Big and Small !
Colin Brownlee , January 20 , 2013
Last night we began to head north away from the polar waters at the ice edge and back towards the Polar Front and sub-polar waters . We are currently about mid-way between the South Orkney Islands and South Georgia in the Scotia Sea . The flat calm , penguins , seals and icebergs have gone , replaced by the more typical uneven water , petrels and albatrosses that we experienced whilst crossing Drake Passage . This is an important part of the cruise since we are passing across significant gradients of carbonate chemistry that occur between polar and sub-polar regions .
The typical scene today , grey seas and skies but with an occasional Albatross @ Jeremy Young
Much of my work on this cruise is to obtain phytoplankton samples for genetic analysis . We are particularly interested in how different types of phytoplankton will respond in the long term to changes in ocean chemistry that are associated with ever increasing levels of carbon dioxide in the atmosphere and ocean surface water . One way of trying to discover this is to try to assess the ways in which different types of phytoplankton respond to experimentally imposed changes . To do this we take freshly isolated phytoplankton cells from the cruise and culture them back in the laboratory at home for more detailed experimental analysis . In parallel we are building a record of genetic variability by taking many samples for DNA analysis . We also extract RNA from our samples which , when analysed , can give an indication of the genes that are switched on or off in particular phytoplankton groups . This kind of molecular genetic analysis can also tell us how much natural variation there is in a single species – and it is that level of variation that can determine how fit a population is to survive changes . In this respect our main interests are in the calcifying coccolithophores , particularly the globally distributed species Emiliania huxleyi .
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