Carbon Isotope Analysis of Land Snail Shells: Implications for Carbon Sources and Radiocarbon Dating

13C and 14C analyses were performed on a series of modern Jamaican land snails in order to quantitatively determine the sources of shell carbon. A model of these carbon sources, the pathways by which carbon reaches the shell, and the fractionation processes involved are presented. The contribution of limestone to shell carbonate is variable but may comprise up to 33% of the shell. About 25–40% of shell carbonate is derived from plants and about 30–60% from atmospheric CO2. Variation among populations and species with respect to 13C and 14C is attributed to the effects of limestone incorporation, snail size (as it affects CO2 exchange rate), physiological characteristics (presence of urease, respiration rate), and activity patterns of the snails. A formula for correction for isotopic fractionation of 14C of shell carbonate, based on 13C measurements, is derived. Bicarbonate-aragonite fractionation is apparently very minimal. Shell organic carbon appears to be derived largely from plants but also to a lesser extent from inorganic hemolymph carbon. This introduces the possibility of a small age anomaly of shell organic 14C due to limestone incorporation.

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Bacterial carbon sources in coastal sediments: a cross-system analysis based on stable isotope data of biomarkers

Biogeosciences ◽

10.5194/bg-3-175-2006 ◽

2006 ◽

Vol 3 (2) ◽

pp. 175-185 ◽

Cited By ~ 93

Author(s):

S. Bouillon ◽

H. T. S. Boschker

Keyword(s):

Fatty Acids ◽

Organic Carbon ◽

Salt Marshes ◽

System Analysis ◽

Carbon Sources ◽

Isotopic Fractionation ◽

Coastal Sediments ◽

Large Variability ◽

Coastal Systems ◽

Sediment Organic Carbon

Abstract. Coastal ecosystems are typically highly productive, and the sediments in these systems receive organic matter from a variety of local and imported sources. To assess if general patterns are present in the origin of carbon sources for sedimentary bacteria and their relation to the origin of the sediment organic carbon pool, we compiled both literature and new data on δ13C of bacterial biomarkers (the phospholipid derived fatty acids i+a15:0), along with δ13C data on sediment organic carbon (δ13CTOC) and macrophyte biomass from a variety of typical near-coastal systems. These systems included mangroves, salt marshes (both C3 and C4-dominated sites), seagrass beds, and macroalgae-based systems, as well as unvegetated sediments. First, our δ13Ci+a15:0 data showed large variability over the entire range of δ13CTOC, indicating that in many settings, bacteria may depend on carbon derived from various origins. Secondly, systems where local macrophyte production is the major supplier of organic carbon for in situ decomposition are generally limited to organic carbon-rich, peaty sites (TOC>10 wt%), which are likely to make up only a small part of the global area of vegetated coastal systems. These carbon-rich sediments also provided a field based estimate of isotopic fractionation between bacterial carbon sources and biomarkers (-3.7±2.1), which is similar to the expected value of about -3 associated with the biosynthesis of fatty acids. Thirdly, only in systems with low TOC (below ~1 wt%), we consistently found that bacteria were selectively utilizing an isotopically enriched carbon source, which may be root exudates but more likely is derived from microphytobenthos. In other systems with between ~1 and 10 wt% TOC, bacteria appear to show on average little selectivity and δ13Ci+a15:0 data generally follow the δ13CTOC, even in systems where the TOC is a mixture of algal and macrophyte sources that generally are believed to have a very different degradability.

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Limestone and the problem of radiocarbon dating of land-snail shell carbonate

Geology ◽

10.1130/0091-7613(1983)11<575:latpor>2.0.co;2 ◽

1983 ◽

Vol 11 (10) ◽

pp. 575 ◽

Cited By ~ 139

Author(s):

Glenn A. Goodfriend ◽

Jerry J. Stipp

Keyword(s):

Radiocarbon Dating ◽

Land Snail ◽

Snail Shell ◽

Shell Carbonate

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Bacterial carbon sources in coastal sediments: a review based on stable isotope data of biomarkers

Biogeosciences Discussions ◽

10.5194/bgd-2-1617-2005 ◽

2005 ◽

Vol 2 (5) ◽

pp. 1617-1644 ◽

Cited By ~ 2

Author(s):

