Community structure of zooplankton in two different habitats of Kotte Kolonnawa Wetland, Sri Lanka

INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 3, No 3, 2012

© Copyright by authors – Licensee IPA – Under Creative Commons license 3.0

Research article ISSN 0976 – 4402

Received on October 2012 Published on November 2012 965

Community structure of zooplankton in two different habitats of Kotte

Kolonnawa Wetland, Sri Lanka

Deepthi D. Wickramasinghe

1, Rushan Abeygunawardena

2, Missaka Hettiarachchi

3

1- Department of Zoology, University of Colombo, Sri Lanka

2- Department of Statistics, University of Colombo, Sri Lanka

3- Department of Engineering, University of Canberra, Australia

doi: 10.6088/ijes.2012030133004

ABSTRACT

Understanding the structure and variation of biotic communities and their interaction with

physic chemical characteristic in wetlands is essential for effective aquatic management. We

examined water quality parameters in two different habitat types, flowing (Kolonnawa

marsh) and stagnated (Heen ela), in Kotte Kolonnawa wetland. The two habitats exhibited a

significant difference in flow rate, pH, conductivity, phosphates and chlorophyll a

concentration. A total of 12 taxa of zooplankton were identified in the wetland. In both sites,

zooplankton community is composed of rotifers, copepods and cladocerans. Rotifers were

dominant in both habitats. Rotifers were composed of eight species and the copepods were

represented by three species. Cladocerans showed least diversity and only one species was

present in both habitats. Density of zooplankton was significantly higher in stagnated habitat

than in the flowing waters.

Keywords: Wetland, water quality, zooplankton, density and diversity.

1. Introduction

Attempts to understand the physico chemical and biological interactions in wetlands often

focus on different biota. Since wetlands are complex, dynamic and productive ecosystems

(Lampert and Sommer, 2007), they exhibit strong variations in water quality parameters

(Davies et al., 2004) as well as community structure of aquatic plants and animals

(Cvetkovic and Fraser, 2011). Zooplankton are microscopic and rapidly reproducing

organisms, that play a major role in energy flow and nutrient cycling in aquatic ecosystems

being parts of aquatic food-webs (James, 1991). They provide the link between primary

producers and the consumers in the higher trophic levels in wetlands. Abiotic features of

aquatic habitats are one of the key factors that determine diversity and abundance of

zooplankton (Attayde and Bozelli, 2011; Sharma, 2011). There is an increasing demand by

environmental monitoring programs using zooplankton for bioindicators of water quality and

environmental changes (Kumari et al., 2007). Any research that reports limnological

information including water quality and community profiles of zooplankton will no doubt be

beneficial in conservation management of wetlands. As such, this research focuses on water

quality and zooplankton community in Kotte Kolonnawa wetland, which is situated in the

heart of an urban area in Sri Lanka. This is the first study to report the community structure

of zooplankton in this habitat. The main objective of the present study was to investigate the

density and diversity of zooplankton in the wetland. Secondly, it also envisaged to examine

Community structure of zooplankton in two different habitats of Kotte Kolonnawa Wetland, Sri Lanka

Deepthi D. Wickramasinghe, Rushan Abeygunawardena, Missaka Hettiarachchi

International Journal of Environmental Sciences Volume 3 No.3, 2012 966

any variation in parameters of water quality and zooplankton in two different habitat types,

i.e. flowing and stagnated, found in the wetland.

2. Study area

The study area belongs to the Colombo Flood Detention Area (CFDA), which is mainly

constituted by three wetlands, namely Kolonnawa Marsh (214.3 ha), Heen Marsh (87 ha) and

Kotte Marsh (95 ha). The geographical location of the CFDA is between Lat. 60 52’ 55’’- 6

0

52’ 45’’ and Longt. 790 52’ 35’’- 79

0 55’ 15’’.

