Identification and isolation of heterotrophic marine particle associated bacteria Bakterien Imhoff sedimentation cones bacterioplankton ecological succession great plate count anomaly microbial diversity phycosphere Primary producers alongside heterotrophic bacteria and viruses modulate the essential global carbon cycle. About half of the Earth’s net primary production originates in the marine environment. By effecting these systems and the burial of carbon bacteria play a significant role in the world’s climate especially with regard to rising temperatures and increasing anthropogenic carbon dioxide production. Particles present substrate rich niches for particle associated bacteria but are rare in the marine system. Particle associated bacteria comprising of chemotactic motile free living and particle attached bacteria were shown to have higher respiration rates were larger in cell and genome size and showed a higher hydrolytic activity of extracellular enzymes compared to the free living fraction. Understanding the contribution of particle associated bacteria to the degradation of algal biomass is essential to understand the marine carbon cycle. However the identification of this group is difficult and required refinement. Sequential filtration the most commonly used technique for the separation of bacterial fractions provides only access to a part of the particle associated microbiome and includes with large and clustered bacteria undesired false positives. To overcome these limitations separation by gravity in Imhoff sedimentation cones was explored in this thesis to access identify and define particle associated microbiomes in comparison and conjunction with the ...