Low virus to prokaryote ratios in the cold: benthic viruses and prokaryotes in a subpolar marine ecosystem (Hornsund, Svalbard)

摘要

The density and spatial distribution of benthic viruses and prokaryotes in relation to biotic and abioticfactors were investigated in sediment cores collected in Hornsund, a permanently cold fjord on the West coast of Svalbard,Norway. The cores were obtained from the mouth of the fjord to the central basin, along a longitudinal transect. Theresults of our analyses showed lower densities of viruses (0.2 × 108 to 5.4 × 108 virus-like particles/g) and lower virus-toprokaryoteratios (0.2-0.6, with the exception of the uppermost layer in the central basin, where the ratio was about 1.2)at the study site than generally found in the temperate areas, despite the relatively high organic matter content in subpolarsediments. Variations in benthic viral and prokaryote abundances along gradients of particle sedimentation rates, phytopigmentconcentrations, and macrobenthic species composition together suggested the influence of particle sedimentationand macrobenthic bioturbation on the abundance and spatial distribution of prokaryotes and viruses in cold habitats.