Description: Author Posting. © American Geophysical Union, 2013. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry, Geophysics, Geosystems 14 (2013): 3730–3750, doi:10.1002/ggge.20230.

Description: The Sr/Ca ratio of coral aragonite is used to reconstruct past sea surface temperature (SST). Twenty-one laboratories took part in an interlaboratory study of coral Sr/Ca measurements. Results show interlaboratory bias can be significant, and in the extreme case could result in a range in SST estimates of 7°C. However, most of the data fall within a narrower range and the Porites coral reference material JCp-1 is now characterized well enough to have a certified Sr/Ca value of 8.838 mmol/mol with an expanded uncertainty of 0.089 mmol/mol following International Association of Geoanalysts (IAG) guidelines. This uncertainty, at the 95% confidence level, equates to 1.5°C for SST estimates using Porites, so is approaching fitness for purpose. The comparable median within laboratory error is 〈0.5°C. This difference in uncertainties illustrates the interlaboratory bias component that should be reduced through the use of reference materials like the JCp-1. There are many potential sources contributing to biases in comparative methods but traces of Sr in Ca standards and uncertainties in reference solution composition can account for half of the combined uncertainty. Consensus values that fulfil the requirements to be certified values were also obtained for Mg/Ca in JCp-1 and for Sr/Ca and Mg/Ca ratios in the JCt-1 giant clam reference material. Reference values with variable fitness for purpose have also been obtained for Li/Ca, B/Ca, Ba/Ca, and U/Ca in both reference materials. In future, studies reporting coral element/Ca data should also report the average value obtained for a reference material such as the JCp-1.

Description: E.C.H. (MARUM Fellowship) and T.F. were supported by the DFG-Research Center/Excellence Cluster ‘‘The Ocean in the Earth System,’’ University of Bremen. HVM was supported by an AINSE Research Fellowship.

Description: 2014-03-23

Description: © The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nature Communications 5 (2014): 4102, doi:10.1038/ncomms5102.

Description: Tropical south-western Pacific temperatures are of vital importance to the Great Barrier Reef (GBR), but the role of sea surface temperatures (SSTs) in the growth of the GBR since the Last Glacial Maximum remains largely unknown. Here we present records of Sr/Ca and δ18O for Last Glacial Maximum and deglacial corals that show a considerably steeper meridional SST gradient than the present day in the central GBR. We find a 1–2 °C larger temperature decrease between 17° and 20°S about 20,000 to 13,000 years ago. The result is best explained by the northward expansion of cooler subtropical waters due to a weakening of the South Pacific gyre and East Australian Current. Our findings indicate that the GBR experienced substantial meridional temperature change during the last deglaciation, and serve to explain anomalous deglacial drying of northeastern Australia. Overall, the GBR developed through significant SST change and may be more resilient than previously thought.

Description: Funding was provided by Deutsche Forschungsgemeinschaft (FE 615/4-1), Australian Research Council (Discovery grant DP1094001), Australia and New Zealand IODP Consortium, Australian Institute of Nuclear Science and Engineering, Natural Environmental Research Council (NE/H014136/1, NE/H014268/1), the Cooperative Research Program of the Center for Advanced Marine Core Research (10B039, 11A013, 11B041), Ministry of Earth Sciences, Govt. of India (with partial support from DST & ISRO-GBP) and Japan Society for the Promotion of Science (JSPS NEXT-GR031).

Description: Author Posting. © American Geophysical Union, 2020. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography and Paleoclimatology 35(12), (2020): e2020PA003962, doi:10.1029/2020PA003962.

Description: The Great Barrier Reef (GBR) is an internationally recognized and widely studied ecosystem, yet little is known about its sea surface temperature (SST) evolution since the Last Glacial Maximum (LGM) (~20 kyr BP). Here, we present the first paleo‐application of Isopora coral‐derived SST calibrations to a suite of 25 previously published fossil Isopora from the central GBR spanning ~25–11 kyr BP. The resultant multicoral Sr/Ca‐ and δ18O‐derived SST anomaly (SSTA) histories are placed within the context of published relative sea level, reef sequence, and coralgal reef assemblage evolution. Our new calculations indicate SSTs were cooler on average by ~5–5.5°C at Noggin Pass (~17°S) and ~7–8°C at Hydrographer's Passage (~20°S) (Sr/Ca‐derived) during the LGM, in line with previous estimates (Felis et al., 2014, https://doi.org/10.1038/ncomms5102). We focus on contextualizing the Younger Dryas Chronozone (YDC, ~12.9–11.7 kyr BP), whose Southern Hemisphere expression, in particular in Australia, is elusive and poorly constrained. Our record does not indicate cooling during the YDC with near‐modern temperatures reached during this interval on the GBR, supporting an asymmetric hemispheric presentation of this climate event. Building on a previous study (Felis et al., 2014, https://doi.org10.1038/ncomms5102), these fossil Isopora SSTA data from the GBR provide new insights into the deglacial reef response, with near‐modern warming during the YDC, since the LGM.

Description: This work was funded by National Science Foundation (NSF) award OCE 13‐56948 to B. K. L, with NSF GRFP support DGE‐11‐44155 to L. D. B., and the Australian Research Council (grant no. DP1094001) and ANZIC IODP. Partial support for B. K. L's work on this project also came from the Vetlesen Foundation via a gift to the Lamont‐Doherty Earth Observatory. T. F. received funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)—Project number 180346848, through Priority Program 527 “IODP.” A. T. received support from the UK Natural Environment Research Council (NE/H014136/1 and NE/H014268/1). M. T. thanks Ministry of Earth Sciences for support (NCPOR contribution no. J‐84/2020‐21). L. D. B. would also like to thank Kassandra Costa for her input regarding error analysis.

