Faculty of Technology
http://ir.lib.ruh.ac.lk/xmlui/handle/iruor/7349
2024-03-28T10:35:15ZDetailed Morphology, with Reference to Abundance, of Acartia Species in Malala Lagoon in Bundala National Park
http://ir.lib.ruh.ac.lk/xmlui/handle/iruor/9426
Detailed Morphology, with Reference to Abundance, of Acartia Species in Malala Lagoon in Bundala National Park
Lasanthi, A.H.P.; Chandana, E.P.S.; Siriwardana, V.P.K.; Weerasinghe, I.M.J.; Senaratna, R.J.P.S.; Athukorale, R.; Piyadarshani, R. K.G.; De S, Amarasinghe N.J.; Peiris, L.D.C.; Samayawardhena, L.A.
Freshwater Calanoid copepods are a group of free-living fresh water crustaceans. They are planktonic
and limnetic and they occur in habitats varying from freshwater to seawater. We investigated detailed
morphology of Acaftia specr'es and some abundance details, possibly the first recording in Malala lagoon,
Bundala National Park. Attention was focused on population dynamics of Acartia specles with water
quality variations. When several other Caianiod copepods were abundant Acartia specles was reduced
to undetectable levels. Basic body measurements (mm) of Acaftia specles were observed as total body
length 1.36 t 0.07, width 0.19 t 0.07, prosome length 0.7310.1 and antennae length'1.16 r 0.11. The
species has a characteristics male 5th leg butwe could not finalize the species name due to some variations
in narrow and longer furcal ramus. There was a slight change in body measurernents (mm) [total length
up to caudal setae changed from 1.36t0.07 to 1.47t0.081 with changes in water quality, specially with a
slight increase in salinity (from 0.78 t 0.15 to 6.59 t 0.92 g/l)and slight decrease in Nitrate (from247 t
6.54 to 167 x 5.47 mg/l). However, no correlation was found with respect to body measurements of
Acartia specles and water quality parameters in Malala lagoon during our visits. Body measurements of
Acartia species and relationships to habitat-ecosystem functions have been emphasized elsewhere.
Therefore, further investigations of morphological variations of this species along with habitat quality
changes are being studied. We believe these ecological relationships are important in habitat management
practices of the Malala ecosystem.
2001-01-01T00:00:00ZPhysico-chemical and biological environment of Malala lagoon at Bundala National park under overwhelming fresh water influence
http://ir.lib.ruh.ac.lk/xmlui/handle/iruor/9423
Physico-chemical and biological environment of Malala lagoon at Bundala National park under overwhelming fresh water influence
Chandana, E.P.S.; Ravindra, R.; Lasanthi, P.; De S, Amarasinghe N. J.; Peiris, L.D.C.; Samayawardhena, L.A.
Bundala National Park situated in Southern Sri Lanka is the only Ramsar wetland system
in the country. Malala lagoon, the largest water body in Bundala National Park is a very
productive ecosystem that is demarcated by a sand bar on east adjacent to sea and a narrow
canal to Embillakala water body. The main objectives of this study were to investigate some
of physico-chemical parameters, variation of the biological component and investigation of
biological indicators dictating the lagoon status due to fresh water input. Two transects
(3000 m) were studied. Each transect was divided to ten sites separated each other by 300
m. Study was carried out from November, 2000 to mid March, 2001 with 7 sampling visits.
Measured salinity levels (from 1.06±0.01 g/L to 0.71±0.02 g/L towards sand bar) along the
transects were low and indicated fresh water conditions. Fresh water rotifer (Brachionis
plicatilis) distribution (From 0 to 131±13 !L towards sand bar), fresh water jelly fish
distribution (From 3 ±0.5 to 131 ±13 /L towards sand bar)and fresh water bivalve(Psidium
conventus)distribution (From 5 ±0.8 to 22± 4 IL towards sand bar) clearly indicated the
fresh water influence. Nutrient loading such as nitrate (ranged from 147.0± 3.8 to 189.4
±3.8 jig/L) and phosphate (from 75.0 ±2.3 to 121.3± 28 ng/L towards sand bar) was much
higher indicating fresh water back up. Freshwater input via Embillakala to Malala lagoon
was overwhelming especially June to February. This increased water input in to lagoons
may result in an increase in the area of wetland. Long-term exposure to fresh water may
change habitat characteristics. Continuous monitoring programs may be necessary to
implement a management system to maintain the lagoon conditions
2001-11-26T00:00:00ZAn Investigation of the Effects of Low Concentrations of Chlorpyrifos on Epididymal Sperm Mutation in Rats
http://ir.lib.ruh.ac.lk/xmlui/handle/iruor/9418
An Investigation of the Effects of Low Concentrations of Chlorpyrifos on Epididymal Sperm Mutation in Rats
De Silva, W.A.J.P.; Deepananda, K.H.M.A.; Chandana, E.P.S.; Peiris, L.D.C.; Samayawardhena, L.A.
