INVESTIGADORES
CUSMINSKY Gabriela Catalina
artículos
Título:
Replicated mesocosm study on the role of natural ultraviolet radiation in high CDOM, shallow lakes
Autor/es:
PATRICIA PÉREZ; MÓNICA M. DÍAZ; MARCELA A. FERRARO; GABRIELA C. CUSMINSKY; HORACIO E. ZAGARESE
Revista:
Photochemical and Photobiological Sciences
Editorial:
Royal Society of Chemistry
Referencias:
Lugar: Londres; Año: 2003 p. 118 - 123
ISSN:
1474-905X
Resumen:
The role of ultraviolet radiation on shallow, high CDOM (colored dissolved organic matter) lakes was investigated
during two consecutive summers (1999 and 2000) in replicated mesocosms (rectangular fiberglass tanks). Each
tank (volume: 300 L; depth: 40 cm) was covered with a layer (¡3 cm) of sediment from lake El Toro (40 14 S; 70fiberglass tanks). Each
tank (volume: 300 L; depth: 40 cm) was covered with a layer (¡3 cm) of sediment from lake El Toro (40 14 S; 70¡3 cm) of sediment from lake El Toro (40 14 S; 70
22 W) and filled with filtered water. The experimental design consisted of two treatments: full natural radiation
(UV-exposed) and natural radiation without ultraviolet radiation (UV-shielded). UV-exposed and UV-shielded
treatments differed in most studied variables as revealed by repeated measures ANOVA. UV-exposed tanks displayed
lower CDOM levels (dissolved absorbance) of lower average molecular size (absorbance ratio between 250 and
365 nm), higher bacterial biomass, and lower chlorophyll a concentration. The effect on consumers (rotifers and
crustaceans) was less noticeable. The results are consistent with UV stimulation of bacteria production mediated by
higher rates of CDOM photobleaching, and the photoinhibition of planktonic algae. Thus, a major effect of UVR
in shallow, high CDOM ecosystems appears to be the stimulation of heterotrophic pathways and a simultaneous
inhibition of photoautotrophs. W) and filled with filtered water. The experimental design consisted of two treatments: full natural radiation
(UV-exposed) and natural radiation without ultraviolet radiation (UV-shielded). UV-exposed and UV-shielded
treatments differed in most studied variables as revealed by repeated measures ANOVA. UV-exposed tanks displayed
lower CDOM levels (dissolved absorbance) of lower average molecular size (absorbance ratio between 250 and
365 nm), higher bacterial biomass, and lower chlorophyll a concentration. The effect on consumers (rotifers and
crustaceans) was less noticeable. The results are consistent with UV stimulation of bacteria production mediated by
higher rates of CDOM photobleaching, and the photoinhibition of planktonic algae. Thus, a major effect of UVR
in shallow, high CDOM ecosystems appears to be the stimulation of heterotrophic pathways and a simultaneous
inhibition of photoautotrophs.ffered in most studied variables as revealed by repeated measures ANOVA. UV-exposed tanks displayed
lower CDOM levels (dissolved absorbance) of lower average molecular size (absorbance ratio between 250 and
365 nm), higher bacterial biomass, and lower chlorophyll a concentration. The effect on consumers (rotifers and
crustaceans) was less noticeable. The results are consistent with UV stimulation of bacteria production mediated by
higher rates of CDOM photobleaching, and the photoinhibition of planktonic algae. Thus, a major effect of UVR
in shallow, high CDOM ecosystems appears to be the stimulation of heterotrophic pathways and a simultaneous
inhibition of photoautotrophs.a concentration. The effect on consumers (rotifers and
crustaceans) was less noticeable. The results are consistent with UV stimulation of bacteria production mediated by
higher rates of CDOM photobleaching, and the photoinhibition of planktonic algae. Thus, a major effect of UVR
in shallow, high CDOM ecosystems appears to be the stimulation of heterotrophic pathways and a simultaneous
inhibition of photoautotrophs.ffect of UVR
in shallow, high CDOM ecosystems appears to be the stimulation of heterotrophic pathways and a simultaneous
inhibition of photoautotrophs.