MODENUTTI Beatriz Estela
Interactive effects of temperature, ultraviolet radiation and food quality on zooplankton alkaline phosphatase activity.
WOLINSKY L; B. MODENUTTI,; M. S. SOUZA,; E. BALSEIRO,
ELSEVIER SCI LTD
Lugar: Amsterdam; Año: 2016 vol. 213 p. 135 - 135
Ultraviolet Radiation (UVR) is a stressor for aquatic organisms affecting enzyme activities in planktonicpopulations because of the increase in reactive oxygen species. In addition, UVR exposure combined withother environmental factors (i.e. temperature and food quality) could have even higher detrimentaleffects. In this work, we aimed to determine the effect of UVR on somatic Alkaline Phosphatase Activity(APA) and Glutathione S-Transferase (GST) activity on the cladoceran Daphnia commutata under twodifferent temperatures (10 C and 20 C) and under three food qualities (carbon:phosphorus ratios: 1150,850 and 550). APA is a biomarker that is considered as a P deficiency indicator in zooplankton. Sincerecovery from UVR damage under dark conditions is an ATP depending reaction we also measured APAduring recovery phases. We carried out a laboratory experiment combining different temperatures andfood qualities with exposition to UVR followed by luminic and dark phases for recovery. In addition, weexposed organisms to H2O2, to establish if the response on APA to UVR was a consequence of the reactiveoxygen species produced these short wavelengths. Our results showed that somatic APA was negativelyaffected by UVR exposure and this effect was enhanced under high temperature and low food quality.Consistently, GST activity was higher when exposed to UVR under both temperatures. The H2O2 experimentsshowed the same trend as UVR exposure, indicating that APA is affected mainly by oxidativestress than by direct effect of UVR on the enzyme. Finally, APA was affected in the dark phase of recoveryconfirming the P demands. These results enlighten the importance of food quality in the interactingeffect of UVR and temperature, showing that C:P food ratio could determine the success or failure ofzooplanktonic populations in a context of global change.