12/25/2022 0 Comments Nebela tincta protists![]() ![]() ![]() These Japanese cedar forests are very dense, limiting the development of ferns and some mosses. 2007), located especially at elevations > 400 m a.s.l. Don forest occupies about 22% of the land area in the Azores (representing 60% of forest plantation area ( Cruz et al. with a close canopy in which a great diversity of ferns and mosses is found ( Elias et al. Dominant tree species of this endemic forest are Juniperus brevifolia (Seub.) Antoine, Laurus azorica (Seub.) Franco and Ilex azorica Loes. 2010, DDRF 2014), being a priority habitat in the Natura 2000 network ( Guimarães and Olmeda 2008). Native forests cover less than 10% of the total area, mostly at elevations > 800 m a.s.l. At top left - The Azores Archipelago in the Atlantic Ocean highlighted by a square at top right, São Miguel Island in the Azores Archipelago highlighted by a square and, at the bottom, the 16 study localities. Geographical location of the study localities. By the end of the nineteenth century, Gerne (1888) and Barrois (1896) published several papers on freshwater biota of the Azores including some additions to testate amoebae fauna (Table (Table1 1). Later, with the Challenger expedition that took place from 1872 to 1876 and which had a brief passage to São Miguel Island, the Irish naturalist Archer ( Archer 1874) studied samples from Lake Furnas and reported six new taxa. Leidy (1879), in his work “Fresh-water rhizopods of North America”, quotes the species again, without adding any comment and Difflugia oligodon was described by Ehrenberg (1844) on the basis of samples from Kurdistan and a 10-word diagnosis. Difflugia azorica was described by Ehrenberg (1871) as an endemic species, although the diagnosis can be applied to many species of the genus and may correspond to a variety of Difflugia pyriformis. Interest in Azorean testate amoebae started almost two centuries ago with the work of Ehrenberg (1854), which reported three protist species Difflugia azorica, Difflugia oligodon and Trinema enchelys, found in soil collected on São Miguel Island. 2014) and previous studies are fragmented and unsystematic. 2020).ĭespite their great importance, current knowledge of testate amoebae in the Azores Archipelago is limited when compared to other groups (e.g. 2015) and for the establishment of their functional traits ( Mitchell et al. ![]() The increasing use of testate amoebae in palaeoecological studies in the last decades demands the knowledge of modern assemblages for comparative analysis ( Mitchell et al. As the species composition of these protists depends on environmental conditions, they are frequently used to reconstruct the past climate and environment ( Ellison 1995, Mitchell et al. In addition, their shells are usually well preserved in sedimentary records and remain nearly unchanged over time. Due to their importance and sensitivity to environmental changes in both systems, they have been frequently used as bioindicators of environmental quality or stress or ecosystem resilience ( Mitchell et al. In aquatic environments, they play an important role, especially in material cycling and energy flow ( Glime 2017), while in terrestrial habitats, they play a crucial role in carbon and nitrogen cycling ( Puppe et al. They have a worldwide distribution, occurring in aquatic and terrestrial systems ( Smith et al. tincta did not have the same trophic position in the microbial food web, probably resulting from their different feeding strategies.Testate amoebae are a polyphyletic group of small size protists, enclosed within a xenosomic or idiosomic shell or test, made from proteinaceous, calcareous and/or siliceous material ( Mitchell et al. Additionally, isotope analyses suggested that H. Nonmetric Multidimensional Scaling analysis clearly demonstrated that the two species did not have the same feeding habit along the “fen-bog” gradient, and furthermore that a significant spatial split exists in the feeding behavior of H. papilio, the most frequently ingested prey were ciliates (55%) and microalgae (35%). tincta were spores and mycelia of fungi (55%), microalgae (25%) and cyanobacteria (8.5%). Among identified food sources, those most frequently ingested by N. papilio was described from top segments, and that of N. Owing to their vertical distribution, the feeding habit of H. Observations of digestive vacuole content and stable isotope analyses (¹☼ and ¹⁵N) were used to establish the feeding behavior of both testate amoeba species. Samples were collected in living “top segments” (0-3cm) and early declining “bottom segments” (3-6cm) of Sphagnum fallax peat. Population dynamics and feeding habits of the testate amoebae Nebela tincta and Hyalosphenia papilio were studied along a short “fen” to “bog” gradient in a Sphagnum-dominated mire (Jura, France). ![]()
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