Browsing by Author "Carrevedo, María Laura"

Now showing 1 - 7 of 7
  • Thumbnail Image
    Item
    A 700-year record of climate and environmental change from a high Andean lake : Laguna del Maule, central Chile (36°S)
    (2015) Carrevedo, María Laura; Frugone, Matías; Latorre H., Claudio; Maldonado, Antonio; Bernárdez, Patricia; Prego, Ricardo; Cárdenas, Daniela; Valero Garcés, Blas
  • Thumbnail Image
    Item
    A 7000‐year high‐resolution lake sediment record from coastal central Chile (Lago Vichuquén, 34°S): implications for past sea level and environmental variability
    (2017) Frugone, M. J.; Latorre H., Claudio; Giralt, Santiago; Polanco Martínez, Josué; Bernárdez, Patricia; Oliva Urcía, Belén; Maldonado, Antonio; Carrevedo, María Laura; Moreno, Ana; Delgado Huertas, Antonio; Prego, Ricardo; Barreiro Lostres, Fernando; Valero Garcés, Blas
  • No Thumbnail Available
    Item
    Factors influencing the presence and relative abundance of Didymosphenia geminata. Impact on the composition of diatom assemblages over a broad latitudinal gradient in Chilean rivers
    (TAYLOR & FRANCIS LTD, 2025) Carrevedo, María Laura; Dézerald, Olivier; Alfaro, Fernando; Bustamante, Ramiro Ociel; Molina, Ximena; Muñoz, Paola Andrea; Montecino, Vivian
    This study explored the abiotic factors influencing Didymosphenia geminata blooms and the combined effect of D. geminata and abiotic factors on local diatom assemblages in 13 Chilean watersheds across a broad latitudinal range (37 degrees-47 degrees S). To understand the multi-scale drivers, we used generalized linear mixed-effects models to assess the abiotic factors most influential on D. geminata presence and relative abundance. We then explored the effects of D. geminata and abiotic factors on the alpha- and beta-diversity of diatom assemblages using generalized linear models and permutational analyses of variance, respectively. Three watersheds lacked D. geminata and another three had low relative abundance. Seasonally, the relative abundance of D. geminata was significantly higher in spring than in autumn. We found positive correlations between elevation, river order, pH and D. geminata presence and relative abundance, while water temperature was negatively correlated with D. geminata relative abundance. Diversity indices were significantly influenced by watershed and to a lower extent by the presence of D. geminata. We found significant spatial (i.e. between watersheds along a south-north latitudinal gradient) and temporal (i.e. between seasons) variations in beta-diversity of diatom assemblages. Moreover, increasing relative abundance of D. geminata in the assemblage was correlated with lower diatom diversity. In addition, the compositions of diatom assemblages with D. geminata were more alike and less variable than those in non-invaded sites. This study is a first attempt to understand the multi-scale drivers of diatom assemblages in Chilean lotic ecosystems.
  • No Thumbnail Available
    Item
    Past responses of modern phytoplankton and subfossil diatoms to volcanism in an Andean lake (central Chile)
    (2025) Carrevedo, María Laura; Caputo, Luciano; Alfaro Ayllón, Fernando Daniel; Herrera, Ana Luisa; Frugone-alvarez, Matias; Garces, Blas Valero; Latorre H., Claudio
    Laguna del Maule is a volcanic basin lake in the Central Chilean Andes that contains a peculiar and poorly understood algal flora from an ecological perspective. We present a comprehensive list of modern phytoplankton and limnological parameters (measured in 2011 and 2015), as well as a subfossil diatom assemblage spanning the past similar to 700 years. We examined the relationship between the past assemblages and two Holocene tephra layers, pH, and the impact of recent warming. Chlorophyll values (1.3-1.8 mu g l-1) are indicative of an oligotrophic lake. Counts (past and modern specimens) totalled two hundred fifty-four taxa: Bacillariophyceae (239, mainly subfossil), Chlorophyta (4), Chrysophyta (3), Cryptophyta (3), Cyanophyta (3) and Dinophyta (2). Diatom groups included: twelve centric (the most abundant specimens) and two hundred twenty-seven pennate taxa; of the latter, thirty-three were araphid and one hundred and ninety-four were either monoraphid or biraphid. An increased richness was observed after deposition of the tephra layers, along with different diatom assemblages associated with each tephra. Alkaliphilous-circumneutral taxa dominated, in concordance with the alkaline basin conditions of Laguna del Maule. A recent megadrought brought a shift from planktic to benthic diatoms, as coastal areas expanded, fostering a higher diversity of biraphid genera. Records of past and present dynamics of Andean lacustrine microorganisms are necessary to further evaluate responses to critical global environmental change and for high-altitude aquatic ecosystem conservation efforts.
  • Thumbnail Image
    Item
    Spatio temporal population dynamics of the invasive diatom Didymosphenia geminata in central-southern Chilean rivers
    (2016) Montecino, V.; Molina, X.; Bothwell, M.; Muñoz, P.; Carrevedo, María Laura; Salinas, F.; Kumar, S.; Castillo, M. L.; Bizama, G.; Bustamante, R. O.
  • Thumbnail Image
    Item
    The palynology of the La Deheza Formation (Carboniferous–Permian; Upper Palaeozoic), Paganzo Basin, San Juan Province, Argentina
    (2016) Balarino, M.; Correa, G.; Gutiérrez, P.; Cariglino, B.; Carrevedo, María Laura
  • Thumbnail Image
    Item
    Volcanism and climate change as drivers in Holocene depositional dynamic of Laguna del Maule (Andes of central Chile-36 degrees S)
    (2020) Frugone, Matías; Latorre H., Claudio; Barreiro Lostres, F.; Giralt, S.; Moreno, A.; Polanco Martínez, J.; Maldonado, A.; Carrevedo, María Laura; Bernardez, P.; Prego, R.; Huertas, A. D.; Fuentealba, M.; Valero Garcés, B.