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Bacillariophyta = Diatoms = Diatomeae --- Luticola --- Antarctic Islands
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BR Staff Publications --- Antarctic Islands --- ecology --- Bacillariophyta = Diatoms = Diatomeae
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USR former USSR --- former USSR --- ecology --- Antarctic Islands
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BR Staff Publications --- Antarctic Islands --- morphology --- new species --- Bacillariophyta = Diatoms = Diatomeae
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Altitudinal gradients provide excellent opportunities to study relationships between species distribution and climatic variables. We studied the species composition of 39 samples of moss-inhabiting diatoms, collected at 50 m intervals from 100-650 m above sea level. The samples contained a total of 130 diatom species, of which 51 occurred in 10 or more samples. Altitude appeared to be the most important variable explaining variation in species composition. Of the 51 common species, 33 showed a significant relationship with altitude. Although the majority of the latter declined with increasing altitude, for nine species the probability of occurrence first increased with increasing elevation, but decreased again at higher altitudes, and four species increased systematically with elevation. As a result, expected species richness per sample decreased from an estimated 43 at 100 m to 25 species per sample at 650 m. Diatom distribution patterns proved to be suitable predictors of the altitudinal position of sample sites. Cross-validation yielded a strong relationship between predicted and observed altitudes
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On Ile de la Possession (Crozet Archipelago, sub-Antarctica), the testate amoebae (Protozoa, Rhizopoda) fauna in soils around abandoned and occupied nests of the wandering albatross (Diomedea exulans) was investigated. A comparison with control samples, a cluster analysis and several ordination techniques indicated that the presence of the breeding albatrosses induced modifications in physico-chemical soil characteristics and in the soil inhabiting testacean fauna. Only 11 testate species occurred frequently in the soils in the albatross' zone. Soils around occupied nests had significantly higher moisture values, less acid pH values, an increased specific conductance and elevated phosphate and ammonium concentrations. Highly influenced testacean communities were characterized by high abundances of Difflugiella oviformis and extremely high abundances of Trinema lineare, resulting in a very low diversity and evenness within these communities. The intermediary situation of one abandoned nest indicated that soils around abandoned ests evolve gradually back to undisturbed soils. Although an overall negative influence on the testacean iversity, a limited albatross' influence may increase the living fraction within the testacean soil communities
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Contemporary eruptive episodes and present volcanic activity at Deception Island have created a mosaic of different environmental conditions. In this study, the microalgal communities inhabiting 18 sites differing in geology, degree of disturbance and physico-chemical features (texture, water, organic matter and nutrient contents) were characterized in terms of composition, species richness and biomass. 140 taxa were recorded, with richest communities associated with stable sites and some of the poorest ones in locations affected by recent eruptions. In accordance, a canonical correspondence analysis ordinated species and sites along the first axis acording to the precentage of coarse particles, and degree of disturbance (eigenvalues 0.79 and 0.65, p=0.04). Results of a cluster analysis grouped firstly algal taxa with high fidelity to one set of environmental conditions, while "ubiquitous" ones had the lowest similarity values. These taxa, mainly filamentous Cyanobacteria and diatoms, are the only colonizers of harsher or recently formed environments
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EAR Earth Sciences --- Algeria --- Antarctic Islands --- Benin ( = Dahomey ) ( = AOF ) --- Cafrine --- Congo = Congo Brazzaville = Republic of Congo = République populaire du Congo --- France --- French Antilles --- Guiana = Guyana (= French Guiana / Guyana = Guyane française ) --- Guinea = Guinée ( = French Guinea = Guinée française ) ( = AOF ) --- India --- Indian Ocean Islands --- Indochina --- Ivory Coast = Côte d'Ivoire ( = AOF ) --- La Réunion --- Madagascar --- Mali ( = French Sudan = Soudan français ) ( = AOF ) --- Morocco --- New Caledonia --- Nossi-Bé --- Oceania --- Saint-Paul Island --- Saint-Pierre Island --- Senegal ( = AOF ) --- Somalia --- Tunisia --- earth sciences --- general geography
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Islands have captured the imagination of scientists and the public for centuries-unique and rare environments, their isolation makes them natural laboratories for ecology and evolution. This authoritative, alphabetically arranged reference, featuring more than 200 succinct articles by leading scientists from around the world, provides broad coverage of all the island sciences. But what exactly is an island? The volume editors define it here as any discrete habitat isolated from other habitats by inhospitable surroundings. The Encyclopedia of Islands examines many such insular settings-oceanic and continental islands as well as places such as caves, mountaintops, and whale falls at the bottom of the ocean. This essential, one-stop resource, extensively illustrated with color photographs, clear maps, and graphics will introduce island science to a wide audience and spur further research on some of the planet's most fascinating habitats.
Islands --- Isles --- Islets --- Landforms --- Islands. --- Habitat. --- Ecology. --- Bionomics --- Ecologies --- Environmental Psychology --- Conservation of Natural Resources --- Environmental Health --- Ecosystem --- Biome --- Ecologic System --- Ecologic Systems --- Ecological System --- Habitat --- Niche, Ecological --- System, Ecological --- Systems, Ecological --- Biomes --- Ecological Niche --- Ecological Systems --- Ecosystems --- Habitats --- System, Ecologic --- Systems, Ecologic --- Ecology --- Environment --- antarctic islands. --- arctic islands. --- asian islands. --- caribbean islands. --- easter island. --- ecology. --- encyclopedia of the natural world. --- island biology. --- island encyclopedia. --- island fauna. --- island flora. --- island formation. --- island geography. --- island issues. --- island nature. --- island reference guide. --- island science. --- islands. --- marine biology. --- natural science. --- nature. --- pacific islands. --- polynesia. --- study of islands. --- volcanic islands. --- world island.
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