Sciences marines : recherche et développement

Abstrait

Global Loss of Freshwater and Salination of Sea

Gaspar Banfalvi

The sea level has continuously fluctuated over geologic time. The best evidence for eustatic sea level changes was provided by geologists who studied the shifts of shorelines and recoveries resulting in sedimentary deposits also referred to as sequence stratification. Continuing global warming raised the question whether or not the melting of the glacial ice and snow reserves could result in earlier high sea levels. To answer the question the sea levels were turned to volumetric data. This was achieved by calculations i) using the radii of Earth, with and without the geometric radius of the geoid Earth, ii) selecting among data for an average sea depth, iii) comparing the volumetric values of best fitting values. Upon reliable data within 0.5% deviation were obtained, linear correlation was found between the volumes of sea that would be needed to achieve different sea levels. The calibration curve revealed that 80% (20 ÃÂ? 106 km3) melting of the available fresh water reserves of polar glaciers, ice sheets and permanent snow (100%, ~25 ÃÂ? 106 km3) would cause about 50 m sea level rise. These calculations prove that earlier high (200-300 m) sea level elevations will never be obtained due to the global loss of water to the outer space. In connection with the water deficiency, the osmotic gap between the osmotic concentration of land vertebrates (0.3 Osm) and that of sea (1.09 Osm) is reflecting the salination of ocean. Salinty changes were distinguished as short term dilution periods and a long-term salination process. Long-term salination contributed by human pollution of sea and fresh water will seriously impact future life on Earth.