Oceans polar

The dominant clay mineral at high latitudes is chlorite. In addition to ice rafting, lithogenous materials are transported in the polar oceans by rivers and winds. Polar seas are also characterized by diatomaceous oozes due to the occurrence of upwelling supported by divergence at 60°N and 60°S. 

Summary of Known and Inferred Subaquatic Gas-Hydrate Occurrences in Atlantic Ocean, Polar Oceans, Continents, and in Inland Seas and Lakes... 

Lemke P. (2001). Open windows to the polar oceans. Science, 292, 1670-1671. 

Leek and Persson (1996) Arctic Polar Ocean (summer) 2.0... 

HoUibaugh, J. T., Bano, N., and Ducklow, H. W. (2002). Widespread distribution in polar oceans of a 16S rRNA gene sequence with affinity to Nitrosospira-]ike ammonia-oxidizing bacteria. Appl. Environ. Microbiol. 68, 1478—1484. 

The macronutrient-rich surface waters of the equatorial upwehings and polar oceans are a particularly dynamic component of the global carbon cycle. In the Southern Ocean, for example, the nutrient-rich and C02-charged waters of the deep sea are exposed to the atmosphere and returned to the subsurface before the available nutrients are fuUy utilized by phytoplankton for carbon fixation. This incomplete utilization of upweUed nutrients aUows for the leakage of biologicaUy sequestered... 

Honjo S. (1990) Particle fluxes and modern sedimentation in the polar oceans. In Polar Oceanography Part B. Chemistry, Biology, and Geology. Academic Press, pp. 687-739. 

For instance, nitrate and phosphate penetrate much further north than does sihcate in the Southern Ocean, the polar ocean surrounding Antarctica (Figures 5(b)-(d)). As silicate is needed by diatoms but not other types of phytoplankton, this difference has major implications for the ecology of the Southern Ocean, present and past. Moreover, since surface water from 40-50° S is fed into the thermocline that... 

Within the polar oceans involved in deep water formation, certain regions are more important than others. The Antarctic Zone, the most polar region in the Southern Ocean, is involved in the formation of both deep and intermediate-depth waters, making this region important to the atmosphere/ocean CO2 balance. The quantitative effect of the Subantarctic Zone on atmospheric CO2 is less certain, depending on the degree to which the nutrient status of the Subantarctic surface influences the preformed nutrient concentration of newly formed subsurface water (Antarctic Intermediate Water and Subantarctic mode water), but its significance is probably much less than that of the Antarctic. 

In the polar ocean, both export production and nutrient status must be known to determine the impact on atmospheric CO2, because both of these terms are needed to determine the ratio of CO2 supply from deep water to CO2 sequestration by export production (Figure 7). For instance, a decrease in export production associated with an increase in surface nutrients would imply an increased leak in the biological pump, whereas a decrease in export production associated with reduced nutrient availability would imply a smaller leak in the pump. In low-latitude regions of upwelling, nutrient status is less important from the perspective of the global biological pump. Nevertheless, since nutrient status is potentially variable in these environments, it must be constrained to develop a tractable list of explanations for an observed change in productivity. 

Charles C. D. and Fairbanks R. G. (1988) Glacial to interglacial changes in the isotopic gradients of southern Ocean surface water. In Geological History of the Polar Oceans Arctic versus Antarctic (eds. U. Bleil and J. Thiede). Kluwer Academic, pp. 519-538. 

Gordon A. L., Taylor H. W., and Georgi D. T. (1977) Antarctic oceanographic zonation. In Polar Oceans (ed. M. J. Dunbar). Arctic Institute of North America, pp. 219-225. 

Kohfeld K. E., Fairbanks R. G., Smith S. L., and Walsh I. D. (1996) Neogloboquadrina pachyderma (sinistral coiling) as paleoceanographic tracers in polar oceans evidence from northeast water polynya plankton tows, sediment traps, and surface sediments. Paleoceanography 11(6), 679-699. 

Bioalkylation of halogens and heavy metals in the polar ocean 3.1. Bioalkylation of Br and / by polar macroalgae... 

Recently, Pongratz and Heumann have shown that besides methylated Hg and Pb also monomethyl-Cd can be detected in the polar ocean (10, 11, 24). Because the experiments with polar macroalgae did not show any production of methylated Cd, it must be assumed that other marine organisms are responsible for the existence of MeCd in the ocean. Incubation experiments with isolated mixed and pure bacterial cultures of polar origin, collected in the Weddell Sea, were therefore carried out and the production of methylated heavy metal eompounds was followed during the growth of these baeteria. The total (inorganic) heavy metal concentration of the natural sea water from the Weddell Sea, used in these... 

The results of these experiments demonstrate that, in principle, bacteria from the polar ocean are also potential sources for the production of methylated heavy metals. Since methylation of Cd was not observed by macroalgae but by bacteria, monomethyl-Cd may be normally a product of marine bacteria. Bacteria show specific fingerprints in the release of methylated heavy metal compounds, as the results with the mixed bacterial cultures have shown, where methylation of Hg could not be observed. It is also known that bacteria are able to demethylate methylated heavy metals, as was found for organo-Hg (46). Also Schedlbauer followed the change of MeHg" concentration in sea water samples in the presence of marine... 

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