Assessment of the ecological health of Vellar and Ennore estuarine ecosystems using health indices

Abstract

Coastal and marine environments face various perturbations which include a variety of industrial wastes and other toxic compounds accruing from shore line industries. Dumping of fly ash slurry and coolant water from thermal power plant is known to affect the physico-chemical nature of the estuarine environment and thereby cause severe damage to the benthic organisms. To combat this, the European Water Framework Directive (WFD) developed a suite of health indices, of which, the AMBI (AZTI- Marine Biotic Index) index is proved to be efficient in assessing the ecological status of marine environment by using the macro benthic communities. In this backdrop, the present study was made to ascertain the ecological health of Vellar and Ennore estuarine regions using AMBI and M-AMBI (Multivariate- AZTI Marine Biotic Index) indices. The AMBI values (0.391 to1.13) and M-AMBI (0.92 to 0.96) calculated for the Vellar estuary indicated relatively undisturbed nature and high ecological quality while the values calculated for Ennore estuary (AMBI: 2.032 to 4.146 and M-AMBI: 0.27 to 0.76) signaled moderately disturbed nature and poor ecological quality of the system. The present study proves that there is an immense scope for application of AMBI & M-AMBI in ecological health assessment studies.