Figure 1: Study area

Kolonnawa Marsh and Heen marsh were selected for the detailed investigation of water

quality and diversity of zooplankton. Two locations each in the Kolonnawa and Heen

marshes were selected for sampling (Figure 1). Locations in the Kolonnawa Marsh are

represented stagnated waters that flow where as those of the Heen Marsh are more or less

flowing.

3. Methodology

The study was carried out from April- August 2010, in Kotte Kolonnawa Wetland. Two study

sites were selected to represent stagnated water (i.e. in Kolonnawa Marsh, sites 1 and 2) and

flowing water (Heen Ela, sites 3 and 4). Study area was selected using 1:50,000 scale

topographic maps & according to stratified random sampling techniques. Each site was

visited at least twice a month. This study is consists of two elements; studying the physico-

chemical parameters of water and studies on zooplankton density and diversity. Water

samples were collected periodically from two sites, during the early hours between 7.00 to

10.00 am. Samples were withdrawn at a depth of 0.5 m from the surface. The biological

parameters studied were chlorophyll a concentration and diversity and abundance of

zooplanktons. The zooplankton samples were collected by filtering 10 litters of water through

standard plankton net (33 µ silk mesh) and the concentration samples were fixed in 5% of

formalin and coloured with Rose Bengal dye. Identification of zooplankton was carried out

with the help of standard references (Fernando and Weerawardhena, 2002). The quantitative

analysis of planktonic organisms was carried out using Sedgwick Rafter plankton counting

chamber in accordance to Welch (1948) and converted the counts as organisms per ml to

express as density. A total of nine physico-chemical parameters were studied to record water

quality. Eight physical properties (water temperature, pH, electrical conductivity, turbidity,

dissolved oxygen, flow rate) and three nutrient parameters (total nitrogen, nitrates and

phosphates). Physical properties were measured in the site and other physico-chemical

parameters were analyzed in the laboratory. A hand held flow meter (Xylem, PH 111) was

used to detect flow rate. The pH was measured using a portable pH meter (Trans 3400),




electrical conductivity was measured using portable multi range conductivity meter (Omega

CDH and PHH), dissolved oxygen levels were measured using a (HANNA 1600) portable

dissolved oxygen meter, turbidity level was measured using a (HACH 2100P) portable

turbidity meter. All other tests were performed according to standard methods (APHA, 1989).

3.1 Statistical analysis

Data on four sites were pooled separately for flowing and stagnated sites in analysis. Two

independent sample t-tests were performed to investigate whether the two habitats (stagnated

and flowing) exhibits a significant difference in water quality parameters and density of

zooplankton species. Furthermore, the results were pooled for four locations and analyzed

using Factor Analysis (FA) with factor extraction method of Principal Component Analysis

to reduce the number of variables in the original data set to a few meaningful composite and

enables to identify hidden relationships of data (Jollifee, 2002). All tests were performed in

SPSS version 13 for windows and unless specified, the significance level was chosen as 0.05.

4. Results

Table 1 depicts the information on water quality parameters in the two habitats, flowing

(Kolonnawa Marsh) and stagnated (Heen Ela). In the stagnated habitat mean value of

conductivity, turbidity, concentration of phosphates and chlorophyll a were higher than the

flowing habitat. Furthermore, in both sites, presence of nitrogen and phosphorus based

nutrients were evident. Another remarkable finding is that certain parameters exhibit high

variation in values as indicated by the high coefficient of variation: DO and phosphates in

flowing water habitat and flow rate in both habitats.

