Three PhD positions available at the Department of Historical Geology, Palaeontology at the University of Bremen, Bremen, Germany

Three PhD positions available at the Department of Historical Geology, Palaeontology at the University of Bremen, Bremen, Germany:

1. Multidisciplinary study of continental/ocean climate dynamics using high-resolution
records from the eastern mediterranean BATII/2 for three years in EuroMarc Project MOCCHA

2. Quantitative estimation of aerobic diagenetic overprint of palaeoproductivity signals
Three years stipendum within the European Graduate College EUROPROX

3. Trace element composition and stable oxygen isotopes of species specific calcareous dinoflagellate cysts. Three years stipendum within the European Graduate College EUROPROX

More information can be found at:
http://www.rcom.marum.de/Dr._Karin_Zonneveld.html

BATII/2 for three years in EuroMarc Project MOCCHA:


Multidisciplinary study of continental/ocean climate dynamics using high-resolution
records from the eastern mediterranean

Continuous marine high-resolution climate records with sufficient time resolution are needed to detect high-frequency variations in paleo-climate. Such records are rare but vital for our understanding of causes and consequences of climate and environmental change at decadal to millennial time scales. Our initial studies at a near-coastal and a deep Mediterranean
anoxic basin site seem to provide a continuous marine paleo-climate record that permits such high-resolution and well dated climate reconstructions for at least the last few kyrs.

We plan to extend our pilot projects to assess if these sites are suitable for high-resolution studies of paleoclimate > 35 kyr, i.e. for future IODP drilling.

Within this project detailed palaeoceanographic reconstructions will be established using organic-walled dinoflagellate cysts.

This project will be carried out in close cooperation with the University of Utrecht (Netherlands), University of Torina (Italy) and the ETH Zürich (Switzerland). Joining a ship expedition forms part of the project.



Three years stipendum within the European Graduate College EUROPROX:

Project 7. Quantitative estimation of aerobic diagenetic overprint of palaeoproductivity signals

Quantitative estimation of past bioproductivity in surface ocean waters forms a key question within the studies on past variability in the global carbon cycle. Establishing a detailed estimation is hampered by several factors of which the diagenesis of organic matter in the ocean water column and bottom sediments forms a major aspect. Fossil organic-walled dinoflagellate cysts associations are a useful tool to reconstruct past oceanographic conditions in upper water masses. Within the last few years it became clear that several cyst species are extremely resistant against aerobic degradation and the influx in the marine sediments reflects past
productivity in surface waters. Other species appear to be vulnerable to early diagenesis and their degradation rates can be used to estimate past diagenetic overprint. However, many aspect of organic-walled dinoflagellate cyst taphonomy are still unclear to date and the following questions can be addressed: (1) What are the species-specific degradation rates of individual
dinoflagellate cysts (2) what is the relationship between the export production of individual cyst species and the bioproductivity in upper water masses, (3) what are the biomolecular structures of the cyst walls of individual species and (4) how can the method be applied to pre-Quaternary records, hence, what extinct species are sensitive or resistant to aerobic
decay.

Within the present PhD projects these questions will be addressed by studying high quality material of modern and pre-Quaternary age as well as from long running preservation experiments in natural environments.

The project will be carried out in close co-operation with Prof. T. Eglinton (Woods Hole, USA) and Dr. I. Harding (SOC, UK). Research visits to the Woods Hole Oceanographic Institute and the Southampton Oceanographic Institute with a duration of several month form part of the program.


Project 15. Trace element composition and stable oxygen isotopes of species specific calcareous dinoflagellate cysts

The isotopic composition and elemental chemistry of carbonatic microfossils form oft the backbone of palaeoceanographic and palaeoclimatic studies. Foraminifera have been most widely used as a result of their abundance in the sediments and the ease in which monospecific samples can be picked. However, biological factors such as the migration of several planktonic species through different water masses, the influence of calcite shell isotopic composition by photosynthetic activity of symbionts and consumption of other organisms and the ontogeny of individual species can hamper the interpretation of these signals. Consequently, species specific equations of
photosynthetic species that form their calcite walls at a stable position within the water column could and do not contain symbionts, might overcome some of these problems such as the calcareous dinoflagellate Thoracosphaera heimii. Recently in a pilot study, the relationship between the stable isotopic composition and temperature of this species has been established. However, several aspects concerning species specific "vital effects" are not clear.

The aim of the study is to establish the relationship between the stable oxygen and carbon isotopic composition of individual calcareous dinoflagellate cyst species with physical parameters and to determine the occurrence and origin of potential disequilibrium or "vital effects". Furthermore the elemental composition, notably the Mg/Ca and Sr/Ca ratio's in relationship with temperature gradients and dinoflagellate production will be established.

To obtain more insight in the "vital effects" and the relationship between the elemental composition of the cyst wall en physical factors of the environment, culture experiments will be carried out. To test the applicability of the method high quality material is available from several sediment cores that contain sediments from Quaternary and pre-quaternary age.

The project will be carried out in close cooperation with Patrizie Ziveri (Barcelona). A research visit of several months to the University of Barcelona forms part of the program.

--
Dr. Silke Bertram
Dept. of Geosciences
University of Bremen
P.O. Box 330 440
D – 28334 Bremen
Phone: + 49 (0) 421 218 3950
Fax: + 49 (0) 421 218 9570



_____________________________
TEUKU REIZA YUANDA

MSc Program in Marine Geosciences
Fachbereich Geowissenschaften
Universität Bremen, DE
P: +4915152348383
E: reiza[at]uni-bremen[dot]de

Chairman
Supervision Board of Activity and Finance
Indonesian Student Association in Germany