before present from paired analyses of Mg/Ca and δ18O on foraminiferal calcite. The sea surface temperature record based on foraminiferal Mg/Ca contains six oscillations and an overall ∼1.5°C warming that appears to be similar to the SeptemberâMarch insolation difference. The δ18O of seawater in the GOM (δ18OGOM) record contains six oscillations, including a −0.8â° excursion that may be associated with the â8.2 ka climate eventâ or a broader climate anomaly. Faunal census records from three GOM cores exhibit similar changes, suggesting subcentennial-scale variability in the incursions of Caribbean waters into the GOM. Overall, our results provide evidence that the subtropics were characterized by decadal- to centennial-scale climatic and hydrologic variability during the early Holocene.
Quinn, T. M., and F. W. Taylor, SST artifacts in coral proxy records produced by early marine diagenesis in a modern coral from Rabaul, Papua New Guinea, Geophys. Res. Lett., 33, L04601, 2006, 15 citations, doi:10.1029/2005GL024972, #1813
We investigated the effects of early marine diagenesis on the skeletal geochemistry of a Porites coral collected live offshore of Rabaul, Papua New Guinea. The lowermost 14 cm of the ∼1.9 m coral core contains physical evidence of alteration, which is clearly visible in X-radiograph, SEM and petrography images. Abrupt and significant increases in coral δ18O and Sr/Ca, and decreases in coral Mg/Ca occur at the transition from unaltered to altered skeleton, all of which imply significant SST cooling, if the altered nature of the coral skeleton went unrecognized. Screening for the effects of early marine diagenesis should become a standard procedure in coral-climate studies.
Quinn, T. M., F. W. Taylor, and T. J. Crowley, Coral-based climate variability in the Western Pacific Warm Pool since 1867, J. Geophys. Res., 111, C11006, 2006, 8 citations, doi:10.1029/2005JC003243, #1907
We have generated monthly resolved, stable isotope (δ 18O and δ 13C) and Sr/Ca time series from a massive Porites coral from Rabaul (4°S, 152°E): a site located in the warmest sector of the Western Pacific Warm Pool (WPWP). The coral δ 18O and Sr/Ca time series are well correlated to each other and positive excursions in both records coincide with times of ENSO warm phase events. These time series contain abundant interannual variability that exhibits the well-recognized pattern of low amplitude ENSO variation between ∼1920â1960 and high amplitude ENSO variation between 1880â1920 and 1960â1997. The ENSO-filtered coral δ 18O and Sr/Ca time series are well matched to each other (r = 0.73) and to similarly filtered coral δ 18O records from Papua New Guinea (r > 0.56). There is no long-term trend in the coral δ 18O record, but there is a long-term trend of increasing coral Sr/Ca from 1867 to 1997. This trend in coral Sr/Ca suggests a cooling of ∼0.7°C, which is rather unlikely and implies that factors other than SST may be influencing the coral Sr/Ca record. The trend in coral Sr/Ca is not an analytical artifact, nor a product of time varying riverine input, nor a product of skeletal diagenesis, nor the results of kinetic effects, but may reflect surface-water variability in Sr/Ca. Despite the presence of a nonclimatic trend in coral Sr/Ca, the Rabaul coral records contain abundant interannual- to multidecadal-scale variability, much of which is coherent with other proxy records from the WPWP and with instrumental records of ENSO variability.
Smith, J. M., T. M. Quinn, K. P. Helme, and R. B. Halley, Reproducibility of geochemical and climatic signals in the Atlantic coral Montastraea faveolata, Paleoceanography, 21, PA1010, 2006, 12 citations, doi:10.1029/2005PA001187, #1905
Monthly resolved, 41-year-long stable isotopic and elemental ratio time series were generated from two separate heads of Montastraea faveolata from Looe Key, Florida, to assess the fidelity of using geochemical variations in Montastraea, the dominant reef-building coral of the Atlantic, to reconstruct sea surface environmental conditions at this site. The stable isotope time series of the two corals replicate well; mean values of δ18O and δ13C are indistinguishable between cores (compare 0.70â° versus 0.68â° for δ13C and −3.90â° versus −3.94â° for δ18O). Mean values from the Sr/Ca time series differ by 0.037 mmol/mol, which is outside of analytical error and indicates that nonenvironmental factors are influencing the coral Sr/Ca records at Looe Key. We have generated significant δ18Oâsea surface temperature (SST) (R = −0.84) and Sr/Ca-SST (R = −0.86) calibration equations at Looe Key; however, these equations are different from previously published equations for Montastraea. Variations in growth parameters or kinetic effects are not sufficient to explain either the observed differences in the mean offset between Sr/Ca time series or the disagreement between previous calibrations and our calculated δ18O-SST and Sr/Ca-SST relationships. Calibration differences are most likely due to variations in seawater chemistry in the continentally influenced waters at Looe Key. Additional geochemical replication studies of Montastraea are needed and should include multiple coral heads from open ocean localities complemented whenever possible by seawater chemistry determinations.
