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artículos
Título:
EFFECTS OF THE HERBICIDE ROUNDUP ON FRESHWATER MICROBIAL
Autor/es:
G. L. PEREZ, A. TORREMORELL, H. MUGNI, P. RODRIGUEZ, M. SOLANGE VERA, M. DO NASCIMENTO, L. ALLENDE, J. BUSTINGORRY, R. ESCARAY, M. FERRARO, I. IZAGUIRRE, H. PIZARRO, C. BONETTO, D. P. MORRIS, H. ZAGARESE
Revista:
ECOLOGICAL APPLICATIONS
Referencias:
Año: 2007 p. 2310 - 2322
ISSN:
1051-0761
Resumen:
The impact of the widely used herbicide glyphosate has been mainly studied in
terrestrial weed control, laboratory bioassays, and field studies focusing on invertebrates,
amphibians, and fishes. Despite the importance of phytoplankton and periphyton
communities at the base of the aquatic food webs, fewer studies have investigated the effects
of glyphosate on freshwater microbial assemblages. We assessed the effect of the commercial
formulation Roundup using artificial earthen mesocosms. The herbicide was added at three
doses: a control (without Roundup) and two treatments of 6 and 12 mg/L of the active
ingredient (glyphosate). Estimates of the dissipation rate (k) were similar in the two treatments
(half-lives of 5.77 and 7.37 d, respectively). The only two physicochemical parameters showing
statistically significant differences between treatments and controls were the downward
vertical spectral attenuation coefficient kd(k), where k is wavelength, and total phosphorus
concentration (TP). At the end of the experiment, the treated mesocosms showed a significant
increase in the ratio kd(490 nm)/kd(550 nm) and an eightfold increase in TP. Roundup affected
the structure of phytoplankton and periphyton assemblages. Total micro- and nanophytoplankton
decreased in abundance in treated mesocosms. In contrast, the abundance of
picocyanobacteria increased by a factor of about 40. Primary production also increased in
treated mesocosms (roughly by a factor of two). Similar patterns were observed in the
periphytic assemblages, which showed an increased proportion of dead : live individuals and
increased abundances of cyanobacteria (about 4.5-fold). Interestingly, the observed changes in
the microbial assemblages were captured by the analysis of the pigment composition of the
phytoplankton, the phytoplankton absorption spectra, and the analysis of the optical
properties of the water. The observed changes in the structure of the microbial assemblages are
more consistent with a direct toxicological effect of glyphosate rather than an indirect effect
mediated by phosphorus enrichment.
the structure of phytoplankton and periphyton assemblages. Total micro- and nanophytoplankton
decreased in abundance in treated mesocosms. In contrast, the abundance of
picocyanobacteria increased by a factor of about 40. Primary production also increased in
treated mesocosms (roughly by a factor of two). Similar patterns were observed in the
periphytic assemblages, which showed an increased proportion of dead : live individuals and
increased abundances of cyanobacteria (about 4.5-fold). Interestingly, the observed changes in
the microbial assemblages were captured by the analysis of the pigment composition of the
phytoplankton, the phytoplankton absorption spectra, and the analysis of the optical
properties of the water. The observed changes in the structure of the microbial assemblages are
more consistent with a direct toxicological effect of glyphosate rather than an indirect effect
mediated by phosphorus enrichment.
concentration (TP). At the end of the experiment, the treated mesocosms showed a significant
increase in the ratio kd(490 nm)/kd(550 nm) and an eightfold increase in TP. Roundup affected
the structure of phytoplankton and periphyton assemblages. Total micro- and nanophytoplankton
decreased in abundance in treated mesocosms. In contrast, the abundance of
picocyanobacteria increased by a factor of about 40. Primary production also increased in
treated mesocosms (roughly by a factor of two). Similar patterns were observed in the
periphytic assemblages, which showed an increased proportion of dead : live individuals and
increased abundances of cyanobacteria (about 4.5-fold). Interestingly, the observed changes in
the microbial assemblages were captured by the analysis of the pigment composition of the
phytoplankton, the phytoplankton absorption spectra, and the analysis of the optical
properties of the water. The observed changes in the structure of the microbial assemblages are
more consistent with a direct toxicological effect of glyphosate rather than an indirect effect
mediated by phosphorus enrichment.
the structure of phytoplankton and periphyton assemblages. Total micro- and nanophytoplankton
decreased in abundance in treated mesocosms. In contrast, the abundance of
picocyanobacteria increased by a factor of about 40. Primary production also increased in
treated mesocosms (roughly by a factor of two). Similar patterns were observed in the
periphytic assemblages, which showed an increased proportion of dead : live individuals and
increased abundances of cyanobacteria (about 4.5-fold). Interestingly, the observed changes in
the microbial assemblages were captured by the analysis of the pigment composition of the
phytoplankton, the phytoplankton absorption spectra, and the analysis of the optical
properties of the water. The observed changes in the structure of the microbial assemblages are
more consistent with a direct toxicological effect of glyphosate rather than an indirect effect
mediated by phosphorus enrichment.
