Depth distribution of δ13C of dissolved ΣCO2 in seawater off eastern Taiwan: Effects of the Kuroshio current and its associated upwelling phenomenon
Journal
Continental Shelf Research
Journal Volume
16
Journal Issue
12
Pages
1609-1619
Date Issued
1996
Author(s)
Abstract
This paper presents depth variations of dissolved O2, ΣCO2, alkalinity, and δ13C of ΣCO2 in seawater off eastern Taiwan. O2 decreases from an averaged surface value of approximately 4.6 ml l-1 to a minimum of about 2.0 ml l-1 at a depth of 1000 m, and then increases gradually to about 3.5 ml l-1 near the seafloor. ΣCO2 concentrations increase from typical values of 1900-2050 μmol kg-1 at the surface to 2100-2300 μmol kg-1 at depths of more than 1000 m, corresponding to an increase in alkalinity from about 2250μeq kg-1 at the surface to 2450 μeq kg-1 in the bottom water. δ13C of ΣCO2 at the surface averages about +0.25% and becomes lighter with increasing depth to approximately -1.0%. The observed depth distributions of O2, ΣCO2, alkalinity and δ13C of ΣCO2 are thus similar to those reported in the open ocean and can be attributed to O2 utilization and CO2 production during organic decomposition. On a close examination, however, rates of O2 decrease and ΣCO2 and alkalinity increases are less profound than those observed in the open ocean, particularly in the Pacific. Furthermore, values of δ13C measured are invariably lighter than those reported in the Pacific. The discrepancy is attributed largely to the presence of the Kuroshio current and its associated upwelling phenomenon in the continental margin off eastern Taiwan.
SDGs
Type
journal article