Mathematical model approaches describing cellular fluxes of carbon and Ca2 in Emiliania huxleyi

• Main Author: Holtz, Lena
• Other Authors: Wolf-Gladrow, Dieter, Thoms, Silke, Bischof, Kai
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Universität Bremen 2013
• Subjects: coccolithophores; calcite precipitation; intracellular carbon fluxes; Ca2 transport; CCM; 570; 570 Life sciences; biology; ddc:570; Ocean acidification
• Online Access: https://media.suub.uni-bremen.de/handle/elib/687; https://nbn-resolving.org/urn:nbn:de:gbv:46-00103858-19

Anthropogenic carbon dioxide (CO2) emissions from fossil carbon storages to atmosphere are causing major impacts on the Earth s climate. The increase of atmospheric temperatures due to a strengthening of the natural greenhouse effect is a well known phenomenon. Moreover, a large fraction of the atmospheric CO2 that has been released by mankind enters the ocean and induces, besides other effects, the acidification of surface waters ( Ocean Acidification ). The effects of increasing partial pressures of atmospheric CO2 on parameters that describe the abiotic environment have been examined extensively. It is now of particular interest to gain a detailed comprehension of the complex interactions between the changing environment and the metabolism of marine organisms. This knowledge is essential when aiming to understand the ongoing changes in their entirety. In the spotlight of this thesis are coccolithophores, unicellular algae that significantly impact the marine carbon cycle. Coccolithophores perform photosynthesis and calcification. Both processes rely on different carbon species and thus have a different effect on the carbonate system of the surface ocean. In connection with the formation of calcite particles, they further impact the sinking rates of particulate carbon from the photic zone into the ocean. The ratio of photosynthesis to calcite precipitation rate varies with the composition of the carbonate system. In order to understand the dependencies of both individual processes on the complex cabonate system, a detailed understanding of cellular carbon fluxes is essential. Until now, it is impossible to measure these fluxes directly. Therefore, mathematical models are used in this thesis to examine these fluxes. All presented models describe Emiliania huxleyi, one of the globally most abundant and important coccolithophores. The first part of this PhD thesis summarises current knowledge concerning the intracellular formation of coccoliths, i.e. the calcite platelets that surround the cells. Former ...