Seasonal variations in phytoplankton diversity in the Bui dam area of the Black Volta in Ghana during the pre- and post-impoundment periods
Phytoplankton constitutes the primary producers of aquatic ecosystems and represents the food chain base that supports the commercial fisheries of most water bodies. Nowadays, there is lack of information on phytoplankton assemblages of most reservoirs in Africa. To contribute with this knowledge, t...
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| Formato: | Online |
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Universidad de Costa Rica
2015
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| Acceso en línea: | https://revistas.ucr.ac.cr/index.php/rbt/article/view/14230 |
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RBT142302022-06-09T17:42:18Z Seasonal variations in phytoplankton diversity in the Bui dam area of the Black Volta in Ghana during the pre- and post-impoundment periods Alhassan, Elliot Haruna impoundment chlorophyceae cyanophyceae seasonal density downstream station Phytoplankton constitutes the primary producers of aquatic ecosystems and represents the food chain base that supports the commercial fisheries of most water bodies. Nowadays, there is lack of information on phytoplankton assemblages of most reservoirs in Africa. To contribute with this knowledge, this study was carried out to determine the density and diversity of seasonal variations of phytoplankton species in the Bui dam area of the Black Volta, during the pre- (2011) and post-impoundment (2012) periods. For this, a three-level stratified random sampling approach was adopted for 22 months. Phytoplankton samples were obtained by towing a 0.5m diameter phytoplankton net (35μm mesh size and 0.25m2 mouth surface area) from a non-motorized canoe through a distance of about 100m against the current from downstream to upstream of the river. In 2011, 35 species of phytoplankton belonging to four classes, Bacillariophyceae (7.6%), Chlorophyceae (43%), Cyanophyceae (48.6%) and Euglenophyceae (0.8%) were identified. In the 2012 sampling, 18 species belonging to three classes, Bacillariophyceae (2.2%), Chlorophyceae (26.1%) and Cyanophyceae (71.7%) were observed. A total of 17 species of phytoplankton, including Gyrosigma sp., Surirella sp., Carteria sp., Chlosterium sp., Chlorogonium sp., Coelastrum sp., Cosmarium sp., Volvox sp., Chroococcus sp., Coelosphaerium sp., Rivularia sp. and Spirulina sp., were absent during the late post-impoundment period. Mean monthly total phytoplankton abundance decreased from June (7 384 cells/m3) to August (106cells/m3) in 2011. In 2012 however, mean total phytoplankton decreased from February (1 237cells/m3) to August (4cells/m3). The results also showed that variations occurred between seasons among some phytoplankton groups. The dry and pre-wet seasons had significantly (p<0.05) higher mean phytoplankton abundance than the wet season during the 22 months of sampling period. The biotic indices of Shannon-Wiener (H1) were homogenously distributed in the four hydrological seasons of the two years. The phytoplankton groups, Bacillariophyceae, Chlorophyceae, Euglenophyceae and total phytoplankton differed significantly (p<0.05) between the pre- and post-impoundment periods. The total phytoplankton was also significantly (p<0.05) higher in the upstream station than the downstream station indicating the impact of the impoundment on the downstream ecology. Hence, river management strategies should be implemented by hydro-biologist to lessen the impact of the dam on the downstream ecology. Universidad de Costa Rica 2015-03-01 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion application/pdf text/html https://revistas.ucr.ac.cr/index.php/rbt/article/view/14230 10.15517/rbt.v63i1.14230 Revista de Biología Tropical; Vol. 63 No. 1 (2015): Volume 63 – Regular number 1 – March 2015; 13–22 Revista de Biología Tropical; Vol. 63 Núm. 1 (2015): Volumen 63 – Número regular 1 – Marzo 2015; 13–22 Revista Biología Tropical; Vol. 63 N.º 1 (2015): Volume 63 – Regular number 1 – March 2015; 13–22 2215-2075 0034-7744 10.15517/rbt.v63i1 eng https://revistas.ucr.ac.cr/index.php/rbt/article/view/14230/17550 https://revistas.ucr.ac.cr/index.php/rbt/article/view/14230/17551 Copyright (c) 2015 Revista de Biología Tropical http://creativecommons.org/licenses/by/4.0 |
