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The global ocean contains a massive reservoir (662 ± 32 Pg C) of dissolved organic carbon (DOC), and its dynamics, particularly in the deepest zones, are only slowly being understood. DOC in the deep ocean is ubiquitously low in concentration (~35 to 48 µmol kg−1) and aged (4000 to 6000 years), persisting for multiple meridional overturning circulations. Deep waters relatively enriched in DOC form in the North Atlantic, migrate to the Southern Ocean to mix with waters from Antarctic shelves and the deep Pacific and Indian Oceans, in turn forming the voluminous waters of the Circumpolar Deep Water. Here we seek evidence for local (autochthonous) versus distant (allochthonous) processes in determining the distribution of DOC in the deep Southern Ocean. Prior analyses on DOC in the deep Southern Ocean have conflicted, describing both conservative and nonconservative traits: the deep DOC field has been reported as uniform in distribution, yet local inputs have been suggested as quantitatively important. We use multiple approaches (multiple linear regression, mass transport, and mass balance calculations) with data from Climate Variability and Predictability Repeat Hydrography sections to evaluate the system. We find that DOC concentrations in the deep Southern Ocean largely reflect the conservative mixing of the several deep waters entering the system from the north. Mass balance suggests that the relatively depleted DOC radiocarbon content in the deep Southern Ocean is a conserved property as well. These analyses advance our understanding of the controls on the DOC reservoir of the Southern Ocean. [ABSTRACT FROM AUTHOR]

Focuses on measurements of total organic carbon (TOC) and nitrogen (TON) which were made on WOCE P18 line, in the eastern Pacific Ocean. Co-ordinates of location given; Information on where TOC accumulated; Observation of boundary separating shallow, TOC-rich and poor water.

Assesses the relative contributions of vertical export and horizontal advection of organic carbon and nitrogen from the equatorial Pacific Ocean through mass balance calculations. Overview of the study; Methods; Results and discussion; Conclusions.

Evaluates the transformations of carbon and nitrogen compounds in the surface waters of the South Equatorial Current of the Pacific Ocean. The calculation of the carbon removed from the surface layer; The effect of degassing and sinking organic particles; The net accumulation of organic matter in the surface layer.