Journal of Environmental Biology

Effect of organic and inorganic turbidity on

the zooplankton community structure of a shallow waterbody

in Central Mexico (Lake Xochimilco, Mexico)

M.A. Gayosso-Morales¹, S. Nandini²*, F.F. Mart?nez-Jeronimo¹ and S.S.S. Sarma²

¹Instituto Polit?cnico Nacional. Escuela Nacional de Ciencias Biol?gicas. Posgrado en Ciencias Quimicobiol?gicas, Carpio y Plan de Ayala S/N,

Mexico City 11340, Mexico

²Laboratory of Aquatic Zoology, National Autonomous University of Mexico, Campus Iztacala, Av. de Los Barrios No.1, AP 314, 54090,

Los Reyes, Tlalnepantla, State of Mexico, Mexico

*Corresponding Author E-mail: nandini@unam.mx

Key words

Cyanobacteria

Shallow lakes

Species diversity turbidity

Publication Data

Paper received : 30.11.2016

Revised received : 03.02.2017

Re-revised received : 27.02.2017

Accepted : 06.03.2017

Abstract

Aim: Lake Xochimilco is shallow (< 2m) water-body in Mexico City consisting of several interconnected canals. It is now eutrophic, with high levels of turbidity as a result of suspended sediment and phytoplankton blooms. We selected two sites, the Rowing channel with organic turbidity due to cyanobacterial blooms and the Main channel with inorganic turbidity from re-suspended clay. The aim of this work was to present data on zooplankton dynamics in two channels of the lake over one year (June, 2013 to May, 2014).

Methodology: We collected zooplankton by filtering 80L of water from two sites in each of the canals, as well as measuring temperature, pH, conductivity, dissolved oxygen, nitrate-N and phosphate-Ps, Chlorophyll-a, and Secchi disk transparency at each of the sites.

Results: The zooplankton community was dominated by rotifers; cladocerans and copepods were few. The common rotifer genera in thelake were Keratella, Brachionus, Polyarthra, Trichocerca, Filinia, Asplanchna chydorid cladocerans like Chydorus sphaericus, Pleuroxus varidentatus, Alona sp. and copepods Acantho cyclops americanus and Microcyclops rubellus. The canonical correspondence analysis (CCA) in the Rowing channel station, showed that the first two ordination axes explained 46% of the variance of the species data in CCA. The first and second axes were well correlated with the environmental data. The Monte Carlo permutation test was significant on the first axis. ?

Interpretation: Our study showed that the presence of organic turbidity as observed in the rowing channel had a greater adverse effect than the inorganic turbidity on zooplankton density and diversity.

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