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Your search keyword '"Carla Eloisa Fernández"' showing total 2 results
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2 results on '"Carla Eloisa Fernández"'

1. Effects of UVB radiation on grazing of two cladocerans from high-altitude Andean lakes.

Author

Carla Eloisa Fernández and Danny Rejas

Subjects
Medicine, Science
Abstract

Climate change and water extraction may result in increased exposition of the biota to ultraviolet-B radiation (UVB) in high-altitude Andean lakes. Although exposition to lethal doses in these lakes is unlikely, sub-lethal UVB doses may have strong impacts in key compartments such as zooplankton. Here, we aimed at determining the effect of sub-lethal UVB doses on filtration rates of two cladoceran species (Daphnia pulicaria and Ceriodaphnia dubia). We firstly estimated the Incipient Limiting Concentration (ILC) and the Gut Passage Time (GPT) for both species. Thereafter we exposed clones of each species to four increasing UVB doses (treatments): i) DUV-0 (Control), ii) DUV-1 (0.02 MJ m2), iii) DUV-2 (0.03 MJ m2) and iv) DUV-3 (0.15 MJ m2); and estimated their filtration rates using fluorescent micro-spheres. Our results suggest that increasing sub-lethal doses of UVB radiation may strongly disturb the structure and functioning of high-altitude Andean lakes. Filtration rates of D. pulicaria were not affected by the lowest dose applied (DUV-1), but decreased by 50% in treatments DUV-2 and DUV-3. Filtration rates for C. dubia were reduced by more than 80% in treatments DUV-1 and DUV-2 and 100% of mortality occurred at the highest UVB dose applied (DUV-3).

Published
2017
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2. Local adaptation to UV radiation in zooplankton: a behavioral and physiological approach

Author

Cintia Bertacchi Uvo, Giuseppe Bianco, Melina Campero, Mikael T. Ekvall, Lars-Anders Hansson, Carla Eloisa Fernández, and Danny Rejas

Subjects
0106 biological sciences, ultraviolet radiation, Photo protection, Population, Zoology, 010603 evolutionary biology, 01 natural sciences, Daphnia, Zooplankton, Daphnia pulex, photo‐protection, lcsh:QH540-549.5, evolutionary memory, education, vertical migration, Ultraviolet radiation, Ecology, Evolution, Behavior and Systematics, Local adaptation, education.field_of_study, Ecology, biology, integumentary system, 010604 marine biology & hydrobiology, fungi, biology.organism_classification, lcsh:Ecology, local adaptation
Abstract

Ultraviolet radiation (UVR) is recognized as a driving force for phenotypic divergence. Here, we aim at assessing the ability of zooplankton to induce UVR tolerance and disentangle the relative importance of local adaptations behind the expression of such tolerance. Two populations of Daphnia pulex, derived from environments strongly differing in UVR conditions, were exposed to UVR for 70 d to induce production of photo‐protective compounds and changes in behavioral responses. We expected greater tolerance to UVR in individuals from the high‐UVR (H‐U) environment as well as a refuge demand inversely related to the level of pigmentation. However, the complementarity between physiological and behavioral strategies was only observed on animals from the Low‐UVR environment (L‐U). L‐U animals developed photo‐protective compounds and decreased their refuge demand when re‐exposed to UVR, that is, tolerated more UVR, compared to their control siblings. Conversely, UVR‐exposed individuals from the H‐U environment even having developed higher levels of photo‐protective compounds increased their refuge demand staying deeper in the water column compared to the control animals, likely expressing an evolutionary memory to seek refuge in deeper waters irrespective of the UVR level. Stronger changes were observed in the H‐U population compared to the L‐U population; thus, our results suggest that although changes in tolerance after UVR exposure were evident for both populations, the strength of the inductions was more related to local adaptation independently of the rearing environment, showing that UVR tolerance is dependent on the evolutionary history of each population.

Published
2020

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