Sediment texture plays an important role in the ecology of benthicinvertebrates [40,41]. The pelagic larvae of macrobenthic organismsbefore finally settling down at the bottom have to cross many barriers,and each type of bottom deposit will attract a very limited and selectedset of species [42]. A common concept in benthic animal-sedimentrelation is that the feeding type of the infauna is in one way correlatedto the sediments [43]. Deposit or detritus feeders constitute animportant and often dominating part of macrobenthic invertebrates[44]. Sediment character has been identified as one of the driving forcesin determining the macrofaunal communities. At station I, speciesdiversity is negatively correlated with sand (r=-0.986) while in stationII and III, positive correlation is obtained between density and silt(r=0.984 and r=0.887) at p<0.05 level (Table 4).This indicates that availability of silty soil sustains to macrofaunaldiversity and density, while sand dominance will reduce the macrofaunalpopulation. Clayey silt substrate is always known to support epifauna[45,46]. Food supply seldom acts as a limiting factor in the seasonalabundance of macrobenthos [47]. Organic nutrients enhance thegrowth of different types of algae that provide food resources for benthos[48]. In the present study, the higher density macrobenthos is observedduring summer season. Higher organic matter gets deposited duringthe post-monsoon season in the mangrove areas. It would be converted
into available organic carbon by various fungal and bacterial sources,
which in turn increase the macrobenthic forms especially polychaetes
[49]. High organic carbon induced abundance of macrofauna in
Coleroon estuary [50]. This confirmed that the abundance of benthic
fauna is highly related to organic carbon.
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