Table 1: Descriptive statistics of water quality parameters of two habitats

Water Quality Parameter

Habitat

(Site) Mean

Standard

Deviation

Coefficient of

Variation

Temperature °C Stagnated 29.15 1.51 5.2

Flowing 30.11 1.19 4.0

Conductivity µs/cm Stagnated 145.88 92.42 63.4

Flowing 84.44 52.27 61.9

Turbidity NTU Stagnated 10.31 4.90 47.5

Flowing 6.25 4.82 77.1

Dissolved Oxygen mg/l (DO) Stagnated 4.22 1.77 41.9

Flowing 4.58 5.46 119.2

pH Stagnated 5.72 0.65 11.4

Flowing 6.33 0.33 5.2

Nitrate mg/l Stagnated 0.39 0.20 51.3

Flowing 0.35 0.15 42.9

Total N mg/l Stagnated 0.46 0.27 58.7

Flowing 0.47 0.15 31.9

Phosphates mg/l Stagnated 0.20 0.11 55.0

Flowing 0.05 0.06 120.0

Chlorophyll a µg/l Stagnated 12.93 6.79 52.5

Flowing 8.13 3.54 43.5

Flow rate m3/s Stagnated 0.03 0.1 333.3

Flowing 0.27 0.33 122.2




A total of 12 taxa of zooplankton were identified in the wetland. In both sites, zooplankton

community is composed of Rotifers, Copepods and Cladocerans (Table 2). Rotifers were

composed of eight species and the Copepods were represented by three species. Cladocerans

showed least diversity and only one species was present in both habitats. There were some

occasional occurrences (only once or twice) of eggs of crustaceans and ostracods which were

omitted from statistical analysis. Almost all taxa other than Asplachna spp, Moina macrura

and Tropocyclops spp were more abundant in the stagnated site indicating the influence of

flow rate on the distribution of zooplanktons. Specially, the density of Moina macrura was

very low in the flowing habitat. In addition, variation of the densities of B. quadridentatus, B.

calyciforus, Moina macrura and Mesocyclops spp in flowing habitats exhibited high values.

Table 2: Descriptive statistics of density of zooplankton in two habitats

Zooplankton Species Habitat (Site)

Mean density

(individuals/ l)

Standard

Deviation

Coefficient

of Variation

Rotifera

Brachionus

calyciflorus

Stagnated 12.56 5.48 43.6

Flowing 6.19 5.06 81.7

B. quadridentatus Stagnated 11.63 6.29 54.1

Flowing 0.75 1.24 165.3

B. calyciforus Stagnated 23.38 16.42 70.2

Flowing 1.44 2.8 194.4

B. forficula Stagnated 27.63 22.53 81.5

Flowing 18.25 11.88 65.1

Filinia longeista Stagnated 21.13 8.37 39.6

Flowing 8.13 4.73 58.2

Keratella tropica Stagnated 31 26.2 84.5

Flowing 31.44 19.35 61.5

Lacane luna Stagnated 49.13 14.04 28.6

Flowing 6.38 3.58 56.1

Asplachna spp Stagnated 11.13 6.49 58.3

Flowing 17.88 3.65 20.4

Cladocera Moina macrura Stagnated 5.75 3.44 59.8

Flowing 0.94 2.38 253.2

Copepoda

Tropocyclops spp Stagnated 11.81 3.04 25.7

Flowing 14.5 10.56 72.8

Thermocyclops

crassus

Stagnated 12.31 5.52 44.8

Flowing 9.94 3.91 39.3

Mesocyclops spp Stagnated 4.88 3.96 81.1

Flowing 1 2.71 271.0

Copepod nauplii Stagnated 26.44 15.2 57.5

Flowing 14.25 7.04 49.4

When compared water quality in stagnated and flowing habitats, pH, conductivity,

phosphates, chlorophyll a content and flow rate were significantly different (Table 3). Higher

phosphate concentration in the stagnated wetland indicates sighs of eutrophication which

could be attributed to high chlorophyll a concentration of that site.




