Schönfeld, Joachim and Altenbach, Alexander Volker (2005) Late Glacial to Recent distribution pattern of deep-water Uvigerina species in the northeastern Atlantic. Marine Micropaleontology, 57 (1-2). pp. 1-24. DOI 10.1016/j.marmicro.2005.05.004.

Text Schönfeld_Altenbach.pdf - Published Version Restricted to Registered users only Download (703kB) | Contact

Abstract

Phases with massive abundances of Uvigerina species recorded in North Atlantic deep-sea cores were previously attributed
to water mass properties or to extended high productivity during the last Glacial. We investigated the Uvigerina distribution in
53 sediment cores and 555 surface samples from the north-eastern Atlantic ranging from 308 to 708N and 1 to 4410 m water
depth. Our results showed that Uvigerina pigmea dominated in late Pleistocene assemblages whereas Uvigerina peregrina and
Uvigerina peregrina parva were common during the Holocene. Uvigerina pigmea lives today in the Gulf of Guinea and South
Atlantic only (98N to 178S), but was present up to 548N during the Last Glacial Maximum. The species retreated north- and
southwards during Termination I and disappeared in the north-eastern Atlantic off northern Portugal 6100 years ago. Uvigerina
peregrina and U. peregrina parva spread out from isolated occurrences along the continental slope off western Iberia at the
onset of Termination I. Uvigerina peregrina exhibited Recent abundance maxima at Goban Spur, Plateau des Landes, and the
Iberian Margin. These areas are subjected to strong lateral advection by downslope transport and sediment focusing. The actual
flux rate of particulate organic matter is locally raised by a factor of 4 to 5. Comparable flux rates were otherwise recorded at U.
peregrina maxima under the NW-African coastal upwelling regime. The Recent distribution of U. pigmea and evidence from
sediment cores show an organic carbon flux of 3.5 g C m-2 yr-1 as minimum for a sustainable population of this species.
Alkenone, pigment and planktonic foraminiferal records from cores MD952039 and MD952040 revealed that a spring bloom
dominated productivity dynamics and a balanced food particle composition of haptophyteae algae and diatoms were limiting
environmental factors for U. pigmea during the Pleistocene. A widespread change from glacial to modern productivity
characteristics during the last Deglaciation may have triggered the early Holocene disappearance of U. pigmea from the
north-eastern Atlantic.

Actions (login required)

View Item