Benthic ecological mapping of the Ayeyarwady delta shelf off Myanmar, using foraminiferal assemblages

Abstract

Information on benthic ecologies is a prerequisite to evaluate marine resources, their management and monitoring the impact arising from their exploitation. In the present study, benthic foraminiferal distributions from 124 surface sediment samples covering a total area of about 2,00,000 km2 of the Ayeyarwady Continental Shelf are studied. 713 benthic species belonging to 222 genera are identified and illustrated herein. The assemblage leads to the assignment of the study-area to the Indo-Pacific foramo-geographic province. The generic abundances have been subjected to R-mode cluster analysis in order to group stations with similar ecologies. the cluster analysis revealed three major clusters: cluster a represents the modern coral reefs in the study area; cluster b represents the near shore low salinity regimes whereas the last cluster c represents outer shelf and slope regimes. these clusters have been described in terms of their constituent taxa, sediment texture and spatial distribution, which interestingly follow the benthic salinity regime in the study area. The present study indicates that the salinity gradient prevalent on the ayeyarwady Delta Shelf controls its benthic environment. the present work serves as a ready-reconnaire for foraminiferal workers in the Indo-Pacific regime