Global ocean

Figure 4 Mean annual net CO2 flux over the global oceans (in 10 " grams of C per year per 5" square)"...

A major opportunity to test the use of " Th as a proxy for POC flux arose with the Joint Global Ocean Flux Study (JGOFS). JGOFS had as a central goal a better understanding of the ocean carbon cycle, including the flux of POC leaving the euphotic zone. Process studies were carried out in the Atlantic Ocean, Pacific Ocean, Arabian Sea and Southern Ocean. " Th profiles were obtained as a part of each process study. 

PFOA observations To evaluate MPI-MCTM model results observational data of PFOA from ship cruises in the Atlantic, Indian and Pacific Oceans were taken from literature (summarised in Yamashita et al (2008)). The data was collected between 2002 and 2006 in a global ocean monitoring initiative. Samples were taken from ocean surface water. Vertical profiles were sampled in the Labrador sea, the Mid Atlantic ocean, the South Pacific ocean and the Japanese sea, where water probes were done at several depths down to 5500 m. The limit of quantification for PFOA was determined as 6 pg/L. 

Fig. 3.17 Vertical and latitudinal distribution of PFOA mass in the global oceans [t] (left), 12/2004, fraction of mass bound to organic matter [%] (right), 06/2004.Upper panels KOC115, lower panels KOC11500.

Fig. 3-1. A simple representation of the general circulation of the global ocean, adapted from Broecker and Peng (1982, p. 382). The arrows denote fluxes of water expressed in Sverdrups (1 Sverdrup = 106 m3/sec). River water is added to the surface reservoirs, and an equal volume of water is removed by evaporation.

Changes in global ocean currents or in the amount of energy emitted by the sun could be a major part of the change. Most of industry including the oil, gas, coal and auto companies see the problem as a theory in need of more research, but many cry for serious action to reduce fossil fuel use. 

An early attempt to resolve the discrepancy between the high values of Sugimura and Suzuki (1988) and more traditional analyses failed to reach a definitive conclusion (Williams, 1992). The start of the Joint Global Ocean Flux Study (JGOFS) field program with the North Atlantic Bloom Experiment in 1989 put additional pressure on the various groups to resolve this issue quickly. The National Science Foundation (NSF) and the National Oceanic and Atmospheric Administration (NOAA) funded a workshop held in Seattle in July 1991 to resolve the issue. 

The urgent need for nutrient standards was demonstrated during the recently completed World Ocean Circulation Experiment (WOCE) and Joint Global Ocean Flux Study (JGOFS) measurements which were made by different laboratories. The internal consistency of the nutrient data was evaluated by comparing measurements made in deep water (depth over 3500 m) at nearby stations on different cruises. If one assumes that nutrient concentrations in deep water at the same location should not... 

JGOFS Joint Global Ocean Flux Study... 

Albarede F, Goldstein SL, Dautel D (1997b) The Nd isotopic composition of Mn-nodules from the Southern and Indian Oceans, the global oceanic Nd budget, and their bearing on deep ocean circulation. Geochim Cosmochim Acta 61 1277-1291... 

Finally, because the Mo ocean budget should be strongly sensitive to bottom water redox conditions, particularly perturbations associated with expanded deep sea anoxia, determination of Mo concentrations or their variations in ancient seawater, via sedimentary proxies, has been proposed as an indicator of global ocean paleoredox change (e.g., Emerson and Huested 1991). 

Based on these considerations, the importance of fractionation in suboxic sedimentary systems for the global ocean Mo isotope budget is probably modest. This conclusion follows from the magnitude of relative to ag. Mno, and the relatively modest importance of suboxic sediments as compared to Mn oxides for the global ocean Mo elemental budget (Morford and Emerson 1999 Emerson and Breckel personal communication). However, this prediction must be assessed by further studies in open ocean reducing sediments. 

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