# California Margin Bamboo Coral Barium Chemistry During the 20th Century #----------------------------------------------------------------------- # World Data Service for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program #----------------------------------------------------------------------- # Template Version 3.0 # Encoding: UTF-8 # NOTE: Please cite original publication, online resource and date accessed when using this data. # If there is no publication information, please cite Investigator, title, online resource and date accessed. # # Description/Documentation lines begin with # # Data lines have no # # # Online_Resource: https://www.ncdc.noaa.gov/paleo/study/27170 # Description: NOAA Landing Page # Online_Resource: http://www1.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/geyman2019/geyman2019-t1104a7_d14c.txt # Description: NOAA location of the template # # Data_Type: Corals and Sclerosponges # # Dataset_DOI: # # Parameter_Keywords: trace metals #--------------------------------------- # Contribution_Date # Date: 2019-07-30 #--------------------------------------- # File_Last_Modified_Date # Date: 2019-07-30 #--------------------------------------- # Title # Study_Name: California Margin Bamboo Coral Barium Chemistry During the 20th Century #--------------------------------------- # Investigators # Investigators: Geyman, Benjamin; Ptacek, Jamie; LaVigne, Michele; Horner, Tristan #--------------------------------------- # Description_Notes_and_Keywords # Description: This dataset contains skeletal Ba/Ca and Ba isotopes from bamboo corals collected from the California Margin (N. Pacific Ocean). Details on coral chronologies and dating methodology can be found below and in Geyman et al. (2019). Seawater barium data published in the Geyman et al. (2019) calibration can be found at BCO-DMO (https://www.bco-dmo.org/dataset/770447 for IrnBru and https://www.bco-dmo.org/dataset/770368 for SAFe). Coral Mg/Ca and Sr/Ca data are of good quality and are provided here for reference, though they are largely beyond the scope of the originating study. # Provided Keywords: barium isotopes, high-Mg calcite #--------------------------------------- # Publication # Authors: Geyman, B.M., J.L. Ptacek, M. LaVigne, and T.J. Horner # Published_Date_or_Year: 2019 # Published_Title: Barium in deep-sea bamboo corals : Phase associations, barium stable isotopes, and prospects for paleoceanography # Journal_Name: Earth and Planetary Science Letters # Volume: # Edition: # Issue: # Pages: # Report_Number: # DOI: # Online_Resource: # Full_Citation: # Abstract: Reconstruction of past seawater d138/134Ba_NIST (barium-isotopic compositions) can augment existing proxies of water mass provenance and deep-ocean circulation. Deep-sea bamboo corals are uniquely poised to record Ba-isotopic variations, given their widespread oceanographic distribution and incorporation of ambient Ba in approximate proportion to that in surrounding seawater. However, the utility of such records requires knowing: the phases hosting Ba in deep-sea coral skeletons, that specimens faithfully capture modern Ba-isotopic chemistry, and that internal skeletal variability relates principally to historical variations in the composition of ambient seawater. We investigated each of these requirements using a stepped cleaning experiment, a 'core-top' comparison of eight live-collected specimens from the California margin (870-2,055 m) against ambient seawater, and through examination of historical variability in skeletal Ba chemistry, respectively. First, we report that non-carbonate phases minimally contribute to bamboo coral Ba/Ca, obviating the need for chemical cleaning of live-collected specimens. Second, using newly-obtained profiles of northeast Pacific Ba-isotopic chemistry, we observe that bamboo corals faithfully reflect ambient seawater with a taxonomically- and environmentally-invariant Ba-isotopic offset, D138/134Ba_coral-SW, of −0.37±0.03 ‰ (±2 SD, n = 8). The partition coefficient for Ba, KD_Ba, is similarly insensitive to taxonomy, but linearly decreases with depth. The driving mechanism is unresolved. Third, we find minimal Ba/Ca and Ba-isotopic variability in historical growth representing the past century. We interpret