Radiocarbon Reservoir Age Variations in the South Peruvian Upwelling During the Holocene

Fontugne, Michel; Carré, Matthieu; Bentaleb, I.; Julien, Michèle; Lavallee, Danielle C.

doi:10.1017/s003382220003558x

Cited by 55 publications

(63 citation statements)

References 22 publications

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“…Our results indicate that the youngest R surf estimates at ca. 800 years, obtained from core MD07-3088 during the upper Holocene, are similar to those obtained during the Middle Holocene and are in agreement with other studies carried out along the SEP margin, as well in the SO, which have revealed no changes in regional R surf during this period [19][20][21][22] . As a consequence, middle to upper Holocene R surf estimate at ca.…”

Section: Resultssupporting

confidence: 80%

Carbon isotope records reveal precise timing of enhanced Southern Ocean upwelling during the last deglaciation

et al. 2013

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International audienceThe Southern Ocean plays a prominent role in the Earth’s climate and carbon cycle. Changes in the Southern Ocean circulation may have regulated the release of CO₂ to the atmosphere from a deep-ocean reservoir during the last deglaciation. However, the path and exact timing of this deglacial CO₂ release are still under debate. Here we present measurements of deglacial surface reservoir ¹⁴C age changes in the eastern Pacific sector of the Southern Ocean, obtained by ¹⁴C dating of tephra deposited over the marine and terrestrial regions. These results, along with records of foraminifera benthic–planktic ¹⁴C age and δ¹³C difference, provide evidence for three periods of enhanced upwelling in the Southern Ocean during the last deglaciation, supporting the hypothesis that Southern Ocean upwelling contributed to the deglacial rise in atmospheric CO₂. These independently dated marine records suggest synchronous changes in the Southern Ocean circulation and Antarctic climate during the last deglaciation

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Section: Resultssupporting

confidence: 80%

Carbon isotope records reveal precise timing of enhanced Southern Ocean upwelling during the last deglaciation

et al. 2013

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“…In order to apply an accurate R correction for 14 C dating of marine shells, it is necessary to estimate past R(t) fluctuations (Goodfriend and Flessa 1997;Ingram and Southon 1997;Siani et al 2001;Reimer and McCormac 2002;Southon et al 2002;Fontugne et al 2004). The same precaution has to be taken in coastal areas especially when high R(t) variability may occur.…”

Section: Reservoir Age Correction During the Holocenementioning

confidence: 99%

“…Several studies have suggested the possibility of significant deviations in regional marine reservoir signature from this average value (Goodfriend and Flessa 1997;Ingram and Southon 1997;Siani et al 2001;Reimer and McCormac 2002;Southon et al 2002;Fontugne et al 2004). The reservoir age in coastal areas may also vary with time in relation to environmental changes, which would modify the respective proportion of marine and freshwater inputs.…”

Section: Introductionmentioning

confidence: 99%

Holocene Variations of Radiocarbon Reservoir Ages in a Mediterranean Lagoonal System

et al. 2010

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ABSTRACT.To obtain a precise radiocarbon Holocene chronology in coastal areas, it is necessary to estimate the modern 14 C reservoir age R(t) and its possible variations with time in relation to paleoenvironmental changes. The modern reservoir 14 C age was estimated by comparing AMS 14 C ages of 2 recent mollusk shells found in sediment cores sampled in the Palavasian lagoonal system (south of France) with ages derived from 210 Pb and 137 Cs data and historical accounts of identifiable storm events. The calculated modern R(t) value of 943 ± 25 14 C yr is about 600 yr higher than the global mean sea surface reservoir age. This high value, probably due to the relative isolation of the lagoon from marine inputs, is in good agreement with other R(t) estimates in Mediterranean lagoonal systems (Zoppi et al. 2001;Sabatier et al. 2008). 14 C ages were also obtained on a series of Holocene mollusk shells sampled at different depths of the ~8-m-long core PB06. Careful examination of the 14 C ages versus depth relationships suggests that R(t) in the past was lower and similar to the value presently measured in the Gulf of Lion (618 ± 30 14 C yr, Siani et al. 2000). The change in R(t) from 618 to 943 yr is thought to result from final closure of the coastal lagoon by the sandy barrier, due to the along-shore sediment transfer.

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“…56). We quantified temporal variations ΔR from coral skeletons in the Gulf of Panamá as a proxy of changes in upwelling intensity from ~6750 cal BP to present [59][60] .…”

Section: Local Reservoir Correctionmentioning

confidence: 99%

Climatic and biotic thresholds of coral-reef shutdown

et al. 2015

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Climate change is now the leading cause of coral-reef degradation and is altering the adaptive landscape of coral populations 1,2 . Increasing sea temperatures and declining carbonate saturation states are inhibiting short-term rates of coral calcification, carbonate precipitation and submarine cementation [3][4][5] . A critical challenge to coral-reef conservation is understanding the mechanisms by which environmental perturbations scale up to influence long-term rates of reef-framework construction and ecosystem function 6,7 . Here we reconstruct climatic and oceanographic variability using corals sampled from a 6,750-year core from Pacific Panamá. Simultaneous reconstructions of coral palaeophysiology and reef accretion allowed us to identify the climatic and biotic thresholds associated with a 2,500-year hiatus in vertical accretion beginning ∼4,100 years ago 8 . Stronger upwelling, cooler sea temperatures and greater precipitation-indicators of La Niña-like conditions-were closely associated with abrupt reef shutdown. The physiological condition of the corals deteriorated at the onset of the hiatus, corroborating theoretical predictions that the tipping points of radical ecosystem transitions should be manifested sublethally in the biotic constituents 9 . Future climate change could cause similar threshold behaviours, leading to another shutdown in reef development in the tropical eastern Pacific.Climatic and oceanographic variability have played a dominant role in the development of reefs throughout the Phanerozoic eon 10 , and the recent past is no exception. In Panamá and several other locations in the Pacific, coral reefs stopped accreting vertically for 2,500 years, beginning ∼4,100 cal yr BP (ref. 8; calibrated 14 C calendar years before 1950; Fig. 1a). Correlations with regional palaeoclimate proxies suggest that enhanced variability of the El Niño/Southern Oscillation (ENSO) was the ultimate cause of reef shutdown in the tropical eastern Pacific 8 (TEP). Climatic shifts at that time led to environmental and cultural impacts on a global scale 11,12 .In this study we investigated the long-term impacts of environmental variability on coral physiology and reef development in the TEP to ascertain the climatic, oceanographic and biotic controls on ecosystem state in the past. We quantified the range of environmental conditions that corals experienced during the past ∼6,750 years to determine whether significant changes in climate or oceanography were associated with changes in coral physiology or reef accretion. We then evaluated the environmental and physiological thresholds that characterized the catastrophic phase shift to the hiatus.In Pacific Panamá, El Niño-like periods are characterized by a warm, dry climate and a reduction in seasonal upwelling. Those conditions are reversed during La Niña-like periods (Supplementary Discussion and Supplementary Fig. 1). Contemporary environmental variability is high at Contadora Island, a site in Pacific Panamá that is exposed to intense seasonal upwelling and ...

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Radiocarbon Reservoir Age Variations in the South Peruvian Upwelling During the Holocene

Cited by 55 publications

References 22 publications

Carbon isotope records reveal precise timing of enhanced Southern Ocean upwelling during the last deglaciation

Carbon isotope records reveal precise timing of enhanced Southern Ocean upwelling during the last deglaciation

Holocene Variations of Radiocarbon Reservoir Ages in a Mediterranean Lagoonal System

Climatic and biotic thresholds of coral-reef shutdown

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