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| Format: | Artículo científico |
| Sprache: | en |
| Veröffentlicht: |
Universitat de Barcelona
2003
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| Online-Zugang: | https://www.redalyc.org/articulo.oa?id=50510402 |
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Inhaltsangabe:
- The fossil record and evolution of freshwater plants: a review C. Martín Closas Ciencias de la Tierra Evolution Charophytes Palaeoecology Freshwater algae Aquatic angiosperms Palaeobotany applied to freshwater plants is an emerging field of palaeontology. Hydrophytic plants reveal evolutionarytrends of their own, clearly distinct from those of the terrestrial and marine flora. During the Precambrian,two groups stand out in the fossil record of freshwater plants: the Cyanobacteria (stromatolites) in benthicenvironments and the prasinophytes (leiosphaeridian acritarchs) in transitional planktonic environments. Duringthe Palaeozoic, green algae (Chlorococcales, Zygnematales, charophytes and some extinct groups) radiated anddeveloped the widest range of morphostructural patterns known for these groups. Between the Permian andEarly Cretaceous, charophytes dominated macrophytic associations, with the consequence that over tens of millionsof years, freshwater flora bypassed the dominance of vascular plants on land. During the Early Cretaceous,global extension of the freshwater environments is associated with diversification of the flora, includingnew charophyte families and the appearance of aquatic angiosperms and ferns for the first time. Mesozoicplanktonic assemblages retained their ancestral composition that was dominated by coenobial Chlorococcales,until the appearance of freshwater dinoflagellates in the Early Cretaceous. In the Late Cretaceous, freshwaterangiosperms dominated almost all macrophytic communities worldwide. The Tertiary was characterised by thediversification of additional angiosperm and aquatic fern lineages, which resulted in the first differentiation ofaquatic plant biogeoprovinces. Phytoplankton also diversified during the Eocene with the development of freshwaterdiatoms and chrysophytes. Diatoms, which were exclusively marine during tens of millions of years,were dominant over the Chlorococcales during Neogene and in later assemblages. During the Quaternary,aquatic plant communities suffered from the effects of eutrophication, paludification and acidification, whichwere the result of the combined impact of glaciation and anthropogenic disturbance. 2003 artículo científico 1695-6133 https://www.redalyc.org/articulo.oa?id=50510402 en http://www.redalyc.org/revista.oa?id=505 Geologica Acta: an international earth science journal application/pdf Universitat de Barcelona Geologica Acta: an international earth science journal (España) Num.4 Vol.1