S. Bouillon ◽

H. T. S. Boschker

Keyword(s):

Organic Carbon ◽

Salt Marshes ◽

Carbon Sources ◽

Isotopic Fractionation ◽

Lipid Synthesis ◽

Coastal Sediments ◽

Large Variability ◽

Coastal Systems ◽

Sediment Organic Carbon ◽

Bacterial Lipid

Abstract. Coastal ecosystems are typically highly productive, and recieve organic matter from a variety of local and imported sources. To assess if general patterns are present in the origin of carbon sources for sedimentary bacteria and their relation to the origin of the sediment organic carbon pool, we compiled both literature and new data on δ13C of bacterial biomarker PLFA (the phospholipid derived fatty acids i+a15:0) along with δ13C data on sediment organic carbon δ13CTOC and macrophyte biomass. Such data were collected from a variety of typical near-coastal systems, including mangroves, salt marshes (both C3 and C4-dominated sites), seagrass beds, and macroalgae-based systems, as well as unvegetated sediments. First, our δ13Ci+a15:0 data showed a large variability over the entire range of δ13CTOC, indicating that in many settings, bacteria may depend on carbon derived from various origins. Secondly, systems where local macrophyte production is the major supplier of organic carbon for in situ decomposition are generally limited to organic carbon-rich, peaty sites (TOC>10 wt%) which are likely to make up only a small part of the global area of vegetated coastal systems. These carbon-rich sediments also provided a field based estimate of isotopic fractionation in bacterial lipid synthesis (-3.7±2.1), that is similar to the expected value. Thirdly, only in systems with low TOC (below ~1 wt%), we consistently found that bacteria were on average selectively utilizing an isotopically enriched carbon source, which may be root exudates but more likely is derived from microphytobenthos. In other systems with between ~1 and 10 wt% TOC, bacteria appear to show on average little selectivity and δ13Ci+a15:0 data generally follow the δ13CTOC, even in systems where the TOC is a mixture of algal and macrophyte sources that generally are believed to have a very different degradability.

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Assimilation of various organic carbon sources by Haematococcus strains

Acta Agronomica Hungarica ◽

10.1556/aagr.57.2009.2.14 ◽

2009 ◽

Vol 57 (2) ◽

pp. 231-237

Author(s):

M. Zych ◽

A. Stolarczyk ◽

K. Maca ◽

A. Banaś ◽

K. Termińska-Pabis ◽

...

Keyword(s):

Organic Carbon ◽

Organic Compounds ◽

Present Experiment ◽

Carbon Sources ◽

Growth Conditions ◽

Mixotrophic Growth ◽

Naturally Occurring ◽

Organic Carbon Sources ◽

Secondary Carotenoids ◽

Colour Changes

Differences in the assimilation of individual organic compounds (5 mM sugars and L-asparagine) under mixotrophic growth conditions were described for three naturally occurring Haematococcus strains.The effects of assimilation were measured by the growth intensity and size of algal cells, and the effect of colour changes in the cultures was observed. Some compounds caused the cell colouration to change from green to yellow, being the result of chlorophyll disappearance and the accumulation of yellow secondary carotenoids. In the present experiment none of the cultures turned red, thus excluding the intense accumulation of the commercially interesting carotenoid, astaxanthin.

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The vulnerability of Arctic shelf sediments to climate change

Environmental Reviews ◽

10.1139/er-2015-0040 ◽

2015 ◽

Vol 23 (4) ◽

pp. 461-479 ◽

Cited By ~ 16

Author(s):

Robie W. Macdonald ◽

Zou Zou A. Kuzyk ◽

Sophia C. Johannessen

Keyword(s):

