Carbon cycling in western equatorial atlantic sediments: Insights from carbon isotopes
Conference
·
OSTI ID:126670
- Woods Hole Oceanographic Institution, Woods Hole, MA (United States)
Sediments from a site on the Ceara Rise in the western equatorial Atlantic Ocean (5{degrees} 17N, 44{degrees}8W) were collected in March 1994 to study the carbon cycle of ocean sediments. Sediments were collected in 3270 m of water, above the calcite saturation horizon ({triangle}CO{sub 3}{sup 2} {approx} 20). Relatively large volumes (20-30 ml) of pore water were extracted from 1-2 cm interval sections of the surface 10 cm of the sediments using both whole core squeezing and centrifugation techniques. The whole core squeezer permits the in-situ or shipboard extraction of large volumes of pore water without sectioning sediment cores. We analyzed the pore water dissolved inorganic carbon ({Sigma}CO{sub 2}) to yield high resolution profiles of concentration, {gamma}{sup 13}C, and {triangle}{sup 14}C at this site. The bottom water values we measured are about 10 {per_thousand} lower than that measured at a nearby site during the GEOSECS Program in 1974. Pore water {gamma}{sup 13}C decreases regularly from a value of 0.75 {per_thousand} in the bottom water to -0.8 {per_thousand} at 11 cm and {triangle}{sup 14}C decreases regularly from -109 {per_thousand} in the bottom water to -180 at 10 cm. The stable isotope results indicate the addition of carbon to the pore water from both the dissolution of CaCO{sub 3} and the oxidation of organic matter. Pore water radiocarbon results indicate that at least one of these carbon sources is quite old. We will use results from isotopic analyses of the sediment organic matter and CaCO{sub 3} to constrain the sediment carbon budget and discuss the implications for oceanic carbon modelling,
- OSTI ID:
- 126670
- Report Number(s):
- CONF-950402--
- Country of Publication:
- United States
- Language:
- English
Similar Records
The radiocarbon age of calcite dissolving at the sea floor: Estimates from pore water data
Sea Water Radiocarbon Evolution in the Gulf of Alaska: 2002 Observations
The CaCO sub 3 profile in a recent Ionian Sea core and the tree ring radiocarbon record over the last two millennia
Journal Article
·
Fri Mar 31 23:00:00 EST 2000
· Geochimica et Cosmochimica Acta
·
OSTI ID:20062609
Sea Water Radiocarbon Evolution in the Gulf of Alaska: 2002 Observations
Journal Article
·
Fri Apr 08 00:00:00 EDT 2005
· Radiocarbon, vol. 48, no. 1, January 30, 2006, pp. 1-15
·
OSTI ID:897991
The CaCO sub 3 profile in a recent Ionian Sea core and the tree ring radiocarbon record over the last two millennia
Journal Article
·
Sat Sep 01 00:00:00 EDT 1990
· Geophysical Research Letters (American Geophysical Union); (USA)
·
OSTI ID:5980777