A multi-proxy investigation of sediment core GeoB7165-1 and AMS 14C dating points from sediment cores off Conceptión (~ 36°S)

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.

Nannoplankton of multi-net samples, sediment surface and sediment core samples from the northern Arabian Sea

Recent nannoplankton from the "Meteor"-stations M 242, M 243 and M 245 in the northern Arabian Sea were studied by means of the light and electron microscope, and 19 species were found. The nannoplankton assemblage of the northern Arabian Sea is compared with those of the eastern and western Mediterranean Sea and the Atlantic Ocean. Gephyrocapsa oceanica (Kamptner), Cyclococcolithus leptoporus (Murray & Blackman), Emiliania huxleyi (Lohmann), Helicopontospbaera kamptneri (Hay & Mohler), and Umbilicosphaera mirabilis (Lohmann) are the most common species in the northern Arabian Sea. Reworked nannoplankton and nannoplankton species agglutinated by tintinnids are discussed.