The genus Eunotia in Tierra del Fuego peatbogs (Argentina)

GABRIELA MATALONI; VALERIA CASA; BART VAN DE VIJVER; LANGE-BERTALOT HORST

Congreso; 12th Central European Diatom meeting; 2019

LIST

Peatlands are worldwide considered being very vulnerable ecosystems and most studies in detail are restricted to the northern hemisphere. Their good functioning is crucial for the biotic communities that are often exclusively confined to these environments. Data on southern hemisphere peatlands are however scarce and apart from published data on the sub-Antarctic islands, Tasmania and New Zealand, almost nothing is known from the diatom flora in other southern hemisphere localities such as Patagonia, African mountain peatlands and the Falkland Islands/Islas Malvinas. Recently, a survey as started on the diatom flora from two peatbogs (Rancho Hambre and Andorra Valley) in Tierra del Fuego, Patagonia, Argentina. Tierra del Fuego is an archipelago off the southernmost tip of the South American mainland, across the Strait of Magellan. It encompasses a vast area of pristine peatlands, making up almost 95% of all peatbogs in Argentina. The pools and peatbogs in the sampled peatlands are characterized by low conductivity, low pH and low nutrient values. The vegetation is mainly dominated by Sphagnum magellanicum. During the survey of the freshwater diatom flora of these Tierra del Fuego peatbogs, a diverse diatom flora was observed, composed of several Eunotia, Brachysira and Pinnularia taxa. A large number of Eunotia taxa was observed in the samples. Only eleven taxa could be assigned to previously described species whereas twelve others could not be identified using the currently available literature. Based on extensive analysis of light and scanning electron microscopy observations, and after comparison with Eunotia taxa worldwide, it is clear that these twelve taxa are new and will need to be properly described. Some of the taxa were also observed (and even described) from the nearby Falkland Islands/Islas Malvinas although almost no similarities were found with the sub-Antarctic region despite the presence of peatbogs and Eunotia in the region. The poster illustrates and discusses several, probably new, Eunotia taxa using light and scanning electron microscopy observations and compares them to previously described taxa. The results confirm the high biodiversity of the Tierra del Fuego peatbogs.