(Table S1, S4) Campanian-Maastrichtian benthic foraminifera from ODP Hole 113-690C

During the latest Cretaceous cooling phase, a positive shift in benthic foraminiferal d18O values lasting about 1.5 Myr (71.5-70 Ma) can be observed at a global scale (Campanian-Maastrichtian Boundary Event, CMBE). This d18O excursion is interpreted as being influenced by a change in intermediate- to deep-water circulation or by temporal build-up of Antarctic ice sheets. Here we test whether benthic foraminiferal assemblages from a southern high-latitudinal site near Antarctica (ODP Site 690) are influenced by the CMBE. If the d18O transition reflects a change in intermediate- to deep-water circulation from low-latitude to high-latitude water masses, then this change would result in cooler temperatures, higher oxygen concentration, and possibly lower organic-matter flux at the seafloor, resulting in a major benthic foraminiferal assemblage change. If, however, the d18O transition was mainly triggered by ice formation, no considerable compositional difference in benthic foraminiferal assemblages would be expected. Our data show a separation of the studied succession into two parts with distinctly different benthic foraminiferal assemblages. Species dominating the older part (73.0-70.5 Ma) tolerate less bottom water oxygenation and are typical components of low-latitude assemblages. In contrast, the younger part (70.0-68.0 Ma) is characterized by species that indicate well-oxygenated bottom waters and species common in high-latitude assemblages. We interpret the observed change in benthic foraminiferal assemblages toward a well-oxygenated environment to reflect the onset of a shift from low-latitude toward high-latitude dominated intermediate- to deep-water sources. This implies that a change in oceanic circulation was at least a major component of the CMBE.

Distribution of molluscs on the Atlantic continental shelf off Southern Spanish Sahara, West Africa

Two hundred and seventy five mollusc species from the continental shelf off Southern Spanish Sahara (depth: 32-60 m) were identified. Their distribution pattern is strongly influenced by the nature of the bottom (firm substrate, shelter, stability of sediment) rather than other factors at that depth interval. This faunal assemblage shows great affinity to the Mediterranean and Lusitanian faunas, and comprises only few (22 %) exclusively Senegalese and species living south of Senegal.

Benthic foraminifera off West Africa (1°N to 32°S)

Recent benthic foraminifera (> 125 µm) were investigated from multicorer samples on a latitudinal transect of 20 stations between 1°N and 32°S along the upper slope off West Africa. Samples were selected from a narrow water depth interval, between 1200 and 1500 m, so that changes in water masses are minimized, but changes in surface productivity are important and the only significant environmental variable. Live (Rose Bengal stained) benthic foraminifera were counted from the surface sediment down to a maximum of 12 cm. Dead foraminifera were investigated in the top 5 cm of the sediment only. Five live and five dead benthic foraminiferal assemblages were identified using Q-mode principal component analysis, matching distinct primary productivity provinces, characterized by different systems of seasonal and permanent upwelling. Differences in seasonality, quantity, and quality of food supply are the main controlling parameters on species composition and distribution of the benthic foraminiferal faunas. To test the sensitivity of foraminiferal studies based on the uppermost centimeter of sediment only, a comparative Q-mode principal component analysis was conducted on live and dead foraminiferal data from the top 1 cm of sediment. It has been demonstrated that, on the upper slope off West Africa, most of the environmental signals as recorded by species composition and distribution of the 'total' live and dead assemblages, i.e., including live and dead foraminifera from the surface sediment down to 12 cm and 5 cm, respectively, can be extracted from the assemblages in the top centimeter of sediment only. On the contrary, subsurface abundance maxima of live foraminifera and dissolution of empty tests strongly bias quantitative approaches based on the calculation of standing stocks and foraminiferal numbers in the topmost centimeter.

Benthic foraminifera of ODP Leg 104 holes

Benthic foraminifers have been studied in about 900 samples from Sites 642, 643, and 644 (ODP Leg 104, Voring Plateau), ranging in age from Eocene to Holocene. This sequence has been subdivided into seven assemblage zones. The Eocene to middle Miocene deposits are characterized by an agglutinated fauna. This reflects an environment causing dissolution of calcareous tests rather than the original living fauna. The upper Miocene to middle Pliocene deposits contain a diverse benthic foraminiferal fauna dominated by calcareous forms. The uppermost part of the sediment record, deposited during late Pliocene to Holocene, is characterized by many barren intervals and samples containing shallow-water species as well as ice-rafted material indicating glacial periods. Interglacials are reflected in samples containing a true oceanic foraminifer assemblage and no coarse clastic material.

Micropaleontology and stable isotope record of ODP Hole 178-1098C

Detailed study of four Holocene sediment intervals from Ocean Drilling Program Site 1098 (Palmer Deep, Antarctic Peninsula) reveals that in situ dissolution of calcareous foraminifers in the core repository has significantly altered and in some cases eliminated calcareous foraminifers. Despite dissolution, the foraminifer and supporting diatom data show that the most open-ocean and reduced sea-ice conditions occurred in the early Holocene. The influence of Circumpolar Deep Water was greatest during the early Holocene but continued to be important throughout the Holocene. An increase in sea-ice proximal diatoms at 3500 cal. BP documents an expansion in the amount of persistent sea ice. The inferred increase in sea ice corresponds with an overall increase in magnetic susceptibility values. Benthic foraminifers are present in all samples from the Palmer Deep, including the middle Holocene pervasively laminated sediments with low magnetic susceptibility values. The consistent presence of mobile epifaunal benthic foraminifers in the laminated sediments demonstrates that the laminations do not represent anoxic conditions. The uniform composition of the agglutinated foraminifer fauna throughout the late Holocene suggests that the Palmer Deep did not experience bottom-water-mass changes associated with the alternating deposition of bioturbated or laminated sediments.