Department of Biosystems Technology

Detailed Morphology, with Reference to Abundance, of Acartia Species in Malala Lagoon in Bundala National Park

2024-10-30T05:03:03Z

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.; Amarasinghe, N.J. De S.; 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.

Physico-chemical and biological environment of Malala lagoon at Bundala National park under overwhelming fresh water influence

2024-10-16T04:39:21Z

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.; Amarasinghe, N.J. De S.; 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

An Investigation of the Effects of Low Concentrations of Chlorpyrifos on Epididymal Sperm Mutation in Rats

2022-11-21T06:35:55Z

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.

Analysis of Socio-Ecological Factors Affecting Bundala National Park

2024-10-16T04:37:31Z

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.; Amarasinghe, N.J. De S.; 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.