@article {2509,
	title = {Quantifying bamboo coral growth rate nonlinearity with the radiocarbon bomb spike: A new model for paleoceanographic chronology development},
	journal = {Deep Sea Research Part I: Oceanographic Research Papers},
	year = {2017},
	month = {Jan-04-2017},
	abstract = {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 Δ14C 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 Δ14C 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 {\textmu}m/year, with a decrease in growth rate evident between the 1957{\textendash}1970 and 1970{\textendash}2007.5 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 Δ14C bomb spike time series from individual corals improves chronology accuracy for all live-collected corals with complete Δ14C 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.},
	keywords = {14C nuclear bomb spike, Bamboo coral, Chronologies, Gorgonin, Growth rate, paleoceanography, radiocarbon},
	issn = {09670637},
	doi = {10.1016/j.dsr.2017.04.006},
	url = {https://doi.org/10.1016/j.dsr.2017.04.006},
	author = {Frenkel, M.M. and LaVigne, M. and Miller, H.R. and Hill, T.M. and McNichol, A. and Gaylord, M. Lardie}
}
@article {2071,
	title = {Changes in the 13C/12C of dissolved inorganic carbon in the ocean as a tracer of anthropogenic CO2 uptake},
	journal = {Global Biogeochemical Cycles},
	volume = {17},
	year = {2003},
	note = {id: 1546},
	month = {2003},
	pages = {1-4},
	author = {Quay, P. and Sonnerup, R. and Westby, T. and Stutsman, J. and McNichol, A.}
}
@conference {1744,
	title = {Plans for expanded 14C analyses at the NOSAMS facility - a status and progress report},
	booktitle = {International Conference on Accelerator Mass Spectrometry},
	year = {2002},
	note = {id: 1685},
	month = {2002},
	address = {Nagoya, Japan},
	author = {von Reden, K. F. and Donoghue, J. and Elder, K. and Gagnon, A. and Gerlach, D. and Griffin, V. and Healy, R. and Long, P. and McNichol, A. and Percy, D. and Roberts, M. L. and Schneider, R. J. and Xu, L. and Hayes, J. M.}
}
@conference {1805,
	title = {Ten Years After--The WOCE AMS Radiocarbon Program},
	booktitle = {8th International Conference on Accelerator Mass Spectrometry},
	year = {1999},
	note = {id: 1757},
	month = {1999},
	address = {Vienna, Austria},
	author = {McNichol, A. and Schneider, R. and von Reden, K. and Gagnon, A. and Elder, K. and Key, R. and Quay, P.}
}
@article {2249,
	title = {AMS Measurement of small samples with high-current system: (Proceedings of the 16th International Radiocarbon Conference, 1997)},
	journal = {Radiocarbon},
	volume = {40},
	year = {1998},
	note = {id: 1815},
	month = {1998},
	pages = {247-253},
	author = {von Reden, K. F. and McNichol, A. and Pearson, A. and Schneider, R.}
}
@article {972,
	title = {Technology revolutionizes tracer oceanography during WOCE},
	journal = {International WOCE Newsletter},
	volume = {30},
	year = {1998},
	note = {id: 324},
	pages = {19-20},
	author = {Key, R. M. and McNichol, A.}
}
@conference {1545,
	title = {14C AMS measurement of C AMS measurement of C AMS measurement of},
	booktitle = {16th International Radiocarbon Conference, Groningen},
	volume = {Book of Abstracts},
	year = {1997},
	note = {id: 952},
	month = {1997},
	pages = {159},
	author = {von Reden, K. and McNichol, A. and Pearson, A. and Schneider, R.}
}
@article {2290,
	title = {The first trans-Arctic 14C section: comparison of the mean ages of the deep waters in the Eurasian and Canadian Basins of the Arctic Ocean; in Proceedings of the 7th International Conference on Accelerator Mass Spectrometry},
	journal = {Nuclear Instruments and Methods},
	volume = {B},
	year = {1997},
	note = {id: 1751},
	month = {1997},
	pages = {431-437},
	author = {Schlosser, P. and Kromer, B. and Ekwurzel, B. and Bonisch, G. and McNichol, A. and Schneider, R. and von Reden, K. and Ostlund, H. and Swift, J.}
}
@conference {1714,
	title = {The NOSAMS sample preparation laboratory: overview of systems and techniques},
	booktitle = {16th International Radiocarbon Conference},
	year = {1997},
	note = {id: 955},
	month = {1997},
	pages = {50},
	publisher = {Book of Abstracts},
	organization = {Book of Abstracts},
	address = {Groningen},
	author = {Gagnon, A. R. and McNichol, A. and Donoghue, J. C. and Merkle, K. M. and Morin, T. J.}
}
@conference {1604,
	title = {Deep water formation and exchange rates in the Arctic Ocean: Implications from the distribution of 14C},
	booktitle = {7th International Conference on Accelerator Mass Spectrometry},
	volume = {38},
	year = {1996},
	note = {id: 947; 1},
	month = {1996},
	pages = {106-107},
	publisher = {Radiocarbon},
	organization = {Radiocarbon},
	address = {Tucson, AZ},
	author = {Schlosser, P. and Kromer, B. and Ekwurzel, B. and Boenisch, G. and McNichol, A. and Schneider, R. and von Reden, K. and Oestlund, G.}
}
