Skip to main content
×
×
Home

Comparison of Large and Ultra-Small Δ14C Measurements in Core Top Benthic Foraminifera from the Okhotsk Sea

  • L D Keigwin (a1) and A R Gagnon (a1)
Abstract

The radiocarbon activity of benthic foraminifera was investigated in surface sediments from a high deposition rate location at a depth of 1000 m in the Okhotsk Sea. Sediments were preserved and stained with Rose Bengal to identify foraminifera that contain cytoplasm. The benthic fauna at this site is dominated by large specimens of Uvigerina peregrina, and bulk samples (∼150 individuals) of stained and unstained specimens were dated. The stained sample was about 240 14C yr younger than the unstained, and the presence of bomb 14C is inferred by comparison to water column data in the nearby open North Pacific. Using new methods, multiple measurements were also made on samples of three stained and unstained individuals (as small as 7 μg C). Results are consistent with those from the bulk samples. This suggests that similar ultra-small measurements could be made at other locations to reveal the age distribution of individuals in a sediment sample in order to assess the extent of bioturbation and the presence of bomb 14C contamination.

Copyright
Corresponding author
Corresponding author. Email: lkeigwin@whoi.edu.
References
Hide All
Barker, S, Broecker, W, Clark, E, Hajdas, I. 2007. Radiocarbon age offsets of foraminifera resulting from differential dissolution and fragmentation within the sedimentary bioturbated zone. Paleoceanography 22(2):PA2205, doi:10.1029/2006PA001354.
Berger, WH, Heath, GR. 1968. Vertical mixing in pelagic sediments. Journal of Marine Research 26(2):134–43.
Bernhard, J, Ostermann, D, Williams, DS, Blanks, JK. 2006. Comparison of two methods to identify live benthic foraminifera: a test between Rose Bengal and CellTracker Green with implications for stable isotope paleoreconstructions. Paleoceanography 21(4):PA4210, doi:10.1029/2006PA001290.
Gagnon, AR, McNichol, AP, Donoghue, JC, Stuart, DR, von Reden, K, Hayes, JM, Schneider, RJ, Elder, KL, Bellino, M, Long, P, Beaudette, R, Handwork, SK. 2000. The NOSAMS sample preparation laboratory in the next millenium: progress after the WOCE program. Nuclear Instruments and Methods in Physics Research B 172(1–4):409–15.
Glass, B. 1969. Vertical dispersal of the Australasian and Ivory Coast microtektite horizons. Earth and Planetary Science Letters 6(6):409–15.
Keigwin, LD. 1996. The Little Ice Age and Medieval Warm Period in the Sargasso Sea. Science 274(5292):1504–8.
Keigwin, LD. 1998. Glacial-age hydrography of the far northwest Pacific Ocean. Paleoceanography 13(4):323–39.
Keigwin, LD, Guilderson, TP. 2009. Bioturbation artifacts in zero-age sediments. Paleoceanography 24(4):PA4212, doi:10.1029/2008PA001727.
Kuzmin, Y, Burr, G, Gorbunov, SV, Rakov, VA, Razjigaeva, NG. 2007. A tale of two seas: reservoir age correction values (R, ΔR) for the Sakhalin Island (Sea of Japan and Okhotsk Sea). Nuclear Instruments and Methods in Physics Research B 259(1):460–2.
Rubin, S, Key, R. 2002. Separating natural and bomb-produced radiocarbon in the ocean: the potential alkalinity method. Global Biogeochemical Cycles 16(4):1105, doi:1110.1029/2001GB001432.
Shah Walter, SR, Gagnon, AR, Roberts, ML, McNichol, AP, Lardie Gaylord, MC, Klein, E. 2015. Ultra-small graphitization reactors for ultra-microscale radiocarbon analysis at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility. Radiocarbon 57(1):109–22.
Talley, LD. 1991. An Okhotsk Sea water anomaly: implications for ventilation in the North Pacific. Deep-Sea Research 38(Supplement 1):S171S190.
Talley, LD. 2007. Hydrographic Atlas of the World Ocean Circulation Experiment (WOCE), Pacific Ocean. World Ocean Circulation Experiment (WOCE) Hydrographic Atlas Series. Sparrow, M, Chapman, P, Gould, J, editors. Southampton, UK: National Oceanography Centre.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Radiocarbon
  • ISSN: 0033-8222
  • EISSN: 1945-5755
  • URL: /core/journals/radiocarbon
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed