Friday, November 17, 2006

Tal como fiz para o Enquadramento geológico de Sintra...

Também esperei para o fazer a Ciclos Geoquímicos. As notas do 1º trabalho prático já saíram, e apesar de todo o meu nervosismo não me posso queixar, tive 16.9, o que não é nada mau (pena de não me ter posto a trabalhar feita um cão desde o 1º ano). Sendo assim, deixo, para quem queira ler, até porque é um assunto interessante, principalmente por quem procure perceber um pouco mais sobre a circulação oceânica, o resumo inicial do meu trabalho. Vai em inglês, porque, desculpem-me o mega-ego a falar, foi das melhores traduções que fiz até hoje, cientificamente.
Retirado de "Estudo gráfico da concentração de Cádmio em relação às diferentes propriedades do Oceano Pacífico" por Claudia Silva, 4º ano Geologia e Recursos Naturais- FCUL, 2006
"Abstract: Two types of oceanic currents characterize the Pacific Ocean: Equatorial (warm waters, rich in organisms with high salinity) and Antarctic (deep colder waters with ability to a bit more reduced salinity level, rich in chemical elements and nutrients). According to a thermocline which extends from 120 metres of deep (approximately) to 500 metres, we can understand the “division” between superficial waters and intermediate waters, that is characterized for being the area where the mixture between the two types of currents already mentioned occurs (warmer and superficial, colder and deep). Connecting the different characteristics of sea water- Temperature (T), Salinity (S), Depth-, it is possible to identify relations between them, especially what concerns to the concentrations of two important elements, Cadmium and Phosphate. Although it’s recognized that Cadmium depends on marine biological activity, emphasising phytoplankton in the euphotic zone, it’s not yet established why it’s concentration has the tendency to increase (along with Phosphate concentration) to deeper regions. For one hand it can be assured that such evidence it’s due to the also bigger increase of marine origin carbonate compounds, all the organisms with shells and structures high in CaCO3, as it’s reached higher depth values, but on the other hand the capacity of mixture in the Ocean currents, contributes to the interference with biochemical sea characteristics, allowing an also progressive increase of the elements concentrations. It is easy to conclude that the Cadmium / Phosphate relation is linear and that their biggest level of concentration may occur exactly to the depth between 120 and 500m, reaching an equilibrium and constant level above these values. The increase factors of elements by carbon dissolution along with the mixture of different water layers are certainly related with these results. Key-words: Equatorial Pacific Current, Antarctic Current, Salinity, Temperature, [Cd], [PO4], Depth, thermocline, carbonates, interference and mixture of waters."

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