Deep−sea benthic Ostracoda (Crustacea) in Icelandic waters are poorly known. Here we report deep−sea ostracode assemblages from the multiple core (MUC) and the epibenthic sledge (EBS) samples collected from Icelandic waters by the first cruise of the IceAGE (Icelandic Marine Animals: Genetics and Ecology) project. Samples from shelf − −edge and lower−bathyal working areas are examined. The results show (1) distinct MUC and EBS faunas due to the large difference in mesh size of MUC and EBS; and (2) distinct shelf−edge and lower−bathyal ostracode faunas. Such remarkable faunal turnover from shelf to bathyal depths is similar to the faunal turnovers reported from depth transects in the adjacent regions of the western North Atlantic Ocean, the Greenland Sea, and the North Sea, but, at the same time, there are certain differences in the faunal composition between the Icelandic waters and these adjacent regions. In addition, we illustrate many Icelandic deep−sea ostracode species with high−resolution scanning electron microscopy and composite all−in−focus stereomicroscopic images for the first time. These results provide important basic information on deep−sea ostracode research and biogeography of this important region connecting North Atlantic proper and Nordic Seas.
Field and laboratory protocols that originally led to the success of published studies have previously been only briefly laid out in the methods sections of scientific publications. For the sake of repeatability, we regard the details of the methodology that allowed broad−range DNA studies on deep−sea isopods too valuable to be neglected. Here, a com− prehensive summary of protocols for the retrieval of the samples, fixation on board research vessels, PCR amplification and cycle sequencing of altogether six loci (three mitochondrial and three nuclear) is provided. These were adapted from previous protocols and developed especially for asellote Isopoda from deep−sea samples but have been successfully used in some other peracarids as well. In total, about 2300 specimens of isopods, 100 amphipods and 300 tanaids were sequenced mainly for COI and 16S and partly for the other markers. Although we did not set up an experimental design, we were able to analyze amplification and sequencing success of different methods on 16S and compare success rates for COI and 16S. The primer pair 16S SF/SR was generally reliable and led to better results than universal primers in all studied Janiroidea, except Munnopsidae and Dendrotionidae. The widely applied universal primers for the barcoding region of COI are problematic to use in deep−sea isopods with a success rate of 45–79% varying with family. To improve this, we recommend the development of taxon−specific primers.