Reproducibility of geochemical and climatic signals in the Atlantic coral <i>Montastraea faveolata</i>

Smith, Jennifer M.; Quinn, T. M.; Helmle, Kevin P.; Halley, Robert B.

doi:10.1029/2005pa001187

Cited by 65 publications

(101 citation statements)

References 76 publications

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“…While brucite precipitation may fractionate oxygen and therefore influence the character of d 18 O available for calcification, it is reasonable to conclude that brucite formation has little or no influence on skeletal d 13 C because it lacks carbon. Smith et al (2006) found heterogeneity in Sr/Ca ratios across skeletal formations in M. faveolata, which, like d 13 C, cannot necessarily be explained by brucite precipitation, but instead likely occurs due to post-deposition thickening of the skeleton, underscoring the need to sample accurately along corallite walls. However, the clear existence of annual cycles in the records described here (e.g., Fig.…”

Section: Long-term Trendsmentioning

confidence: 93%

Stable isotopic records of bleaching and endolithic algae blooms in the skeleton of the boulder forming coral Montastraea faveolata

et al. 2010

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Within boulder forming corals, fixation of dissolved inorganic carbon is performed by symbiotic dinoflagellates within the coral tissue and, to a lesser extent, endolithic algae within the coral skeleton. Endolithic algae produce distinctive green bands in the coral skeleton, and their origin may be related to periods of coral bleaching due to complete loss of dinoflagellate symbionts or ''paling'' in which symbiont populations are patchily reduced in coral tissue. Stable carbon isotopes were analyzed in coral skeletons across a known bleaching event and 12 blooms of endolithic algae to determine whether either of these types of changes in photosynthesis had a clear isotopic signature. Stable carbon isotopes tended to be enriched in the coral skeleton during the initiation of endolith blooms, consistent with enhanced photosynthesis by endoliths. In contrast, there were no consistent d 13 C patterns directly associated with bleaching, suggesting that there is no unique isotopic signature of bleaching. On the other hand, isotopic values after bleaching were lighter 92% of the time when compared to the bleaching interval. This marked drop in skeletal d 13 C may reflect increased kinetic fractionation and slow symbiont recolonization for several years after bleaching.

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Section: Long-term Trendsmentioning

confidence: 93%

Stable isotopic records of bleaching and endolithic algae blooms in the skeleton of the boulder forming coral Montastraea faveolata

et al. 2010

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“…In addition, of those coral-based studies undertaken at annual to pent-annual resolutions (Dunbar et al 1994;Cole et al 2000;Hendy et al 2002;Pelejero et al 2005;Calvo et al 2007;Linsley et al 2008;Abram et al 2009;Wei et al 2009;Deng et al 2013;Zinke et al 2014), few have focused on the replication of the lowresolution geochemical records of multiple coral cores. Some studies have evaluated the climatic significance of annual coral records averaged using monthly or sub-annual values from each year (Lough 2004;Smith et al 2006;Pfeiffer et al 2009). However, such approaches may suffer from biases caused by the attenuation of the coral geochemical records, which leads to an overestimate of the changes in sea surface temperature (SST) over decadal to millennial timescales (Gagan et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of annual resolution coral geochemical records as climate proxies in the Great Barrier Reef of Australia

et al. 2014

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Sampling of annually banded massive coral skeletons at annual (or higher) resolutions is increasingly being used to obtain replicate long-term time series of changing seawater conditions. However, few of these studies have compared and calibrated the lower annual resolution records based on coral geochemical tracers with the corresponding instrumental climate records, although some studies have inferred the climatic significance of annual coral series derived from averages of monthly or sub-annual records. Here, we present annual resolution analysis of coral records of elemental and stable isotopic composition that are approximately 70 years long. These records were preserved in two coexisting colonies of Porites sp. from Arlington Reef, on the Great Barrier Reef in Australia, and are used to evaluate the climatic significance of annually resolved coral geochemical proxies. The geochemical records of coral sample ''10AR2,'' with its faster and relatively constant annual growth rate, appear to have been independent of skeletal growth rate and other vital effects. The annual resolution of Sr/Ca and Dd 18 O time series was shown to be a good proxy for annual sea surface temperature (SST; r = -0.67, n = 73, p \ 0.0000001) and rainfall records (r = -0.34, n = 67, p \ 0.01). However, a slower growing coral sample, ''10AR1'' showed significantly lower correlations (r = -0.20, n = 71, p = 0.05 for Sr/Ca and SST; r = -0.19, n = 67, p = 0.06 for Dd 18 O and rainfall), indicating its greater susceptibility to biological/metabolic effects. Our results suggest that while annually resolved coral records are potentially a valuable tool for determining, in particular, long timescale climate variability such as Pacific Decadal Oscillation, Interdecadal Pacific Oscillation, and other climatic factors, the selection of the coral sample is important, and replication is essential.