Table 3: Results of T tests to compare water quality parameters of two sites

Levene's Test for

Equality of Variances

t-test for

Equality of

Means

Sig. (2-tailed) Sig. (2-tailed) Mean Difference

Temperature °C 0.421 0.054* -0.96

Conductivity µs/cm 0.024* 0.030* 61.44

Turbidity NTU 0.794 0.025* 4.06

Dissolved Oxygen mg/l 0.000* 0.809 -0.35

pH 0.000* 0.003* -0.61

Nitrate mg/l 0.649 0.561 0.04

Total N mg/l 0.001* 0.93 -0.01

Phosphate mg/l 0.212 0.000* 0.15

Chlorophylle a µg/l 0.003* 0.020* 4.81

Flow rate m3/s 0.000* 0.011* -0.24

* Significant at 5% level

Similarly, density of zooplanktons too showed significant differences among the stagnated

and flowing sites (Table 4) and they were mostly rotifers i.e. Brachionus quadridentatus, B.

calyciforus, B. forcicula, Lacana luna, Asplachna spp. In addition Moina macrura

(Cladocera) and Tropocyclops, Mesocyclops (Copepoda) species and copepod nauplii too

showed a significant difference in density.

Table 4: Results of T tests to compare density of zooplankton of two sites

Levene's Test for Equality

of Variances

t-test for

Equality

of Means

Sig. (2-tailed)

Sig. (2-

tailed) Mean Difference

B. calyciflorus 0.948 0.002* 6.38

B. quadridentatus 0.003* 0.000* 10.88

B. calyciforus 0.000* 0.000* 21.94

B. forficula 0.002* 0.155 9.38

Filinia longeista 0.336 0.000* 13

Keratella tropica 0.257 0.958 -0.44

Lacane luna 0.045* 0.000* 42.75

Asplachna spp 0.036* 0.001* -6.75

Moina macrura 0.031* 0.000* 4.81

Tropocyclops spp 0.000* 0.341 -2.69

Thermocyclops crassus 0.363 0.170 2.38

Mesocyclops spp 0.027* 0.003* 3.88

Copepod nauplii 0.008* 0.008* 12.19

* Significant at 5% level




The Factor Analysis generated four significant Principle Components which explain 75.7 %

of the variance in the dataset which are sufficient to interpret results. This could further be

justified by the Scree Plot (Figure 2) which indicates that there are four components with

variances higher than eigenvalue 1. Component 1 which explains 31.0 % of the total variance

has high loadings on phosphates and chlorophyll. Component 2, which explains 18.6 % of the

total variance, includes temperature, turbidity and dissolved oxygen while component 3, has a

high loading on flow rate and explains 14.0 % of the total variance. And finally, the fourth

component which explains 11.9 % of the variance has high loadings on nitrates.

Table 5: Total Variance Explained in water quality parameters

Total Variance Explained

Component Initial Eigenvalues

Extraction Sums of

Squared Loadings

Rotation Sums of

Squared Loadings

To

tal

% o

f

Var

ian

ce

Cu

mu

lati

ve

%

To

tal

% o

f

Var

ian

ce

Cu

mu

lati

ve

%

To

tal

% o

f

Var

ian

ce

Cu

mu

lati

ve

%

1 3.11 31.09 31.09 3.11 31.09 31.09 2.60 25.99 25.99

2 1.86 18.64 49.73 1.86 18.64 49.73 2.22 22.19 48.19

3 1.40 14.02 63.75 1.40 14.02 63.75 1.53 15.27 63.46

4 1.20 11.99 75.74 1.20 11.99 75.74 1.23 12.28 75.74

5 0.81 8.15 83.89

6 0.63 6.32 90.21

7 0.36 3.60 93.81

8 0.32 3.16 96.97

9 0.20 2.02 98.99

10 0.10 1.01 100.00

According to the Scree Plot (Figure 2) which depicts the fraction of total variance in the data

as explained or represented by each component, considering up to four factors are sufficient

for analysis.

