Document Detail

Annual and short-term variability in primary productivity by phytoplankton and correlated abiotic factors in the Jurumirim Reservoir (São Paulo, Brazil).
MedLine Citation:
PMID:  16710518     Owner:  NLM     Status:  MEDLINE    
The annual variability of the photosynthetic production (PP) by phytoplankton in the lacustrine zone of the Jurumirim Reservoir (São Paulo, Brazil) was evaluated in a three-year study to identify recurrent patterns and their causes. Variability in PP was measured daily during two periods of the year (the dry and rainy seasons). An analysis of the PP data failed to identify a recurrent pattern, since the PP values showed no correlation with hydrological factors (rainfall, water level and discharge, and washout) nor, apparently, with the waters nutritional conditions. A principal component analysis revealed that the PP and assimilation ratio were higher when the PO4(3-) and N-NH(4+) contents were low and the ZEU/ZMIX ratios were at their highest. Areal primary productivity can be predicted based on the ratio between the maximum volumetric productivity and the coefficient of vertical extinction of light. However, the biomass integrated for ZEU was a poor predictor of areal primary productivity. No correlation was found between water temperature and areal and maximum volumetric productivity. Thus, the three-year PP study indicated that the variability pattern is typically chaotic. As for the short-term measurements, the PP was found to be higher in the dry season than in the rainy, although both seasons showed an areal PP variability of 35 to 40%. This pattern was attributed to the daily variation in the nutritional conditions and the magnitude of light penetrating through the water, combined with the mixing of phytoplanktonic cells. A comment about the relationship between primary production by phytoplankton and fish yield is also briefly discussed here.
R Henry; M G Nogueira; M L M Pompeo; V Moschini-Carlos
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2006-05-15
Journal Detail:
Title:  Brazilian journal of biology = Revista brasleira de biologia     Volume:  66     ISSN:  1519-6984     ISO Abbreviation:  Braz J Biol     Publication Date:  2006 Feb 
Date Detail:
Created Date:  2006-05-19     Completed Date:  2006-08-31     Revised Date:  2007-09-06    
Medline Journal Info:
Nlm Unique ID:  101129542     Medline TA:  Braz J Biol     Country:  Brazil    
Other Details:
Languages:  eng     Pagination:  239-61     Citation Subset:  IM    
Dept. of Zoology, Institute of Biosciences, UNESP, Botucatu, SP, Brazil.
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MeSH Terms
Fresh Water
Photosynthesis / physiology*
Phytoplankton / physiology*

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