Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Microalgal Community Structure in Eutrophic Ponds of Mymensingh District of Bangladesh

Md. R. Kabir
Department of Fisheries Management, Bangladesh Agricultural University, Mymensingh

Md.M. Haque
Department of Fisheries Management, Bangladesh Agricultural University, Mymensingh

S. Khan
Department of Fisheries Management, Bangladesh Agricultural University, Mymensingh

R. K. Adhikary
Department of Fisheries Management, Bangladesh Agricultural University, Mymensingh

Z. B. Mostafa
Department of Fisheries Management, Bangladesh Agricultural University, Mymensingh

Abstract/ Executive Summary:

A study on the microalgal community structure i.e., the species composition and the qualitative and quantitative variations of microalgae in respect to the physico-chemical qualities of water in eutrophic ponds was carried out in five naturally eutrophicated ponds. The ponds located in Mymensingh district were arbitrarily numbered as 1 to 5 for a period of eight months from April to November, 2007. Out of 41 microalgal genera identified, 10 belong to Cyanophyceae, 10 to Bacillariophyceae, 18 to Chlorophyceae and the rest Euglenophyceae. The highest abundance of microalgae was found as 227.7×104 cells/l of water in pond-3 in June and the lowest was 39.8×104 cells/l in the same pond in August. Cyanophyceae was dominated by Microcystis, Oscillatoria, Spirulina, Aphanothece and Gomphosphaeria with Microcystis as the main blue-green algae represented and the maximum cell density was observed as 137.0×104 cells/l in pond-1 in June. The highest abundance of Bacillariophyceae was found to be 34.2×104 cells/l in pond-5 in May and dominated by Nitzschia, Navicula, Cyclotella, Fragillaria and Cocconeis. Chlorophyceae ranked first in respect to the number of genera and was dominated by Chlorella, Scenedesmus, Pleurococcus, Tetraedron and Stichococcus. The maximum abundance of Chlorophyceae was observed as 83.0×104 cells/l in pond-5 in April. Euglenophyceae ranked first in respect to the abundance but fourth in respect to the number of genera. Euglena was the most dominant genera among the Euglenophyceae. The highest abundance of Euglenophyceae was found as 80.0×104 cells/l in pond-3 in November. Total microalgal population was significantly (P<0.05) correlated with nitrate-nitrogen and phosphate-phosphorus in all the studied ponds throughout the study period.

Keywords: Microalgal community, Nitrate-nitrogen, Phosphate-phosphorus

Location: Mymensingh district

Start Date: 00-04-2007

End Date: 00-11-2007

Program Area: Animal Health and Management

Commodity:

Objectives:

The aim of the present study was to investigate the seasonal variation in the abundance and community structure of the microalgae in eutrophic ponds and the environmental factors that trigger and control harmful and noxious algal blooms.

Methodology:

The present study was conducted in five naturally eutrophicated ponds of Mymensingh district (24°40′ to 24°54′ N and 90°12′ to 90°30′ E), Bangladesh for a period of 8 months from April to November, 2007, to observe the microalgal community structure in eutrophic ponds. To observe the physico-chemical and microalgal conditions of the ponds, water samples were collected at monthly interval. The ponds were selected by physical observation of water colour and surrounding conditions. The ponds were situated at three different areas of Mymensingh district named as Naomahal Pocha pond (Pond-1), LGED (Local Government and Engineering Department) pond (Pond-2), Morakhola west pond (Pond-3), Morakhola east pond (Pond-4) and Morakhola GP (Grameen Phone) pond (Pond-5). All the ponds are owned by the Government of Bangladesh but they have been leased to the local people who culture carps, tilapia, pangas etc. in traditional fish culture system in these ponds. No supplemental feeds were used throughout the experimental period. Fertilizers and lime were used occasionally. Plastic bottles with stopper having a volume of 250 ml were first labeled with pond name and sampling date. Water samples were collected from each pond at a monthly interval, using two bottles from each pond; one for chemical analysis of water quality parameters and another for qualitative and quantitative analysis of microalgae. Water samples for the analysis of microalgae were collected by passing 5 liters of surface water through fine mesh (25 μ) plankton net. Filtered samples were taken into a measuring cylinder and carefully made up to a standard volume of 50 ml. The collected plankton samples were preserved in 5% buffered formalin in small plastic bottles each for subsequent studies. Samplings were done within 9:30 to 11:00 am. Surface water temperature was determined by an electronic thermometer (HANNA, HI 8424); pH of water was determined by using an electronic pH meter (HANNA, HI 8424); transparency was measured with a secchi disc of 20 cm diameter. Alkalinity of the water sample was determined by titrimetric method using methyl orange indicator. It was calculated by the following formula- Total alkalinity (mg/l) as CaCO3 = A × 20 (when amount of sample is 50 ml) Where, A = Total ml of titrant used The concentration of nitrate-nitrogen (NO3-N) was determined by HACH kit (DR-2010, a direct reading spectrophotometer) using NitraVer-6 and NitriVer-3 powder pillows. The same HACH kit and Phosver-3 powder pillows were used to determine phosphate-phosphorus (PO4-P). For the identification of microalgal genera, preserved samples were gently shaken to resuspend all materials and allowed to settle for one minute. Then 1 ml sub-sample was examined using a Sedge Wick-Rafter cell (S-R cell) and a binocular microscope (NOVEX, Holland). The Sedge Wick- Rafter counting cell is a special type of slide having a counting chamber which is 50 mm long, 20 mm wide and 1mm deep; the volume of the chamber is 1 ml. The counting chamber is equally divided into 1000 fields, each having a volume of 0.001 ml. One ml sub sample from each sample was transferred to the S-R cell and then all microalgal organisms present in 10 fields of the cell were chosen randomly, identified and counted. Plankton identification was performed. For each pond, counting results were summarized as cells per liter. The quantitative estimation of plankton was done using the following formula: N = [(Ax1000xC)/(VxFxL)] Where, N = number of plankton cells or units per liter of original water, A = total number of plankton counted, C = volume of final concentrate of the sample in ml, V = volume of field in cubic mm, F = number of field counted, and L = volume of original water in liter. For the statistical analysis of the data, a one-way ANOVA and DMRT (Duncan Multiple Range Test) were done by using the SPSS-12 (Statistical Package for Social Survey). Significance was assigned at 5% level. Duncan test was used to test the results of multiple ranges for comparing the mean values.

Source of Information: J. Environ. Sci. & Natural Resources, 2(1): 97-102, 2009; ISSN 1999-7361

Article Link (Online Journal):

Funding Source:

Total Budget (Tk.) :

Achievement/Findings:

The highest abundance of Bacillariophyceae was found to be 34.2×104 cells/l in pond-5 in May and dominated by Nitzschia, Navicula, Cyclotella, Fragillaria and Cocconeis. Chlorophyceae ranked first in respect to the number of genera and was dominated by Chlorella, Scenedesmus, Pleurococcus, Tetraedron and Stichococcus. The maximum abundance of Chlorophyceae was observed as 83.0×104 cells/l in pond-5 in April. Euglenophyceae ranked first in respect to the abundance but fourth in respect to the number of genera. Euglena was the most dominant genera among the Euglenophyceae. The highest abundance of Euglenophyceae was found as 80.0×104 cells/l in pond-3 in November. Total microalgal population was significantly (P<0.05) correlated with nitrate-nitrogen and phosphate-phosphorus in all the studied ponds throughout the study period.

Knowledge Management: Journal