10987654321

Component Number

3

2

1

0

Eig

enva

lue

Scree Plot

Figure 2: Scree plot of factors on water quality parameters




Table 6: Component Matrix (a) for water quality parameters

Rotated Component Matrix (a)

Component

1 2 3 4

Temperature °C -0.3771 0.8132 0.0607 -0.0926

Conductivity µs/cm 0.3458 0.5882 -0.1281 0.1876

Turbidity NTU 0.5796 0.7111 -0.0249 -0.0263

Dissolved Oxygen mg/l 0.1404 0.8074 0.2422 -0.0361

pH 0.1029 0.1780 0.6557 -0.5684

Nitrate mg/l 0.0614 0.0501 0.1599 0.9020

Total N mg/l 0.6564 0.0134 0.5260 0.0549

Phosphates mg/l 0.8748 0.0645 -0.2304 -0.0126

Chlorophylle a µg/l 0.8712 0.1175 0.0890 0.0232

Flow rate m3/s -0.1137 0.0455 0.8090 0.2050

Values indicated in bold show high loadings for each component. Rotation Method: Varimax with Kaiser Normalization.

As shown in Table 7, when zooplankton data were subjected to analyze factor analysis, four

components are responsible of 74 % of variation explained. According to Figure 3, the Scree

Plot indicates that there are four components which posses values higher than 1, meaning

four components could be used to explain results. As such, Lacane luna, and Moina macrura

have loaded heavily on the first component where as Copepod nauplii has heavy loadings on

the second component. Keratella tropica and Tropocyclops spp are heavy loaded on the third

and fourth components respectively. It is thus not unfair to argue that these groups play

significant roles in the zooplankton community in the wetland.

Table 7: Total Variance Explained in zooplankton density

Total Variance Explained

Componen

t Initial Eigenvalues

Extraction Sums of

Squared Loadings

Rotation Sums of Squared

Loadings

Tota

l

% o

f

Var

iance

Cum

ula

tive

%

Tota

l

% o

f

Var

iance

Cum

ula

tive

%

Tota

l

% o

f

Var

iance

Cum

ula

tive

%

1 4.81 37.03 37.03 4.81 37.03 37.03 4.18 32.18 32.18

2 2.66 20.48 57.51 2.66 20.48 57.51 2.57 19.77 51.95

3 1.12 8.59 66.10 1.12 8.59 66.10 1.77 13.64 65.59

4 1.03 7.92 74.02 1.03 7.92 74.02 1.09 8.42 74.02

5 0.86 6.61 80.63

6 0.63 4.84 85.47

7 0.56 4.28 89.76

8 0.41 3.18 92.93

9 0.36 2.80 95.74

10 0.23 1.79 97.53

11 0.16 1.21 98.74

12 0.09 0.72 99.46

13 0.07 0.54 100.00




13121110987654321

Component Number

5

4

3

2

1

0

Eigen

value

Scree Plot

Figure 3: Scree Plot of Zooplankton Data

Table 8: Component Matrix (a) for zooplankton taxa

Component

1 2 3 4

B.calyciflorus .660 .053 -.188 -.158

B.quadridentatus .608 .318 -.213 -.213

B.calyciforus .688 .104 .560 -.218

B.forficula -.059 .679 .544 -.080

Filinia longeista .469 .711 .005 -.107

Keratella tropica -.214 .214 .880 .082

Lacane luna .828 .482 .005 -.038

Asplachna spp -.772 -.125 .262 .015

Moina macrura .844 -.033 .243 .098

Tropocyclops spp -.042 -.002 .010 .964

Thermocyclops crassus -.028 .722 .422 .051

Mesocyclops spp .787 -.005 -.048 .090

Copepod_nauplii .142 .819 -.008 .036

Values indicated in bold show high loadings for each component.

Rotation Method: Varimax with Kaiser Normalization

5. Discussion

The results of this study indicate that the two habitats differ in basic limnological

characteristics, physico chemical and biological qualities of water. Stagnated habitat is more

favourable for the accumulation of substances. A good example is phosphates and nitrates

which might have led to facilitate the growth of phytoplankton as evident from high

chlorophyll a concentrations (Rudek et al., 1991, Andrew et al., 2005, Faithful et al, 2011).

