International Journal of Marine Science, 2017, Vol.7, No.12, 102-113
102
Research Article
Open Access
Occurrence and Distribution of Macrobenthos in Relation to Physico-chemical
Parameters in the Lower Meghna River Estuary, Bangladesh
Abu Sayeed Muhammad Sharif
1
, Shafiqul Islam
2
, Mohidul Islam
3
1 Bangladesh Oceanographic Research Institute, Cox’s Bazar, Bangladesh
2 Institute of Marine Science and Fisheries, University of Chittagong, Bangladesh
3 Bangladesh Fisheries Research Institute, Cox’s Bazar, Bangladesh
Corresponding email:
International Journal of Marine Science, 2017, Vol.7, No. 12 doi:
Received: 08 Mar., 2017
Accepted: 31 Mar., 2017
Published: 03 May, 2017
Copyright © 2017
Sharif et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article
:
Sharif A.S.M., Islam S., and Islam M., 2017, Occurrence and distribution of macrobenthos in relation to physico-chemical parameters in the lower Meghna
River estuary, Bangladesh, International Journal of Marine Science, 7(12): 102-113 (doi:
Abstract
Present study was conducted in the lower Meghna River and its Estuary at Chandpur, Barisal, Bhola, Hatiya and Sandwip
during monsoon and post-monsoon season. A total of 17 major taxa were identified of which 10 and 15 were recorded during
monsoon and post-monsoon season respectively. Macrobenthos abundance was comparatively greater during post-monsoon than
monsoon. The water at lower Meghna was slightly acidic in both seasons. Salinity, soil pH and water temperature were found to be
responsible for the variations in benthos assemblage (p<0.05). Canonical Corresponding Analysis (CCA) also indicated that most of
the macrobenthos had close dependency to salinity, water temperature, soil pH, organic carbon and organic matter both in monsoon
and post-monsoon. Benthos diversity (H') did not show much temporal variation (0.92±0.52 and 0.85±0.40 for the monsoon and
post-monsoon seasons respectively). The highest macrobenthos diversity (H') was 1.53 at Bhola and the lowest was 0.29 at Chandpur
both during the monsoon season. The macrobenthos evenness (J') also showed less variation between seasons (0.64±0.32 and
0.51±0.26 during monsoon and post-monsoon respectively). The maximum evenness value was found at Sandwip (0.95) during the
monsoon season whereas the minimum value was at Barisal (0.20) during the post-monsoon.
Keywords
Macrobenthos; Occurrence; Distribution; Biodiversity; Water and soil physico-chemical parameters; Lower Meghna
River; Estuary
Introduction
The Ganges is one of the most important river systems of the Indian subcontinent. It flows about 2,510 km from
the Himalayas to the north, central and southeast India, then enters in Bangladesh as the Padma river and is joined
by the Brahmaputra; the joint flow of the Padma-Brahmaputra as Padma again is joined by the Meghna River (the
name by which it is known thereafter); finally, it ends in the Bay of Bengal forming the huge Meghna river estuary.
At the Bay, the Meghna estuary is about 30 km (20 miles) wide. The confluence of marine and limnetic ecosystem
considered as estuaries, is one of the most productive natural habitats on earth (Alongi, 1998). Bangladesh is
blessed with this widespread estuarine that is regularly influenced by the strong interactions of biotic and abiotic
factors (Kamal and Khan, 2009) due to tropical monsoon (southerly or southwesterly winds) and winter (north
and northwest winds).
Biodiversity is a function of species richness and evenness with which the individuals are distributed (Margalef,
1958). Benthos is organisms that inhabit in the bottom of lakes, ponds and river (Khan et al., 2007) as well as
other aquatic systems. They are subjected to tropical cycles and erosion (Hossain, 2011). Many macrobenthic taxa
serve as direct food for organisms in higher trophic levels and play significant role in mineralization (Lind, 1979)
and this may facilitate to evaluate water quality (Milbrink, 1983). Macrobenthic fauna are greatly influenced by
nutrient cycles, primary productivity, decomposition, and translocation of materials (Wallace and Webster, 1996).
The abundance and distribution of macrobenthos are greatly affected by several physical and chemical variables,
such as depth, water current, organic matter, pollution, sediment toxicity and sedimentation processes (Pearson,
1970). Many environmental factors (i.e. food supply, water salinity, oxygen concentrations, currents, temperature,