this invariance as evidencing the overall fidelity of deep-sea bamboo corals for ambient Ba chemistry over their long lifespans. The insensitivity of D138/134Ba_coral-SW to environmental gradients indicates that the Ba-isotopic composition of bamboo corals can be interpreted solely in terms of seawater composition, which should find myriad applications to the study of past ocean circulation over a range of timescales. #--------------------------------------- # Funding_Agency # Funding_Agency_Name: National Science Foundation # Grant: OCE-1420984, OCE-1443577, OCE-173694 #--------------------------------------- # Site_Information # Site_Name: T1104 A7 Monterey Canyon # Location: North Pacific Ocean # Country: # Northernmost_Latitude: 36.74 # Southernmost_Latitude: 36.74 # Easternmost_Longitude: -122.03 # Westernmost_Longitude: -122.03 # Elevation: -870 #--------------------------------------- # Data_Collection # Collection_Name: T1104 A7 D14C Geyman2019 # First_Year: 1956.4 # Last_Year: 2007.5 # Time_Unit: AD # Core_Length: # Notes: Chronologies described in supplemental information with Geyman et al. (2019) #--------------------------------------- # Species # Species_Name: Isidella sp. # Common_Name: bamboo coral # Tree_Species_Code: #--------------------------------------- # Chronology_Information # Chronology: # Age models were constructed for each of the six corals used for paleoceanographic reconstructions of Ba/Ca and barium isotopes. We used existing D14C data published by Frenkel et al., (2017) for three of the corals (T1101 A7, T1101 A10, T1102 A12), data published by Hill et al., (2014) for T664 A1, and new D14C data collected in this study for T1104 A7, and T1102 A10. We followed the method described in Frenkel et al. (2017) to decalcify, clean, and separate peels from the gorgonin nodes of specimens T1104 A7 and T1102 A10. Coral peels were sub-sampled and analyzed for D14C at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility in Woods Hole, MA. Samples were first combusted using an elemental analyzer (Costech 4010) and resulting CO2 gas was cryogenically separated from the helium carrier gas stream (Burke et al., 2010; Lardie Gaylord et al., in press) and converted to solid graphite targets (Gagnon et al., 2000). Graphite targets were analyzed on the USAMS instrument (3MV Tandetron; von Reden et al., 2004; Longworth et al., 2015). The corals used in this study spanned a larger depth and spatial range than the specimens used in the Frenkel et al., (2017) study. Therefore, we identified chronological tie points for T1104 A7, and T664 A1, based on inflection points for each of these new coral D14C records generated here rather than determining tie points by interpolating to a consistent D14C value across all corals (as was done in Frenkel et al., 2017). In order to apply the age models calculated from the gorgonin nodes to the samples extracted from the calcitic internodes, the gorgonin-based age models were scaled to the size of the calcitic internodes. Although the the gorgonin nodes used for chronology development were adjacent to the calcitic internode used for Ba/Ca and d138/134Ba analysis, the gorgonin nodes and the calcitic internodes are not exactly equal in size (radius and area). Therefore, the chronological tie point locations determined for the gorgonin nodes were scaled to their equivalent proportional distance from the edge of the calcitic nodes. The dA/dt values that were used to develop the age model for the calcitic internode Ba/Ca and d138/134Ba data were calculated using these scaled tie point locations. We propagated a ± 2 year uncertainty associated with the onset of the D14C increase (1957) and maximum (1970) in Northern Hemisphere surface waters (Frenkel et al., 2017). This chronological uncertainty does not incorporate uncertainty associated with the width of the samples analyzed, consistent with previous studies (Roark et al., 2005; Sherwood et al., 2009; Hill et al., 2014; Schiff et al., 2014; Frenkel et al., 2017). # Coral ID ID numbers assigned to individual specimens used in this study (as in Table 1 in Geyman et al., 2019) # Tie Point Distance (mm) Location of live edge and/or 14C bomb spike inflection point in coral gorgonin used as tie point to assign