Diversity and distribution of nano- and picoplankton in Antarctic and Arctic waters

Sammendrag

Information on the diversity, distribution and abundance of pico- (0.2-2 µm) and nano-plankton (2-20 µm), that cannot be identified to species level under the light microscope, is still limited. The aim of this study is to explore the pico- and nano-eukaryotic diversity and distribution in Antarctic and Arctic waters by advanced microscopy and molecular biological techniques, such as environmental clone libraries and 454-pyrosequencing. Another aim is to obtain new information on the influence of environmental factors on the plankton biodiversity and species composition in polar waters. Water samples and net hauls were collected and physical and chemical parameters measured during austral summer 2008 with the Norwegian R/V G.O. Sars in the Atlantic sector of the Southern Ocean, at stations along a N-S transect between 45-67o S at 15°E. During summer 2009, stations were sampled with the R/V Lance along an E-W transect from Spitsbergen into the Fram Strait. The Antarctic transect was conducted in open ocean, while the Arctic took place in a fjord, open ocean and along the ice edge. Water samples were size fractioned (>3, 45-3 and 3-0.6 µm) by filtration on board, for DNA isolation and analysis in the laboratory. Clone libraries are under construction and massive parallel tag sequencing will be tried to explore the diversity of planktonic pico- and nanoeukaryotes and their distribution along the transects. Light and scanning electron microscopy will be used as a comparison. We have a focus on the algal division Haptophyta, an important component of the pico- and nano-plankton community in the ocean. The study may give new information on plankton diversity and distribution in polar waters, as well as on differences in ecosystem functioning between the Southern Ocean and Arctic waters.