An international group of researchers has succeeded in identifying a previously unknown group of algae. As currently reported in the scientific journal Science, the newly discovered algae are found among the smallest members of photosynthetic plankton - the picoplankton (‘Picobiliphytes: A marine picoplanktonic algal group with unknown affinities to other Eukaroytes” Science, Vol. 316’). On account of the minute size of the organisms (no more than a few thousandth of a millimetre) and the appearance of phycobili-proteins, researchers have termed the new group Picobiliphytes.
Approximately 50 percent of global photosynthesis is conducted in the world’s oceans where it is dominated by microscopic algae, the so-called phytoplankton. Scientists estimate that up to 90 percent of phytoplanktonic species are currently unidentified. In the present study, scientists used molecular techniques to investigate the smallest members of the plankton, the picoplankton. Because picoplankton algae are so extremely small, they are almost impossible to study by means of microscopy.
Researchers investigated gene sequences of the 18S gene, common to all cells. The identity of new organisms can be deduced from a comparison of familiar and unfamiliar gene sequences. “The gene sequences found in these algae could not be associated with any previously known group of organisms”, explain Dr Klaus Valentin and Dr. Linda Medlin, co-authors of the study and molecularbiologists at the Alfred Wegener Institute in Bremerhaven. The algae in this study were found in plankton samples originating from various regions of the North Atlantic and the Mediterranean. The scientists have discovered a group of organisms which, despite being completely new to science, have a wide distribution. “This is a good indication for how much there is still to discover in the oceans, especially using molecular tools”, says Valentin.
Apart from the unfamiliar gene sequences, the researchers also detected a phycobiliprotein-containing plastid in the novel cells. In red algae, for example, these proteins occur as photosynthetic pigments. Hence, it provides a clear indication that the researchers are dealing with previously unidentified species of algae. Referring to their small size and the presence of phycobili proteins, the researchers named the new group Picobiliphytes.
On January 12, 2007, the study entitled ‘Picobiliphytes: A marine picoplanktonic algal group with unknown affinities to other Eukaroytes’ will be published in the scientific journal Science.
Bremerhaven January 12th, 2007
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The Alfred Wegener Institute (AWI) conducts research in the Arctic, Antarctic and in oceans of temperate and high latitudes. The AWI coordinates polar research in Germany, and provides important infrastructure, such as the research icebreaker Polarstern and research stations in the Arctic and Antarctic for international scientific enterprises. The Alfred Wegener Institute is one of 15 research centres of the 'Helmholtz-Gemeinschaft' (Helmholtz Association), the largest scientific organisation in Germany.