Elemental distribution vertical

Through the influence of speciation on oceanic input and removal processes it is expected that chemical form should strongly influence not only overall chemical concentrations in the ocean but also chemical distributions. In view of this expectation, assessments of speciation and comparative chemistries in this chapter are made in the context of vertical distributions (concentrations vs depth) of chemical species in the ocean. Since elemental distributions are influenced not... 

Fig. 12-27. Element distributions in a vertical profile from bedrock containing sphalerite veins through to the soil layer at the Bastyan dam-site road cutting (from Carr et al., 1986).

As an example of potential distribution, Fig. 20-8 shows the potential on the vertical axis in a 300-liter electric storage reservoir. The water had an extremely low conductivity of x (20°C) = 30 fiS cm l A Mg rod anode served for cathodic protection it reached to just above the built-in heating element to give uniform current distribution. This was confirmed by the measurements. 

The superposition of the vertical biological cycle on the horizontal ocean circulation pattern leads to three general features in the distribution of the elements involved in this cycle. 

In the foregoing discussion on network elements, we have not accounted for the elevation difference between the two vertices adjoining the network element. This difference, although negligible in many applications, is important in the transportation of liquids as, for example, in water distribution networks. In these applications a term pg(zj — z,) should be added to the pressure drop equation. 

In conclusion, AES is mainly used to study the elemental surface composition of conducting samples. It can be used to make chemical maps of heterogeneous surfaces and to study the vertical distribution of elements as a function of depth. The technique is of great importance in surface science and materials science, but less in the characterization of supported catalysts. 

In conclusion, LEIS is extremely surface sensitive and suitable for determining outer layer compositions of catalysts and alloys, provided that proper calibration can be achieved. The shape of the background contains information about the vertical distribution of elements in the surface region. 

The vertical distribution of biolimiting elements is characterized by deep-water enrichments and surface-water depletions. As described above, this vertical segregation is caused by the remineralization of biogenic particles in the deep sea. Not all particulate matter that sinks into the deep zone is remineralized. Some survives to become buried in the sediments. How much of the biogenic particle flux escapes from surfece waters How much of this particle flux is remineralized in the deep zone How much is lost from the ocean by burial in the sediments What effect does this have on the concentrations of the biolimiting elements ... 

The horizontal and vertical distributions of trace metals in seawater are determined by their relative rates of supply and removal. In this section, we inspect a variety of concentration profiles and assess the processes responsible for determining their shapes. In the case of the vertical profiles, the trace metals can be classified into one of the following types (1) nutrient, (2) conservative, and (3) scavenged, with some elements exhibiting a mixture of these types. 

The influence of river water inputs on trace metal distributions is illustrated in Figure 11.17c, which shows that the surface-water concentration of dissolved Mn in the Pacific Ocean decreases with increasing distance from the California coast. The vertical profile measured in the coastal zone (Figme 11.17b) exhibits a strong surface enrichment characteristic of scavenged trace elements. A similar vertical gradient is seen in the... 

---