Radiocarbon Concentration in Pacific Ocean Water

Abstract

Results of C14 determinations in surface water from the Pacific were in agreement with those reported by Rafter and Fergusson. However, abnormal C14 concentrations seem to exist locally, for which no oceanographic explanation can be given. It seems premature to draw conclusions from existing determinations as to the rate of increase of C" in surface ocean water resulting from the uptake of C14 produced in the atmosphere by atomic bombs. Samples from a constant depth of about 3,500 meters show a C14 content decreasing from south to north. This decrease may be attributed to radioactive decay of C14 during the time of migration. From this the northward component of the rate of water movement of about 0.06 cm/sec can be calculated. The ClS determinations, for the purpose of correcting the C" values for isotope fractionation effects. were found to be remarkably consistent, although made on reburned acetylene.

Seasonal radiocarbon and oxygen isotopes in a Galapagos coral: Calibration with climate indices

“…A source of water to the EEP that has an even lower ∆ 14 C value than SAMW is called shallow overturning water from the northern subpolar Pacific (J. R. T., unpublished data). This northern shallow overturning water has a very low, prebomb ∆ 14 C value, ~−87 to −101‰ during the 1940s and 1950s, as measured in shells and seawater from the California coast and Vancouver Island [ Robinson and Thompson , ; Bien et al ., ; McNeely et al ., ]. This ∆ 14 C range is lower than the value in SAMW, ~−72‰ [ Toggweiler et al ., ; Druffel , ].…”

North Pacific Intermediate Water studied chiefly with radiocarbon

“…This maximum must be due to the artificial radiocarbon formed after 1950's or chiefly in 1960's by the nuclear explosion tests, because the value is higher than that in the surface water in the prebomb era (ca. -40‰ according to Bien et al, 1960;Broecker et al, 1960;Broecker and Peng, 1982).…”

Review of Tropospheric Bomb 14C Data for Carbon Cycle Modeling and Age Calibration Purposes

“…The large pulse of artificial 14 C injected to the atmosphere enables us to use 14 C as a unique and powerful tracer for studying exchanges between carbon reservoirs and the global carbon cycle (Nydal 1968;Oeschger et al 1975;Broecker et al 1980;Druffel and Suess 1983;Levin and Hesshaimer 2000). A few laboratories conducted early measurements to document changes in atmospheric and oceanic 14 C, e.g., Vogel and Marais (1971), Manning and Melhuish (1994) for atmospheric samples; and Broecker et al (1960), Bien et al (1960), Rafter (1968) for oceanic samples. Tans (1981) compiled bomb 14 C data for use in global carbon model calculations.…”