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Casamayor E.O.,CSIC - Center for Advanced Studies of Blanes
Aquatic Microbial Ecology | Year: 2010

Vertical distributions of viable (most probable number, MPN) aerobic chemoautotrophic thiobacilli-like sulfur-oxidizing bacteria (ca. 70 samples in triplicate for MPN counts) and dark 14C-bicarbonate incorporation rates were analyzed in a series of sulfide-rich lakes. A special device for sampling sharply stratified populations on the scale of a few centimeters was used. Detailed analyses focused on the oxic-anoxic transition zone where aerobic sulfur-oxidizing bacteria should display positive chemotaxis, and in both fully oxic epilimnia and sulfide-rich anoxic hypolimnia. Kinetics of sulfide and thiosulfate potential oxidations in the presence of oxygen were followed in microcosm enrichments in one of the lakes. The highest MPN counts (>10 4 to 105 cells ml-1) were observed at the oxic-anoxic interfaces and in the depleted hypolimnia (1.3 μ 4.4 × 104 cells ml-1), whereas 1 order of magnitude lower concentrations were detected in the epilimnia (1.0 μ 2.3× 10 3 cells ml-1). Dark 14C-bicarbonate incorporation rates were higher at the oxic-anoxic interface (11.4 μ 9.5 μg C l-1 h-1) than in the hypolimnia (6.4 μ 5.9 μg C l-1 h-1) and epilimnia (1.0 μ 2.1 μg C l-1 h-1). A lack of correspondence between abundance of MPN thiobacilli, location at the sulfide interface, and dark carbon fixation rates was, however, consistently observed in a correlation analysis. Patterns of in situ potential aerobic thiosulfate oxidation did not match dark carbon fixation rates or MPN vertical distributions. The chemoautotrophic guild of these lakes emerged as a metabolically complex, taxonomically diverse group of aerobic, microaerophilic, and anaerobic microorganisms coexisting in the same lake. Thiobacilli may actively fix CO2 at certain depths but the question of which types of bacteria contribute most to dark CO2 fixation in the investigated lakes is still open, and the application of culture-independent molecular tools and single-cell analyses should be used to substantiate and further explore these findings. © Inter-Research 2010. Source

Macpherson E.,CSIC - Center for Advanced Studies of Blanes
Scientia Marina | Year: 2011

A new species of Munidopsis Whiteaves, 1874 is reported from the south of Crete, at 2046-2104 m, in the eastern Mediterranean Sea. The species (M. ariadne) is morphologically closely related to M. maunga Schnabel and Bruce, 2006, from New Zealand. The species is also close to M. polymorpha Koelbel, 1892, from Lanzarote, Canary Islands, and M. talismani A. Milne Edwards and Bouvier, 1894, from the NW Africa. The new species is described and illustrated and a diagnosis along with full illustration is provided for the latter 2 species. Source

Bacardit M.,CSIC - Center for Advanced Studies of Blanes
Environmental science and pollution research international | Year: 2010

BACKGROUND, AIM, AND SCOPE: High mountain soils constitute a long-term cumulative record of atmospherically deposited trace elements from both natural and anthropogenic sources. The main aims of this study were to determine the level of major and trace metals (Al, Ti, Mn, Fe, and Zr) of lithologic origin and airborne contaminating trace elements (Ni, Cu, Zn, As, Cd, and Pb) in soils in the Central Pyrenees as an indication of background contamination over SW Europe, to establish whether there is a spatial pattern of accumulation of trace elements in soils as a function of altitude, and to examine whether altitude-related physicochemical properties of soils affect the accumulation of major metals and trace elements. METHODS: Major metals and trace elements were measured in "top" (i.e., first 10 cm) and "bottom" (i.e., below 10 cm) soil samples along an altitudinal transect (1,520-2,880 m a.s.l.) in the Central Pyrenees. Total concentrations were determined by X-ray fluorescense spectrometry. Total major metal concentrations were analysed by conventional X-ray fluorescence spectrometry (XRF) with a Siemens SRS 303 instrument. Total trace element concentrations were determined with an energy-dispersive multielement miniprobe XRF analyser. Acid-extractable concentrations were measured by inductively coupled plasma after previous extraction with nitric acid and hydrogen peroxide in closed beakers. Acid-extractable major metal concentrations were measured by inductively coupled plasma (ICP)-Optic Emission Spectrometry with a Perkin Elmer 3200 RL Instrument. Acid-extractable trace element concentrations were determined by ICP-Mass Spectrometry with a Perkin Elmer ELAN 6000. RESULTS: Trace element concentration ranges were (in mg kg(-1), inventories in g m(-2) between parenthesis) <2-58 (0.5-6.6) for Ni, 6-30 (0.2-3.4) for Cu, 38-236 (1.6-32.4) for Zn, 6-209 (0.2-12.8) for As, 0.02-0.64 (<0.04) for Cd, and 28-94 (0.6-13.0) for Pb. These concentrations were, in general, comparable to those recorded in soils from other European mountainous areas and were in many cases above the threshold recommended for ecosystem protection by regional and European environmental authorities. The highest concentrations were found at lower altitudes, indicating an effect of local contamination up to ∼2,300 m a.s.l. Only above this altitude can trace elements in soils be considered representative of a background, long-range atmospheric contamination. CONCLUSIONS: None of the storage capacity properties of soils examined were determinant of the differences in elemental concentrations along the altitudinal transect. At the upper altitude range, Ni, Cu, and Pb showed a approximately two- to fivefold increase over the average concentration of the local dominant lithology, reflecting the regional and global background of atmospheric contamination in the area. Source

