Eastern Tropical South Pacific

Codispoti, L. A., and Christensen, J. P. (1985). Nitrification, denitrification and nitrous oxide cycling in the Eastern Tropical South Pacific Ocean. Mar. Chem. 16, 277—300. 

Figure 6.5 Dissolved oxygen on the 26.5 sigma theta surface. Note the three main pelagic water column ODZs, the eastern tropical North Pacific, the eastern tropical South Pacific and the Arabian Sea. Althouth oxygen levels are very low in the Bay of Bengal, this area does not appear to be a location of water column denitrification (Rao et al., 1994).

Measurement of the enzyme activity of the respiratory electron transport system (ETS activity) has also been used to estimate denitrification rates in the Arabian Sea (Naqvi and Shail a, 1993) and eastern tropical South Pacific (Codispoti and Packard, 1980) denitrification zones. To measure the ETS activity a crude enzyme extract is made by grinding filtered seawater samples in a buffered medium to liberate the enzymes, after which the ETS substrates NADT1+ and NADPT1+ along with tetrazo-hum salt are added as an artificial electron acceptor. Samples are then incubated for a... 

Lipschultz, F., Wofiy, S. C., Ward, B. B., Codispoti, L. A., Friedrich, G., and Elkins, J. W. (1990). Bacterial transformations of inorganic nitrogen in the oxygen-deficient waters of the eastern tropical South-Pacific ocean. Deep Sea Res. Part a-Oceanogr. Res. Pap. 37(10), 1513. 

Nitrite Nitrite is an intermediate in oxidative and reductive processes such as nitrification and denitrification. It also serves as a substrate for anammox and can be assimilated by phytoplankton. Only when these processes become uncoupled, such as at the base of the euphotic zone and in oxygen minimum zones, does nitrite accumulate to significant levels (0.1-10 (iM). In some oxygen-deficient regions of the water column in the eastern tropical North Pacific, eastern tropical South Pacific, and the Arabian Sea, nitrite can represent as much as 25% of the pool of nitrogen oxides (NOs -F NO2-). 

Consequently, under normal trade wind conditions there is a secondary maximum of atmospheric CO2 in the neighborhood of the equator in the eastern Tropical Pacific (Figure 8). That this is due to an influx of oceanic CO2 to the atmosphere and not to tropical deforestation is clearly shown by the isotopic ratio of carbon 13 to carbon 12, which increases continuously from high northern latitudes where fossil fuel CO2 which, like the CO2 of the land biota, is low in carbon 13, enters the atmosphere, to about 20 south latitude. 

The Tropical Analysis and Forecast Branch (TAFB) of the TPC provides year-round weather analysis and forecast products for the waters of the eastern North and South Pacific and North Atlantic Basin. Forecast products include the following ... 

High seas forecasts for the tropical and subtropical Atlantic, eastern Pacific, and south Pacific Oceans These are updated every 6 h. Topics covered include information about winds, waves, marine, and convection. The forecasts address marine warnings for gale, storm, tropical cyclone conditions, reduced visibility, and other marine hazards. 

Division of the Meteorium and Papillaria species into two major clades also seems to reflect their geographical distribution (Quandt et al., 2004). Meteorium is most diverse in warm temperate and tropical south-east Asia, especially southern China, the eastern Himalayas and Indochina, although some South American (M. deppei) and almost pan tropical species (M. nigrescens) also exist. In Papillaria, distribution of species is concentrated in Australia, the southern Pacific and South America. 

The austral wintertime upper-level circulation (Fig. 2.1b) over South America is characterized by weak winds over the tropics, while the subtropical westerly jet is stronger and located more equatorward than in summer, in agreement with the descending branch of the Hadley-type circulation over that area. At lower levels, a northward-displaced near-equatorial low-pressure trough and SST maximum characterize the circulation (Fig. 2. Id). A northward cross-equatorial flow turning clockwise is found over the tropical eastern Pacific and Atlantic Oceans (Fig. 2.1b). 

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