Project properties

Title Internship at the Alfred-Wegener-Institute for Polar and Marine Research in Bremerhaven, Germany, starting in September 2013.
Group Aquatic Ecology and Water Quality Management Group
Project type internship
Credits 24-39
Supervisor(s) Tim Eberlein (AWI), Björn Rost (AWI), Dedmer van de Waal (NIOO-KNAW, The Netherlands)
Staff AEW
Examiner(s) M. Scheffer
Contact info edwin.peeters@wur.nl
Tim.Eberlein@awi.de
Begin date 2013/06/26
End date 2014/03/01
Description Background: Due to anthropogenic activities (burning of fossil fuels and alteration in land-use) atmospheric CO2 levels are rising at a yet unprecedented rate. As a consequence, more CO2 will be taken up by the surface ocean water and increase aquatic CO2 concentrations. These alterations will lead to changes in several aspects of seawater carbonate chemistry, which likely impact on marine biota. A lowered pH (i.e. ocean acidification) for instance may negatively affect the production of calcium carbonates by marine organisms. Higher CO2 concentrations, on the other hand, could stimulate growth of phytoplankton, which use light energy to convert CO2 and nutrients into organic compounds.
These responses may further be strongly modified under nutrient limitation. After carbon, nitrogen is among the most required nutrients and often limits primary production in the ocean. As the assimilation of carbon and nitrogen by phytoplankton is closely linked, elevated CO2 may thus affect both carbon as well as nitrogen assimilation and alter the sensitivity of phytoplankton towards global change.
Aim: In this project, the student will investigate the impact of elevated CO2 under nitrogen limitation on a calcareous dinoflagellate. More specifically, we aim to determine whether elevated CO2 may affect the nutrient use efficiency, and thus support a higher population density under similar nitrogen limited conditions. By analysis of the elemental composition of the species we will capture effects on carbon and nitrogen quotas per cell.
The experiments will be performed in newly developed chemostats. The potential candidate will grow a calcareous dinoflagellate exposed to high CO2 and low nitrogen conditions. Samples will be taken on a regular base in order to follow growth by population density estimates, changes in seawater chemistry and nitrogen concentrations. Once the cultures reach steady-state, cells will be harvested and parameters will be taken for subsequent analyses. Consequently, the student will determine the carbonate chemistry from pH, total alkalinity and DIC, potential calcite cyst formation from inverted microscopy and scanning electron microscopy observations, and elemental composition by means of mass spectrometry.
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