Diversity of zooplankton taxonomic groups (rotifers, copepods, and cladocerans) identified in

this study are in general fairly similar to most of the studies reported in the literature. There

have been several studies describing water quality and zooplankton community parameters in

fresh water habitats in Sri Lanka (Wignaraja and Amarasiriwardena, 1983; Piyasiri and

Chandrananda, 1988; Piyasiri and Jayakody, 1991; Kamaladasa and Jayatunga, 2007).

Taxonomic composition of major groups that we reported (rotifera, copepod and cladocera)

are in agreement with the above literature. It seems however clear that Kotte Kolonnawa




wetland is somewhat poor in zooplankton taxonomic diversity (12) when compared to the

said reports and the number of taxa reported being 10 and 36. The largest fluctuations in

density were exhibited by crustacean zooplankton Moina macrura and Mesocyclops spp.

Some researchers have reported that elevated prosperous levels tend to increase zooplankton

populations (Mukerjee et al., 2010; Heise, 2011) but in the case of Kollonnawa wetland, such

trend could not be observed.

Of the zooplankton, this study reports a clear differentiation of the density of taxa in flowing

and stagnated habitats, which appears to constitute a new and previously unrecognized trend

in any Sri Lankan wetland. This may be due to the higher residence time of water in

stagnated habitats, as reported by Scholl and Kiss (2008) and high occurrence of

phytoplankton (El-Sherbiny et al., 2011). At the same time, this could be a result of lower

densities of planktonivorous fish (Ning et al., 2010) in the stagnated habitat.

However, for future research, we would like to suggest a refined methodological approach to

overcome the limitations of the present study, i.e. expanding the sampling period to include

both rainy and non rainy seasons and to study smaller zooplankton to represent the

community structure precisely.

Acknowledgement

Authors are grateful to the logistical support provided by the Universities of Colombo and

Moratuwa and to helpful comments received from the colleagues. Our thanks goes to Mr.

Pubudu Wewalwala, Dr. Chandima Dangalle and Ms. Chethika Gunasiri of the University of

Colombo and to Ms. Kusum Athukorala for various support.

References

1. Andrew, R., Wan, S., Lim, N., Spotts, W.W., and Huggins , D.G., (2005), Nutrient

limitation of phytoplankton growth in central plains reservoirs, USA journal of

plankton research, 27(6), pp 587-595.

2. APHA. (1989), Standards methods for the examination of water and wastewater. 20th

Ed. Washington, D.C. USA.

3. Attayde, J. L, and Bozelli, R. L., (1998), Assessing the indicator properties of

zooplankton assemblages to disturbance gradients by canonical correspondence

analysis. Canadian journal of fisheries and aquatic sciences, 55(8), pp 1789-1797.

http://dx.doi. org/10.1139/f 98-033

4. Cvetkovic, M. and Fraser, P.C. (2011), Use of ecological indicators to assess the

quality of Great Lakes coastal wetlands. Ecological Indicators, 11(6), pp 1609–1622.

5. Davies, J.-M., Nowlin, W.H. and Mazumder, A., (2004), Temporal changes in

nitrogen and phosphorus co-deficiency of plankton in Coastal and Interior British

Columbia. Canadian Journal of Fisheries and Aquatic Sciences, 61(8), pp 1538-1551.




6. El Sherbny, M.M., Al Aidroos, L. M. and Gab Alla, A., (2011), Seasonal composition

and population density of zooplankton in Lake Timsah, Suez Canal, Egypt.

Oceanologia, 53(3), pp 837–859.

7. Faithfull, C.L., Bergström, A.K. and Vrede, T., (2011), Effects of nutrients and

physical lake characteristics on bacterial and phytoplankton production: A meta-

analysis . Limnol. Oceanogr., 56(5), pp 1703-1713.

