Radiocarbon Content of Marine Shells from the California and Mexican West Coast

Berger, Rainer; Taylor, R. E.; Libby, W. F.

doi:10.1126/science.153.3738.864

Cited by 91 publications

(79 citation statements)

References 16 publications

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“…Most pre-bomb mollusks used to estimate ∆R in eastern Pacific waters were derived from mainland beaches or estuarine settings where isotope values are more likely to be influenced by terrestrial runoff (Berger et al 1966;Ingram and Southon 1996;Robinson and Trimble 1980;Taylor and Berger 1967). Freshwater inputs would lower shell δ 13 C and δ 18 O values, assuming that shells continued to grow with greater freshwater influences.…”

Section: Oxygen and Carbon Isotopic Analysismentioning

confidence: 99%

Intrashell Radiocarbon Variability in Marine Mollusks

Culleton¹,

Kennett

Ingram

et al. 2006

Radiocarbon

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We demonstrate variable radiocarbon content within 2 historic (AD 1936) and 2 prehistoric (about 8200 BP and 3500 BP) Mytilus californianus shells from the Santa Barbara Channel region, California, USA. Historic specimens from the mainland coast exhibit a greater range of intrashell variability (i.e. 180–240 14C yr) than archaeological specimens from Daisy Cave on San Miguel Island (i.e. 120 14C yr in both shells). δ13C and δ18O profiles are in general agreement with the up welling of deep ocean water depleted in 14C as a determinant of local marine reservoir correction (ΔR) in the San Miguel Island samples. Upwelling cycles are difficult to identify in the mainland specimens, where intrashell variations in 14C content may be a complex product of oceanic mixing and periodic seasonal inputs of 14C-depeleted terrestrial runoff. Though the mechanisms controlling ΔR at subannual to annual scales are not entirely clear, the fluctuations represent significant sources of random dating error in marine environments, particularly if a small section of shell is selected for accelerator mass spectrometry (AMS) dating. For maximum precision and accuracy in AMS dating of marine shells, we recommend that archaeologists, paleontologists, and 14C lab personnel average out these variations by sampling across multiple increments of growth.

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Section: Oxygen and Carbon Isotopic Analysismentioning

confidence: 99%

Intrashell Radiocarbon Variability in Marine Mollusks

Culleton¹,

Kennett

Ingram

et al. 2006

Radiocarbon

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“…** Average surface and deep ⌬ 14 C DOC values, respectively, for Sta. M measured between February 1992 and July 1993 cates the presence of postbomb 14 C (Berger et al 1966) produced from atmospheric testing of nuclear weapons in the late 1950s and early 1960s. However, these bacterial ⌬ 14 C values were significantly lower than the respective surface (25 m) water POC susp and DIC ⌬ 14 C values of 66 Ϯ 11‰ (n ϭ 4, Druffel et al 1996) and 70 Ϯ 7‰ (n ϭ 11, Massiello et al 1998) measured at Sta.…”

Section: Doc Use In the Open Ocean-mentioning

confidence: 99%

Radiocarbon in marine bacteria: Evidence for the ages of assimilated carbon

Cherrier

Bauer

Druffel

et al. 1999

Limnology & Oceanography

107

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It is generally accepted that marine bacteria utilize labile, recently produced components of bulk dissolved organic matter. This interpretation is based largely on indirect measurements using model compounds and plankton‐derived organic matter. Here, we present an assessment of the relative proportions of modern and older dissolved organic carbon (DOC) utilized by marine bacteria. Bacterial nucleic acids were collected from both estuarine (Santa Rosa Sound, FL) and open‐ocean (eastern North Pacific) sites, and the natural radiocarbon signatures of the nucleic acid carbon in both systems were determined. Bacterial nucleic acids from Santa Rosa Sound were significantly enriched in radiocarbon with respect to the bulk DOC and were similar to the radiocarbon signature of atmospheric CO2 at the time of sampling, indicating that these bacteria exclusively assimilate a modern component of the estuarine bulk DOC. In contrast, bacterial nucleic acids from the oceanic site were enriched in 14C relative to the bulk DOC but depleted in 14C with respect to modern surface dissolved inorganic carbon (DIC) and suspended particulate organic carbon (POCsusp). This suggests that open‐ocean bacteria assimilate both modern and older components of DOC. The distinct radiocarbon signatures of the nucleic acids at these two sites (i.e., +120 ± 17‰ estuarine vs. −34 ± 24‰ oceanic) demonstrate that natural 14C abundance measurements of bacterial biomarkers are a powerful tool for investigations of carbon cycling through microbial communities in different aquatic systems.

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“…The surface R value of +90 ± 40 yr is significantly lower than those from other tropical/subtropical eastern boundary upwelling areas, which range as high as 250-350 yr (Berger et al 1966;Ingram and Southon 1996;Jones et al 2007;Ortlieb et al 2011; see http://calib.qub.ac.uk/marine for a database of R values). Together with the large and variable 14 C age offset of 120 ± 95 yr between surface and lower mixed layer/upper thermocline foraminifera, this argues for a partial decoupling of the surface from the effects of upwelling induced by along-shore southeast monsoon winds.…”

Section: Dr Valuesmentioning

confidence: 99%

Planktic Foram Dates from the Indonesian Arc: Marine 14C Reservoir Ages and a Mythical AD 535 Volcanic Eruption

Southon

2013

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ABSTRACT. The Indonesian Arc represents the subduction of the Indian-Australian plate beneath Asia. It has been the scene of catastrophic tectonic activity, including the recent 2004 M=9.1 Aceh earthquake and resulting Indian Ocean tsunami. We have dated planktonic forams associated with historic tephras (Tambora, 1815 and Krakatau, 1883) in marine sediment cores to determine radiocarbon reservoir ages for 2 locations along the arc. Our best estimates for 19th century regional reservoir corrections (R) are +90 ± 40 yr for surface-dwelling species and +220 ± 40 yr for mixed planktic assemblages containing some upper thermocline species, but scatter in the data suggests that past surface reservoir ages may have varied by about ±100 yr. We used the results of this study to investigate a proposed very large AD 535 eruption at or near Krakatau. We find no evidence for ash from such an eruption, and although this is negative evidence, we consider it sufficiently strong to rule out any possibility that one took place.

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Radiocarbon Content of Marine Shells from the California and Mexican West Coast

Abstract: The radiocarbon content of contemporary pre-bomb marine shells from the upwelling environment of the California and the West Mexican coast has been determined. In addition, factors leading to the apparent ages of different magnitude for various marine environments are discussed.

Cited by 91 publications

References 16 publications

Intrashell Radiocarbon Variability in Marine Mollusks

Intrashell Radiocarbon Variability in Marine Mollusks

Radiocarbon in marine bacteria: Evidence for the ages of assimilated carbon

Planktic Foram Dates from the Indonesian Arc: Marine 14C Reservoir Ages and a Mythical AD 535 Volcanic Eruption

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