Browsing by Author "Alonso, Miguel"

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    Branquiópodos de las masas de agua lacustre del Parque Nacional Cajas (Andes Australes, Ecuador) inventario y notas autoecológicas
    (Universidad de Cuenca, 2017) Alonso, Miguel; Mosquera, Pablo; Hampel, Henrietta; Vázquez, Raúl F.
    Extensive sampling of 202 lentic water bodies (lakes, lagoons and ponds) located between 3150 and 4460 m a.s.l. in the Cajas National Park (South Ecuadorian Andes) has revealed the high interest of these mountain enclaves in tropical latitudes for the investigation of faunal and ecological aspects of the branchiopod fauna. The first results allowed to recognize 21 species, 15 of them new to Ecuador, of which 2 are in process of description to be published as new to science. All species are characteristic of little mineralized and oligotrophic waters, 8 of them appear in the plankton and the rest in the limnetic littoral benthos.
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    Crustáceos bentónicos y macrófitos como indicadores de calidad ecológica en los lagos de los Andes Australes de Ecuador
    (Universidad de Cuenca, 2017) Alonso, Miguel; Mosquera, Pablo; Hampel, Henrietta; Vázquez, Raúl F.
    The taxonomic composition of the litoral benthic limnetic crustacean communities, (branchiopods, copepods and ostracods) and macrophytes of the lacustrine water bodies of the Cajas National Park located in the Southern Andes of Ecuador have been studied in order to identify the most suitable taxa to be used as indicators of the ecological status of lakes. Among the crustaceans (22 taxa) three groups were differentiated. A first group with taxa of higher indicator value including Branchinecta papillata, Ilyocryptus spinosus, Alonella sp, Pleuroxus sp. Paralona pigra and Alona sp. gr. manueli. A second group with medium indicator value including Alona glabra, Alona guttata, Microcyclops sp. Eucyclops sp. and Paracyclops sp. The third group was formed by taxa of the lower indicator value, either because of its eurioic and / or cosmopolitan character or because of its rarity. Macrophytes have been evaluated as good indicators of the ecological and conservation status of the lakes. The taxa which were submerged, floating and rooted in the sediment were identified to be a good indicator for the water body, and helophytes and hygrophytes for the limnetic litoral zone.
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    Limnology and trophic status of glacial lakes in the tropical Andes (Cajas National Park, Ecuador)
    (2017) Van Colen, Willem; Mosquera, Pablo; Vanderstukken, Maarten; Goiris, Koen; Carrasco Espinoza, María Cecilia; Decaestecker, Ellen; Alonso, Miguel; León Tamariz, Fabián; Muylaert, Koenraad
    The tropical Andes has a high density of glacial lakes that are situated in the high-altitude páramo (3500–4500 m). Ecological information about such lakes is scant despite the fact that these lakes are an important source of water for drinking, irrigation and electricity generation and feed several major tributaries of the Amazon. In this study, we provide data on a survey of 31 lakes in Cajas National Park (Ecuador). Two of the lakes were monitored monthly during one year. In situ nutrient addition experiments were carried out in three of the lakes. Seasonal monitoring in two lakes revealed a thermal stratification of the water column between October and June, with a small temperature difference between epi- and hypolimnion (2–3 °C). Oxygen depletion of the hypolimnion towards the end of the stratification period indicated that no complete mixing of the water column occurred during stratification. There was no evidence of depletion of nutrients in the epilimnion or accumulation in the hypolimnion during stratification. There were also no clear seasonal changes in chlorophyll-a (Chl-a) concentration nor in phytoplankton community composition in the two lakes. Inputs of dissolved organic carbon (DOC) from the vegetated catchment resulted in high DOC concentrations (median 2.9 mg L−1) compared to temperate mountain lakes. Water transparency was relatively low, with a median extinction coefficient for photosynthetic active radiation of 0.50 m−1 and for UV-B radiation of 10.13 m−1. Although the thermocline was deep and water transparency was low, estimates of the critical depth for photosynthesis were deeper than the mean water depth in all lakes, suggesting that phytoplankton was not light limited. The phytoplankton community was dominated by chlorophytes (e.g. Oocystis), diatoms (small Cyclotella spp.) or small colonial cyanobacteria (Aphanocapsa, Merismopedia). The zooplankton community was either dominated by large cladocerans and cyclopoid copepods, or by the calanoid copepod Boeckella occidentalis. Total concentrations of phosphorus (P) and nitrogen (N) were comparable to those in temperate mountain lakes (4–35 μg P L−1 and 162–758 μg N L−1) while Chl-a concentrations were in the lower range (<1 μg L−1). A large part of the total nutrient pool consists of dissolved organic N and P that appeared to have a low bioavailability to phytoplankton. The median seston N:P ratio of 44, a positive correlation between Chl-a and total P concentration, as well as nutrient addition assays carried out in three lakes all pointed to P limitation of phytoplankton. © 2016 John Wiley & Sons Ltd