The Lagos lagoon, Nigeria receives lots of organic wastes from anthropogenic sources. The biodegr... more The Lagos lagoon, Nigeria receives lots of organic wastes from anthropogenic sources. The biodegradation of these wastes by aerobic microbes has resulted in the depletion of the dissolved oxygen. Study of this area of the lagoon was conducted for two years to investigate the impact of hypoxia on the distribution, abundance and diversity of benthic macroinvertebrates. Water and benthic samples were collected monthly along the study stretch and analysed in a standard laboratory. Temporal variation in water physico-chemistry was largely controlled by rainfall pattern while the spatial variation was influenced by proximity to the Harbour as well as the pollution sources and types. A total of 3,159 individuals comprising three phyla, five classes, nineteen families and twenty three species were recorded. Iddo I, Iddo II, Ogudu and Agboiyi monitoring stations recorded very low individuals, but, relatively high number of polychaetes. Benthic macroinvertebrate community was dominated by the molluscs. Margalef’s index of species richness ranged from 0.79 to 2.57 while Shannon-Wiener index ranged from 0.40 to 2.19. Species evenness index ranged from 0.29 to 0.80. There was generally low biodiversity indicating the stressed nature of the study area.
The west of the Lagos lagoon, Nigeria has been subjected to lots of stress resulting from various... more The west of the Lagos lagoon, Nigeria has been subjected to lots of stress resulting from various anthropogenic activities around it. The sedentary nature of the benthic macrofauna makes them a very useful tool for assessing the health of this water body. Ecological study of these benthic organisms was conducted between January, 2007 and December, 2008 with the aim of using them to assess the pollution status of this part of the lagoon. Water and benthic samples were collected monthly and analysed in a standard laboratory. Results of the analysis of the physico-chemical parameters of water samples indicated that their temporal variation was controlled by the rainfall pattern while their spatial variation was controlled by proximity to sea and pollution sources. A total of 3,159 individuals comprising three phyla, five classes, nineteen families and twenty-three species were recorded. More individuals were recorded in the dry than in wet season. Iddo I, Iddo II, Ogudu and Agboiyi recorded very low individuals, but relatively high number of opportunistic species like the polychaetes. There was generally low biodiversity which indicates the stressed nature of the study area.
A study of the morphological and physiological respiratory adaptations to hypoxia of three nereid... more A study of the morphological and physiological respiratory adaptations to hypoxia of three nereid polychaete species from Roscoff, France coast axis of the English Channel was conducted. Result of the analysis of their notopodia showed that Nereis diversicolor had the greatest specific branchial surface area (SBSA) followed by Platynereis dumerilii while Perinereis cultrifera had the least. The affinity of their purified haemoglobins to oxygen, interpreted by the values of their P50, also followed the same pattern. The results of this study show that Nereis diversicolor, which lives in muddy sediment is better adapted to hypoxia than Platynereis dumerilii which lives in tubes under rocks and Perinereis cultrifera which lives in sandy sediments under rocks.
The Lagos lagoon, Nigeria receives lots of organic wastes from anthropogenic sources. The biodegr... more The Lagos lagoon, Nigeria receives lots of organic wastes from anthropogenic sources. The biodegradation of these wastes by aerobic microbes has resulted in the depletion of the dissolved oxygen. Study of this area of the lagoon was conducted for two years to investigate the impact of hypoxia on the distribution, abundance and diversity of benthic macroinvertebrates. Water and benthic samples were collected monthly along the study stretch and analysed in a standard laboratory. Temporal variation in water physico-chemistry was largely controlled by rainfall pattern while the spatial variation was influenced by proximity to the Harbour as well as the pollution sources and types. A total of 3,159 individuals comprising three phyla, five classes, nineteen families and twenty three species were recorded. Iddo I, Iddo II, Ogudu and Agboiyi monitoring stations recorded very low individuals, but, relatively high number of polychaetes. Benthic macroinvertebrate community was dominated by the molluscs. Margalef’s index of species richness ranged from 0.79 to 2.57 while Shannon-Wiener index ranged from 0.40 to 2.19. Species evenness index ranged from 0.29 to 0.80. There was generally low biodiversity indicating the stressed nature of the study area.
The west of the Lagos lagoon, Nigeria has been subjected to lots of stress resulting from various... more The west of the Lagos lagoon, Nigeria has been subjected to lots of stress resulting from various anthropogenic activities around it. The sedentary nature of the benthic macrofauna makes them a very useful tool for assessing the health of this water body. Ecological study of these benthic organisms was conducted between January, 2007 and December, 2008 with the aim of using them to assess the pollution status of this part of the lagoon. Water and benthic samples were collected monthly and analysed in a standard laboratory. Results of the analysis of the physico-chemical parameters of water samples indicated that their temporal variation was controlled by the rainfall pattern while their spatial variation was controlled by proximity to sea and pollution sources. A total of 3,159 individuals comprising three phyla, five classes, nineteen families and twenty-three species were recorded. More individuals were recorded in the dry than in wet season. Iddo I, Iddo II, Ogudu and Agboiyi recorded very low individuals, but relatively high number of opportunistic species like the polychaetes. There was generally low biodiversity which indicates the stressed nature of the study area.
A study of the morphological and physiological respiratory adaptations to hypoxia of three nereid... more A study of the morphological and physiological respiratory adaptations to hypoxia of three nereid polychaete species from Roscoff, France coast axis of the English Channel was conducted. Result of the analysis of their notopodia showed that Nereis diversicolor had the greatest specific branchial surface area (SBSA) followed by Platynereis dumerilii while Perinereis cultrifera had the least. The affinity of their purified haemoglobins to oxygen, interpreted by the values of their P50, also followed the same pattern. The results of this study show that Nereis diversicolor, which lives in muddy sediment is better adapted to hypoxia than Platynereis dumerilii which lives in tubes under rocks and Perinereis cultrifera which lives in sandy sediments under rocks.
Uploads
from Roscoff, France coast axis of the English Channel was conducted. Result of the analysis of their notopodia
showed that Nereis diversicolor had the greatest specific branchial surface area (SBSA) followed by Platynereis
dumerilii while Perinereis cultrifera had the least. The affinity of their purified haemoglobins to oxygen, interpreted
by the values of their P50, also followed the same pattern. The results of this study show that Nereis diversicolor,
which lives in muddy sediment is better adapted to hypoxia than Platynereis dumerilii which lives in tubes under
rocks and Perinereis cultrifera which lives in sandy sediments under rocks.
from Roscoff, France coast axis of the English Channel was conducted. Result of the analysis of their notopodia
showed that Nereis diversicolor had the greatest specific branchial surface area (SBSA) followed by Platynereis
dumerilii while Perinereis cultrifera had the least. The affinity of their purified haemoglobins to oxygen, interpreted
by the values of their P50, also followed the same pattern. The results of this study show that Nereis diversicolor,
which lives in muddy sediment is better adapted to hypoxia than Platynereis dumerilii which lives in tubes under
rocks and Perinereis cultrifera which lives in sandy sediments under rocks.