Kilbourne, K. H., T. M. Quinn, and F. W. Taylor, A fossil coral perspective on western tropical climate ~350 ka, Paleoceanography, 19, PA1019, 2004, 10 citations, doi:10.1029/2003PA000944, #1730
The nature of tropical climate variability ∼350 ka is addressed using δ18O and Sr/Ca records from a modern and a fossil coral from Vanuatu (southwestern tropical Pacific Ocean). Modern El Niño events at Vanuatu produce positive coral δ18O and Sr/Ca anomalies; similar anomalies observed in the fossil coral records suggest that El Niño was operative 350 kyr ago. Seasonal variations in coral Sr/Ca, a sea surface temperature (SST) proxy, have the same amplitude in both corals, whereas seasonal δ18O variations are smaller in the fossil coral than in the modern coral. This is consistent with displacement of the South Pacific Convergence Zone toward the southwest during the boreal summer ∼350 ka. Mathematical modeling results preclude warmer SST and higher SSS at Vanuatu during this time, but permit the surface ocean to be ∼2°C cooler and 0â2 psu fresher than today. Assessing the potential of variations in late Quaternary seawater Sr/Ca remains the largest obstacle to accurately reconstructing tropical SST using pristine fossil corals.
Kilbourne, K. H., T. M. Quinn, F. W. Taylor, T. Delcroix, and Y. Gouriou, El Niño-Southern Oscillation-related salinity variations recorded in the skeletal geochemistry of a Porites coral from Espiritu Santo, Vanuatu, Paleoceanography, 19, PA4002, 2004, 17 citations, doi:10.1029/2004PA001033, #1754
Coral skeletal geochemistry offers the potential to reconstruct the sea surface salinity (SSS) history of the tropical oceans on seasonal to interannual and perhaps centennial timescales because of the strong link between variation in SSS and seawater δ18O in tropical regions. We explore this potential using a monthly resolved, 65-year record of skeletal δ18O and Sr/Ca variations in a Porites coral from Espiritu Santo, Vanuatu. We demonstrate that El NiñoâSouthern Oscillationârelated climate variability strongly influences coral δ18O at Santo through local salinity changes associated with the position of the South Pacific Convergence Zone and the movement of its associated salinity front. Such a demonstration provides the âground truthâ data that can be used to place paleoclimate variability estimated using existing fossil coral records from this region into a modern conceptual framework. We also evaluate different methods of combining coral δ18O and Sr/Ca to reconstruct SSS and conclude that the coral δ18O anomaly time series provides the best fit to recent in situ SSS data at Santo.
Stephans, C. L., T. M. Quinn, F. W. Taylor, and T. Correge, Assessing the reproducibility of coral-based climate records, Geophys. Res. Lett., 31, L18210, 2004, 18 citations, doi:10.1029/2004GL020343, #1755
Multi-channel seismic reflection data acquired in the Pacific Ocean off the Muroto peninsula of Shikoku Island, Japan reveal the two-dimensional distribution of fine structures in the Kuroshio Current. Eighty-one seismic sections, each extending 80 km perpendicular to the current and separated by 100 m, were acquired from 20 June to 15 August 1999 (57 days). The seismic data clearly show that fine structures extend over 40 km perpendicular to the current in almost all of the profiles. A simulation study using acoustic model from CTD data demonstrates that fine structure of temperature and salinity identified in CTD data acquired from the Kuroshio Current off the Ashizuri peninsula yield a synthetic seismic profile with characteristics similar to the Muroto transect profiles.