Organic Carbon ◽

Carbon Sources ◽

The Arctic ◽

Sedimentary Environments ◽

Carbon Supply ◽

Shelf Sediment ◽

Wide Range ◽

Metabolic Conditions ◽

Shelf Sediments ◽

Ocean Ecosystem

The sediments of the pan-Arctic shelves contribute an important component to the Arctic Ocean ecosystem by providing a habitat for biota (benthos), a repository for organic and inorganic non-conservative substances entering or produced within the ocean, a reactor and source of transformed substances back to the water column, and a mechanism of burial. Sediments interact with ice, ocean, and the surrounding land over a wide range of space and time scales. We discuss the vulnerability of shelf sediment to changes in (i) organic carbon sources, (ii) pathways of sediment and organic carbon supply, and (iii) physical and biogeochemical alteration (diagenesis). Sedimentary environments of the shelves and basins are likely to exhibit a wide variance in their response to global change because of their wide variation in sediment sources, processes, and metabolic conditions. In particular, the Chukchi and Barents shelves are dominated by inflowing waters from oceans to the south, whereas the interior shelves are more closely tied to terrigenous sources due to river inflow and coastal erosion.

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Analysis of the Context and Contents of an Ulua-Style Marble Vase from the Palmarejo Valley, Honduras

Latin American Antiquity ◽

10.7183/1045-6635.25.1.82 ◽

2014 ◽

Vol 25 (1) ◽

pp. 82-100 ◽

Cited By ~ 2

Author(s):

E. Christian Wells ◽

Karla L. Davis-Salazar ◽

José E. Moreno-Cortes ◽

Glenn S. L. Stuart ◽

Anna C. Novotny

Keyword(s):

Stable Isotope ◽

Stable Isotope Analysis ◽

Radiocarbon Dating ◽

Isotope Analysis ◽

Human Remains ◽

Classic Period ◽

Late Classic ◽

Residential Group ◽

Holistic Understanding ◽

Political Economic

Ulúa-style marble vases played important social, political, economic, and religious roles in southern Mesoamerica during the seventh through eleventh centuries A.D. However, most such vessels known to archaeologists are part of looted collections or else were unearthed before the advent of modern archaeological practices. As a result, little is known about the context, use, and chronology of these objects. Recent investigations at the site of Palos Blancos in northwest Honduras discovered an Ulúa-style marble vase in an undisturbed mortuary context. Excavation of the burial context, along with bioarchaeological and stable isotope analysis of the human remains, suggests that the vase was placed as an offering, possibly to an ancestor of the residential group. Phosphate and pollen studies indicate that the vase once held a corn-based beverage . Radiocarbon dating of four charcoal samples from immediately below and adjacent to the vase yielded a range of dates from the beginning of the Late Classic period, ca.A.D. 600-800. Through analyses of the context and contents of the vase, this research contributes to a more holistic understanding of the use and meaning of Ulúa-style marble vases in southern Mesoamerica.

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Radiocarbon Dating and Dietary Stable Isotope Analysis of Kwaday Dän Ts'inchí

American Antiquity ◽

10.2307/25470442 ◽

2007 ◽

Vol 72 (4) ◽

pp. 719-734 ◽

Cited By ~ 19

Author(s):

Michael P. Richards ◽

Sheila Greer ◽

Lorna T. Corr ◽

Owen Beattie ◽

Alexander Mackie ◽

...

Keyword(s):

Radiocarbon Dating ◽

Isotope Analysis ◽

Human Remains ◽

Isotopic Analysis ◽

High Elevation ◽

Bone Collagen ◽

Contact Period ◽

European Contact ◽

Ams Dating ◽

The Individual

We report here on the results of AMS dating and isotopic analysis of the frozen human remains named Kwaday Dän Ts'inchí and associated materials recovered from a glacier located in Northwest British Columbia, Canada in 1999. The isotopic analysis of bone collagen (bulk and single amino acids) from the individual indicates a strongly marine diet, which was unexpected given the location of this find, more than 100 km inland eroding out of a high elevation glacier; however, bulk hair and bone cholesterol isotopic values indicate a shift in diet to include more terrestrial foods in the year before death. The radiocarbon dating is not straightforward, as there are difficulties in determining the appropriate marine correction for the human remains, and the spread of dates on the associated artifacts clearly indicates that this was not a single use site. By combining the most recent date on a robe worn by Kwaday Dän Ts'inchi with direct bone collagen dates we conclude that the individual likely dates to between cal A.D. 1670 to 1850, which is in the pre-(or early) European contact period for this region.

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