Constraining initial 230Th activity in incrementally deposited, biogenic aragonite from the Bahamas

Rosenheim, B. E.; Swart, Peter K.; Eisenhauer, Anton

doi:10.1016/j.gca.2007.05.025

Cited by 8 publications

(7 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Radiocarbon ratios were corrected15 for isotope fractionation using both stable isotope measurements. Age models based on 230 Th in‐growth in sclerosponge aragonite16 were used to calculate age‐corrected Δ 14 C 15. These values are compared with values measured by conventional carbonate acid digestion methodology corrected to the same age models.…”

Section: Resultsmentioning

confidence: 99%

Selected‐Control Fabrication of Multifunctional Fluorescent–Magnetic Core–Shell and Yolk–Shell Hybrid Nanostructures

Liu

Wang

Zhang

et al. 2012

Chemistry A European J

View full text Add to dashboard Cite

The selected-control preparation of uniform core-shell and yolk-shell architectures, which combine the multiple functions of a superparamagnetic iron oxide (SPIO) core and europium-doped yttrium oxide (Y(2)O(3):Eu) shell in a single material with tunable fluorescence and magnetic properties, has been successfully achieved by controlling the heat-treatment conditions. Furthermore, the shell thickness and interior cavity of SPIO@Y(2)O(3):Eu core-shell and yolk-shell nanostructures can be precisely tuned. Importantly, as-prepared SPIO@Y(2)O(3):Eu yolk-shell nanocapsules (NCs) modified with amino groups as cancer-cell fluorescence imaging agents are also demonstrated. To the best of our knowledge, this is the first report on the selected-control fabrication of uniform SPIO@Y(2)O(3):Eu core-shell nanoparticles and yolk-shell NCs. The combined magnetic manipulation and optical monitoring of magnetic-fluorescent SPIO@Y(2)O(3):Eu yolk-shell NCs will open up many exciting opportunities in dual imaging for targeted delivery and thermal therapy.

show abstract

Section: Resultsmentioning

confidence: 99%

Selected‐Control Fabrication of Multifunctional Fluorescent–Magnetic Core–Shell and Yolk–Shell Hybrid Nanostructures

Liu

Wang

Zhang

et al. 2012

Chemistry A European J

View full text Add to dashboard Cite

show abstract

“…For the sclerosponge, the chronology was derived solely from U/Th ages, which were measured at nine different locations in the sclerosponge skeleton and corrected for initial 230 Th incorporation following Rosenheim et al . []. The amount of initial 230 Th incorporation was estimated with the aid of two chronological constraints present in the sclerosponge skeleton: (1) the known age at the surface (2003) and (2) the location where bomb 14 C was initially present in the skeleton, which must have occurred after 1955 (when bomb 14 C was initially present in the atmosphere).…”

Section: Methodsmentioning

confidence: 99%

Ventilation time scales of the North Atlantic subtropical cell revealed by coral radiocarbon from the Cape Verde Islands

et al. 2015

Self Cite

View full text Add to dashboard Cite

We present coral-and sclerosponge-based reconstructions of the 14 C content in North Atlantic dissolved inorganic carbon (DIC) during the last~100 years from the subtropical cells (STCs). These waters are sensitive to the dynamics of the shallow overturning meridional circulation that transports heat and water masses from the subtropics to the tropics. We use these records to investigate the circulation patterns of the off-equatorial upwelling regions of the STCs, which are not well understood. Coral and sclerosponge skeletons provide long time series of ocean DIC 14 C content, a tracer of oceanic circulation, effectively extending the observational record back in time. Sclerosponge data from the Bahamas were used to extend the existing subtropical 14 C time series to the 21st century. Coral 14 C data from the Cape Verde Islands (1890-2002) captured the 14 C signature of water brought to the surface in the off-equatorial regions of the STC present near the West African coast. We observe a unique postbomb trend at Cape Verde that is similar to the upwelling regions in the Pacific, and we interpret this trend as the result of the slow penetration of bomb 14 C into the interior ocean as part of the STC circulation. Using a multibox mixing model we constrain the time history of bomb 14 C in the eastern tropical Atlantic, and we estimate a 20 year time scale for ventilation of the thermocline in this area of the ocean. The similarity between the Atlantic and Pacific 14 C-based records of upwelling suggests that both are caused by bomb 14 C penetration rather than more complex explanations that invoke changes in thermocline depth (e.g., related to El Niño-Southern Oscillation variability) or changes in the strength of the subtropical cells. Our results offer constraints for models of tropical ocean circulation and anthropogenic CO 2 uptake that attempt to reproduce the characteristics of the shallow wind-driven circulation in the Atlantic.

show abstract

“…For regional comparison, sclerosponges (C. nicholsoni) from different depths in Exuma Sound, Bahamas ( Fig. 1) were also analyzed, using U/Th dates for chronology (Rosenheim et al, 2007) because these sclerosponges were too deep for fluorochrome staining by scuba divers. They were collected by submersible between 1992 and 1995 at depths ranging between 67 and 136 m. For comparison of isotope records from the same site in Jamaica, a specimen of zooxanthellate coral Montastraea faveolata was also taken from the top of the cryptic reef enclosure (14 m depth) in which the sclerosponges grew.…”

Section: Sclerosponge and Coral Sample Recoverymentioning

confidence: 99%

“…In all sclerosponges, samples mixed both pseudo-calyx Table 1 Sclerosponge sampling information. Extension rates were calculated by measuring calcein bands (PTB) or from U/Th chronology (LSI sclerosponges, Rosenheim et al, 2007). The difference between conventional and incremental depth transects is explained in the text.…”

Section: Skeletal Sub-samplingmentioning

confidence: 99%

Calibration of sclerosponge oxygen isotope records to temperature using high-resolution δ18O data

Rosenheim

Swart

Willenz

2009

Geochimica et Cosmochimica Acta

Self Cite

View full text Add to dashboard Cite

Constraining initial 230Th activity in incrementally deposited, biogenic aragonite from the Bahamas

Cited by 8 publications

References 56 publications

Selected‐Control Fabrication of Multifunctional Fluorescent–Magnetic Core–Shell and Yolk–Shell Hybrid Nanostructures

Selected‐Control Fabrication of Multifunctional Fluorescent–Magnetic Core–Shell and Yolk–Shell Hybrid Nanostructures

Ventilation time scales of the North Atlantic subtropical cell revealed by coral radiocarbon from the Cape Verde Islands

Calibration of sclerosponge oxygen isotope records to temperature using high-resolution δ18O data

Contact Info

Product

Resources

About