Planktonic trophic interactions in a temperate Shallow Lake from a South American Wetland
We have analysed the planktonic communities and their trophic interactions in a vegetated wetland from the Lower Paraná River (Otamendi Natural Reserve, Argentina). The studies combined field surveys, and in situ experiments at microcosms and mesocosms scales. Fields studies carried out in the main...
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todo:paper_97816045_v_n_p133_Sinistro2023-10-03T16:44:04Z Planktonic trophic interactions in a temperate Shallow Lake from a South American Wetland Sinistro, R. Izaguirre, I. We have analysed the planktonic communities and their trophic interactions in a vegetated wetland from the Lower Paraná River (Otamendi Natural Reserve, Argentina). The studies combined field surveys, and in situ experiments at microcosms and mesocosms scales. Fields studies carried out in the main shallow lake of the wetland and in abandoned meanders of the river (relict oxbow lakes) show that the free-floating plants cover was one of the driving forces in the regulation of the structure of planktonic communities. Later on, the effect of the light attenuation due to floating macrophytes was simulated at microcosms scale, which showed changes in the structure of the microbial planktonic communities in response to the light penetration. In particular we found changes in the relationship autotrophs/heterotrophs + mixotrophs, depending on light conditions inside the enclosures. Further experiments with fluorescent-labeled bacteria (FLB), revealed the presence of mixotrophic phytoplankton species, which are frequent components of the phytoplankton in this wetland. The zooplankton predation impact on phytoplankton was assessed using experiments at mesocosms scale in terms of abundance, size fraction structure and species composition. Likewise, the cascading responses of other components the microbial chains were also explored (heterotrophic nanoflagellates, ciliates and picoplankton) On the other hand, the effect of nutrients (bottom up) and predation (top down) on the phytoplankton communities were simultaneously assessed. Regarding the top down effect, the impact of planktivorous fish predation over zooplankton was analyzed, as well as the consecutive cascading effect on phytoplankton. Moreover, the effect of nutrient release from natural lake sediments, was assessed. In this communication we propose a first model of functioning of the plankton communities and their main interactions for this South American wetland, based on field and experimental data, which have been obtained along a six-years study period. © 2009 by Nova Science Publishers, Inc. All rights reserved. Fil:Sinistro, R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Izaguirre, I. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. CHAP info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_97816045_v_n_p133_Sinistro |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| description |
We have analysed the planktonic communities and their trophic interactions in a vegetated wetland from the Lower Paraná River (Otamendi Natural Reserve, Argentina). The studies combined field surveys, and in situ experiments at microcosms and mesocosms scales. Fields studies carried out in the main shallow lake of the wetland and in abandoned meanders of the river (relict oxbow lakes) show that the free-floating plants cover was one of the driving forces in the regulation of the structure of planktonic communities. Later on, the effect of the light attenuation due to floating macrophytes was simulated at microcosms scale, which showed changes in the structure of the microbial planktonic communities in response to the light penetration. In particular we found changes in the relationship autotrophs/heterotrophs + mixotrophs, depending on light conditions inside the enclosures. Further experiments with fluorescent-labeled bacteria (FLB), revealed the presence of mixotrophic phytoplankton species, which are frequent components of the phytoplankton in this wetland. The zooplankton predation impact on phytoplankton was assessed using experiments at mesocosms scale in terms of abundance, size fraction structure and species composition. Likewise, the cascading responses of other components the microbial chains were also explored (heterotrophic nanoflagellates, ciliates and picoplankton) On the other hand, the effect of nutrients (bottom up) and predation (top down) on the phytoplankton communities were simultaneously assessed. Regarding the top down effect, the impact of planktivorous fish predation over zooplankton was analyzed, as well as the consecutive cascading effect on phytoplankton. Moreover, the effect of nutrient release from natural lake sediments, was assessed. In this communication we propose a first model of functioning of the plankton communities and their main interactions for this South American wetland, based on field and experimental data, which have been obtained along a six-years study period. © 2009 by Nova Science Publishers, Inc. All rights reserved. |
| format |
CHAP |
| author |
Sinistro, R. Izaguirre, I. |
| spellingShingle |
Sinistro, R. Izaguirre, I. Planktonic trophic interactions in a temperate Shallow Lake from a South American Wetland |
| author_facet |
Sinistro, R. Izaguirre, I. |
| author_sort |
Sinistro, R. |
| title |
Planktonic trophic interactions in a temperate Shallow Lake from a South American Wetland |
| title_short |
Planktonic trophic interactions in a temperate Shallow Lake from a South American Wetland |
| title_full |
Planktonic trophic interactions in a temperate Shallow Lake from a South American Wetland |
| title_fullStr |
Planktonic trophic interactions in a temperate Shallow Lake from a South American Wetland |
| title_full_unstemmed |
Planktonic trophic interactions in a temperate Shallow Lake from a South American Wetland |
| title_sort |
planktonic trophic interactions in a temperate shallow lake from a south american wetland |
| url |
http://hdl.handle.net/20.500.12110/paper_97816045_v_n_p133_Sinistro |
| work_keys_str_mv |
AT sinistror planktonictrophicinteractionsinatemperateshallowlakefromasouthamericanwetland AT izaguirrei planktonictrophicinteractionsinatemperateshallowlakefromasouthamericanwetland |
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1782025610828185600 |