ALBERT

Description: We present a high-resolution record of calcareous nannofossils from the northern Red Sea for the last 22 kyr. Extreme conditions with enhanced salinities during the Last Glacial Maximum are characterized by high values of Gephyrocapsa ericsonii. The dominance of Emiliania huxleyi in Heinrich event 1 indicates a climatic cooling favoring the bloom of opportunistic species. The calcareous nannofossils record a two-step onset of the postglacial humid climate, punctuated by the Younger Dryas. Both steps show an early oligotrophic phase dominated by Florisphaera profunda and Gladiolithus flabellatus and a subsequent fertile phase characterized by E. huxleyi. The Younger Dryas is described by high values of Gephyrocapsa oceanica, indicating an increased mixing of the water column. In the late Holocene, repetitive increases in abundance of F. profunda and G. flabellatus reflect restricted oligotrophic conditions, caused by the high aridity following the Holocene humid period.

Description: Due to its restricted connection with the Indian Ocean, the desert-enclosed Red Sea is extremely sensitive to global sea level changes and thus ideally suited for paleoceanographic studies of what occurred during the last glaciation. The understanding of its glacial history is, however, still limited. A serious obstacle to obtain satisfactory paleoecological information has been the rarity of microfossil proxy species caused by high salinities. Here, we present a continuous and well-dated calcareous nannoplankton record from the northern Red Sea, covering the interval from 60–14.5 ka BP. Our investigation shows that the composition of the calcareous nannoplankton community varied between ∼32 ka BP and 14.5 ka BP in response to rapid environmental changes which are closely correlated to climatic fluctuations described from the North Atlantic region. Heinrich events H3, H2 and H1 are dominated by Emiliania huxleyi. Gephyrocapsa oceanica and especially Gephyrocapsa ericsonii are abundant between H3–H2 and H2–H1. A less pronounced response of the calcareous nannoplankton to the high latitudinal climatic oscillations is documented prior to ∼32 ka BP, suggesting that a strong atmospheric coupling between the northern Red Sea and the North Atlantic realmwas established in the late Marine Isotope Stage 3. In contrast to the previously held view of a sea level related salinity increase as the major cause for changes of the plankton communities within the glacial Red Sea, we interpret the documented variations as being caused by local hydrographic changes under the atmospheric control from the extratropics. Temperature changes and especially variations of the water stratification appear to be critical selective factors for the calcareous nannoplankton composition.