Journal: Applied and Environmental Microbiology

Article Title: Colonization in the Photic Zone and Subsequent Changes during Sinking Determine Bacterial Community Composition in Marine Snow

doi: 10.1128/AEM.02570-14

Figure Lengend Snippet: (Top) Drawing of one of the collection cylinders deployed on the sediment trap. The cylinder was filled with the different densities of GF/F-filtered seawater. The lower layer was denser than the layers above. This created three distinct density layers. By adding formaldehyde to the middle layer, we were able to fix the microbial community within marine snow and other aggregates sinking through this layer. The bottom density layer did not contain any formaldehyde and served to wash the fixed marine snow and other aggregates to avoid overfixation of the attached microbes, which prevents the use of fluorescence in situ hybridization. A collection cup filled with a viscous cryogel was placed at the very bottom of the sediment trap cylinder. The viscous gel collected the fixed and washed marine snow and other aggregates and preserved their size and structure. (Bottom) Images of the aggregates collected in the cryogel at 100 m (left) and 400 m (right).

Article Snippet: At each collection depth, two 1-m-long trap cylinders with an inner diameter of 10.4 cm were equipped with ∼200 ml of a viscous cryogel (Tissue-Tek OCT [optimum cutting temperature] compound cryogel; Sakura Finetek, Alphen aan den Rijn, Netherlands) to intercept and preserve settling particles without destroying their original size and structure.

Techniques: Fluorescence, In Situ Hybridization