nstantaneous and historical temperature effects on a-pinene
Temporal variation of phytoplankton from the
tropical reservoir Valle de Bravo, Mexico
Author Details
MarthaLeticiaGaytan-Herrera
Research and Postgraduate
Division (UIICSE-CyMA Project), UniversidedNacionalAutonoma
De
Mexico/FES-Iztacala,
Avenida de los Barrios
No. 1, 54090 Tlalnepantla,
Estado de
Mexico, Mexico
V?ctor Martinez-Almeida
Faculty of Science, UniversidedNacionalAutonoma De Mexico, CiudadUniversitaria,
C.P. 04360
MariaGuadalupeOliva-Martinez
Botanical Laboratory UniversidedNacionalAutonoma
De Mexico/FES-Iztacala-UMF, C.P.
54090
?ngelDuran-Diaz
Biomathematics Department UniversidedNacionalAutonoma
De Mexico/FES-Iztacala-School of Biology
PedroRamirez-Garcia
(Corresponding author)
Research
and Postgraduate Division (UIICSE-CyMA Project),
UNAM/FES-Iztacala, Avenida
de los Barrios
No.
1, 54090 Tlalnepantla,
Estado de
Mexico, Mexico
e-mail:
micro@servidor.unam.mx
Publication Data
Paper received:
15
June 2009
Revised
received:
07
March 2010
Accepted:
20 April 2010
Abstract
Valle de Bravo reservoir is used for
aquatic, fishing and as a source of drinking water to Mexico City. Annual data on composition,
abundances, species richness and diversity of the phytoplankton surface
community and some physical-chemical parameters variations were discussed.
Results showed a spatial homogeneity for environmental descriptors and
phytoplankton samples but a temporal significant difference between months.
Pulses of high algal densities corresponded to late stratification (October,
103 x103 cell ml-1), early stratification (April, 107
x103 cell ml-1) and plenty stratification (June, 69 x103
cell ml-1). Taxa that reached higher
densities were: Microcystisspp.,
Snowellaseptentrionalis,
Anabaena spp., Aphanizomenonyezoense and Fragilariacrotonensis. Contribution of each taxon
to the total phytoplankton density showed that majorities were rare (41%) or
dominants (40%). Frequent alternation between pulses and low densities and
diversity of phytoplankton as well as a relative high number of taxa found (68), could be explained by daily strong
winds, unstable epilimnion thickness and
incorporation and extraction of substantial volumes of water occurred in the
reservoir. Dominances of cyanobacteria and some chlorococcal species and a high temporal fluctuated
Shannon-Wiener diversity index (0.45- 2.35 bits) pointing to eutrophic and perturbed conditions.
Key words
Phytoplankton composition, Temporal
variation, Tropical lakes-reservoirs, Valle de Bravo reservoir, Mexico
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