Trace element variations in fossil corals from Tahiti collected by IODP Expedition 310: Reconstruction of marine environments during the last deglaciation (15 to 9 ka)

Inoue, Mayuri; Yokoyama, Yūsuke; Harada, Mariko; Suzuki, Atsushi; Kawahata, Hodaka; Matsuzaki, Hiroyuki; Iryu, Yasufumi

doi:10.1016/j.margeo.2010.02.016

Cited by 23 publications

(18 citation statements)

References 32 publications

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“…Our study is the first to suggest upwelling signals in corals from the GBR, and this pattern agrees with results from other workers using coral Ba/Ca as a proxy for upwelling in the Galapagos [33], [41], New Caledonia [42], [43], Papua New Guinea [44], [45], Tahiti [46], the Arabian Sea [47], northern Japan [27], and Venezuela [48]. Intriguingly, the Myrmidon coral showed sustained periods of elevated skeletal Ba/Ca over the course of the summer, despite the fact that upwelling events as indicated by temperature excursions were often pulsed and brief.…”

Section: Discussionsupporting

confidence: 92%

Environmental Records from Great Barrier Reef Corals: Inshore versus Offshore Drivers

2013

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The biogenic structures of stationary organisms can be effective recorders of environmental fluctuations. These proxy records of environmental change are preserved as geochemical signals in the carbonate skeletons of scleractinian corals and are useful for reconstructions of temporal and spatial fluctuations in the physical and chemical environments of coral reef ecosystems, including The Great Barrier Reef (GBR). We compared multi-year monitoring of water temperature and dissolved elements with analyses of chemical proxies recorded in Porites coral skeletons to identify the divergent mechanisms driving environmental variation at inshore versus offshore reefs. At inshore reefs, water Ba/Ca increased with the onset of monsoonal rains each year, indicating a dominant control of flooding on inshore ambient chemistry. Inshore multi-decadal records of coral Ba/Ca were also highly periodic in response to flood-driven pulses of terrigenous material. In contrast, an offshore reef at the edge of the continental shelf was subject to annual upwelling of waters that were presumed to be richer in Ba during summer months. Regular pulses of deep cold water were delivered to the reef as indicated by in situ temperature loggers and coral Ba/Ca. Our results indicate that although much of the GBR is subject to periodic environmental fluctuations, the mechanisms driving variation depend on proximity to the coast. Inshore reefs are primarily influenced by variable freshwater delivery and terrigenous erosion of catchments, while offshore reefs are dominated by seasonal and inter-annual variations in oceanographic conditions that influence the propensity for upwelling. The careful choice of sites can help distinguish between the various factors that promote Ba uptake in corals and therefore increase the utility of corals as monitors of spatial and temporal variation in environmental conditions.

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Section: Discussionsupporting

confidence: 92%

Environmental Records from Great Barrier Reef Corals: Inshore versus Offshore Drivers

2013

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“…The timing of the Acropora appearance is coincident with or subsequent to local oceanographic and atmospheric changes, but it is unclear if these changes had a direct relationship with the shift in the coral communities. Recent palaeoclimate work on Tahiti corals suggests that from 12.7 to 9.8 ka (Inoue et al, 2010) water temperatures were likely 2-4°C cooler than modern and 1-2°C cooler than 14.2-13 ka (Cohen and Hart, 2004;Asami et al, 2009;Inoue et al, 2010). This indicates that cooler water temperatures did not hinder profuse Acropora growth in Tahiti, which was coincident with minimum recorded SST values.…”

Section: Coral Assemblagesmentioning

confidence: 84%

“…This indicates that cooler water temperatures did not hinder profuse Acropora growth in Tahiti, which was coincident with minimum recorded SST values. Data from Inoue et al (2010) also suggest higher variability and slightly higher average values of nutrient content of Tahiti waters from 12.7 to 9.8 ka. Such variations did not affect the persistent development of Acropora after~12.5 ka.…”

Section: Coral Assemblagesmentioning

confidence: 87%

Variation in deglacial coralgal assemblages and their paleoenvironmental significance: IODP Expedition 310, “Tahiti Sea Level”

