Vertical distribution andtemporal variation fmarine planktonic archaea in the Gerlache Strait, Antarctica, during early spring

• Main Authors: Ramon Massana, Lance T. Taylor, Alison E. Murray, Ke Y. Wu, Wade H. Jefsyey, Edward F. Delong
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; Antarctic Peninsula; Austral; Gerlache; Gerlache Strait; Southern Ocean; The Antarctic; Antarc*; Antarctica
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.531.2596; http://www.aslo.org/lo/toc/vol_43/issue_4/0607.pdf

A station located in the Gerlache Strait (Antarctic Peninsula) was sampled during early spring to determine the vertical distribution of marine planktonic archaea nd to further describe the dynamic environment where they live. Chlorophyll concentration i dicated that sampling occurred uring the early stages of austral spring algal devel-opment. As expected, prokaryote abundance was higher at surface than at depth, and prokaryotic a tivity estimated by leucine incorporation was low at the surface and extremely low at 500 m. The relative abundance of planktonic archaeal, eucaryal, and bacterial ribosomal RNA was determined by quantitative rRNA hybridization, and the performance of two different universal probes used to normalize group-specific probe hybridization response was compared. Archaeal rRNA was detected in all samples analyzed, and was more abundant at depth (up to 25 % of total rRNA) than at the surface. Inboth years, the archaeal signal decreased uring the sampling period, particularly at surface. Most of the archaeal signal was attributable to group I archaea, affiliated with the kingdom Crenarchaeota. Planktonic euryarchaeotes (group II archaea) showed a larger contribution tothe archaeal assemblage in surface waters than at depth. In total, our results verify that planktonic archaea are dynamic and abundant components in marine picoplankton assemblages ofthe Antarctic Peninsula. The Southern Ocean includes all the water surrounding the Antarctic continent south of the Antarctic Convergence (Vincent 1988; Karl 1993). It is one of the largest contiguous ecosystems on Earth and is one of the least understood, be-ing undersampled with respect o other more accessible o-cations. Ingeneral, the Southern. Ocean is characterized by oligotrophic conditions interms of biomass and production. However, certain regions have a seasonal cycle that includes a very high productivity and an active and dynamic food web. The Gerlache Strait, a region west of the Antarctic Peninsula, is one of these productive areas ...