Eine wissenschaftsphilosophische Betrachtung gegensätzlicher Positionen in der Grundeinkommensdebatte in Deutschland und anderen Ländern. Zweck ist es, eine Überprüfung der zeitgemäßen Berechtigung der gängigsten Argumente für, bzw. gegen ein Grundeinkommen unter Berücksichtigung ihres Entstehungshintergrundes anzuregen, um eine objektive Beurteilung der Grundeinkommensidee zu gewährleisten.

Earlier studies indicate that the interaction between heterotrophic bacteria and dissolved organic matter is rather different in rivers and estuaries. The aim of my thesis was to elucidate if bacteria are regulated differently in the Råne river and estuary during a spring situation. Surface water was collected at both locations and a bioassay performed to study limiting substances for bacterial production, proportion bio-available dissolved organic carbon (DOC) in the water and bacterial growth efficiencies (BGE). The Carbon, Nitrogen and Phosperous concentrations were all higher in the estuary than in the river. The bioassay showed that nitrogen-phosphorus limited the bacterial production at both locations, while DOC occurred in excess. The bio-available part of the DOC pool was larger in the estuary (~6%) than in the river (~3%). However, the BGE was much higher in the river (~40%) than in the estuary (~5%), indicating that a larger proportion of the consumed DOC was used for respiration in the estuary. I conclude that heterotrophic bacteria are limited by the same substance, but that the bacterial metabolism is quite differently regulated in the river and in the estuary.

Une approche in situ et expérimentale sont menées en baie de Marseille. Des mesures simultanées de PB, de RB, de la phosphatase alcaline (phos) et de la protéase (prot) sont réalisées. Des gradients de températures (12-32°C) de ces 4 activités sont effectués. Les résultats montrent que 1) les températures optimales et les Q10 varient saisonnièrement, 2) le BGE ne diminue pas nécessairement lorsque la température augmente et 3) quelles que soit les conditions in situ, l'assemblage bactérien possède un BGE à la température in situ proche de sa température optimale. Des expériences d'enrichissements en PO4 et glucose incubées à température in situ et température in situ + 3°C montrent que la nature de l'interaction entre la température et les ressources est principalement synergétique. L'hypothèse d'un scénario supposant des changements relatifs de PB, prot et phos lors d'un changement de température suggère que les taux prot/PB et phos/PB diminuent lors d'un réchauffement et augmentent lors d'un refroidissement. Enfin, ces expériences témoignent que la température et la disponibilité du PO4 sont les principaux facteurs limitant les activités hétérotrophes. L'étude du mode d'apport de la MO (pulsé ou en continu) menée sur 4 cultures saisonnières montre que selon les conditions environnementales et le mode d'apport de la MO, l'AB, la PB et la RB varient significativement. Toutefois, l'AB, la PB, la RB et le BGE ne montrent pas de différences significatives entre les réservoirs d'ajouts pulsés et d'ajouts continus de MO suggérant des communautés bactériennes peu sensibles à la nature de la perturbation nutritionnelle alors que leurs activités en sont fortement dépendantes. / In this work, in situ and experimental approaches have been carried out in Marseilles' Bay. Simultaneous measurements of bacterial production (BP), bacterial respiration (BR), alkaline phosphatase activity (phos) and protease activity (prot) have been performed. Kinetic temperatures (12-32°C) of these 4 activities have been also conducted. The results demonstrate that i) the optimum temperature and Q10 values vary seasonally, ii) BGE value does not necessarily decrease with increasing temperature and iii) whatever the in situ conditions, the bacterial assemblage has a in situ temperature BGE value close to its optimal temperature. Enrichments experiments in PO4 and glucose incubated at in situ temperature and in situ temperature + 3°C allow to observe that the synergistic nature of the interaction between temperature and resources. The assumption of a scenario assuming that BP, prot and phos changes during a temperature change suggests that prot:BP and phos:BP ratios decrease with a warming and increase with a cooling. Finally, these experiments show that temperature and PO4 availability are the main factors controlling heterotrophic activities. The study on OM availability and associated timing (pulsed or continuous) conducted during 4 seasonal cultures demonstrates that at different seasons and according to the delivery mode of OM, BA, BP and BR are varying significantly. However, the BA, BP and the BR does not show significant differences between the tanks with pulse OM addition and continuous OM addition suggesting that predominant bacterial communities are insensitive to the nature of nutritional disturbance whereas bacterial activities are highly dependent.

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