In situ measurements of respiration and mineralisation processes - Interaction between fauna and geochemical fluxes at active interfaces.

The main aim of this thesis was to show the importance of in situ data for achieving a reliable record for the estimation of the interaction between geochemical processes and fauna in the processes of organic carbon degradation and energy utilization. It could be shown that multidisciplinary approaches made the quantitative determination of many single processes within carbon cycling and energy transfer possible. The effect of daily migrating macrofauna for the organic carbon transport and oxygen consumption in the benthic boundary layer could be shown by the use of a profiling lander, a chamber lander and pore water profiles. Calculated on an area basis the oxygen consumption and therefore the carbon oxidation of the animals was 25-fold higher than the turnover rates of the sediment. This study showed three examples of the effects that fauna has on transportation processes at the sediment / water interface and effects that geochemical conditions have on the development of biological systems and adaptations of animals.