Ramon Massana

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Very small eukaryotic organisms (picoeukaryotes) are fundamental components of marine planktonic systems, often accounting for a significant fraction of the biomass and activity in a system. Their identity, however, has remained elusive, since the small cells lack morphological features for identification. We determined the diversity of marine(More)
Bacterial and archaeal assemblages have been studied in a multipond solar saltern using a range of microbial ecology techniques by four laboratories simultaneously. These include 16S rDNA sequencing from both denaturing gradient gel electrophoresis (DGGE) and clone libraries, and culturing methods. Water samples from eight ponds were analysed, covering a(More)
We used denaturing gradient gel electrophoresis (DGGE) to study the diversity of picoeukaryotes in natural marine assemblages. Two eukaryote-specific primer sets targeting different regions of the 18S rRNA gene were tested. Both primer sets gave a single band when used with algal cultures and complex fingerprints when used with natural assemblages. The(More)
A previous report of high levels of members of the domain Archaeal in Antarctic coastal waters prompted us to investigate the ecology of Antarctic planktonic prokaryotes. rRNA hybridization techniques and denaturing gradient gel electrophoresis (DGGE) analysis of the bacterial V3 region were used to study variation in Antarctic picoplankton assemblages. In(More)
Syndiniales are a parasitic order within the eukaryotic lineage Dinophyceae (Alveolata). Here, we analysed the taxonomy of this group using 43655 18S rRNA gene sequences obtained either from environmental data sets or cultures, including 6874 environmental sequences from this study derived from Atlantic and Mediterranean waters. A total of 5571 out of the(More)
Newly described phylogenetic lineages within the domain Archaea have recently been found to be significant components of marine picoplankton assemblages. To better understand the ecology of these microorganisms, we investigated the relative abundance, distribution, and phylogenetic composition of Archaea in the Santa Barbara Channel. Significant amounts of(More)
Microbial communities inhabiting a multipond solar saltern were analysed and compared using SSU rRNA polymerase chain reaction (PCR)-based fingerprintings carried out in parallel by four laboratories. A salinity gradient from seawater (3.7%) to NaCl precipitation (37%) was studied for Bacteria, Archaea and Eukarya, and laboratories applied their own(More)
We analyzed microbial eukaryote diversity in perennially cold arctic marine waters by using 18S rRNA gene clone libraries. Samples were collected during concurrent oceanographic missions to opposite sides of the Arctic Ocean Basin and encompassed five distinct water masses. Two deep water Arctic Ocean sites and the convergence of the Greenland, Norwegian,(More)
A quantitative PCR (QPCR) assay based on the use of SYBR Green I was developed to assess the abundance of specific groups of picoeukaryotes in marine waters. Six primer sets were designed targeting four different taxonomic levels: domain (Eukaryota), division (Chlorophyta), order (Mamiellales) and genus (Bathycoccus, Micromonas, and Ostreococcus). Reaction(More)
Culture-independent molecular analyses of open-sea microorganisms have revealed the existence and apparent abundance of novel eukaryotic lineages, opening new avenues for phylogenetic, evolutionary, and ecological research. Novel marine stramenopiles, identified by 18S ribosomal DNA sequences within the basal part of the stramenopile radiation but unrelated(More)