Environmental Engineering Reference
In-Depth Information
Pearson's correlation between rotifer diversity and temperature as well
as pH revealed that rotifers thrive well in warm alkaline part of the river.
In addition nitrate nitrogen and chlorophyll-a levels had a signifi cant
positive infl uence on rotifer community composition. To sum it up in the
current study, we observed that water chemistry does infl uence rotifer
community in Vishwamitri River and the prominent among the chemical
parameters that infl uence the rotifer community are pH and chlorophyll-a.
The right blend of these abiotic factors together with the presence of
aquatic macrophytes makes the upstream sampling stations of Vishwamitri
richer in terms of rotifer diversity as compared to their more polluted
downstream stations.
Keywords
Rotifer • Distribution • Diversity • Gujarat
Introduction
environmental parameters (Marneffe et al.
1998
).
Most of these factors follow a seasonal pattern of
change within an annual cycle. Seasonal varia-
tion is clearly driven by climate (Green
2001
).
Rotifers, due to their high turnover rates, are
particularly sensitive to changes in water quality
(Sladecek
1983
).
Changes in community structure can be
explained numerically with diversity index
(Kaushik and Saksena
1995
). These indices are
useful in assessing water quality. Diversity indi-
ces are used to characterize species abundance
and their relationships in the communities. These
mathematical expressions describe the compo-
nents of community structure, namely, richness
(number of species), evenness (uniformity in the
distribution of individuals among species), and
abundance (total number of organisms), that
reveal the response of a community to the quality
of its environment (Ludwig and Reynolds
1988
).
In addition to the changes in the physicochemical
composition, interspecifi c and intraspecifi c
composition, pollution level and the presence or
absence of predators are some factors infl uencing
rotifer species composition and structure
(Kaushik and Saksena
1995
). This chapter dis-
cusses the infl uence of various physicochemical
parameters on the rotifer community structure in
the various seasons in river Vishwamitri.
Extensive environmental variation is one of the
most basic facts of life for any organism living in
the tropical water bodies. Among the most nota-
ble contributors to this environmental variation
are the temperature and chemistry of water.
Chemical analysis measures an essential part of
the environment, and when closely related with
biological study, it greatly enhances its value.
Hynes (
1978
) stated that when the chemist and
the biologist both work on the assessment of
pollution, they can discover much more than
either can alone. Physicochemical analysis of the
water is an important aspect from the point of
view of aquatic biology. Tebutt (
1992
) observed
that the physicochemical characteristics of water
have a direct bearing on the faunal composition
of ponds. Lougheed et al. (
1998
) stated that vari-
ability in abiotic factors contributes to seasonal
and spatial variability in water quality character-
istics and the amount of available habitat and
aquatic invertebrates. Yoshinaga et al. (
2001
) also
stated that animal populations live in a diversity
of environments, and therefore their population
dynamics are regulated by a complex mixture of
environmental factors. Zooplankton species suc-
cession and spatial distribution is a function of
their tolerance to various abiotic and biotic
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