Application of fluorometry (Phyto-PAM) for assessing food selection by cladocerans
Por:
Chesney T., Sastri A.R., Beisner B.E., Nandini S., Sarma S.S.S., Juneau P.
Publicada:
1 feb 2019
Ahead of Print:
1 ene 2018
Categoría:
Aquatic science
Resumen:
Cladocerans feed on a variety of phytoplankton food sources, which are
variable across space and time. Different phytoplankton groups represent
different nutritional quality to Daphnia magna (Straus) due to
differences in their Redfield stoichiometry or digestibility. We used
chlorophyll fluorescence to directly measure phytoplankton group
quantity and composition (green algae and cyanobacteria) in the guts of
live D. magna and thereby directly assessed differences in gut transit
time (GTT). We observed a decrease of GTT with lower food quality
relative to the most suitable diet treatment composed only of the green
alga: Scenedesmus obliquus (Turpin) Kutzing (GTT=27min 20s). Mixed,
lower quality diets composed of 75% cyanobacteria, Microcystis
aeruginosa (Kutzing) and 25% S. obliquus resulted in faster GTT, as did
diets exclusively composed of microcystin-lacking cyanobacteria
(GTT=19min 42s). The GTT could not be measured when diets were composed
exclusively of microcystin-producing M. aeruginosa due to insignificant
ingestion of the cyanobacteria. Using Ivlev's Electivity index, we
demonstrate that provided with mixed algal food, D. magna was able to
avoid ingesting lower quality food (cyanobacteria) in favor of more
valuable material (green alga). However, this ability decreases or is
lost when exposed to food mixtures dominated by cyanobacteria.
Filiaciones:
Chesney T.:
Département des Sciences biologiques – GRIL - TOXEN, Ecotoxicology of Aquatic Microorganisms Laboratory, Université du Québec à Montréal, Succ. Centre-Ville, C.P. 8888, Montreal, QC H3C 3P8, Canada
Sastri A.R.:
Département des Sciences biologiques – GRIL - TOXEN, Ecotoxicology of Aquatic Microorganisms Laboratory, Université du Québec à Montréal, Succ. Centre-Ville, C.P. 8888, Montreal, QC H3C 3P8, Canada
Department of Biological Sciences and GRIL, Université du Québec à Montréal, C.P. 8888, Succ. Centre-Ville, Montreal, QC H3C 3P8, Canada
Department of Biology and Ocean Networks Canada, University of Victoria, Victoria, BC V8W 2Y2, Canada
Beisner B.E.:
Department of Biological Sciences and GRIL, Université du Québec à Montréal, C.P. 8888, Succ. Centre-Ville, Montreal, QC H3C 3P8, Canada
Nandini S.:
National Autonomous University of Mexico (UNAM), Campus Iztacala, Av. de los Barrios No. 1, Tlalnepantla, State of Mexico, Mexico
Sarma S.S.S.:
National Autonomous University of Mexico (UNAM), Campus Iztacala, Av. de los Barrios No. 1, Tlalnepantla, State of Mexico, Mexico
Juneau P.:
Département des Sciences biologiques – GRIL - TOXEN, Ecotoxicology of Aquatic Microorganisms Laboratory, Université du Québec à Montréal, Succ. Centre-Ville, C.P. 8888, Montreal, QC H3C 3P8, Canada
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