FS Poseidon Fahrtbericht Cruise report POS316 : Carbonate mounds and aphotic corals in the NE Atlantic ; Reykjavik Lissabon 03.08. 17.08.04 POSEIDON No 316 was a multidisciplinary cruise addressing biological geological and hydrographical scientific objectives in the carbonate mound and aphotic coral province west of Ireland in the eastern Porcupine Seabight and at the western Rockall Bank. The main objective was to investigate the interrelation between the rich aphotic coral ecosystems found in these regions and diurnal and seasonal processes in the ambient hydro dynamical and depositional regime as these factors seem to bias the conditions of coral growth and reproduction. The cruise started in Reykjavik and ended in Lisbon and continued the 2004 investigations in the Irish carbonate mound province with FS METEOR (M61 leg 1 20040418 20040505). The scientific work is embedded in the ESF DFG Moundforce project of the EUROMARGINS Programme. Together with the previous M61 cruise the POSEIDON activities document Germanys strong scientific and logistic support for the success of this challenging programme. Investigations are also designed as a preparatory cruise for the EU project HERMES (Hotspot Ecosystem Research on the Margins of European Seas; start 20050401). The institutions participating in POSEIDON 316 are partners in HERMES Work Package 2 Coral Reef and Carbonate Mound Systems . (MOD)