Atlantic Base Section

In the Atlantic, deep water anomalies in 3He were found to be considerably less than in the Pacific, in accord with the conclusions based on total saturation anomalies (Section 4.3), but nevertheless quite definitely present in a characteristic level <5 He = 5% (Jenkins et al., 1972). Albeit at a lower level than in the Pacific, the deep Atlantic 3He excesses also show considerable structure in a detailed study of the western Atlantic, Jenkins, and Clarke (1976) observed a maximum <53He of 13% and identified a localized source in the Gibbs Fracture Zone southwest of Iceland. To the south (at about 30°N), a section across the Mid-Atlantic Ridge shows no perceptible influence of the ridge itself on <53He (Lupton, 1976), a result in marked contrast to the comparable data for the East Pacific Rise (Figure 4.4). 

The Geochemical Ocean Section Program (GEOSECS) has produced data from which it is possible to profile the saturation state of seawater with respect to calcite and aragonite in the Atlantic and Pacific oceans. Representative north-south calcite saturation profiles for the Western Atlantic and Central Pacific oceans are presented in Figures 5 and 6 (based on 39). It was observed that the saturation state of seawater with respect to calcite at the CCD was close to constant ( 2 = 0.70 I" 0,05) except in the southern extremes (39). Broecker and Takahashi (31) have recently found that the carbonate ion concentration is close to constant at the FL, when appropriate corrections are made for pressure. The saturation state of seawater at the FL, calculated by the method presented in this paper, is 0.80 0.05. Berger (40) has presented profiles for Rq, FL, CCD and CSL (calcite saturation level) in the eastern and western Atlantic ocean (see... 

This section is based on an economic evaluation of the Rodale Farming System Trial as presented in Hanson, James C., Erik Lichtenberg and Steven E. Peters, Organic versus conventional grain production in the mid-Atlantic an economic and fanning system overview , American Journal of Alternative Agriculture, Vol. 12, 1 November 1997, pp. 2-9. 

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