Grazing rates of protists in wetlands under contrasting light conditions due to floating plants

We examined the effect of light attenuation, due to floating plants, on the community structure of the main phagotrophic protists and their grazing rates in a wetland in the Lower Paraná Basin. Ingestion experiments (winter and summer) were conducted at 2 sites in the same shallow lake that had cont...

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Autores principales: Izaguirre, I., Sinistro, R., Schiaffino, M.R., Sánchez, M.L., Unrein, F., Massana, R.
Formato: JOUR
Materias:
Grazing rates
Light attenuation
Mixotrophic algae
Phagotrophy
Protists
Wetland
algae
Bacteria (microorganisms)
Ciliophora
Cryptophyta
Mastigophora (flagellates)
Protista
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_09483055_v65_n3_p221_Izaguirre
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_09483055_v65_n3_p221_Izaguirre2023-10-03T15:49:34Z Grazing rates of protists in wetlands under contrasting light conditions due to floating plants Izaguirre, I. Sinistro, R. Schiaffino, M.R. Sánchez, M.L. Unrein, F. Massana, R. Grazing rates Light attenuation Mixotrophic algae Phagotrophy Protists Wetland algae Bacteria (microorganisms) Ciliophora Cryptophyta Mastigophora (flagellates) Protista We examined the effect of light attenuation, due to floating plants, on the community structure of the main phagotrophic protists and their grazing rates in a wetland in the Lower Paraná Basin. Ingestion experiments (winter and summer) were conducted at 2 sites in the same shallow lake that had contrasting light scenarios: open waters (light) and under profuse macrophyte coverage (dark: light attenuation ∼97%). We compared the rates at which protists ingested 3 types of tracer prey: fluorescently labelled heterotrophic bacteria (FLB), picocyanobacteria (FLC) and picoeukaryotic algae (FLA). Light influenced both the structure of the microbial communities and the protistan grazing rates. Heterotrophic flagellates (HF) were more abundant under the macrophytes, whereas mixotrophic algae (cryptophytes) and autotrophic and heterotrophic picoplankton populations attained higher abundances in open waters. Specific grazing rates (SGRs) of mixotrophs on heterotrophic bacteria (HB) were higher in the light (7.9 to 15.5 prey cells grazer -1 h -1), than in darkness (0.1 to 5.1 prey cells grazer -1 h -1); the same trend was observed on picocyanobacteria (Pcy) (1.1 and 0.2 prey cells grazer -1 h -1, light and dark). SGRs of HF were 1.0 to 7.3 cells grazer -1 h -1 (on HB) and 0.01 to 1.8 prey cells grazer -1 h -1 (on Pcy), with highest values in summer and no pattern in relation to light. SGRs of ciliates were higher in summer and in darkness. Clearance rates (CR) on Pcy were higher than on HB, for both HF and mixotrophic algae. In winter, cryptophytes contributed up to 93% of the microbial grazing in the light, whereas HF were more important in darkness; in summer, bacterivory was dominated by heterotrophs in both light scenarios. Our experimental results highlight the importance of light conditions in structuring bacterial grazing by protists. © Inter-Research 2012. Fil:Izaguirre, I. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Sinistro, R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Schiaffino, M.R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Sánchez, M.L. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Unrein, F. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_09483055_v65_n3_p221_Izaguirre
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Grazing rates
Light attenuation
Mixotrophic algae
Phagotrophy
Protists
Wetland
algae
Bacteria (microorganisms)
Ciliophora
Cryptophyta
Mastigophora (flagellates)
Protista
spellingShingle Grazing rates
Light attenuation
Mixotrophic algae
Phagotrophy
Protists
Wetland
algae
Bacteria (microorganisms)
Ciliophora
Cryptophyta
Mastigophora (flagellates)
Protista
Izaguirre, I.
Sinistro, R.
Schiaffino, M.R.
Sánchez, M.L.
Unrein, F.
Massana, R.
Grazing rates of protists in wetlands under contrasting light conditions due to floating plants
topic_facet Grazing rates
Light attenuation
Mixotrophic algae
Phagotrophy
Protists
Wetland
algae
Bacteria (microorganisms)
Ciliophora
Cryptophyta
Mastigophora (flagellates)
Protista
description We examined the effect of light attenuation, due to floating plants, on the community structure of the main phagotrophic protists and their grazing rates in a wetland in the Lower Paraná Basin. Ingestion experiments (winter and summer) were conducted at 2 sites in the same shallow lake that had contrasting light scenarios: open waters (light) and under profuse macrophyte coverage (dark: light attenuation ∼97%). We compared the rates at which protists ingested 3 types of tracer prey: fluorescently labelled heterotrophic bacteria (FLB), picocyanobacteria (FLC) and picoeukaryotic algae (FLA). Light influenced both the structure of the microbial communities and the protistan grazing rates. Heterotrophic flagellates (HF) were more abundant under the macrophytes, whereas mixotrophic algae (cryptophytes) and autotrophic and heterotrophic picoplankton populations attained higher abundances in open waters. Specific grazing rates (SGRs) of mixotrophs on heterotrophic bacteria (HB) were higher in the light (7.9 to 15.5 prey cells grazer -1 h -1), than in darkness (0.1 to 5.1 prey cells grazer -1 h -1); the same trend was observed on picocyanobacteria (Pcy) (1.1 and 0.2 prey cells grazer -1 h -1, light and dark). SGRs of HF were 1.0 to 7.3 cells grazer -1 h -1 (on HB) and 0.01 to 1.8 prey cells grazer -1 h -1 (on Pcy), with highest values in summer and no pattern in relation to light. SGRs of ciliates were higher in summer and in darkness. Clearance rates (CR) on Pcy were higher than on HB, for both HF and mixotrophic algae. In winter, cryptophytes contributed up to 93% of the microbial grazing in the light, whereas HF were more important in darkness; in summer, bacterivory was dominated by heterotrophs in both light scenarios. Our experimental results highlight the importance of light conditions in structuring bacterial grazing by protists. © Inter-Research 2012.
format JOUR
author Izaguirre, I.
Sinistro, R.
Schiaffino, M.R.
Sánchez, M.L.
Unrein, F.
Massana, R.
author_facet Izaguirre, I.
Sinistro, R.
Schiaffino, M.R.
Sánchez, M.L.
Unrein, F.
Massana, R.
author_sort Izaguirre, I.
title Grazing rates of protists in wetlands under contrasting light conditions due to floating plants
title_short Grazing rates of protists in wetlands under contrasting light conditions due to floating plants
title_full Grazing rates of protists in wetlands under contrasting light conditions due to floating plants
title_fullStr Grazing rates of protists in wetlands under contrasting light conditions due to floating plants
title_full_unstemmed Grazing rates of protists in wetlands under contrasting light conditions due to floating plants
title_sort grazing rates of protists in wetlands under contrasting light conditions due to floating plants
url http://hdl.handle.net/20.500.12110/paper_09483055_v65_n3_p221_Izaguirre
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AT schiaffinomr grazingratesofprotistsinwetlandsundercontrastinglightconditionsduetofloatingplants
AT sanchezml grazingratesofprotistsinwetlandsundercontrastinglightconditionsduetofloatingplants
AT unreinf grazingratesofprotistsinwetlandsundercontrastinglightconditionsduetofloatingplants
AT massanar grazingratesofprotistsinwetlandsundercontrastinglightconditionsduetofloatingplants
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