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“…However, Smith et al, 2006] predict SST spanning more than 10C at a given Sr/Ca ratio, and make climatic interpretations using this species difficult. Evidence for growth-related effects on Sr/Ca in other coral genera [deVilliers et al, 1995;Goodkin et al, 2005] raises the possibility that disparate Montastrea calibrations may be related to growth.…”

Section: Acknowledgementsmentioning

confidence: 99%

“…Nevertheless, interpreting coral geochemistry in terms of climatic parameters is not always straightforward [Lough, 2004]. For example, Sr/Ca-SST calibrations derived to date from single colonies of the Atlantic coral Montastrea, a predominant genus in both modem and fossil reefs [Weil and Knowlton, 1994;Hubbard et al, 2005] show significant, yet unexplained differences [Swart et al, 2002;Smith et al, 2006]. This implies that paleo-SST estimates derived using these calibrations depend heavily on which calibration is applied.…”

Section: Introductionmentioning

confidence: 99%

Low-latitude western north atlantic climate variability during the past millennium : insights from proxies and models

Saenger¹

2009

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Estimates of natural climate variability during the past millennium provide a frame of reference in which to assess the significance of recent changes. This thesis investigates new methods of reconstructing low-latitude sea surface temperature (SST) and hydrography, and combines these methods with traditional techniques to improve the present understanding of western North Atlantic climate variability. A new strontium/calcium (Sr/Ca) -SST calibration is derived for Atlantic Montastrea corals. This calibration shows that Montastrea Sr/Ca is a promising SST proxy if the effect of coral growth is considered. Further analyses of coral growth using Computed Axial Tomography (CAT) imaging indicate growth in Siderastrea corals varies inversely with SST on interannual timescales. A 440-year reconstruction of low-latitude western North Atlantic SST based on this relationship suggests the largest cooling of the last few centuries occurred from -1650-1730 A.D., and was -I°C cooler than today. Sporadic multidecadal variability in this record is inconsistent with evidence for a persistent 65-80 year North Atlantic SST oscillation. Volcanic and anthropogenic radiative forcing are identified as important sources of externally-forced SST variability, with the latter accounting for most of the 2 0 th century warming trend. An 1800-year reconstruction of SST and hydrography near the Gulf Stream also suggests SSTs remained within about I°C of modern values. This cooling is small relative to other regional proxy records and may reflect the influence of internal oceanic and atmospheric circulation. Simulations with an atmospheric general circulation model (AGCM) indicate that the magnitude of cooling estimated by proxy records is consistent with tropical hydrologic proxy records. AcknowledgementsI thank my advisors Anne Cohen and Delia Oppo for their time and support. Listening to their ideas has been inspirational, and their willingness to listen to mine has been appreciated. They will be role models to me throughout my scientific career. The generous and selfless contributions of my thesis committee, including Bill Curry, Ping Chang, Ed Boyle and Jeff Donnelly are also greatly appreciated. My only regret is not taking greater advantage of their collective knowledge.I also express my appreciation to the members of WHOI's Paleoceanography group, within which the analytical efforts of Rindy Ostermann, Scot Birdwhistell, Simon Thorrold, Darlene Ketten, Julie Arruda, Kathyrn Rose and Luping Zou deserve special recognition. The support of the Academic Programs Office is unparalleled and is greatly appreciated. I also thank the Geology and Geophysics administrative staff, the MIT Education Office and WHOI's Facilities staff for their efforts to make daily operations run smoothly.I am grateful to know my fellow Joint Program students and I thank them for their encouragement, shop talk and countless dinner parties. Thanks also to the larger Woods Hole community. I will miss sharing a smile and a wave as I ride past. Finally, to Em....

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Reproducibility of geochemical and climatic signals in the Atlantic coral Montastraea faveolata

Cited by 65 publications

References 76 publications

Stable isotopic records of bleaching and endolithic algae blooms in the skeleton of the boulder forming coral Montastraea faveolata

Stable isotopic records of bleaching and endolithic algae blooms in the skeleton of the boulder forming coral Montastraea faveolata

Evaluation of annual resolution coral geochemical records as climate proxies in the Great Barrier Reef of Australia

Low-latitude western north atlantic climate variability during the past millennium : insights from proxies and models

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