Efecto de agua tratada sobre la biomasa del perifiton de dos sitios del área lacustre de Xochimilco utilizando un microcosmos artificial

Abstract

Abstract Lake Xochimilco receives treated water since 1971, since then has reported different environmental problems appeared showing decrement in water quality. This study evaluated the effect of treated water on the functional structure of the periphyton community based on changes in chlorophyll a and total biomass (ashes). Was built one artificial microcosms system with 20 PVC channels, 90 x 10 x 8 cm, distributed in two experimental and control plots with five replicates each. Water from lakes Tlilac and Huetzalin was sampled which was added in the corresponding channels; microscope slides were used as artificial substrates for the colonization of natural periphyton communities. Four weeks later water from experimental lots was substituted by treated water carefully so as not remove periphyton. In the studied lakes and source of treated water phytoplankton species were identified and were carried out analysis of dissolved oxygen and inorganic nutrients. Through first four weeks both sites showed different algal growth and total biomass. When treated water was added to experimental lots, increment en both parameters was observed, showing that treated water comes enriched with inorganic nutrients, promoters of periphyton growth and species representatives of water with high contents of organic matter, such as cyanobacteria, chlorophytes and diatoms, which explains the eutrophication in the natural channels.