Full Length
Research Paper
Population
Dynamics and Diversity of Cladocera in Relation to
Some Physicochemical Status of Freshwater Lake Ramala,
Chandrapur.
Rajlaxmi Ranrag Kulkarni[1]
Department
of Zoology, Sardar Patel College, Chandrapur,
India.
ARTICLE
DETAILS ABSTRACT
1.
Introduction:
Zooplanktons are important for their role
in tropic dynamics and in energy transfer in the aquatic ecosystem. They
provide food for fishes in freshwater lakes, ponds and river and play a major
role in fish production. A notable contribution of planktonic forms of
freshwater ecosystem is available due to Sharma 1996, Kodarkar
1999.Zooplankton occupy a central position between the autotrophs and
heterotrophs. In general, they belong to five main taxonomic groups. Protozoa, Rotifera, Cladocera,
Ostracoda and Copepoda.
The Copepoda and Cladocera
are dominant groups of crustaceans found in freshwater habitat.
Zooplanktons include a variety of
assemblage of taxonomically unrelated microscopic organism having common
habitat and thus common ecological characteristics. Many species of Zooplankton
are primary consumers and feed on phytoplankton. They themselves are used as a
food by fishes. Among the different zooplankton the Cladoceran
population constitute a group of microscopic organisms, occurring in a variety
of aquatic habitats. Cladocerans constitute the
dominant groups of freshwater habitats. Sharma and Michael (1987) explained
that the limnetic zooplankton community invariably dominated by the species of Cladocera. Cladocerans popularly
called as water flea prefer to live in deep water. Generally, they inhabit the
ponds, lakes, rivers and reservoirs and reported to occur dominantly in lentic
waters (Raghunathan, 1989 and Sharma, 1991).
Ramala lake is a historical impoundment built up by Gond King around Chandrapur city
for drinking and irrigation purpose. It is situated about 232 meters above sea
level and is at 79°18’15” E longitude and 19°18’15” N latitude. It harbours
variety of aquatic plants and animal species. It is the only reminisce of
greenery in this polluted and overcrowded city like Chandrapur.
Present paper deals with study of Zooplankton species present in Ramala lake, which is perineal
water body. Freshwater zooplankton is an important component of aquatic
ecosystem, whose main function is to act as a primary and secondary link in the
food chain. (Hutchinson, 1967).
Adequate knowledge of the zooplankton communities and their population
dynamics is a major requirement for better understanding of life processes in a
freshwater body since eutrophication influences both the composition and
productivity of zooplankton. (Bhora and Kumar, 2004)
Since they are longer and easier to identity than phytoplankton, sample can be
processed more rapidly, and biologists can be trained in a relatively short
time. Zooplankton communities are very sensitive to environmental changes and
thus are of considerable potential value as water quality indicators.
1.1 Objectives:
·
To analyse
the physicochemical characteristics of Ramala lake during study period.
·
To identify
and study different cladoceran species.
·
To find out correlation
between physicochemical status of water body and species composition as well as
abundance of Cladoceran.
·
To propose
conservation methods.
2.
Material and
method:
2.1 Study area:
Ramala lake is perennial rainfed water
body centrally located in Chandrapur city
(Maharashtra). The lake water is used for various domestic purposes, washing,
bathing, swimming, religious activities, etc. On the basic of topography, three
sampling sites were selected for collection of samples. Samples were collected
on monthly basis during June 2018 and May 2019. Monthly samples were collected
for the study of zooplankton using plankton net made of botting
nylon cloth (mesh 25 cm) by filtering water samples from three different sites
of Ramala lake. For
identification of Zooplankton species water samples were examined under the
microscope with high magnification. For such work the preserved material should
be as fresh as possible because long term preservation often distorts the
specimens. Standard literature was used for identification of zooplankton
species such as Tonapi (1980), Battish
(1992) and Murigan et al (1998). Zooplankton samples
were collected monthly from June 2018 to May 2019. Physico-chemical analysis of
samples was carried out according to APHA (1992) and Trivedi
and Goyal (1986). For numerical estimation of
zooplankton, the organisms were observed under light microscope using Sedgwick
Ratter Cell as per the procedure given in standard methods (ADHA 1992).
3.
