Oceanic zone

Fig. 2. Type of manganese nodules found in north central Pacific Ocean zone. (Woods Hole Oceanographic Institution)...

Recent modeling efforts explicitly representing oceanic N2 fixation using physiological growth requirements also have come to the conclusion that there are distinct oceanic zones with regard to predominant limiting factors for diazotrophs (Coles and Hood, 2006 Krishnamurthy et al., 2007). 

The biogeochemical provinces of the Southern Ocean, as defined by Treguer andjacques (1992), are the Polar Front Zone, the Permanently Open Ocean Zone, the Marginal and Seasonal Ice Zones, and the Coastal and Continental Shelf Zone (Fig. 12.1). Note that the Marginal Ice Zone is a seaward subzone of the Seasonal Ice Zone delimited by the recent melting of ice, a seasonally migrating band of recendy exposed surface waters within the Seasonal Ice Zone (Moore et ah, 2000). The... 

Figure 12.1 The sectors of the Southern Ocean and the four biogeochemical provinces the Polar Front Zone, the Permanently Open Ocean Zone, the Marginal and Seasonal Ice Zones, and the Coastal and Continental Shelf Zones.

Pondaven, P., Fravalo, C., Ruiz-Pino, D., Treguer, P., Queguiner, B., and Jeandel, C. (1998). Modelling the silica pump in the permanendy open ocean zone in the Southern Ocean. J. Mar. Syst. 17, 587-619. 

See also Abyssal plain Coast and beach Hydrothermal vents Ocean zones Oceanography Sea level Seamounts Tides. 

From the standpoint of living organisms, the euphotic zone is probably the most important of all oceanic zones since it is the only place in which any significant amount of photosynthesis takes place. By some estimates, about two-thirds of all the photosynthetic activity that occurs on Earth (on land and in the water) takes place within the euphotic zone. 

The thermocline acts as a barrier separating reservoirs of the surface and deep ocean zones. Chemical perturbations associated with human activity mainly impact only on the surface zone. 

Less spectacular but of considerable practical importance is the study of the continental shelves. Oceanographic studies of coastal ocean zones contribute increasingly to key economic development schemes, most notably (but with increasingly controversial environmental implications) in seeking zones for commercial exploitation of undersea petroleum reserves. 

The oceanic zone reaches from 200 meters deep... 

Oceanic zone Depth (m) Area Mfhtr ) % immersed surface... 

The Rio Convention (1992) and the Manila Declaration which supplements it (1992), do not seem to take account of the oceanic zones without sovereignty, such as Antarctica or the abyssal hydrothermal zones located outside any exclusive economic region. See, on this subject, the Report of the Workshop on Bioprospection in the High Seas organized in Dunedin, New Zealand, on 28-29 November 2003, the text of which can be downloaded from the Internet. 

It is often useful to have works which assist in the identification of marine organisms. These books, generally written by biologists and illustrated by various artists, often contain excellent scientific information there are several for each of the oceanic zones. As an example, the following works are indispensable for studying the organisms of the Indo-Pacific and Atlantic zones. 

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