65 resultados para ANGIOTENSIN-(1-12)
Resumo:
A high-resolution sea surface temperature and paleoproductivity reconstruction on a sedimentary record collected at 36°S off central-south Chile (GeoB 7165-1, 36°33'S, 73°40'W, 797 m water depth, core length 750 cm) indicates that paleoceanographic conditions changed abruptly between 18 and 17 ka. Comparative analysis of several cores along the Chilean continental margin (30°-41°S) suggests that the onset and the pattern of deglacial warming was not uniform off central-south Chile due to the progressive southward migration of the Southern Westerlies and local variations in upwelling. Marine productivity augmented rather abruptly at 13-14 ka, well after the oceanographic changes.We suggest that the late deglacial increase in paleoproductivity off central-south Chile reflects the onset of an active upwelling system bringing nutrient-rich, oxygen-poor Equatorial SubsurfaceWater to the euphotic zone, and a relatively higher nutrient load of the Antarctic Circumpolar Current. During the Last Glacial Maximum, when the Southern Westerlies were located further north, productivity off central-south Chile, in contrast to off northern Chile, was reduced due to direct onshore-blowing winds that prevented coastal upwelling and export production.
Resumo:
Muskoxen populations were surveyed in the course of 3 expeditions to North East Greenland to provide data on present status and habitat requirements in the region between 72 and 74 deg latitude North. The distribution is primarily affected by the snow cover pattern and shows densities from less than 0.1 ind/km**2 to 1.5 ind/km**2. Ranges unutilized by muskoxen prior to 1940 now support high densities. The snow cover influences also the population dynamics, as shown by the streng correlation between the calf crop and the amount of snow. The total population is estimated to be about 1000 to 1500 individuals far the whole region.