| institution |
Universidad de Costa Rica |
| collection |
Revista de Biología Tropical |
| language |
eng |
| format |
Online |
| author |
Alhassan, Elliot Haruna |
| spellingShingle |
Alhassan, Elliot Haruna Seasonal variations in phytoplankton diversity in the Bui dam area of the Black Volta in Ghana during the pre- and post-impoundment periods |
| author_facet |
Alhassan, Elliot Haruna |
| author_sort |
Alhassan, Elliot Haruna |
| description |
Phytoplankton constitutes the primary producers of aquatic ecosystems and represents the food chain base that supports the commercial fisheries of most water bodies. Nowadays, there is lack of information on phytoplankton assemblages of most reservoirs in Africa. To contribute with this knowledge, this study was carried out to determine the density and diversity of seasonal variations of phytoplankton species in the Bui dam area of the Black Volta, during the pre- (2011) and post-impoundment (2012) periods. For this, a three-level stratified random sampling approach was adopted for 22 months. Phytoplankton samples were obtained by towing a 0.5m diameter phytoplankton net (35μm mesh size and 0.25m2 mouth surface area) from a non-motorized canoe through a distance of about 100m against the current from downstream to upstream of the river. In 2011, 35 species of phytoplankton belonging to four classes, Bacillariophyceae (7.6%), Chlorophyceae (43%), Cyanophyceae (48.6%) and Euglenophyceae (0.8%) were identified. In the 2012 sampling, 18 species belonging to three classes, Bacillariophyceae (2.2%), Chlorophyceae (26.1%) and Cyanophyceae (71.7%) were observed. A total of 17 species of phytoplankton, including Gyrosigma sp., Surirella sp., Carteria sp., Chlosterium sp., Chlorogonium sp., Coelastrum sp., Cosmarium sp., Volvox sp., Chroococcus sp., Coelosphaerium sp., Rivularia sp. and Spirulina sp., were absent during the late post-impoundment period. Mean monthly total phytoplankton abundance decreased from June (7 384 cells/m3) to August (106cells/m3) in 2011. In 2012 however, mean total phytoplankton decreased from February (1 237cells/m3) to August (4cells/m3). The results also showed that variations occurred between seasons among some phytoplankton groups. The dry and pre-wet seasons had significantly (p<0.05) higher mean phytoplankton abundance than the wet season during the 22 months of sampling period. The biotic indices of Shannon-Wiener (H1) were homogenously distributed in the four hydrological seasons of the two years. The phytoplankton groups, Bacillariophyceae, Chlorophyceae, Euglenophyceae and total phytoplankton differed significantly (p<0.05) between the pre- and post-impoundment periods. The total phytoplankton was also significantly (p<0.05) higher in the upstream station than the downstream station indicating the impact of the impoundment on the downstream ecology. Hence, river management strategies should be implemented by hydro-biologist to lessen the impact of the dam on the downstream ecology. |
| title |
Seasonal variations in phytoplankton diversity in the Bui dam area of the Black Volta in Ghana during the pre- and post-impoundment periods |
| title_short |
Seasonal variations in phytoplankton diversity in the Bui dam area of the Black Volta in Ghana during the pre- and post-impoundment periods |
| title_full |
Seasonal variations in phytoplankton diversity in the Bui dam area of the Black Volta in Ghana during the pre- and post-impoundment periods |
| title_fullStr |
Seasonal variations in phytoplankton diversity in the Bui dam area of the Black Volta in Ghana during the pre- and post-impoundment periods |
| title_full_unstemmed |
Seasonal variations in phytoplankton diversity in the Bui dam area of the Black Volta in Ghana during the pre- and post-impoundment periods |
| title_sort |
seasonal variations in phytoplankton diversity in the bui dam area of the black volta in ghana during the pre- and post-impoundment periods |
| publisher |
Universidad de Costa Rica |
| publishDate |
2015 |
| url |
https://revistas.ucr.ac.cr/index.php/rbt/article/view/14230 |
| work_keys_str_mv |
AT alhassanelliotharuna seasonalvariationsinphytoplanktondiversityinthebuidamareaoftheblackvoltainghanaduringthepreandpostimpoundmentperiods |
| _version_ |
1810114655744425984 |