Barberan A.,CSIC - Center for Advanced Studies of Blanes | Casamayor E.O.,CSIC - Center for Advanced Studies of Blanes
Aquatic Microbial Ecology | Year: 2010

We aimed to identify phylogenetic community patterns in abundant planktonic bacteria (Alpha-, Beta-, and Gammaproteobacteria, Actinobacteria, Cyanobacteria, and Bacteroidetes) from a worldwide range of surface waters (lakes and seas-34 sites and ca. 4500 16S rRNA gene sequences). At each site we assessed the number of observed bacterial groups and the genetic relatedness of the most abundant groups through a community phylogenetic metaanalysis approach in order to (1) explore which potential ecological processes were consistent with the observed phylogenetic patterns in community assembly and (2) disentangle the effects of space and environment in β-diversity patterns for the different bacterial groups. Inland waters had significantly more bacterial groups and were more diverse than marine waters. Marine habitats showed a higher percentage of clustered sites than lakes, and bacterial communities were more closely related than expected by chance. Phylogenetic β-diversity analyses revealed different patterns to both salt composition (marine vs. inland salt lakes) and salt concentration for the dominant bacteria. We observed that while â-diversity patterns for Bacteroidetes were mostly shaped by salinity concentration, patterns in Alphaproteobacteria and Gammaproteobacteria were controlled by salt composition. Actinobacteria, Betaproteobacteria and Sphingobacteria were largely absent from marine habitats and from saline continental sites. In general and despite the lack of contextual metadata, environmental similarity was more relevant than spatial distribution for bacterial β-diversity patterns. However, we detected a geographic signal for some inland waters' groups (i.e. Actinobacteria, Beta-, and Gammaproteobacteria). Overall, the analyses indicated differences among phylogenetic groups and reflected patterns upon which further exploration of community assembly theory could be based. © Inter-Research 2010. Source

Barberan A.,University of Colorado at Boulder | Casamayor E.O.,CSIC - Center for Advanced Studies of Blanes | Fierer N.,University of Colorado at Boulder
Frontiers in Microbiology | Year: 2014

There has been a recent explosion of research within the field of microbial ecology that has been fueled, in part, by methodological improvements that make it feasible to characterize microbial communities to an extent that was inconceivable only a few years ago. Furthermore, there is increasing recognition within the field of ecology that microorganisms play a critical role in the health of organisms and ecosystems. Despite these developments, an important gap still persists between the theoretical framework of macroecology and microbial ecology. We highlight two idiosyncrasies of microorganisms that are fundamental to understanding macroecological patterns and their mechanistic drivers. First, high dispersal rates provide novel opportunities to test the relative importance of niche, stochastic, and historical processes in structuring biological communities. Second, high speciation rates potentially lead to the convergence of ecological and evolutionary time scales. After reviewing these unique aspects, we discuss strategies for improving the conceptual integration of microbes into macroecology. As examples, we discuss the use of phylogenetic ecology as an integrative approach to explore patterns across the tree of life. Then we demonstrate how two general theories of biodiversity (i.e., the recently developed theory of stochastic geometry and the neutral theory) can be adapted to microorganisms. We demonstrate how conceptual models that integrate evolutionary and ecological mechanisms can contribute to the unification of microbial ecology and macroecology. © 2014 Barberán, Casamayor and Fierer. Source

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