Result and
Discussion:
During the present study, it was observed that zooplankton found in Ramala lake water mainly compromised of five groups. Protozoa, Rotifera, Cladocera,
Copepoda and Ostracoda
along with nauplii Larvae and eggs. Cladocerons are filter feeders and feed on algae and phytoplakton. At the same time, they themselves are
favourable prey of aquatic animals including fishes. Thus, cladocerans
represent a key group in energy transfer along food chain. The group Cladocera of Ramala lake is represented by eight species. The group was
flourished as a second dominant group at all stations contributing 25% of the
total zooplankton, with maximum density in summer and minimum in winter. Representative members of this group were Cereodaphnia cornuta, Moina mirura, Alona
pulchella, Chydorus sp., Pleuroxus similis, Macrothrix laticornis, Senocephalus sp., Leydigia sp. etc.
Cereodaphnia corruta
was found continuously throughout the study period. Alona
sp. was found only in winter months. Out of 11 families of Cladocera, eight families have been reported from Indian
water, which represent about one fourth of world cladoceran
fauna (Rao and Chaubey,
1993)
A relative abundance of Cladocerans especially
the members of family Chyrodidae indicate eutrophic
conditions (Khan and Seshagirirao, 1981). According to
Mahajan (1981) Diaphanosoma,
Simocephalus and Ceraodaphnia
are indicators of Eutrophication. The factors like water temperature, dissolved
oxygen, turbidity and transparency plays an important role in controlling the
diversity and density of Cladocerans. Presence of
more nutrients leads to eutrophic condition of water body, which is favourable
condition for growth of cladocerans. Higher nutrient
content is the indicator of rich zooplankton.
Maximum population density was observed in winter during present study
which may be due to favourable temperature and availability of abundant food.
Most of the Cladoceran species feed on microscopic
algae and detritus matter. Similar observations were recorded by Pulle and Khan (2003) and Thirumathal
(2006).
Table 1
: Cladoceran diversity (No/L) during June 2018- May 2019
|
Months |
S1 |
S2 |
S3 |
Total |
|
June |
03 |
01 |
02 |
06 |
|
July |
09 |
10 |
06 |
25 |
|
Aug |
09 |
08 |
11 |
28 |
|
Sept |
12 |
11 |
08 |
31 |
|
Oct |
14 |
10 |
12 |
36 |
|
Nov |
13 |
09 |
11 |
33 |
|
Dec |
11 |
08 |
09 |
28 |
|
Jan |
12 |
08 |
08 |
28 |
|
Feb |
08 |
07 |
09 |
24 |
|
March |
07 |
08 |
05 |
20 |
|
April |
05 |
06 |
04 |
15 |
|
May |
04 |
02 |
03 |
09 |
Table 2: Monthly variations in Physicochemical parameters
values in Ramala lake from
June 2018 to May 2019.
|
Month |
pH |
Temp (°C) |
Sulphate(mg/L) |
Phosphate (mg/L) |
Nitrate
(mg/L) |
Turbidity (NTU) |
|
June |
7.8 |
27.5 |
8.4 |
3.24 |
1.62 |
27.8 |
|
July |
7.6 |
26.8 |
7.3 |
3.22 |
1.22 |
32.20 |
|
August |
7.5 |
24.3 |
7.8 |
4.32 |
1.14 |
30.71 |
|
September |
7.6 |
27.2 |
8.6 |
3.28 |
0.96 |
28.96 |
|
October |
7.8 |
27.8 |
7.8 |
2.12 |
0.82 |
22.44 |
|
November |
7.9 |
7.5 |
7.5 |
1.54 |
0.68 |
21.00 |
|
December |
7.4 |
7.2 |
7.2 |
1.04 |
0.56 |
15.08 |
|
January |
7.6 |
6.8 |
6.8 |
1.38 |
0.88 |
14.08 |
|
February |
7.9 |
8.2 |
8.2 |
1.48 |
1.40 |
15.22 |
|
March |
7.8 |
7.4 |
7.4 |
2.28 |
1.26 |
18.98 |
|
April |
7.2 |
8.6 |
8.6 |
3.14 |
1.74 |
21.62 |
|
May |
7.5 |
8.2 |
8.2 |
3.56 |
2.16 |
23.16 |
4.
Conclusion
The zooplankton population density is generally affected by water
quality, availability of food, carnivorous zooplankton and other animals in the
water body. The present study revealed that different physicochemical
parameters like pH, temperature, turbidity, sulphate, phosphate, nitrate, etc.
are acting as limiting factors and are influencing the diversity as well as
population of Cladocera. As the Cladocerans
are connecting link in the food web, it is necessary to conserve the diversity
of this group along with other biotic components.
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1.