Picobiliphyte

Picobiliphytes or Picobiliphyta are a recently discovered group of eukaryotic algae which are found among the smallest members of photosynthetic picoplankton.

Discovery
At the end of the 1990s with the European project "Picodiv" it would be clarified which organisms occur in picoplankton. In addition, for a period of two years, samples were taken in the Atlantic, in the Mediterranean, before the coast of Scotland, Alaska and Norway. Picobiliphyta were found particularly within the nutrient-poor ranges from cold coastal seas, where they can constitute up to 50 percent of the biomass.

Affinities to other organisms
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 molecular biologists at the Alfred Wegener Institute for Polar and Marine Research 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 phycobiliproteins. In red algae, for example, these proteins occur as pigments. But in this newly discovered group of algae, the phycobiliproteins are contained inside the plastids, where the photosynthesis occurs. Hence, it provides a clear indication that the researchers are dealing with previously unidentified group of algae. Referring to their small size and the presence of phycobiliproteins, the researchers named the new group "Picobiliphyta".

Literature

 * Fabrice Not u. a.: Picobiliphytes: A Marine Picoplanktonic Algal Group with Unknown Affinities to Other Eukaryotes. In: Science. Bd. 315, Nr. 5809, 2007, S. 253-255.
 * Georg Kääb: Eine neue Welt so klein. Neue Klasse von Eukaryoten entdeckt: Picobiliphyta. In: biologen heute. Nr. 1, 2007, S. 18f., ISSN 1432-8631.

Picobiliphyta ピコビリ藻 Picobiliphyta