TY - JOUR
T1 - Organic carbon and apparent oxygen utilization in the western South Pacific and the central Indian Oceans
AU - Doval, M. D.
AU - Hansell, Dennis A.
N1 - Funding Information:
This work was conducted as a component of the NOAA Office of Global Programs' OACES, through NOAA Award NA56GP0207 to DAH. MDD was supported from the NOAA Award NA 56GP0207, from a fellowship from the Bermuda Biological Station for Research, Grant-in-Aid program, and from `Direccion General de Universidades e Investigacion de la Xunta de Galicia'. Rachel Parson, Susan Becker and Tye Waterhouse performed the analyses of TOC during the cruises. We thank Calvin Mordy (PMEL), who provided us with inorganic nitrogen data. We gratefully acknowledge the officers, crew and technicians of the NOAA Ships Discoverer and Malcom Baldrige for their assistance. Thanks to E.T. Peltzer and two anonymous reviews for their contribution to improve the manuscript. This is Contribution No. 1519 from the Bermuda Biological Station for Research.
PY - 2000/1
Y1 - 2000/1
N2 - Samples for total organic carbon (TOC) analysis were collected on WOCE Line P15S (0°to 67°S along 170°W) and from 53°to 67°S along 170°E in the western South Pacific, and on Line I8 (5°N to 43°S along 80°/90°E) in the central Indian Ocean. TOC concentrations in the upper ocean varied greatly between the regions studied. Highest surface TOC concentrations (81-85 μM C and 68-73 μM C) were observed in the warmest waters (> 27°C) of the western South Pacific and central Indian Oceans, respectively. Lowest Surface TOC concentrations (45-65 μM C) were recorded in the southernmost waters occupied (> 50°S along 170°W and 170°E). Deep Water (> 1000 m) TOC concentrations were uniform across all regions analyzed, averaging between 42.3 and 43 μM C (SD: ± 0.9 μM C). Mixing between TOC-rich surface waters and TOC-poor deep waters was indicated by the strong correlations between TOC and temperature (r2 > 0.80, north of 45°S) and TOC and density (r2> 0.50, southernmost regions). TOC Was inversely correlated with-apparent oxygen utilization (AOU) along isopycnal surfaces north of the Polar Frontal Zone (PFZ) and at depths < 500 m. The TOC:AOU molar ratios at densities of σ(τ) 23-27 ranged from -0.15 to -0.34 in the South Pacific and from -0.13 to -0.31 in the Indian Ocean. These ratios indicate that TOC oxidation was responsible for 21%-47% and 18%-43% of oxygen consumption in the upper South Pacific and Indian Oceans, respectively. At greater depths, TOC did not contribute to the development of AOU. There was no evidence for significant export of dissolved and suspended organic carbon along isopycnal surfaces that ventilate near the PFZ.
AB - Samples for total organic carbon (TOC) analysis were collected on WOCE Line P15S (0°to 67°S along 170°W) and from 53°to 67°S along 170°E in the western South Pacific, and on Line I8 (5°N to 43°S along 80°/90°E) in the central Indian Ocean. TOC concentrations in the upper ocean varied greatly between the regions studied. Highest surface TOC concentrations (81-85 μM C and 68-73 μM C) were observed in the warmest waters (> 27°C) of the western South Pacific and central Indian Oceans, respectively. Lowest Surface TOC concentrations (45-65 μM C) were recorded in the southernmost waters occupied (> 50°S along 170°W and 170°E). Deep Water (> 1000 m) TOC concentrations were uniform across all regions analyzed, averaging between 42.3 and 43 μM C (SD: ± 0.9 μM C). Mixing between TOC-rich surface waters and TOC-poor deep waters was indicated by the strong correlations between TOC and temperature (r2 > 0.80, north of 45°S) and TOC and density (r2> 0.50, southernmost regions). TOC Was inversely correlated with-apparent oxygen utilization (AOU) along isopycnal surfaces north of the Polar Frontal Zone (PFZ) and at depths < 500 m. The TOC:AOU molar ratios at densities of σ(τ) 23-27 ranged from -0.15 to -0.34 in the South Pacific and from -0.13 to -0.31 in the Indian Ocean. These ratios indicate that TOC oxidation was responsible for 21%-47% and 18%-43% of oxygen consumption in the upper South Pacific and Indian Oceans, respectively. At greater depths, TOC did not contribute to the development of AOU. There was no evidence for significant export of dissolved and suspended organic carbon along isopycnal surfaces that ventilate near the PFZ.
KW - Apparent oxygen utilization
KW - Central Indian Ocean
KW - Dissolved organic carbon
KW - Total organic carbon
KW - Western South Pacific Ocean
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U2 - 10.1016/S0304-4203(99)00081-X
DO - 10.1016/S0304-4203(99)00081-X
M3 - Article
AN - SCOPUS:0033973628
VL - 68
SP - 249
EP - 264
JO - Marine Chemistry
JF - Marine Chemistry
SN - 0304-4203
IS - 3
ER -