Growth rate determinations from radiocarbon in bamboo corals (genus Keratoisis)

• Published in: Deep Sea Research Part I: Oceanographic Research Papers
• Main Authors: Farmer, Jesse R., Robinson, Laura F., Hönisch, Bärbel
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2015
• Subjects: Bamboo coral; Deep-sea coral; Growth rates; Radiocarbon; North Atlantic
• Online Access: https://hdl.handle.net/1983/8846ab56-c2c3-4ae5-a909-c491fd2cc568; https://research-information.bris.ac.uk/en/publications/8846ab56-c2c3-4ae5-a909-c491fd2cc568; https://doi.org/10.1016/j.dsr.2015.08.004; http://www.scopus.com/inward/record.url?scp=84939621446&partnerID=8YFLogxK

Radiocarbon ( 14 C) measurements are an important tool for determining growth rates of bamboo corals, a cosmopolitan group of calcitic deep-sea corals. Published growth rate estimates for bamboo corals are highly variable, with potential environmental or ecological drivers of this variability poorly constrained. Here we systematically investigate the application of 14 C for growth rate determinations in bamboo corals using 55 14 C dates on the calcite and organic fractions of six bamboo corals (identified as Keratoisis sp.) from the western North Atlantic Ocean. Calcite 14 C measurements on the distal surface of these corals and five previously published bamboo corals exhibit a strong one-to-one relationship with the 14 C of dissolved inorganic carbon (DI 14 C) in ambient seawater (r 2 =0.98), confirming the use of Keratoisis sp. calcite 14 C as a proxy for seawater 14 C activity. Radial growth rates determined from 14 C age-depth regressions, 14 C plateau tuning and bomb 14 C reference chronologies range from 12 to 78μmy -1 , in general agreement with previously published radiometric growth rates. We document potential biases to 14 C growth rate determinations resulting from water mass variability, bomb radiocarbon, secondary infilling (ontogeny), and growth rate nonlinearity. Radial growth rates for Keratoisis sp. specimens do not correlate with ambient temperature, suggesting that additional biological and/or environmental factors may influence bamboo coral growth rates.