Abbey

Webster

Braga

et al. 2011

Global and Planetary Change

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“…Whilst reef cores have provided insights into sea level, reef growth, geomorphology and evolution [e.g., Ladd and Schlanger, 1960;Ladd et al, 1970;Lincoln and Schlanger, 1987;Webb et al, 2016], reef coring techniques remain relatively underutilized in terms of coral geochemistry-based environmental reconstructions for the Holocene. However, coring of submerged reefs, such as Integrated Ocean Drilling Program legs 310 and 325, have provided Holocene and deglacial corals for paleoclimate studies [Asami et al, 2009;Felis et al, 2014;Inoue et al, 2010] and deeper coring from reef flats, as documented here, may also provide appropriate corals for analysis.…”

Section: Introductionmentioning

confidence: 91%

Reef cores as records of Holocene water temperatures of the southern Great Barrier Reef: Geochemical analysis of traditional (Porites) and non-traditional (Acropora) reef building corals

Sadler¹

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In order to accurately predict future climate variations induced by natural and anthropogenic forcings, we require a detailed understanding of the Earth's climate system. With such temporally limited instrumental records, proxy-based reconstructions are an invaluable source of climate information. Current paleoclimate databases indicate a lack of records representing the southern hemisphere and tropics; key regions that can be represented by high resolution, coral geochemistry-based climate reconstructions.Reef coring techniques allow the recovery of significant proportions of coral material from throughout the Holocene, Pleistocene and beyond. Given the high species diversity of IndoPacific coral reefs, the presence of massive Porites commonly used for climate reconstruction is likely to be limited in reef cores. Corymbose Acropora, however, displays a high abundance in modern and fossil reef records and thus could act as a major source of new climate information from the Earth's recent history.Previous investigations of Acropora geochemistry have focused on branches, with significant levels of secondary thickening smoothing environmental signals otherwise recorded by the Sr/Ca ratio paleothermometer. This project investigates the potential of Acropora interbranch skeleton as a climate archive, following the identification of annual density banding patterns in computed tomography scans. Scanning electron microscopy based documentation of structure and growth patterns reveal that inter-branch skeleton is atypical for Acropora.Low linear extension rates, a simplified skeletal structure with limited secondary aragonite deposition, approximately horizontal density bands and seasonal cyclicity in Sr/Ca ratios bear a greater resemblance to massive corals such as Porites. These observations, combined with a high abundance in past and present Indo-Pacific reefs, suggest that inter-branch skeletal growth in Acropora may prove to be a valuable source of untapped paleoclimate information.A site-specific calibration for Acropora inter-branch skeleton Sr/Ca ratios to water temperature was conducted using modern corymbose Acropora colonies and concomitant instrumental water temperature records from the lagoon and fore-reef slope of Heron Reef, southern Great Barrier Reef (GBR). Large inter-colony differences in Sr/Ca ratios were observed in the modern cores, suggesting that inter-branch skeleton may not be a suitable archive for absolute temperature reconstruction. Normalisation of each Sr/Ca record to the corresponding core mean does, however, remove these inter-colony differences and allows the reconstruction of the seasonal water temperature amplitude with a sensitivity of −0.05 ii mmol/mol/°C. Application of the resulting transfer equation to the modern inter-branch skeleton Sr/Ca record successfully identified the greater seasonal temperature range of the lagoon compared to the adjacent reef slope. A site-specific calibration also was completed for southern GBR Porites at Heron Reef using the reef slope water te...

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Trace element variations in fossil corals from Tahiti collected by IODP Expedition 310: Reconstruction of marine environments during the last deglaciation (15 to 9 ka)

Cited by 23 publications

References 32 publications

Environmental Records from Great Barrier Reef Corals: Inshore versus Offshore Drivers

Environmental Records from Great Barrier Reef Corals: Inshore versus Offshore Drivers

Variation in deglacial coralgal assemblages and their paleoenvironmental significance: IODP Expedition 310, “Tahiti Sea Level”

Reef cores as records of Holocene water temperatures of the southern Great Barrier Reef: Geochemical analysis of traditional (Porites) and non-traditional (Acropora) reef building corals

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