Data from: Effects of UVB radiation on grazing of two cladocerans from high-altitude Andean lakes

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)

4° Coloquio Internacional RIIA "Red de Investigación sobre la Ictiofauna Amazónica" : Libro de Resúmenes

International audienceBook of abstracts of the 4th International Conference of The Research Network on Amazonian Ichthyofauna (RIIA) celebrated in Cochabamba, Bolivia

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

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)

Filtration rates of Daphnia pulicaria and Ceriodaphnia dubia under UVB radiation

Experimental data of filtration rates of Daphnia pulicaria and Ceriodaphnia dubia under 3 different doses of UVB radiation

Variacion de la amplitud del nicho isotopico de tres especies de peces en un gradiente de disponibilidad de recursos

International audienceTo study the effect of resource availability on the trophic niche width of fishes in the Bolivian Amazonbasin, we compared isotopic niche widths (as a surrogate for trophic niche) of three fish species(Acestrorhynchus altus, Hoplias malabaricus and Pygocentrus nattereri) in a gradient of prey availability.We sampled fishes in lakes located in the floodplain of the rivers Blanco (low prey availability), Iténez(intermediate prey availability) and San Martín (high prey availability), analyzed them for ratios ofstable isotopes (δ13C and δ15N), and estimated the standard ellipse and isotopic niche width using theSIBER package in R. Acestrorhynchus altus behaved as an optimal forager, showing wider isotopic nichewhere prey were less abundant, and less wide isotopic niche in rivers with intermediate and high preyavailability. P. nattereri showed wider trophic niche at intermediate prey densities and H. malabaricusshowed no effect of prey availability on isotopic niche width. This indicates that, for these species,factors such as prey selectivity, water transparency, mouth size or feeding habits, may be more importantthan prey availability in determining trophic niche width.Con el objetivo de estudiar el efecto de la disponibilidad de recursos sobre la amplitud del nicho tróficoen peces de la Amazonia boliviana, comparamos los nichos isotópicos (como sustituto del nicho trófico)de tres especies de peces (Acestrorhynchus altus, Hoplias malabaricus y Pygocentrus nattereri) en ungradiente de disponibilidad de presas. Tomamos muestras de peces en lagos localizados en la llanura deinundación de los ríos Blanco (baja disponibilidad de presas), Iténez (disponibilidad intermedia) y SanMartín (disponibilidad alta), analizamos los ratios de isótopos estables (δ13C and δ15N) y estimamos laselipses estándar y amplitud de nicho isotópico (área) empleando el paquete SIBER en R. Acestrorhynchusaltus se comportó como un forrajero óptimo, mostrando un nicho isotópico más amplio a menordisponibilidad de presas y un nicho más estrecho en los sitios con disponibilidad intermedia y alta.Pygocentrus nattereri mostró un nicho más amplio a densidades de presa intermedias, y no encontramosefecto de la disponibilidad de presas sobre la amplitud del nicho trófico de H. malabaricus. Esto indicaque, para estas dos especies, factores tales como la selectividad de presas, transparencia del agua, tamañode la boca y hábitos alimenticios, podrían ser más importantes que la disponibilidad de presas paradeterminar la amplitud del nicho trófico

Gut passage time of Daphnia pulicaria

Gut passage time of Daphnia pulicaria was determined by testing 8 feeding times

Incipient Limiting Concentration of Ceriodaphnia dubia

Incipient Limiting Concentration of Ceriodaphnia dubia determinated in 6 food concentration

Gut passage time of Ceriodaphnia dubia

Gut passage time of Ceriodaphnia dubia was determined by testing 4 feeding times

Variacion de la amplitud del nicho isotopico de tres especies de peces en un gradiente de disponibilidad de recursos

International audienceTo study the effect of resource availability on the trophic niche width of fishes in the Bolivian Amazonbasin, we compared isotopic niche widths (as a surrogate for trophic niche) of three fish species(Acestrorhynchus altus, Hoplias malabaricus and Pygocentrus nattereri) in a gradient of prey availability.We sampled fishes in lakes located in the floodplain of the rivers Blanco (low prey availability), Iténez(intermediate prey availability) and San Martín (high prey availability), analyzed them for ratios ofstable isotopes (δ13C and δ15N), and estimated the standard ellipse and isotopic niche width using theSIBER package in R. Acestrorhynchus altus behaved as an optimal forager, showing wider isotopic nichewhere prey were less abundant, and less wide isotopic niche in rivers with intermediate and high preyavailability. P. nattereri showed wider trophic niche at intermediate prey densities and H. malabaricusshowed no effect of prey availability on isotopic niche width. This indicates that, for these species,factors such as prey selectivity, water transparency, mouth size or feeding habits, may be more importantthan prey availability in determining trophic niche width.Con el objetivo de estudiar el efecto de la disponibilidad de recursos sobre la amplitud del nicho tróficoen peces de la Amazonia boliviana, comparamos los nichos isotópicos (como sustituto del nicho trófico)de tres especies de peces (Acestrorhynchus altus, Hoplias malabaricus y Pygocentrus nattereri) en ungradiente de disponibilidad de presas. Tomamos muestras de peces en lagos localizados en la llanura deinundación de los ríos Blanco (baja disponibilidad de presas), Iténez (disponibilidad intermedia) y SanMartín (disponibilidad alta), analizamos los ratios de isótopos estables (δ13C and δ15N) y estimamos laselipses estándar y amplitud de nicho isotópico (área) empleando el paquete SIBER en R. Acestrorhynchusaltus se comportó como un forrajero óptimo, mostrando un nicho isotópico más amplio a menordisponibilidad de presas y un nicho más estrecho en los sitios con disponibilidad intermedia y alta.Pygocentrus nattereri mostró un nicho más amplio a densidades de presa intermedias, y no encontramosefecto de la disponibilidad de presas sobre la amplitud del nicho trófico de H. malabaricus. Esto indicaque, para estas dos especies, factores tales como la selectividad de presas, transparencia del agua, tamañode la boca y hábitos alimenticios, podrían ser más importantes que la disponibilidad de presas paradeterminar la amplitud del nicho trófico