Sea Water Radiocarbon Evolution in the Gulf of Alaska: 2002 Observations

Journal Article · Fri Apr 08 04:00:00 EDT 2005 · Radiocarbon, vol. 48, no. 1, January 30, 2006, pp. 1-15

OSTI ID:897991

Guilderson, T P; Roark, E B; Quay, P D; Flood-Page, S R; Moy, C

Oceanic uptake and transport of bomb radiocarbon as {sup 14}CO{sub 2} created by atmospheric nuclear weapons testing in the 1950s and 1960s has been a useful diagnostic to determine the carbon transfer between the ocean and atmosphere. In addition, the distribution of radiocarbon in the ocean can be used as a tracer of oceanic circulation. Results obtained from samples collected in the Gulf of Alaska in the summer of 2002 provide a direct comparison with results in the 1970s during GEOSECS and in the early 1990s during WOCE. The open gyre values are 20-40{per_thousand} more negative than those documented in 1991 and 1993 (WOCE) although the general trends as a function of latitude are reproduced. Surface values are still significantly higher than pre-bomb levels ({approx}-105{per_thousand} or lower). In the central gyre, we observe {Delta}{sup 14}C-values that are lower in comparison to GEOSECS (stn 218) and WOCE P16/P17 to a density of {approx}26.8{sigma}t. This observation is consistent with the overall decrease in surface {Delta}{sup 14}C values, and reflects the erosion of the bomb-{sup 14}C transient. We propose that erosion of the bomb-{sup 14}C transient is accomplished by entrainment of low {sup 14}C water via vertical exchange within the Gulf of Alaska and replenishment of surface and sub-thermocline waters with waters derived from the far northwest Pacific.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 897991
• Report Number(s): UCRL-JRNL-213370
• Journal Information: Radiocarbon, vol. 48, no. 1, January 30, 2006, pp. 1-15, Journal Name: Radiocarbon, vol. 48, no. 1, January 30, 2006, pp. 1-15
• Country of Publication: United States
• Language: English

Related Subjects

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE
58 GEOSCIENCES
BOMBS
CARBON
DISTRIBUTION
ENTRAINMENT
GULF OF ALASKA
NUCLEAR WEAPONS
OCEANIC CIRCULATION
SEAS
TESTING
TRANSIENTS
TRANSPORT
WATER