| 1. |
- Logares, Ramiro, et al.
(författare)
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Infrequent marine-freshwater transitions in the microbial world
- 2009
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Ingår i: Trends in Microbiology. - : Elsevier BV. - 0966-842X .- 1878-4380. ; 17:9, s. 414-422
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Forskningsöversikt (refereegranskat)abstract
- Until recently, the evolutionary relationships between marine and freshwater microbes were unclear, but the use of molecular phylogenies is beginning to shed light on this subject. An increasing amount of studies are showing that marine and freshwater microbes (including viruses) are usually not closely related, often grouping into distinct marine and freshwater phylogenetic clusters, similar to what has been reported before for macroorganisms. These studies indicate that marine–freshwater transitions have been infrequent events during the diversification of microbes and that most of these transitions occurred a long time ago in evolutionary terms. Here we discuss the significance of recent studies addressing this question and consider possible avenues for future research.
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| 2. |
- Mertens, Kenneth Neil, et al.
(författare)
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A review of recent freshwater dinoflagellate cysts: taxonomy, phylogeny, ecology and palaeocology
- 2012
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Ingår i: Phycologia. - : Informa UK Limited. - 0031-8884 .- 2330-2968. ; 51:6, s. 612-619
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Forskningsöversikt (refereegranskat)abstract
- Resting stages (e.g. cysts) play an important role in the life history and ecology of phytoplankton, e.g. the survival, reproduction, genetic recombination, and dispersal of many species. Marine dinoflagellates cysts have been intensively studied by both geologists and biologists, but freshwater cysts have received less attention. There are approximately 350 freshwater dinoflagellate species, and resting cysts have been described for 84 species. We evaluated the descriptions, and we reproduced images for each cyst type. The review highlighted the importance of cyst characters for taxonomy and phylogeny. We suggested that shape, wall ornamentation and possibly the archeopyle and color were important morphological characteristics at the generic level and above. The ecology of freshwater dinoflagellate cysts was reviewed, and the ecological role of cysts was discussed. The potential of freshwater cysts for Quaternary palaeoecological reconstructions was highlighted, revealing that these could serve as useful indicators of temperature, pH and productivity.
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