sup 222 Rn, sup 226 Ra, and sup 228 Ra as tracers for the evolution of warm core rings

Thesis/Dissertation · Thu Dec 31 23:00:00 EST 1987

OSTI ID:6747265

Orr, J C

Naturally occurring levels of {sup 228}Ra, {sup 226}Ra, and {sup 222}Rn were measured in and around warm core rings to enhance interpretation provided by conventional conservative tracers. Surplus {sup 222}Rn was found in warm core ring 82B, thereby indicating penetration of rapidly advecting shelf water (transit time {le} 16 days). An in situ pumping system has been developed to rapidly extract {sup 228}Ra from seawater. This instrument may also simplify large-volume sampling for other trace species in seawater. Coincidence counting ({beta}-{gamma}) has been applied to analysis of oceanic {sup 228}Ra, providing precise, low-level determinations shortly after sampling with relatively high counting efficiency (5.3%), low background (0.0054 cpm) and reasonable ease of analytical processing. Results show, {sup 228}Ra activity within ring 82B increased with ring age, marking infiltration of surrounding waters. Also {sup 228}Ra must have been lost from ring 82B before it was 2 months old, an interpretation supported by physical evolution models of ring 82B and distributions of particulate Mn and {sup 228}Ra. Because {sup 226}Ra is not similarly lost, {sup 228}Ra could not have been scavenged. Particulate Mn is the only species found to correlate with {sup 228}Ra. Loss of both species in young ring 82B is attributed to their incorporation into rapidly sinking fecal material. Latter, enhanced zooplankton activity indirectly facilitated solubilization of adsorbed {sup 228}Ra; particles subsequently lost were deficient in {sup 228}Ra. Like warm core rings, the Gulf Stream loses {sup 228}Ra at a rate 60 times faster than explainable by radioactive decay, without corresponding loss of {sup 226}Ra or particulate Ba. Evaluation of counting methods reveals a fivefold sensitivity jump is feasible for {sup 228}Ra.

• Research Organization: Texas A and M Univ., College Station, TX (USA)
• OSTI ID: 6747265
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540310 -- Environment
Aquatic-- Basic Studies-- (1990-)
58 GEOSCIENCES
580000* -- Geosciences
AGE DEPENDENCE
ALKALINE EARTH ISOTOPES
ALPHA DECAY RADIOISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBON 14 DECAY RADIOISOTOPES
CHEMISTRY
CURRENTS
DAYS LIVING RADIOISOTOPES
ELEMENTS
EVEN-EVEN NUCLEI
GEOCHEMISTRY
GEOLOGIC STRUCTURES
GULF STREAM
HEAVY ION DECAY RADIOISOTOPES
HEAVY NUCLEI
HYDROGEN COMPOUNDS
ISOTOPES
MANGANESE
METALS
NUCLEI
OCEANOGRAPHY
ORIGIN
OXYGEN COMPOUNDS
PARTICLES
PARTICULATES
RADIOISOTOPES
RADIUM 226
RADIUM 228
RADIUM ISOTOPES
RADON 222
RADON ISOTOPES
SAMPLING
SEAWATER
TEMPERATURE DISTRIBUTION
TRANSITION ELEMENTS
WATER
WATER CHEMISTRY
WATER CURRENTS
YEARS LIVING RADIOISOTOPES