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  4. Ecology and stable isotope geochemistry of modern planktonic foraminifera in the Northeast Atlantic
 
Zitierlink URN
https://nbn-resolving.de/urn:nbn:de:gbv:46-00107001-17

Ecology and stable isotope geochemistry of modern planktonic foraminifera in the Northeast Atlantic

Veröffentlichungsdatum
2018-11-27
Autoren
Rebotim, Andreia Seia  
Betreuer
Kucera, Michal  
Gutachter
Brummer, Geert-Jan  
Zusammenfassung
The understanding of the relationship between planktonic foraminifera and their surrounding environment, as well as each individual speciesa habitat and calcification behaviour are of fundamental importance to improve their use as a paleoceanographic tool. To this end, vertically stratified plankton tow hauls were used to study the vertical and horizontal distribution and stable isotope geochemistry of planktonic foraminifera in the eastern North Atlantic, a region that plays an important role in monitoring changes in the North Atlantic circulation and where the environmental conditions are particularly diverse. This work provides new insights into the vertical and horizontal distribution of individual species of planktonic foraminifera and the respective factors (temperature, chlorophyll, mixed layer depth, lunar/seasonal cycle) potentially controlling their distribution. New findings concerning the stable isotope signal recorded in the shells of four deep dwelling planktonic foraminifera species are also reported. The vertical distribution of planktonic foraminifera varied among species, allowing us to identify different groups of species, such as species living typically above 100 m, species occurring commonly between the surface (50 m) and intermediate waters (100 m) and species living mostly below 100 m. In most cases, the vertical habitat also varied within species, but the variation was found to be predictable by a combination of environmental factors and ontogenetic migration. Horizontally, species distribution is linked to the surrounding environmental conditions, resulting in specific regional and seasonal faunal associations. Unlike the composition of sedimentary assemblages, plankton assemblages are predicted by multiple environmental parameters, indicating that the strong temperature signal in fossil assemblages is the result of seasonal and interannual accumulation and averaging. The stable isotopic analysis of four deep-dwelling species confirmed that either larger size or presence of a secondary crust cause heavier isotopic signal. In three out of the four studied species, the oxygen isotopic signal could be better predicted by the Shackleton paleotemperature, whereas Globorotalia scitula signal is better described by the Kim and Oa Neil paleotemperature equation. Finally, we found inconsistencies between the living depth and the calcification depth of each species, revealing that the calcification depth does not correspond entirely to the habitat depth of a species.
Schlagwörter
planktonic foraminifera

; 

stable isotopes

; 

Northeast Atlantic

; 

ecology planktonic foraminifera

; 

living planktonic foraminifera

; 

habitat depth planktonic foraminifera

; 

distribution planktonic foraminifers

; 

oxygen isotopes

; 

Canary Islands

; 

Iberian Margin

; 

Azores Front/ Current
Institution
Universität Bremen  
Fachbereich
Fachbereich 05: Geowissenschaften (FB 05)  
Dokumenttyp
Dissertation
Zweitveröffentlichung
Nein
Sprache
Englisch
Dateien
Lade...
Vorschaubild
Name

00107001-1.pdf

Size

11.67 MB

Format

Adobe PDF

Checksum

(MD5):540b45a2ea8df66218c068fa086467b2

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