A molecular gut content study of Themisto abyssorum ( Amphipoda) from Arctic hydrothermal vent and cold seep systems

• Published in: Molecular Ecology
• Main Authors: Olsen, Bernt Rydland, Troedsson, Christofer, Hadziavdic, Kenan, Pedersen, Rolf B., Rapp, Hans Tore
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2013
• Subjects: Themisto abyssorum; Themisto
• Online Access: http://dx.doi.org/10.1111/mec.12511; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fmec.12511; https://onlinelibrary.wiley.com/doi/pdf/10.1111/mec.12511

Abstract The use of DNA as a marker for prey inside the gut of predators has been instrumental in further understanding of known and unknown interactions. Molecular approaches are in particular useful in unavailable environments like the deep sea. Trophic interactions in the deep sea are difficult to observe in situ, correct deep‐sea experimental laboratory conditions are difficult to obtain, animals rarely survive the sampling, or the study organisms feed during the sampling due to long hauls. Preliminary studies of vent and seep systems in the N ordic S eas have identified the temperate‐cold‐water pelagic amphipod T hemisto abyssorum as a potentially important predator in these chemosynthetic habitats. However, the prey of this deep‐sea predator is poorly known, and we applied denaturing high performance liquid chromatography ( DHPLC ) to investigate the predator–prey interactions of T . abyssorum in deep‐water vent and seep systems. Two deep‐water hydrothermally active localities (The J an M ayen and L oki's C astle vent fields) and one cold seep locality (The H åkon M osby mud volcano) in the N ordic S eas were sampled, genomic DNA of the stomachs of T . abyssorum was extracted, and 18 S rDNA gene was amplified and used to map the stomach content. We found a wide range of organisms including micro‐eukaryotes, metazoans and detritus. Themisto abyssorum specimens from L oki's Castle had the highest diversity of prey. The wide range of prey items found suggests that T . abyssorum might be involved in more than one trophic level and should be regarded as an omnivore and not a strict carnivore as have previously been suggested.