Quinn, T. M., T. J. Crowley, F. W. Taylor, C. Henin, P. Joannot, and Y. Joan, A multicentury stable isotope record from a New Caledonia coral: Interannual and decadal sea surface temperature variability in the southwest Pacific since 1657 A. D., Paleoceanography, 13, 412-426, 1998, 98 citations, #1332
A 335 year stable isotope record from a New Caledonia coral (22°S, 166°E) helps fill a large gap in historical climate reconstructions. Although the long-term coral δ18O-based sea surface temperature (SST) trend is one of warming, there are notable decadal fluctuations, especially in the early 18th and early 19th centuries. Mean annual SSTs between 1658 and 1900 are estimated to be ∼0.3°C lower than the 20th century average, with interdecadal excursions of 0.5°-0.8°C. Time series analyses of the coral isotope record reveals significant concentrations of variance in the El Niño band; an inderdecadal spectral peak is present, but its robustness requires additional statistical evaluation. A secular but irregular decrease in coral δ13C values begins in the mid-1800s and may reflect the anthropogenic perturbation of the carbon reservoir. These and other results indicate that the New Caledonia coral isotope record is a valuable source of information on southwest Pacific climate history.
Crowley, T. J., T. M. Quinn, F. W. Taylor, C. Henin, and P. Joannot, Evidence for a volcanic cooling signal in a 335-year coral record from New Caledonia, Paleoceanography, 12, 633-639, 1997, 31 citations, #1333
Although volcanic cooling events have been detected in tree ring records, their occurrence in marine records has received much less attention. Herein we report results from a 335-year oxygen isotope record (1657-1992) from a New Caledonia coral indicating that as many as 16 interannual-scale cooling events occur within 1 year of a volcanic eruption as determined by ice core records. There are also pentadal/decadal-scale cooling events beginning in 1675, 1813, and 1903 that immediately postdate volcanic eruptions. However, the interannual correspondences are complicated by the fact that some of the cooling events also coincide with El Niños, which cause cooling in this part of the western South Pacific. If our conclusions are substantiated by further work, occurrence of distinct volcanic cooling signals may enable refinement of coral chronologies by use of the "event stratigraphic" approach, with the most promising correlation horizons being associated with the following eruptions: 1808 (Unknown), 1813-1821 (several eruptions), 1835 (Coseguina), 1883 (Krakatau), and possibly 1963 (Agung).
Quinn, T. M., F. W. Taylor, T. J. Crowley, and S. M. Link, Evaluation of sampling resolution in coral stable isotope records: A case study using records from New Caledonia and Tarawa, Paleoceanography, 11, 529-542, 1996, 65 citations, #1236
We have generated a 40-year-long, monthly stable isotope record from a Porites lutea coral collected offshore of Amedee, New Caledonia (22°S, 167°E) to investigate the relation between sampling resolution in coral isotope studies and retrieval of sea-surface environmental information. We interpret the high correlation between our oxygen isotope record and a twenty-year long sea-surface temperature record at the monthly timescale (r=0.88) to indicate that our coral isotope record is an accurate monitor of environmental conditions offshore of Amedee. The character of the signal and the percent variance explained in the record at the annual band, at the quasi-biennial oscillation band ((QBO) 2.0-2.4 years), and at the El Nino-Southern Oscillation band ((ENSO) 3-8 years) changes little in response to a reduction in sampling density from monthly to bimonthly to quarterly. Similar results have been obtained in a reanalysis of a coral isotope record from Tarawa, Kiribati. Our results indicate that a significant amount of the information obtained from high-density sampling can also be retrieved from lower-density sampling. In particular, bimonthly sampling yields virtually no drop-off in variance explained, and quarterly sampling is satisfactory for resolving interannual and decadal-scale trends in time series. The proposed sampling approach may enable a more rapid filling in of numerous spatial holes in coral sampling sites needed for reconstruction of long-term decadal-scale variations in climate.
Quinn, T. M., T. J. Crowley, and F. W. Taylor, New stable isotope results from a 173-year coral record from Espiritu Santo, Vanuatu, Geophys. Res. Lett., 23, 3413-3416, 1996, 26 citations, #1237
Long coral records provide valuable information on pentadal‐decadal scale climate variability. Previously we have reported on a preliminary analysis of a 173‐year record (1806â1978) from the island of Espiritu Santo (Republic of Vanuatu). Although this record contained information in the pentadal‐decadal band, low sampling resolution raised questions about the validity of the results. Herein we report new data from the Santo record, in which the sampling resolution has been doubled and the validation database expanded. Variations in coral δ18O at Santo record the combined effects of variations in SST and rainfall‐induced salinity changes. The most prominent spectral peaks in the time series are at the annual cycle and 14â15 and 7.4 years. The robust occurrence of the 14â15 year peak provides additional support to the importance of this oscillation as a cause of decadal‐scale climate variability. Overall, our new results provide greater credibility to the conclusions raised in the earlier study and indicate that the Santo record can more confidently be incorporated into the still‐small network of multicentury coral records of climate change.
