PhD Student Opportunity
Baltic Sea Ice Biogeochemistry
Department of Biological and Environmental Sciences
University of Helsinki
Application Deadline: 15 October 2007
For further information about the Department of Biological and
Environmental Sciences, please go to:
http://www.helsinki.fi/bioscience/index.htm
or contact:
Anssi Vahatalo
University of Helsinki
E-mail: anssi.vahatalo [at] helsinki.fi
The Department of Biological and Environmental Sciences at University of
Helsinki announces a PhD student opportunity in "Baltic Sea Ice
Biogeochemistry: The Role of Photochemistry and Bacterial Processes."
The proposed PhD studies are related to the Sea Ice Ecology consortium
(SIE), which covers microbial biodiversity and metabolisms as well as
physical and chemical processes in Baltic Sea ice. The consortium
includes researchers from University of Helsinki; University of Lapland;
Tvarminne Zoological Station; Finnish Institute of Marine Research
(FIMR); University of Umea, Sweden; University of Wales, Bangor, UK; and
National Environmental Research Institute, Denmark. SIE also coordinates
a Nordic (NordForsk) network around sea ice research. The fieldwork of
the announced PhD position is carried out primarily at the Tvarminne
Zoological Station (Baltic Sea) and laboratory studies are performed in
the Department of Biological and Environmental Sciences and FIMR.
Sea ice traps organic matter and biological communities into a shallow
and relatively stable surface stratum. Because pure ice itself
attenuates very little UVR (ultraviolet radiation), the organic matter
within the sea ice matrix is exposed directly to solar UVR. In the
Baltic Sea, some of the organic matter is trapped into ice for up to 120
days and thus receives extensive cumulative doses of solar UVR.
Evidently, solar radiation-induced photochemical reactions interfere
with the biogeochemistry of organic matter in sea ice and thus
potentially serve as a vector providing nutrients and/or bioavailable
substrates for plankton and bacteria.
In order to assess the nature and availability of photochemically borne
nutrients and substrates in the ice ecosystem, the following five
objectives will be addressed:
- Photochemical transformation of chromophoric dissolved organic matter;
- Photochemistry of nitrogen in sea ice;
- Photochemical mineralization of dissolved organic carbon to CO2;
- Impact of irradiance on the activity of phosphomonoesterase; and
- Photochemical changes in the bioavailability of dissolved organic
matter.
As part of the research strategy, controlled experimental studies
concerning these objectives will be carried out in the laboratory with
sea ice (natural or experimentally grown) and brine collected from sea
ice and artificial brine solutions. The studies are designed for the
determination of apparent quantum yields (AQY) for the photochemical
reactions in sea ice. AQYs will then be applied into optical models in
order to quantify the in situ rates of photochemical reactions in sea
ice. Field studies will be conducted to compare the modeled outcomes to
natural conditions and to reveal other underlying processes that affect
the fate of the products of photochemical reactions in sea ice.
Applicants should have a good academic record, previous laboratory and
field experience, and motivation to achieve a PhD from the described
topic. The successful candidate will be selected according to his/her
fit to the described PhD research.
To apply, please submit a curriculum vitae, excerpt of undergraduate
studies and research interests, and contact details of two referees no
later than 15 October 2007 to:
Anssi Vahatalo
E-mail: anssi.vahatalo [at] helsinki.fi
Department of Biological and Environmental Sciences
Viikinkaari 1
P.O. Box 65
FIN-00014 University of Helsinki
Finland