8. Fernando, C.H. and Weerewardhena, S.R., (2002), Sri Lanka freshwater fauna and

fisheries. Third millennium book. Colombo, pp 17-98.

9. Hsieh, C.H., Sakai, Y., Ban, S., Ishikawa, K., Ishikawa, T., Ichise, S., Yamamura, N.

and Kumagai, M., (2011), Eutrophication and warming effects on long-term variation

of zooplankton in Lake Biwa. Biogeosciences, 8, pp 1383-1399.

10. James, M.R., (1991), Sampling and preservation methods for the quantitative

enumeration of microzooplankton. New Zealand journal of marine and freshwater

research, 25, pp 305-310.

11. Jolliffe, I.T (2002), Principal component analysis. 2 nd ed. Springer-Verlag. New

York. 123.

12. Kamaladasa, A.I. and Jayatunga, Y.N.A. (2007), Composition, density and

distribution of zooplankton in south west and east lakes of Beira lake soon after the

restoration of south west lake. Cey. J. Sci. (bio. sci.), 36 (1), pp 1-7.

13. Kumari, P., Dhadse, S., Chaudhari, P.R., and Wate, S.R., (2007), Bioindicators of

pollution in lentic water bodies of Nagpur city. J Environ Sci Eng., 49(4), pp 317-324.

14. Lampert, W. and Sommer, U., (2007), Limnoecology: The Ecology of Lakes and

Streams. 2nd Ed. Oxford University Press. New York, p 324.

15. Nash M. S., Heggem D. T., Ebert D., Wade, T. G., and Hall R. K., (2009), Multi-scale

landscape factors influencing stream water quality in the state of Oregon.

Environmental Monitoring and Assessment, 156, pp 343–360.

16. Ning, N.S.P., Nielsen, D.L., Hillman,T.J. and Suter, P.J., (2010), The influence of

planktivorous fish on zooplankton resting-stage communities in riverine slackwater

regions. J. Plankton Res. (2010) 32(4): 411-421 doi:10.1093/plankt/fbp146.

17. Piyasiri, S. and Chandrananda, W.P.N., (1998), Studies on the population structure of

zooplankton in the Kotmale Reservoir. Journal of the National Science Council of Sri

Lanka, 26, pp 59- 76.




18. Piyasiri, S. and Jayakody, J.K.U., (1991), Ecology of zooplankton in Victoria

Reservoir, Sri Lanka: I. Composition and population structure of zooplankton. Verh.

Internat. Verein. Limnol, 24, pp 1430-1435.

19. Rudek, J., Paerl, H.W., Mallin, M.A., and Bates, P.W., (1991), Seasonal and

hydrological control of phytoplankton nutrient limitation in the lower Neuse River

Estuary, North Carolina. Marine Ecology Progress Series, 75, pp 133- 142.

20. Schöll, K. and Kiss, A., (2008), Spatial and temporal distribution patterns of

zooplankton assemblages (Rotifera, Cladocera, Copepoda) in the water bodies of the

Gemenc floodplain (Duna-Dráva National Park, Hungary). Opuscula Zoologica

Budapest, 39, pp 65–76.

21. Sharma, B.K., (2011), Zooplankton communities of Deepor Beel (a Ramsar site),

Assam (N. E. India): ecology, richness, and abundance. Tropical Ecology, 52(3), pp

293-302.

22. Welch, P.S., (1948), Limnological Methods. McGraw-Hill. New York, p 381.

23. Wignarajah, S. and Amarasiriwardena, P., (1983), Some Aspects of the Limnology of

Bolgoda Lake 11, Sri Lanka. 1. Composition and seasonal fluctuation of Zooplankton.

J. Nat. Sci. Coun. Sri Lanka, 11(2), pp 255-268.

Community structure of zooplankton in two different habitats of Kotte Kolonnawa Wetland, Sri Lanka

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