Chlorophyll and primary production in the North Atlantic.

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Macroscopic patterns in marine plankton

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Bacterial biomass distribution in the global ocean

International audienceWe compiled a database of bacterial abundance of 39 766 data points. After gridding with 1 spacing, the database covers 1.3% of the ocean surface. There is data covering all ocean basins and depth except the Southern Hemisphere below 350m or from April until June. The average bacterial biomass is 3.9±3.6 μg l−1 5 with a 20-fold decrease between the surface and the deep sea. We estimate a total ocean inventory of about 1.3×1029 bacteria. Using an average of published open ocean measurements for the conversion from abundance to carbon biomass of 9.1 fg cell−1, we calculate a bacterial carbon inventory of about 1.2 PgC. The main source of uncertainty in this inventory is 10 the conversion factor from abundance to biomass

Health-related quality-of-life and psychological distress of young adult survivors of childhood cancer in Hong Kong

10.1002/pon.3396Psycho-Oncology232229-236POJC

Metagenomic retrieval of a ribosomal DNA repeat array from an uncultured marine alveolate

9 pages, 4 figures, 1 table.-- PMID: 18266757 [PubMed]The aim of this study was to explore the use of large-scale sequencing to better describe the genome content of naturally occurring, uncultured protists. We constructed a metagenomic fosmid library from a picoplanktonic assemblage (0.2–3 mm size cells) collected at the Blanes Bay Microbial Observatory (Western Mediterranean). Seven clones contained a small-subunit ribosomal RNA gene (SSU rDNA) affiliating with prasinophytes and uncultured alveolates. One clone (FBB25; 35 kb in size) was completely sequenced and found to be a tandem repeat array (5.5 times) of the rDNA operon, including three rRNA genes (SSU, large-subunit and 5.8S rDNAs) and three spacer regions (internal transcribed spacers 1, 2 and intergenic spacer). The SSU rDNA of FBB25 affiliated with the marine alveolates group I, cluster 1, and was almost identical to sequences retrieved only in marine surveys from a wide geographic and ecological range. Phylogenetic trees using the different rRNA genes showed FBB25 as an independent branch among the main alveolate groups, but their closest affiliation varied between the SSU tree (dinoflagellates) and the large-subunit and 5.8S trees (perkinsids). The spacer regions of FBB25 were particularly short when compared with other eukaryotes, indicating a possible genome streamlining in this picoeukaryote. Finally, not a single polymorphism was found in the rDNA repeat array, suggesting that the high SSU rDNA variability typically found in molecular surveys derives from organismal and not intragenomic diversity. This first report on the rDNA genomic structure of an uncultured marine alveolate improves their phylogenetic position and helps interpreting data generated during picoeukaryotic molecular surveysThis study was supported by Projects ESTRAMAR (CTM2004-12631/MAR, MEC) and Marine Genomics (FP6–505403, EU).Peer reviewe