Bacterial community patterns along small- and large-scale environmental radients in Arctic deep-sea sediments

One focus of this study was to detect local coherences between deep-sea benthic bacterial community patterns and an ice-edge related input of organic material (Fram Strait, Arctic Ocean) as well as physical disturbances (Ardencaple Canyon, Greenland Sea). Such large-scale patterns along a depth-dependent gradient were compared to small scales patterns within the sediment column. A further aim was to assess the local impact of small biogenic structures (Macrofaunal crawling and feeding tracks, burrows, plough traces, faeces, Tentorium semisuberites) on benthic bacterial communities by increasing microhabitat heterogeneity through the modification of near-bottom flows and hence deposition patterns in deep-sea surface sediments. As the retrieval and incubation procedures of all deep-sea sediments sampled for this study were performed in absence of pressure-retaining gears, bacterial viability and activity has been assessed by different approaches to estimate bulk metabolic pathways.