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Sampling and Analysis of Particulate and Dissolved Matter
Published in Roger S. Wotton, The Biology of Particles in Aquatic Systems, 2020
Sugimura and Suzuki8 developed an improved direct injection system for DOC in 1988. Using this system, they found DOC values in the North Pacific between three to six times the accepted wet oxidation values for the region. The differences between the methods were greatest in the surface waters and at depth, approaching agreement at the depth of the oxygen minimum. A close inverse agreement was found between the DOC and the apparent oxygen utilization (AOU). These findings suggested that a large portion of the DOC is resistant to chemical and photochemical oxidation, but available for biological utilization. If these findings hold for the oceans in general, the total amount of organic carbon sequestered by the oceans would be more than doubled, and would far exceed the sequestering of organic carbon by terrestrial plants. Furthermore, the close relationship between DOC and AOU must imply that the particulate organic material plays very little role in biological activities in the water column, an implication contradicting the sediment trap and LVFS data.
Estimates of methane emissions from the Southern Ocean from quasi-continuous underway measurements of the partial pressure of methane in surface seawater during the 2012/13 austral summer
Published in Tellus B: Chemical and Physical Meteorology, 2018
Oanh Thi Ngoc Bui, Sohiko Kameyama, Hisayuki Yoshikawa-Inoue, Masao Ishii, Daisuke Sasano, Hiroshi Uchida, Urumu Tsunogai
The Southern Ocean is one of the most biologically productive oceanic regions in the world; it is characterised by high biomasses of zooplankton, Antarctic krill, and salps (Knox, 2007), all of which having the potential to produce CH4. Although some researchers have measured CH4 concentrations in the Southern Ocean (Lamontagne et al., 1973; Tilbrook and Karl, 1994; Bates et al., 1996; Heeschen et al., 2004; Yoshida et al., 2011), accurate assessment of the sea–air flux of CH4 has been limited by the sparsity of available data. An important aim of this study was to clarify the spatial distribution of the sea–air flux of CH4 in the Southern Ocean and thus to reduce the uncertainties in understanding the ocean as a source of atmospheric CH4. Here, we present the distribution of the sea–air flux of oceanic CH4 along the course of a scientific cruise in the Pacific and Indian sectors of the Southern Ocean during the 2012/13 austral summer; we use the correlation of SR and apparent oxygen utilisation (AOU) to examine the climatological flux of CH4 from the entire Southern Ocean south of 50°S during the austral summer.