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  • 1
    Publikationsdatum: 2023-03-14
    Schlagwort(e): Alkalinity, total; Calcite saturation state; Calculated using CO2SYS; Carbonate ion; CARIACO_Trap; Cariaco Basin; DATE/TIME; DEPTH, water; Difference; Measured; pH; Phosphate; Salinity; Sample ID; Silicate; Species; Trap, sediment; TRAPS
    Materialart: Dataset
    Format: text/tab-separated-values, 316 data points
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
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    PANGAEA
    In:  Supplement to: Marshall, Brittney J; Thunell, Robert C; Henehan, Michael J; Astor, Yrene; Wejnert, Katherine (2013): Planktonic foraminiferal area density as a proxy for carbonate ion concentration: A calibration study using the Cariaco Basin ocean time series. Paleoceanography, 28(2), 363-376, https://doi.org/10.1002/palo.20034
    Publikationsdatum: 2023-01-13
    Beschreibung: Biweekly sediment trap samples and concurrent hydrographic measurements collected between March 2005 and October 2008 from the Cariaco Basin, Venezuela, are used to assess the relationship between [CO3]2- and the area densities (ho A) of two species of planktonic foraminifera (Globigerinoides ruber (pink) and Globigerinoides sacculifer). Calcification temperatures were calculated for each sample using species-appropriate oxygen isotope (d18O) temperature equations that were then compared to monthly temperature profiles taken at the study site in order to determine calcification depth. Ambient [CO3]2- was determined for these calcification depths using alkalinity, pH, temperature, salinity, and nutrient concentration measurements taken during monthly hydrographic cruises. The rho A, which is representative of calcification efficiency, is determined by dividing individual foraminiferal shell weights (±0.43 µg) by their associated silhouette areas and taking the sample average. The results of this study show a strong correlation between rho A and ambient [CO3]2- for both G. ruber and G. sacculifer (R**2 = 0.89 and 0.86, respectively), confirming that [CO3]2- has a pronounced effect on the calcification of these species. Though the rho A for both species reveal a highly significant (p 〈 0.001) relationship with ambient [CO3]2-, linear regression reveals that the extent to which [CO3]2- influences foraminiferal calcification is species specific. Hierarchical regression analyses indicate that other environmental parameters (temperature and [PO4]3-) do not confound the use of G. ruber and G. sacculifer rho A as a predictor for [CO3]2-. This study suggests that G. ruber and G. sacculifer rho A can be used as reliable proxies for past surface ocean [CO3]2--
    Schlagwort(e): CARIACO_Trap; Cariaco Basin; Trap, sediment; TRAPS
    Materialart: Dataset
    Format: application/zip, 2 datasets
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    Publikationsdatum: 2023-02-12
    Schlagwort(e): Calcification depth, apparent; Calcification temperature; Calculated from stable oxygen isotopes; CARIACO_Trap; Cariaco Basin; DATE/TIME; DEPTH, water; Difference; Globigerinoides ruber; Globigerinoides ruber pink, area; Globigerinoides ruber pink, area, standard deviation; Globigerinoides ruber pink, density, standard deviation; Globigerinoides ruber pink, density per area; Globigerinoides ruber pink, weight; Globigerinoides ruber pink, weight, standard deviation; Globigerinoides ruber pink, δ18O; Globigerinoides sacculifer; Globigerinoides sacculifer, area; Globigerinoides sacculifer, area, standard deviation; Globigerinoides sacculifer, density, standard deviation; Globigerinoides sacculifer, density per area; Globigerinoides sacculifer, weight; Globigerinoides sacculifer, weight, standard deviation; Globigerinoides sacculifer, δ18O; Sample ID; Trap, sediment; TRAPS
    Materialart: Dataset
    Format: text/tab-separated-values, 454 data points
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
    Publikationsdatum: 2018-09-12
    Beschreibung: Much uncertainty exists about the state of the oceanic and atmospheric circulation in the tropical Pacific over the last glacial cycle. Studies have been hampered by the fact that sediment cores suitable for study were concentrated in the western and eastern parts of the tropical Pacific, with little information from the central tropical Pacific. Here we present information from a suite of sediment cores collected from the Line Islands Ridge in the central tropical Pacific, which show sedimentation rates and stratigraphies suitable for paleoceanographic investigations. Based on the radiocarbon and oxygen isotope measurements on the planktonic foraminifera Globigerinoides ruber, we construct preliminary age models for selected cores and show that the gradient in the oxygen isotope ratio of G. ruber between the equator and 8°N is enhanced during glacial stages relative to interglacial stages. This stronger gradient could reflect enhanced equatorial cooling (perhaps reflecting a stronger Walker circulation) or an enhanced salinity gradient (perhaps reflecting increased rainfall in the central tropical Pacific).
    Materialart: Article , PeerReviewed
    Format: text
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
    Publikationsdatum: 2019-02-01
    Beschreibung: The Line Islands Ridge (LIR), located south of the Hawaiian Islands between 7°N and 1°S, is one of the few large central Pacific regions shallower than the regional carbonate compensation depth. Thick sequences of carbonate sediments have accumulated around the LIR despite it being located in the sediment-starved central tropical Pacific. The LIR is an important source of carbonates to the surrounding region and deposition around the LIR has expanded the equatorial Pacific carbonate sediment tongue by about 5% of its total area. Furthermore, sediments on the ridge are potentially important paleoceanographic archives. A recent survey at the crest of the LIR finds evidence for high current activity, significant erosion, but overall net sediment deposition. Currents are strong enough to form sediment waves and lee drifts in the Palmyra Basin, at the northern terminus of the LIR. Sediments along the LIR are pelagic foraminiferal sands that are easily eroded and flow out into the surrounding abyssal plain in active submarine channel systems. As channels migrate, pelagic sediments fill in the abandoned channel arms. Despite significant sediment losses from the top of the ridge, 1.3 km of sediment has accumulated in the upper Palmyra Basin over basement formed 68 to 85 million years ago (Ma). Late Neogene erosion may be more extensive than earlier erosion cycles, in response to reduced sediment production as the Palmyra Basin exited the high productivity equatorial latitudes. Sediments with good stratigraphic order needed for paleoceanographic study are limited in this dynamic sedimentary environment, but can be found with proper survey.
    Materialart: Article , PeerReviewed
    Format: text
    Standort Signatur Einschränkungen Verfügbarkeit
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