Description: 2021-06-11

Description: The Sr/Ca ratio of coral aragonite is used to reconstruct past sea surface temperature (SST). Twentyone laboratories took part in an interlaboratory study of coral Sr/Ca measurements. Results show interlaboratory bias can be significant, and in the extreme case could result in a range in SST estimates of 7°C. However, most of the data fall within a narrower range and the Porites coral reference material JCp- 1 is now characterized well enough to have a certified Sr/Ca value of 8.838 mmol/mol with an expanded uncertainty of 0.089 mmol/mol following International Association of Geoanalysts (IAG) guidelines. This uncertainty, at the 95% confidence level, equates to 1.5°C for SST estimates using Porites, so is approaching fitness for purpose. The comparable median within laboratory error is 〈0.5°C. This difference in uncertainties illustrates the interlaboratory bias component that should be reduced through the use of reference materials like the JCp-1. There are many potential sources contributing to biases in comparative methods but traces of Sr in Ca standards and uncertainties in reference solution composition can account for half of the combined uncertainty. Consensus values that fulfil the requirements to be certified values were also obtained for Mg/Ca in JCp-1 and for Sr/Ca and Mg/Ca ratios in the JCt-1 giant clam reference material. Reference values with variable fitness for purpose have also been obtained for Li/Ca, B/Ca, Ba/Ca, and U/Ca in both reference materials. In future, studies reporting coral element/Ca data should also report the average value obtained for a reference material such as the JCp-1.

Description: We reconstructed a 237-year record of SST and salinity using a coral core collected at Bicol, southern Luzon, Philippines, which is at the northern edge of the western Pacific warm pool. A 2.5-m-long core (SWGM03–01) was collected from a Porites sp. colony at 6 m below mean sea level on 16 March 2002. Temporal resolution of the Sr/Ca analyses for the most recent 46 years of the record was approximately monthly, whereas for the rest of about 190 years, the resolution was mostly bimonthly. The temporal resolution of the d18O analyses was bimonthly throughout most of the core.

Description: A 2.5-m-long core (SWGM03–01) was collected from a Porites sp. colony at 6 m below mean sea level on 16 March 2002. The core was drilled vertically from the top of the colony and then cut into 7-mm-thick slabs in the laboratory. The δ18Ocoral values of samples covering the period from 1890 to 2002 was analyzed using an online system comprising an IsoPrime Isotope-ratio mass spectrometer (GV Instruments Ltd.) coupled to a Multicarb automatic sample treatment system at the Geological Survey of Japan (GSJ), whereas the δ18Ocoral values of samples predating 1890 were determined by the Center for Advanced Marine Core Research at Kochi University (KCC) using a same system used at GSJ. All δ18Ocoral data were normalized to Vienna Pee Dee Belemnite (V-PDB) using the NBS-19 standard (δ18O = +2.2‰) from the U.S. National Institute of Standards and Technology. The International Atomic Energy Agency standard IAEA-603 (δ18O = –2.37 ± 0.04‰) was also used for some measurements conducted at KCC. The standard deviations of replicate δ18O measurements of the standards during the mass spectrometer runs were 0.04‰ (1s) and 〈 0.10‰ (1s) at GSJ and KCC, respectively. Concentrations of Ca and Sr were measured by inductively coupled plasma optical emission spectrometry (ICP-OES) using an IRIS Advantage system (Thermo Electron Co., Ltd) at GSJ and an Agilent 720 system (Agilent Technologies) at Okayama University. Each sample was first weighed (100 ± 10 µg) and then dissolved in 2% HNO3. Sr/Ca analyses of samples covering the period after 1883 were conducted at GSJ, and samples predating 1890 were analyzed at Okayama University, respectively, with a 6-year overlap to confirm measurement consistency. The analytical precision (RSD) of the Sr/Ca measurements was 〈 0.37% (1s) made at both facilities. Measurements of Sr/Ca were mostly performed on microsamples, every 0.8 mm and 1.6 mm for the first 46 years and the remainder of the record, respectively. Given that mean growth rate is approximately 8.0 mm/yr, temporal resolution of the Sr/Ca analyses for the most recent 46 years of the record was approximately monthly, whereas for the rest of about 190 years, the resolution was mostly bimonthly. The temporal resolution of the d18O analyses was bimonthly throughout most of the core. An age model for the period before 1982 was constructed using the Sr/Ca ratios with Sr/Ca maxima (indicating relatively cool SSTs) corresponding to growth mainly in winter (January or February). Other Sr/Ca ratios in this time interval were then converted to the time domain by simple linear interpolation. For the period 1982–2002 in which Sr/Ca analyses were conducted with higher time resolution, the precise timing of the coolest SSTs was determined using IGOSS weekly SSTs then converted to the time domain. This age model for the entire core was confirmed and fine-tuned by counting annual density bands on the X-radiographs of the coral core and applied to d18O record as well.

Description: We reconstructed a 237-year record of SST and salinity using a coral core collected at Bicol, southern Luzon, Philippines, which is at the northern edge of the western Pacific warm pool. A 2.5-m-long core (SWGM03–01) was collected from a Porites sp. colony at 6 m below mean sea level on 16 March 2002. Temporal resolution of the Sr/Ca analyses for the most recent 46 years of the record was approximately monthly, whereas for the rest of about 190 years, the resolution was mostly bimonthly. The temporal resolution of the d18O analyses was bimonthly throughout most of the core.