Seasonality in the flux of natural radionuclides and plutonium in the deep Sargasso Sea. Technical report

Technical Report · Tue Jan 01 00:00:00 EST 1985

OSTI ID:6105713

Bacon, M P; Fleer, A P; Deuser, W G

A record of radionuclide fluxes at a deep-ocean station near Bermuda (32/sup 0/ 05 min N, 64/sup 0/ 15 min W) was obtained from analysis of a 3-year collection of sediment-trap samples. The trap was placed at a depth of 3200 m, 1000 m above the sea floor, and the samples were recovered at 2-month intervals. Concentrations of U-238, -234, Th-232, -230, -228, Pa-231, Pb-210, Po-210, and Pu-239 and -240 were measured in the trapped material. Most of the radionuclide activity was found in the <37-micron sieved fraction. All radionuclide fluxes showed seasonal variations in phase with the variations in total sediment flux, which had been previously shown to be closely tied to the annual cycle of primary production in the overlying surface water. Seasonal variations are especially noteworthy for Th-230 and Pa-231, considering that most of their production occurs in the water column below the euphotic zone. Evidently the seasonal influence is transmitted downward by the varying particle flux so that radionuclide scavenging rates at depth, as well as at the surface, are affected. It is suggested that this could be brought about by seasonal variations in the flux of marine snow or in the rate of fecal-matter production in the deep-water column. Keywords: Pelagic sedimentation.

• Research Organization: Woods Hole Oceanographic Institution, MA (USA)
• OSTI ID: 6105713
• Report Number(s): AD-A-162675/3/XAB; WHOI-CONTRIB-5452
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
LEAD 210
MONITORING
PLUTONIUM ISOTOPES
POLONIUM 210
PROTACTINIUM 231
SARGASSO SEA
NATURAL RADIOACTIVITY
THORIUM ISOTOPES
URANIUM ISOTOPES
BERMUDA
MATERIALS
PRODUCTION
SEASONAL VARIATIONS
SEDIMENTATION
SNOW
SURFACE WATERS
WATER
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
ATLANTIC OCEAN
ATMOSPHERIC PRECIPITATIONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
DAYS LIVING RADIOISOTOPES
EUROPE
EVEN-EVEN NUCLEI
HEAVY NUCLEI
HYDROGEN COMPOUNDS
ISLANDS
ISOTOPES
LEAD ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
OXYGEN COMPOUNDS
POLONIUM ISOTOPES
PROTACTINIUM ISOTOPES
RADIOACTIVITY
RADIOISOTOPES
SEAS
UNITED KINGDOM
VARIATIONS
WESTERN EUROPE
YEARS LIVING RADIOISOTOPES
520301* - Environment
Aquatic- Radioactive Materials Monitoring &amp; Transport- Water- (1987)