Quinn, T. M., F. W. Taylor, and A. N. Halliday, Strontium-isotopic dating of neritic carbonates at Bougainville Guyot (site 831), New Hebrides island arc, Proc. Ocean Drill. Prog., Sci. Results, 134, 89-95, 1994, #980
Taylor, F. W., T. M. Quinn, C. D. Gallup, and R. L. Edwards, Quaternary plate convergence rates at the New Hebrides island arc from the chronostratigraphy of Bougainville Guyot (site 831), Proc. Ocean Drill. Prog., Sci. Results, 134, 47-57, 1994, #982
Quinn, T. M., F. W. Taylor, and T. J. Crowley, A 173 year stable isotope record from a tropical South Pacific coral, Quaternary Sci. Rev., 12, 407-418, 1993, 59 citations, doi:10.1016/S0277-3791(05)80005-8, #1017
We have generated a 173 year-long time series (A.D. 1806 to 1979) of changes in the δ18O and δ13C composition of a coral head (Platygyra lamellina) to investigate environmental change in the climatologically sensitive region of the tropical South Pacific. Little is known about decadal- and centennial-scale climate change at sea level in this region. Our coral is from near the south coast of Espiritu Santo Island (15°S, 167°E), Republic of Vanuatu. The stable isotope record from this coral is consistent with meteorological and oceanographic records during the period of overlap in the records (1964â1978): δ18O values positively correlate with SST (r=0.77) and δ13C values are highly coherent with rainfall (r=0.82) at the annual cycle. These relations suggest that the δ18O signal in this coral is a function of variations in SST and rainfall-induced changes in SSS, whereas the δ13C signal may be related to rainfall and cloud cover modulation of photosynthesis in the coral. δ18O and δ13C values are positively correlated over the entire length of the record (r=0.65), a relation that is even stronger between 1806 and 1866 (r=0.81), i.e. prior to the time of possible anthropogenic influence on the δ13C record. Because of the positive correlation between temperature and rainfall in this region, we interpret the long-term record of δ18O in terms of joint variations of these two variables. The most significant cool/dry excursion in the Santo record occurs during the nineteenth century (1832â1866) and ends abruptly in 1866 with a change to modern values. Superimposed on this pattern is a slight (0.2%.), cooling/drying toward the end of the twentieth century. Cross-spectral analysis of the δ18O and δ13C records indicates a strong concentration of variance at the quasi-biennial (2 years) and El Nino/Southern Oscillation (ENSO) (4â5 years) frequency bands, in addition to a 15 year peak found also in global temperature records. Cross-spectral analysis of coral isotope records from Santo and the Philippine Sea, indicate a concentration of variance at ENSO (4â5 years) frequency bands. However, comparison of the Santo coral isotope record with high-latitude northern hemisphere temperature records indicates that the major cool/dry excursion in the Santo record (1832â1866) is not seen in the northern hemisphere record. If verified in other tropical South Pacific coral records, the results have implications concerning the global scale of cooling for Little Ice Age events.
Collot, J.-Y., H. G. Greene, L. Srokking, K. Akimoto, M. V. S. Ask, P. E. Baker, L. Briqueu, T. Chabernaud, M. Coltorti, M. A. Fisher, M. Good, T. Hasenaka, M. Hobart, A. Krammer, J. Leanard, J. B. Martin, J. I. Martinez-Rodriguez, S. Menger, M. Meschede, B. Pelletier, R. C. B. Perembo, T. M. Quinn, P. Roperch, P. Reid, W. R. Riedel, T. S. Sraerker, F. W. Taylor, and X. Zhao, Resultats preliminaires du Leg 134 de l'ocean drilling program dans la zone de collision entre l'arc insulaires des Nouvelles-Hebrids et la zone d'Entrecasteaux, C. R. Acad. Sci. Paris, 313, Ser. II, 539-546, 1991, #874