| Resumo: |
The inorganic carbon cycle in the Red Sea has been examined based on various datasets from six different years during the period 1977 and 2007. The study has been performed parameter wise, and the processes biological production/remineralization (soft tissue and hard parts), calcium carbonate sedimentation, air-sea gas exchange, and evaporation/precipitation have been considered. The surface water was relatively warm in the central part of the Red Sea due to wind convergence, and colder towards the south and north due to influence of relative cold Gulf of Aden water and net evaporation, respectively. The surface salinity increased all the way from the south towards the north, due to evaporation, and this explained the major part of the northwards increasing concentration in both surface AT and DIC. The surface AT was, in addition slightly influenced by biological production. Air-sea CO2 exchange was believed to influence the surface DIC, however, this effect seemed to be hidden in the random error of the observed data. For the deep water, the AT concentration was mainly influenced by calcium carbonate sedimentation, while remineralization/respiration could explain the major part of the DIC variations observed. fCO2 was positively correlated to the sea surface temperature. During the period 1977 - 2007, the fCO2 of the water increased at a similar rate as the atmospheric fCO2, however, while the atmospheric CO2 increase had obvious reasons, the oceanic increase most likely was a result of an increase in surface temperature. Air-sea CO2 flux was calculated, and the Red Sea was in general a small source for atmospheric carbon for all years except 1991 and 1992, when the southern parts of the ocean appeared as a large source and the northern part had turned into a small sink for atmospheric carbon. This particular situation in the north was connected to strong NNW wind and subsequent upwelling in the north during these two years.
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