chronology. Tie points expressed as mm from coral core based on midpoint of peel identified as tie point- or interpolated point calculated (see Frenkel et al., 2017) for details - and additional notes below # Date Assigned Date assigned to inflection points in bomb spike curve (tie points): additional text in chronology notes above # Date Meth Dating method # dA/dt_gorgonin (mm2/yr) Areal growth rate of gorgonin internodes calculated for period spanning date assigned in above row to date in present row (i.e., 1957-1970) # dA/dt_gorgonin Uncertainty (mm2/yr) Uncertainty in areal growth rate of gorgonin internodes during period described above # Tie Point Distance Calcite (mm) Location in calcite internodes corresponding to gorgonin tie points # dA/dt_calcite (mm2/yr) Areal growth rate of calcite nodes calculated for period spanning date assigned in above row to date in present row (i.e., 1957-1970) # dA/dt_calcite Uncertainty (mm2/yr) Uncertainty in areal growth rate of calcite nodes during period described above # # Coral ID Tie Point Distance (mm) Date Assigned Date Meth dA/dt_gorgonin (mm2/yr) dA/dt_gorgonin Uncertainty (mm2/yr) Tie Point Distance Calcite (mm) dA/dt_calcite (mm2/yr) dA/dt_calcite Uncertainty (mm2/yr) # T1101 A7 1.58 1957 interpolated from bomb spike - - 1.74 - - # T1101 A7 4.5 1970 interpolated from bomb spike 4.28 0.93 4.95 5.2 0.39 # T1101 A7 7.67 2007.5 coral edge 3.23 0.17 8.45 3.92 0.21 # # T1101 A10 3.56 1957 interpolated from bomb spike - - 3.28 - - # T1101 A10 5.87 1970 interpolated from bomb spike 5.26 1.14 5.4 4.46 0.34 # T1101 A10 7.8 2007.5 coral edge 2.21 0.12 7.18 1.87 0.1 # # T1102 A12 3.12 1957 interpolated from bomb spike - - 2.87 - - # T1102 A12 4.68 1970 interpolated from bomb spike 2.94 0.64 4.3 2.49 0.19 # T1102 A12 6.86 2007.5 coral edge 2.1 0.11 6.31 1.78 0.1 # # T1104 A7 3.78 1957 interpolated from bomb spike - - 5.94 - - # T1104 A7 6.45 1970 interpolated from bomb spike 6.6 1.44 10.13 16.27 1.23 # T1104 A7 8.94 2007.5 coral edge 3.21 0.17 14.04 7.91 0.42 # # T664 A1 14.1 1957 interpolated from bomb spike - - 8.67 - - # T664 A1 15.5 1970 interpolated from bomb spike 10.01 2.18 9.53 3.79 0.29 # # T1102 A10 5.132 1957 interpolated from bomb spike - - 5.405 - - # T1102 A10 6.168 1966.9 interpolated outer peel date 3.7 0.81 6.5 4.108 0.31 # # Additional notes from Geyman et al. (2019): NaN NaN NaN NaN NaN NaN NaN NaN # Coral specimens T664 A1 and T1102 A10 exhibited incomplete bomb spikes NaN NaN NaN NaN NaN NaN NaN NaN # #--------------------------------------- # Variables # Data variables follow that are preceded by "##" in columns one and two. # Variables list, one per line, shortname-tab-longname components (9 components: what, material, error, units, seasonality, archive, detail, method, C or N for Character or Numeric data) ## Coral_ID Sample identification,Isidella sp.,,,,Corals and Sclerosponges,,,C,ID numbers assigned to individual corals used in this study (as in Table 1 in Geyman et al., 2019) ## Dist_from_core Depth,Isidella sp.,,millimeter,,Corals and Sclerosponges,,,N,Sample location in core measured as radial distance from coral core (mm): based on midpoint of peel ## Peel_width layer thickness,Isidella sp.,,millimeter,,Corals and Sclerosponges,,,N,Width of gorgonin peel; Peels of concentric gorgonin layers as described in Frenkel et al., 2017 and references therein ## D14C Delta 14C,Isidella sp.,,per mil NBS oxalic acid,,Corals and Sclerosponges,,accelerator mass spectrometry,N, ## D14C_err Delta 14C,Isidella sp.,one standard deviation,per mil NBS oxalic acid,,Corals and Sclerosponges,,accelerator mass spectrometry,N,AMS counting error; Internal statistical error (E) was calculated using the total number (n) of 14C counts measured for each target (E=1/n) and external error was calculated from the reproducibility of ten separate 14C/12C measurements obtained over the course of a run. The final error reported is the larger of the internal and external errors. #------------------------ # Data: # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing_Values: -999 Coral_ID Dist_from_core Peel_width D14C D14C_err T1104 A7 9.5 2.2 -116.9 3.1 T1104 A7 11.7 0.3 -86.2 3.4 T1104 A7 12 2.1 -100.5 3.4 T1104 A7 14.1 1.4 -74.2 3.5 T1104 A7 15.5 2 81.3 4