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Photosynthetic picoplankton is the fraction of the phytoplankton performing photosynthesis composed by cells between 0.2 and 2 µm (picoplankton). It is especially important in the central oligotrophic regions of the world oceans that have very low concentration of nutrients. == History == * 1952: Description of the first truly picoplanktonic species, ''Chromulina pusilla'', by Butcher.〔Butcher, R. (1952). Contributions to our knowledge of the smaller marine algae. ''Journal of the Marine Biological Association UK'' 31: 175-91.〕 This species was renamed in 1960 to ''Micromonas pusilla''〔Manton, I. & Parke, M. (1960). Further observations on small green flagellates with special reference to possible relatives of ''Chromulina pusilla'' Butcher. ''Journal of the Marine Biological Association UK'' 39: 275-98.〕 and a few studies have found it to be abundant in temperate oceanic waters, although very little such quantification data exists for eukaryotic picophytoplankton. * 1979 : Discovery of marine ''Synechococcus'' by Waterbury〔Waterbury, J. B. ''et al.'' (1979). Wide-spread occurrence of a unicellular, marine planktonic, cyanobacterium. ''Nature'' 277: 293-4.〕 and confirmation with electron microscopy by Johnson and Sieburth.〔Johnson, P. W. & Sieburth, J. M. (1979). Chroococcoid cyanobacteria in the sea: a ubiquitous and diverse phototrophic biomass. ''Limnology and Oceanography'' 24: 928-35.〕 * 1982 : The same Johnson and Sieburth demonstrate the importance of small eukaryotes by electron microscopy.〔Johnson, P. W. & Sieburth, J. M. (1982). In-situ morphology and occurrence of eucaryotic phototrophs of bacterial size in the picoplankton of estuarine and oceanic waters. ''Journal of Phycology'' 18: 318-27.〕 * 1983 : W.K. Li and Platt show that a large fraction of marine primary production is due to organisms smaller than 2 µm.〔Li, W. K. W. ''et al.'' (1983). Autotrophic picoplankton in the tropical ocean. ''Science'' 219: 292-5.〕 * 1986 : Discovery of "prochlorophytes" by Chisholm and Olson in the Sargasso Sea,〔Chisholm, S. W. ''et al.'' (1988). A novel free-living prochlorophyte occurs at high cell concentrations in the oceanic euphotic zone. ''Nature'' 334: 340-3.〕 named in 1992 as ''Prochlorococcus marinus''.〔Chisholm, S. W. ''et al.'' (1992). ''Prochlorococcus marinus'' nov. gen. nov. sp.: an oxyphototrophic marine prokaryote containing divinyl chlorophyll ''a'' and ''b''. ''Archives of Microbiology'' 157: 297-300.〕 * 1994 : Discovery in the Thau lagoon in France of the smallest photosynthetic eukaryote known to date, ''Ostreococcus tauri'', by Courties.〔Courties, C. ''et al.'' (1994). Smallest eukaryotic organism. ''Nature'' 370: 255.〕 * 2001 : Through sequencing of the ribosomal RNA gene extracted from marine samples, several European teams discover that eukaryotic picoplankton are highly diverse.〔López-García, P. ''et al.'' (2001). Unexpected diversity of small eukaryotes in deep-sea Antarctic plankton. ''Nature'' 409: 603-7.〕〔Moon-van der Staay, S. Y. ''et al.'' (2001). Oceanic 18S rDNA sequences from picoplankton reveal unsuspected eukaryotic diversity. ''Nature'' 409: 607-10.〕 This finding followed on the first discovery of such eukaryotic diversity in 1998 by Rappe and colleagues at Oregon State University, who were the first to apply rRNA sequencing to eukaryotic plankton in the open-ocean, where they discovered sequences that seemed distant from known phytoplankton〔Rappe, M. ''et al.'' (1998). Phylogenetic diversity of ultraplankton plastid Small-Subunit rRNA genes recovered in environmental nucleic acid samples from the Pacific and Atlantic coasts of the United States. ''Applied and Environmental Microbiology'' 64294-303.〕 The cells containing DNA matching one of these novel sequences were recently visualized and further analyzed using specific probes and found to be broadly distributed.〔Kim, E., Harrison, J., Sudek, S. ''et al.'' (2011). Newly identified and diverse plastid-bearing branch on the eukaryotic tree of life. Proceedings of the National Academy of Sciences USA. Vol. 108: 1496-1500.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Photosynthetic picoplankton」の詳細全文を読む スポンサード リンク
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