Water quality indicators in Lake Xochimilco, Mexico: zooplankton and Vibrio cholerae
Por:
Nandini, Sarma, Ramirez Garcia, Pedro, Sarma, S. S. S.
Publicada:
1 ene 2016
Resumen:
Lake Xochimilco is a eutrophic water body in Mexico City used by the
local population for aquaculture and agriculture. Water level is
maintained with inputs of partially treated waste water from the Cerro
de la Estrella treatment plant. In this study we analyzed the water
quality at two sites of Lake Xochimilco, Lake Xaltocan and the Santa
Cruz Canal using various indicators such as zooplankton diversity,
saprobic indices, bacterial concentrations and physico-chemical
variables. Eighty liters of water were filtered from Lake Xochimilco
from each site, once a month from March to October of 2012, and the
rotifers, cladocerans and copepods were enumerated and identified.
Physico-chemical parameters such as temperature, pH, Secchi depth, water
depth, nitrogen and phosphorus and chlorophyll a concentrations, and
bacterial densities were measured. During the study we recorded 33
species of rotifers, the most abundant being Brachionus angularis, B.
calyciflorus and B. havanaensis. Among the microcrustaceans the most
abundant were the cladoceran Moina micrura and the copepods
Acanthocyclops americanus and Arctodiaptomus dorsalis. The species
diversity was around 2 bits/ind. and the saprobic index between 1.5-2.0,
indicating that both sites were beta meso-saprobic. At both sites
nitrogen was < 1 mg/L and phosphorus ranged between 2.5-7.8 mg/L.
Chlorophyll a concentrations were between 66-136 mu g/L. The toxigenic
(Vibrio cholerae NoO1/ No-O139) and the non-toxigenic (Vibrio cholerae
No-O135) strains of the bacterium were recorded, closely associated with
littoral rotifers and cladocerans particularly Brachionus quadridentatus
and Alona sp. All variables indicate that these sites in Lake Xochimilco
are eutrophic and highly contaminated and that the water quality needs
to be improved.
Filiaciones:
Nandini, Sarma:
Univ Nacl Autonoma Mexico, Div Res & Postgrad Studies, Campus Iztacala,Ave Barrios 1, Tlalnepantla, State Of Mexico, Mexico
Ramirez Garcia, Pedro:
Univ Nacl Autonoma Mexico, Div Res & Postgrad Studies, Campus Iztacala,Ave Barrios 1, Tlalnepantla, State Of Mexico, Mexico
Sarma, S. S. S.:
Univ Nacl Autonoma Mexico, Div Res & Postgrad Studies, Campus Iztacala,Ave Barrios 1, Tlalnepantla, State Of Mexico, Mexico
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