*..........................
Three PhD positions available at the Department of Historical Geology,
Palaeontology at the University of **Bremen**, **Bremen**, **Germany**:*
* *
1. *M**ultidisciplinary 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:*
* *
*M**ultidisciplinary 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
[Non-text portions of this message have been removed]
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