The present study investigated effects of extremely low concentrations of Chlorpyrifos
(Pyrimec) to reproductive structure and function of male rats. First, a group o f animals
(4 groups; n=10) were given oral dose of 0.6(T1), 0.25(T2), 0.125(T3) mg/kg/body weight,
every other day for 14 days. They were sacrificed on the 14th day, testicular and epididymal
sperm number and motility were recorded. Second, a group of male rats (4 group, n=6) were
gavaged either Chlorpyrifos (3.2 mg kg/BW) or distilled water only (control animals). Treated
animals were sacrificed at 7-day intervals post-treatment until 21st day. Testicular and
epididymal sperm count and motility was recorded.
Results showed total sperm counts of treated groups were significantly reduced than those of
control group. Although caput total sperm count was not significantly different in treatment
groups T1 and T2 it was significantly reduced in treatment group T3 (P<0.05). Proximal and
distal cauda sperm counts were significantly different to those of control group for all treated
groups (P<0.05). There was a significant increase in percentage of immotile sperm in proximal
and distal cauda (P<0.001). From distal corpus to distal cauda sperm motility parameters were
decreased. In the second group of study, testicular sperm count showed a significant decrease
(P<0.05) until the day 21st. Similarly there was a significant loss (P<0.05) of epididymal sperm
motility. Histological observations in treated groups showed a significant (P<0.05) reduction in
the thickness of cauda epididymal epithelium, while microvilli o f cauda epididymis o f all
treated groups have disappeared. It is clear that at least some of the observed effects were a
result o f structural hence functional changes of epididymal epithelium due to Chlorpyrifos
exposure. We conclude that effects of Chlorpyrifos may be inversely dose dependent on the
reproductive system in rats. In low concentrations epididymal epithelium structure is affected
and thereby epididymal functions on sperm maturation were in jeopardy.
2001-11-26T00:00:00ZAnalysis of Socio-Ecological Factors Affecting Bundala National Park
http://ir.lib.ruh.ac.lk/xmlui/handle/iruor/9414
Analysis of Socio-Ecological Factors Affecting Bundala National Park
Chandana, E.P.S.; Dewasurendra, R.; Dharmadasa, L.; Priyangani, P.M.C.; De Silva, P.M.C.; Ravindra, R.; Lasanthi, P.; De S, Amarasinghe N. J.; Peiris, L.D.C.; Samayawardhena, L.A.
Bundala National Park (BNP) is the only Ramsar wetland in Sri Lank4 which is reputed for its
rich biological diversity of avifauna. The objective of this study was to investigate the socioecological
influence of people living in and near the Park. Questionnaires were prepared for the
general community and fishing community separatcly. On education level, living condition,
personal inforrntion, occupational information and usage of park r€sources- According to the
findingB inhabitants were using the park resources to a considerable extent. Our results revealed
this might be due to settlement of people close to the national park boundary. Over 90o/o of
people knew that the BNP is a National Park but only a few knew that it is a Ramsar wetland.
Similarly bird migration is a known factor (80% of people) but not the importance of the habitat
for such birds. lncome level of people was poor and over 90oZ percent of the people did not
have a permanent income. In the fishing community 50% families had 4-6 family members than
the other families (3-4 members per family). Fuel wood collection, killing wild life for
economic purposes, over-fishing with disturbing aquatic environments, usage of water bodies as
a dumping ground, unsuitable land use practices and agricultural practices were i{entified
harmful to the park ecosystem balance. Data indicates land ownership is high and practices are
independent. Most families engaged in paddy cultivation (70%) and a few families engaged in
chena eultivation (30%). Over 30% famities used forests for fuel wood collection and hunting
wild life. The study revealed that poor living conditions and some occupational practices might
have profound effects on the Park environment and water bodies. Proper managem€nt plans are
required to secure the funre of BNP ecosystem to provide the people better livelihoods.
Comrnunity participation in management and conservation practices could be proposed as a tool
in BNP.
2001-11-26T00:00:00Z