Benthic Foraminifera as Proxies in Contourite Drift Systems
Benthic foraminifera are highly adaptable to a wide range of environments, which makes them excellent tools for the reconstruction of palaeoenvironments. Certain species prefer regions with significantly increased current velocities, such as present in contourite drift systems (CDS). Contourites for...
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| Format: | Doctoral or Postdoctoral Thesis |
| Language: | German English |
| Published: |
2023
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| Online Access: | https://kups.ub.uni-koeln.de/70064/ https://kups.ub.uni-koeln.de/70064/1/Benthic%20Foraminifera%20as%20Proxies%20in%20Contourite%20Drift%20Systems_Saupe_2023.pdf |
| Summary: | Benthic foraminifera are highly adaptable to a wide range of environments, which makes them excellent tools for the reconstruction of palaeoenvironments. Certain species prefer regions with significantly increased current velocities, such as present in contourite drift systems (CDS). Contourites form elongated sedimentary bodies that are deposited under persistent, contour-parallel bottom currents and cover extensive areas of the Atlantic Ocean. An increased current activity substantially affects the composition of the associated epibenthic community, and some benthic foraminiferal species preferably settle on elevated substrates, summarised as elevated epifauna (EEF). EEF species optimise the acquisition of food particles carried by strong bottom currents, giving them a competitive advantage over other epibenthic microorganisms. The EEF was established at the Iberian Margin (Northeast Atlantic Basin) within the Mediterranean Outflow Water (MOW) and evaluated for its suitability as a bottom current indicator (Schönfeld, 1997). In this thesis, biogeographic distribution patterns of benthic foraminifera in sediment surface samples from CDSs beyond the Northeast Atlantic Basin, within the low and high latitudes of the Atlantic Ocean, are evaluated. Investigations along the Brazilian continental margin (Campos and Brazil basins, 11-22°S, 36-40°W) reveal a diverse foraminiferal community, although with a rather poor EEF, that is almost exclusively represented by Cibicidoides wuellerstorfi. Samples from the North Atlantic Iceland (Björn and Gardar Drift, 55-62°N, 23-28°W) and Irminger basins (Eirik Drift, 57-59°N, 45-49°W) also reveal lacking or sparse EEF occurrences. Instead, tubular agglutinated suspension feeders, such as Rhabdammina abyssorum or Saccorhiza ramosa, preferably colonise the weak to moderate current regime in the Björn and Gardar drifts. In the slightly enhanced currents of the Eirik Drift, abundances of EEF taxon Cibicidoides wuellerstorfi are recorded. The integration of the new data sets with ... |
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