Carbon and nitrogen export during the JGOFS North Atlantic Bloom experiment estimated from 234Th: 238U disequilibria
- 1 July 1992
- journal article
- Published by Elsevier BV in Deep Sea Research Part A. Oceanographic Research Papers
- Vol. 39 (7-8), 1115-1137
- https://doi.org/10.1016/0198-0149(92)90060-7
Abstract
The disequilibrium between the particle-reactive tracer 234 Th ( t 1 2 = 24.1 days) and its soluble parent, 238 U, was used to examine Th scavenging and export fluxes during the U.S. JGOFS North Atlantic Bloom Experiment (24 April–30 May 1989) at ∼47°N, 20°W. Four profiles of dissolved and particulate 234 Th in the upper 300 m and a non-steady box model were used to quantify dissolved 234 Th uptake and particle export rates. The highest export fluxes occured during the first half of May. From POC/ 234 Th and PON/ 234 Th ratios, particulate organic C and N fluxes were calculated. Results were 5–41 mmol C m −2 day −1 and 0.9–6.5 mmol N m −2 day −1 from the 0–35 m layer. The ratio of POC export flux to primary production ranged from 0.05 to 0.42, peaking in the first half of May. The estimated fluxes agree with the observed losses of total C and N from the upper ocean during the bloom, but yield significantly higher fluxes than were measured by floating traps at 150 and 300 m.Keywords
This publication has 38 references indexed in Scilit:
- Mesoscale and upper ocean variabilities during the 1989 JGOFS bloom studyDeep Sea Research Part II: Topical Studies in Oceanography, 1993
- A high-temperature catalytic oxidation method for the determination of non-volatile dissolved organic carbon in seawater by direct injection of a liquid sampleMarine Chemistry, 1988
- Determination of transuranic and thorium isotopes in ocean water: In solution and in filterable particlesJournal of Radioanalytical and Nuclear Chemistry, 1987
- f-Ratio and its relationship to ambient nitrate concentration in coastal watersJournal of Plankton Research, 1987
- Oceanic stratified euphotic zone as elucidated by 234Th: 238U disequilibria1Limnology and Oceanography, 1987
- Monthly satellite‐derived phytoplankton pigment distribution for the North Atlantic Ocean basinEos, 1986
- 238U,234U and232Th in seawaterEarth and Planetary Science Letters, 1986
- Oxygen utilization rates in North Atlantic subtropical gyre and primary production in oligotrophic systemsNature, 1982
- The removal rates of234Th and228Th from waters of the New York BightEarth and Planetary Science Letters, 1981
- 234Th/238U ratios in the oceanEarth and Planetary Science Letters, 1968