Environmental Engineering Reference
In-Depth Information
6
Structure and Dynamics of Rotifer
Community in a Lotic Ecosystem
S. Dhuru , P. Patankar , I. Desai , and B. Suresh
Abstract
The Vishwamitri is one of the major rivers of central Gujarat and on its
banks evolved the picturesque city of Vadodara. Like any other lotic eco-
system of the modern era, the Vishwamitri too is used as a dumping ground
for domestic and industrial wastes. Nevertheless, the river inhabits a sizable
population of microfauna and the notable among them is rotifer. The current
study was aimed at understanding the factors infl uencing the structure and
dynamics of rotifer community in the river Vishwamitri. Seasonal sampling
was done during 2002-2004 from fi ve selected sampling stations that were
representing upstream, midstream, and downstream of Vishwamitri. These
stations, therefore, varied in their pollution loads. The taxonomic analysis
of rotifers revealed the presence of 59 species, belonging to 24 genera and
17 families. The Lecanidae family had the maximum representation with
18 species followed by Brachionidae with 15 species. However, species
belonging to
Brachionus
genus are found as the predominant group,
among rotifers, in Vishwamitri. Further, a defi nite periodicity in the rotifer
community was noticed on a temporal scale at all the stations. The species
diversity was observed to be highest during the post-monsoon, whereas the
least diversity was observed during winter. Analysis for water chemistry
followed by suitable statistical analysis revealed that the rotifer community
responded differently to various physicochemical cues. Dissolved oxygen,
normally a major rate-limiting parameter for aquatic life, was found to
have no statistically signifi cant infl uence in regulating rotifer diversity.
The study further revealed that elevated levels of suspended solids and
total reactive phosphate have a negative infl uence on the rotifer diversity.
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