Use of 210Pb/226Ra disequilibria in the dating of deep-sea whale falls Article

Schuller, D, Kadko, D, Smith, CR. (2004). Use of 210Pb/226Ra disequilibria in the dating of deep-sea whale falls . EARTH AND PLANETARY SCIENCE LETTERS, 218(3-4), 277-289. 10.1016/S0012-821X(03)00690-3

cited authors

  • Schuller, D; Kadko, D; Smith, CR

authors

abstract

  • Deep-sea whale falls, in particular the skeletal remains of whales that have sunk to the seafloor, are remarkable temporary reducing habitats. Reduced chemical species created by anaerobic microbial decay of lipid and organic compounds within the whale bone matrix fuel chemosynthetic-based communities, including bacteria, mussels, limpets, snails, and clams. Many of these species exhibit taxonomic affinities to other chemosynthetic deep-sea organisms colonizing hydrothermal vents and cold seeps. Knowledge of the timescales of whale fall community succession and persistence of these assemblages is needed to reliably estimate the abundance of whale fall habitats and to understand the dynamics of the whale fall communities and their potential roles as stepping stones for sulfophilic species. We have developed a radiochemical method based on 210Pb/226Ra disequilibria for estimating the ages of seafloor whale bone communities. Measurements of 210Pb/226Ra performed on known age bone samples yielded radioisotope ages in good agreement with the known ages. Our results indicate that this technique is valid for bones 10-85 years old (time since cetacean death). This technique, applied to multiple bones of unknown age whale falls taken from Monterey Canyon, Santa Catalina Basin, and San Nicholas Basin, constrained the upper limit ages of these systems (in 2002) to 6.3±1.0 years, 44.0±7.0 to 53.4±8.3 years, and 66.4±9.6 to 82.6±11 years, respectively. These ages were in reasonable agreement with faunal and/or skeletal observations. In addition, a preliminary lipid degradation rate was calculated for the Santa Catalina Basin whale fall using an independent time series and calibrated to the radiochemically determined age. Both radiochemical and lipid degradation evidence suggest that the whale fall microhabitat is able to support life for many decades. © 2003 Elsevier B.V. All rights reserved.

publication date

  • February 15, 2004

published in

Digital Object Identifier (DOI)

start page

  • 277

end page

  • 289

volume

  • 218

issue

  • 3-4