(half-lives of 5.77 and 7.37 d, respectively). The only two physicochemical parameters showing
statistically significant differences between treatments and controls were the downward
vertical spectral attenuation coefficient kd(k), where k is wavelength, and total phosphorus
concentration (TP). At the end of the experiment, the treated mesocosms showed a significant
increase in the ratio kd(490 nm)/kd(550 nm) and an eightfold increase in TP. Roundup affected
the structure of phytoplankton and periphyton assemblages. Total micro- and nanophytoplankton
decreased in abundance in treated mesocosms. In contrast, the abundance of
picocyanobacteria increased by a factor of about 40. Primary production also increased in
treated mesocosms (roughly by a factor of two). Similar patterns were observed in the
periphytic assemblages, which showed an increased proportion of dead : live individuals and
increased abundances of cyanobacteria (about 4.5-fold). Interestingly, the observed changes in
the microbial assemblages were captured by the analysis of the pigment composition of the
phytoplankton, the phytoplankton absorption spectra, and the analysis of the optical
properties of the water. The observed changes in the structure of the microbial assemblages are
more consistent with a direct toxicological effect of glyphosate rather than an indirect effect
mediated by phosphorus enrichment.
the structure of phytoplankton and periphyton assemblages. Total micro- and nanophytoplankton
decreased in abundance in treated mesocosms. In contrast, the abundance of
picocyanobacteria increased by a factor of about 40. Primary production also increased in
treated mesocosms (roughly by a factor of two). Similar patterns were observed in the
periphytic assemblages, which showed an increased proportion of dead : live individuals and
increased abundances of cyanobacteria (about 4.5-fold). Interestingly, the observed changes in
the microbial assemblages were captured by the analysis of the pigment composition of the
phytoplankton, the phytoplankton absorption spectra, and the analysis of the optical
properties of the water. The observed changes in the structure of the microbial assemblages are
more consistent with a direct toxicological effect of glyphosate rather than an indirect effect
mediated by phosphorus enrichment.
concentration (TP). At the end of the experiment, the treated mesocosms showed a significant
increase in the ratio kd(490 nm)/kd(550 nm) and an eightfold increase in TP. Roundup affected
the structure of phytoplankton and periphyton assemblages. Total micro- and nanophytoplankton
decreased in abundance in treated mesocosms. In contrast, the abundance of
picocyanobacteria increased by a factor of about 40. Primary production also increased in
treated mesocosms (roughly by a factor of two). Similar patterns were observed in the
periphytic assemblages, which showed an increased proportion of dead : live individuals and
increased abundances of cyanobacteria (about 4.5-fold). Interestingly, the observed changes in
the microbial assemblages were captured by the analysis of the pigment composition of the
phytoplankton, the phytoplankton absorption spectra, and the analysis of the optical
properties of the water. The observed changes in the structure of the microbial assemblages are
more consistent with a direct toxicological effect of glyphosate rather than an indirect effect
mediated by phosphorus enrichment.
the structure of phytoplankton and periphyton assemblages. Total micro- and nanophytoplankton
decreased in abundance in treated mesocosms. In contrast, the abundance of
picocyanobacteria increased by a factor of about 40. Primary production also increased in
treated mesocosms (roughly by a factor of two). Similar patterns were observed in the
periphytic assemblages, which showed an increased proportion of dead : live individuals and
increased abundances of cyanobacteria (about 4.5-fold). Interestingly, the observed changes in
the microbial assemblages were captured by the analysis of the pigment composition of the
phytoplankton, the phytoplankton absorption spectra, and the analysis of the optical
properties of the water. The observed changes in the structure of the microbial assemblages are
more consistent with a direct toxicological effect of glyphosate rather than an indirect effect
mediated by phosphorus enrichment.
k) were similar in the two treatments
(half-lives of 5.77 and 7.37 d, respectively). The only two physicochemical parameters showing
statistically significant differences between treatments and controls were the downward
vertical spectral attenuation coefficient kd(k), where k is wavelength, and total phosphorus
concentration (TP). At the end of the experiment, the treated mesocosms showed a significant
increase in the ratio kd(490 nm)/kd(550 nm) and an eightfold increase in TP. Roundup affected
the structure of phytoplankton and periphyton assemblages. Total micro- and nanophytoplankton
decreased in abundance in treated mesocosms. In contrast, the abundance of
picocyanobacteria increased by a factor of about 40. Primary production also increased in
treated mesocosms (roughly by a factor of two). Similar patterns were observed in the
periphytic assemblages, which showed an increased proportion of dead : live individuals and
increased abundances of cyanobacteria (about 4.5-fold). Interestingly, the observed changes in
the microbial assemblages were captured by the analysis of the pigment composition of the
phytoplankton, the phytoplankton absorption spectra, and the analysis of the optical
properties of the water. The observed changes in the structure of the microbial assemblages are
more consistent with a direct toxicological effect of glyphosate rather than an indirect effect
mediated by phosphorus enrichment.
