Benthic foraminifera asemblages and isotopic composition of surface sediment samples off Morocco

The influence of different primary productivity regimes on live (Rose Bengal stained) and dead benthic foraminiferal distribution, as well as on the stable carbon isotopic composition of foraminiferal tests, was investigated in sediment surface samples (0-1 cm) from the upwelling region off Morocco between Cape Ghir (31°N) and Cape Yubi (27°N). A combination of factor analysis, detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA) was applied to the benthic foraminiferal data sets. Five major assemblages for both the live and dead fauna were revealed by factor analysis. In the cape regions organic matter fluxes are enhanced by high chlorophyll-a concentrations in the overlying surface waters. Here, benthic foraminiferal faunas are characterized by identical live and dead assemblages, high standing stocks, and low species delta13C values, indicating constant year-round high productivity. Bulimina marginata dominates the unique fauna at the shallowest station off Cape Ghir indicating highest chlorophyll-a concentrations. Off both capes, the succession of the Bulimina aculeata/Uvigerina mediterranea assemblage, the Sphaeroidina bulloides/Gavelinopsis translucens assemblage, and the Hoeglundina elegans assemblage from the shelf to the deep sea reflects the decrease in chlorophyll-a concentrations, hence the export flux. In contrast, the area between the capes is characterized by differently composed live and dead assemblages, low standing stocks, and less depleted delta13C values, thus reflecting low primary productivity. High foraminiferal numbers of Epistominella exigua, Eponides pusillus, and Globocassidulina subglobosa in the dead fauna indicate a seasonally varying primary productivity signal. Significantly lower mean delta13C values were recorded in Bulimina mexicana, Cibicidoides kullenbergi, H. elegans, U. mediterranea and Uvigerina peregrina. Cibicidoides wuellerstorfi is a faithful recorder of bottom water delta13C in the Canary Islands regions. The mean delta13C signal of this species is not significantly influenced by constant high organic matter fluxes. The species-specific offset between live and dead specimens is the same.

Data and Resources

This dataset has no data

Cite this as

Eberwein, Astrid, Mackensen, Andreas (2006). Dataset: Benthic foraminifera asemblages and isotopic composition of surface sediment samples off Morocco. https://doi.org/10.1594/PANGAEA.738378

DOI retrieved: 2006

Additional Info

Field Value
Imported on November 30, 2024
Last update November 30, 2024
License CC-BY-3.0
Source https://doi.org/10.1594/PANGAEA.738378
Author Eberwein, Astrid
Given Name Astrid
Family Name Eberwein
More Authors
Mackensen, Andreas
Source Creation 2006
Publication Year 2006
Resource Type application/zip - filename: Eberwein_Mackensen_2006
Subject Areas
Name: Oceans

Related Identifiers
Title: Regional primary productivity differences off Morocco (NW-Africa) recorded by modern benthic foraminifera and their stable carbon isotopic composition
Identifier: https://doi.org/10.1016/j.dsr.2006.04.001
Type: DOI
Relation: IsSupplementTo
Year: 2006
Source: Deep Sea Research Part I: Oceanographic Research Papers
Authors: Eberwein Astrid , Mackensen Andreas .

Title: Holocene and Last Glacial Maximum (paleo-)productivity off Morocco: Evidence from benthic foraminifera and stable carbon isotopes ((Paläo-)Produktivität im Holozän und Letzten Glazialen Maximum vor Marokko erschlossen aus benthischen Foraminiferen und stabilen Kohlenstoffisotopen)
Identifier: https://doi.org/10.2312/BzPM_0548_2007
Type: DOI
Relation: References
Year: 2007
Source: Berichte zur Polar- und Meeresforschung = Reports on Polar and Marine Research
Authors: Eberwein Astrid .