California Margin Bamboo Coral Delta 14C data during the 20th Century Frenkel, M.; LaVigne, M.; Miller, H.R.; Hill, T.M.; McNichol, A.; Lardie Gaylord, M. Frenkel, M. LaVigne, M. Miller, H.R. Hill, T.M. McNichol, A. Lardie Gaylord, M. earth science/paleoclimate/corals and sclerosponges (Delta 14C,Isidella sp.,null,per mil NBS oxalic acid,null,corals and sclerosponges,null,accelerator mass spectrometry,N,null) earth science/paleoclimate/corals and sclerosponges (depth,null,null,millimeter,null,corals and sclerosponges,null,null,N,Sample location in coral measured as radial distance from coral core (mm): based on midpoint of peel) earth science/paleoclimate/corals and sclerosponges (age,null,null,year Common Era,null,corals and sclerosponges,interpolated,null,N,null) earth science/paleoclimate/corals and sclerosponges (Delta 14C,Isidella sp.,null,per mil NBS oxalic acid,null,corals and sclerosponges,null,accelerator mass spectrometry,N,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 10 separate sample 14C/12C measurements obtained over the course of a run. The final error associated with fraction modern values was determined from the larger of the internal or external errors.) earth science/paleoclimate/corals and sclerosponges (sample identification,null,null,null,null,corals and sclerosponges,null,null,C,ID numbers assigned to individual corals used in this study (as in Table 1 in Frenkel et al. 2017)) earth science/paleoclimate/corals and sclerosponges (T1101 A7 Pioneer Seamount>LATITUDE 37.3728>LONGITUDE -123.403317) (T1101 A17 Pioneer Seamount>LATITUDE 37.3743>LONGITUDE -123.4162) (T1102 A12 Davidson Seamount>LATITUDE 35.7312>LONGITUDE -122.72605) (T1101 A14 Pioneer Seamount>LATITUDE 37.370533>LONGITUDE -123.4092) (T1101 A10 Pioneer Seamount>LATITUDE 37.371467>LONGITUDE -123.4065) (T1101 A5 Pioneer Seamount>LATITUDE 37.372633>LONGITUDE -123.403533) Bamboo corals, long-lived cold water gorgonin octocorals, offer unique paleoceanographic archives of the intermediate ocean. These Isididae corals are characterized by alternating gorgonin nodes and high Mg-calcite internodes, which synchronously extend radially. Bamboo coral calcite internodes have been utilized to obtain geochemical proxy data, however, growth rate uncertainty has made it difficult to construct precise chronologies for these corals. Previous studies have relied upon a single tie point from records of the anthropogenic ?14C bomb spike preserved in the gorgonin nodes of live-collected corals to calculate a mean radial extension rate for the outer ~50 years of skeletal growth. Bamboo coral chronologies are typically constructed by applying this mean extension rate to the entire coral record, assuming constant radial extension with coral age. In this study, we aim to test this underlying assumption by analyzing the organic nodes of six California margin bamboo corals at high enough resolution (< 0.5 mm) to identify the ?14C bomb spike, including two tie points at 1957 and 1970, plus the coral collection date (2007.5) for four samples. Radial extension rates between tie points ranged from 10 to 204 ֭/year, with a decrease in growth rate evident between the 1957ֱ970 and 1970ֲ007.5 periods for all four corals. A negative correlation between growth rate and coral radius (r =-0.7; p=0.04) was determined for multiple bamboo coral taxa and individuals from the California margin, demonstrating a decline in radial extension rate with specimen age and size. To provide a mechanistic basis for these observations, a simple mathematical model was developed based on the assumption of a constant increase in circular cross sectional area with time to quantify this decline in radial extension rate with coral size between chronological tie points. Applying the area-based model to our ?14C bomb spike time series from individual corals improves chronology accuracy for all live-collected corals with complete ?14C bomb spikes. Hence, this study provides paleoceanographers utilizing bamboo corals with a method for reducing age model uncertainty within the anthropogenic bomb spike era (~1957-present). Chronological uncertainty is larger for the earliest portion of coral growth, particularly for skeleton precipitated prior to bomb spike tie points, meaning age estimations for samples living before 1957 remain uncertain. Combining this technique with additional chronological markers could improve age models for an entire bamboo coral. Finally, the relative consistency in growth rate in similarly-aged corals of the same depth and location supports the hypothesis that skeletal growth may be limited by local environmental conditions. STUDY NOTES: Provided Keywords: Bamboo Coral, Gorgonin, Chronologies, Radiocarbon, Growth rate, 14C nuclear bomb spike NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Frenkel, M. Investigator : LaVigne, M. Investigator : Miller, H.R. Investigator : Hill, T.M. Investigator : McNichol, A. Investigator : Lardie Gaylord, M. 2017-08-14 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/21911 https://www1.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/frenkel2017/frenkel2017-a5.txt https://www1.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/frenkel2017/frenkel2017-a14.txt https://www1.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/frenkel2017/frenkel2017-a12.txt https://www1.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/frenkel2017/frenkel2017-a10.txt https://www1.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/frenkel2017/frenkel2017-a17.txt https://www1.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/frenkel2017/frenkel2017-a7.txt https://www1.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/frenkel2017/frenkel2017-a5.txt https://www1.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/frenkel2017/frenkel2017-a14.txt https://www1.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/frenkel2017/frenkel2017-a12.txt https://www1.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/frenkel2017/frenkel2017-a10.txt https://www1.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/frenkel2017/frenkel2017-a17.txt https://www1.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/frenkel2017/frenkel2017-a7.txt English https://www.ncdc.noaa.gov/paleo/study/21911 https://www1.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/frenkel2017/frenkel2017-a5.txt https://www1.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/frenkel2017/frenkel2017-a14.txt https://www1.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/frenkel2017/frenkel2017-a12.txt https://www1.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/frenkel2017/frenkel2017-a10.txt https://www1.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/frenkel2017/frenkel2017-a17.txt https://www1.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/frenkel2017/frenkel2017-a7.txt Frenkel, M.M., M. LaVigne, H.R. Miller, T.M. Hill, A. McNichol, and M. Lardie Gaylord2017Quantifying bamboo coral growth rate nonlinearity with the radiocarbon bomb spike: A new model for paleoceanographic chronology developmentDeep Sea Research Part I12526-3910.1016/j.dsr.2017.04.006http://www.sciencedirect.com/science/article/pii/S0967063716303934 START YEAR: 1888 AD * END YEAR: 2008 AD -123.4162 35.7312 -122.72605 37.3743