Viral, bacterial and ciliate abundance and viral-bacterial diversity in mesocosm experiments, 2007-2008, Kongsfjorden

• Main Authors: Sandaa, Ruth-Anne, Larsen, Aud, Thyrhaug, Runar, Egge, Jorun K, Töpper, Birte
• Format: Dataset
• Language: English
• Published: PANGAEA 2016
• Subjects: DATE/TIME; File content; File format; File size; Kongsfjorden-mesocosm; MESO; Mesocosm experiment; Principal investigator; Svalbard; Uniform resource locator/link to file; Arctic; Kongsfjord*; Kongsfjorden; Ny Ålesund; Ny-Ålesund; PAME; Phytoplankton
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.865353; https://doi.org/10.1594/PANGAEA.865353

Two mesocosm experiments, PAME-I and PAME-II were conducted in 2007 and 2008 to investigate fate of organic carbon in the arctic microbial food web. Mesocosms were nutrient fertilized initially to induce phytoplankton bloom development. In PAME-I eight units (each 700 L) formed two four point gradients of additional DOC in form of glucose (0, 0.5, 1 and 3 times Redfield ratio in terms of carbon relative to the nitrogen and phosphorus additions) (Fig. 1). All the eight units also got a daily dose of NH4+ and PO4**3- in Redfield ratio. Two gradients were set up, one with silicate addition, performed in the Arctic location Ny Ålesund, Svalbard, have previously been reported to give different food-web level responses to similar nutrient perturbations. In PAME-II all ten units (each 900 L) formed two four point gradients of additional DOC in form of glucose (0, 0.5, 1, 2 and 3 times Redfield ratio in terms of carbon relative to nitrogen and phosphorus additions). The two gradients in glucose were kept silicate replete. NH4+ was used as the DIN source in one gradient (units 1 to 5) and NO3- in the other (units 6-9). All units got a daily dose of PO4**3- in Redfield ratio. Prokaryotes and viruses were measured by flow cytometry, while ciliate abundances were counted using a Flow Cam. Viral and bacterial diversity was measured by PFGE and DGGE, respectively. In PAME-II the abundance of ciliates was lower than in PAME-I, presumably caused by higher copepod grazing. The abundances of prokaryotes and viruses were also lower in PAME-II compared to PAME-I. Further, less diversity was detected in the viral community (FCM and PFGE) in PAME-II, and no response was observed in the bacterial community structure due to addition of organic carbon.