the structure of phytoplankton and periphyton assemblages. Total micro- and nanophytoplankton
decreased in abundance in treated mesocosms. In contrast, the abundance of
picocyanobacteria increased by a factor of about 40. Primary production also increased in
treated mesocosms (roughly by a factor of two). Similar patterns were observed in the
periphytic assemblages, which showed an increased proportion of dead : live individuals and
increased abundances of cyanobacteria (about 4.5-fold). Interestingly, the observed changes in
the microbial assemblages were captured by the analysis of the pigment composition of the
phytoplankton, the phytoplankton absorption spectra, and the analysis of the optical
properties of the water. The observed changes in the structure of the microbial assemblages are
more consistent with a direct toxicological effect of glyphosate rather than an indirect effect
mediated by phosphorus enrichment.
concentration (TP). At the end of the experiment, the treated mesocosms showed a significant
increase in the ratio kd(490 nm)/kd(550 nm) and an eightfold increase in TP. Roundup affected
the structure of phytoplankton and periphyton assemblages. Total micro- and nanophytoplankton
decreased in abundance in treated mesocosms. In contrast, the abundance of
picocyanobacteria increased by a factor of about 40. Primary production also increased in
treated mesocosms (roughly by a factor of two). Similar patterns were observed in the
periphytic assemblages, which showed an increased proportion of dead : live individuals and
increased abundances of cyanobacteria (about 4.5-fold). Interestingly, the observed changes in
the microbial assemblages were captured by the analysis of the pigment composition of the
phytoplankton, the phytoplankton absorption spectra, and the analysis of the optical
properties of the water. The observed changes in the structure of the microbial assemblages are
more consistent with a direct toxicological effect of glyphosate rather than an indirect effect
mediated by phosphorus enrichment.
the structure of phytoplankton and periphyton assemblages. Total micro- and nanophytoplankton
decreased in abundance in treated mesocosms. In contrast, the abundance of
picocyanobacteria increased by a factor of about 40. Primary production also increased in
treated mesocosms (roughly by a factor of two). Similar patterns were observed in the
periphytic assemblages, which showed an increased proportion of dead : live individuals and
increased abundances of cyanobacteria (about 4.5-fold). Interestingly, the observed changes in
the microbial assemblages were captured by the analysis of the pigment composition of the
phytoplankton, the phytoplankton absorption spectra, and the analysis of the optical
properties of the water. The observed changes in the structure of the microbial assemblages are
more consistent with a direct toxicological effect of glyphosate rather than an indirect effect
mediated by phosphorus enrichment.
kd(k), where k is wavelength, and total phosphorus
concentration (TP). At the end of the experiment, the treated mesocosms showed a significant
increase in the ratio kd(490 nm)/kd(550 nm) and an eightfold increase in TP. Roundup affected
the structure of phytoplankton and periphyton assemblages. Total micro- and nanophytoplankton
decreased in abundance in treated mesocosms. In contrast, the abundance of
picocyanobacteria increased by a factor of about 40. Primary production also increased in
treated mesocosms (roughly by a factor of two). Similar patterns were observed in the
periphytic assemblages, which showed an increased proportion of dead : live individuals and
increased abundances of cyanobacteria (about 4.5-fold). Interestingly, the observed changes in
the microbial assemblages were captured by the analysis of the pigment composition of the
phytoplankton, the phytoplankton absorption spectra, and the analysis of the optical
properties of the water. The observed changes in the structure of the microbial assemblages are
more consistent with a direct toxicological effect of glyphosate rather than an indirect effect
mediated by phosphorus enrichment.
the structure of phytoplankton and periphyton assemblages. Total micro- and nanophytoplankton
decreased in abundance in treated mesocosms. In contrast, the abundance of
picocyanobacteria increased by a factor of about 40. Primary production also increased in
treated mesocosms (roughly by a factor of two). Similar patterns were observed in the
periphytic assemblages, which showed an increased proportion of dead : live individuals and
increased abundances of cyanobacteria (about 4.5-fold). Interestingly, the observed changes in
the microbial assemblages were captured by the analysis of the pigment composition of the
phytoplankton, the phytoplankton absorption spectra, and the analysis of the optical
properties of the water. The observed changes in the structure of the microbial assemblages are
more consistent with a direct toxicological effect of glyphosate rather than an indirect effect
mediated by phosphorus enrichment.
kd(490 nm)/kd(550 nm) and an eightfold increase in TP. Roundup affected
the structure of phytoplankton and periphyton assemblages. Total micro- and nanophytoplankton
decreased in abundance in treated mesocosms. In contrast, the abundance of
picocyanobacteria increased by a factor of about 40. Primary production also increased in
treated mesocosms (roughly by a factor of two). Similar patterns were observed in the
periphytic assemblages, which showed an increased proportion of dead : live individuals and
increased abundances of cyanobacteria (about 4.5-fold). Interestingly, the observed changes in
the microbial assemblages were captured by the analysis of the pigment composition of the
phytoplankton, the phytoplankton absorption spectra, and the analysis of the optical
properties of the water. The observed changes in the structure of the microbial assemblages are
more consistent with a direct toxicological effect of glyphosate rather than an indirect effect
mediated by phosphorus enrichment.
Key words: glyphosate; herbicide; optical properties; periphyton; phytoplankton; pigments; primary
production; Roundup; water chemistry; wetlands.