Phytoplankton community indices in assessing the ecological quality status (EcoQS) of a coastal ecosystem (Thane Creek, India): Mono-metric vs multi-metric approach

Abstract

The ecological quality status (EcoQS) of Thane Creek which is surrounded by the urbanized and industrialized sector of Mumbai was assessed by considering six phytoplankton community indices. Sampling was carried out during Premonsoon to compare the efficiency of selected indices in the tropical setting. Principal component analysis (PCA) revealed anthropogenic inputs formed a major source of nutrient load into the creek. Ecostatus proposed by selected phytoplankton indices assigned a"moderate-good" status to phytoplankton zone (PZ)-I,"moderate-poor" to PZ-II while"bad" to PZ-III. Comparatively, the multi-metric phytoplankton index (MMPI) appeared to be the most efficient water quality index because of its capability in discriminating between acceptable and not acceptable EcoQS. The gradient of anthropic activities along the creek played a major role in deciding the EcoQS of Thane Creek. Limitations of all indices in evaluating environmental quality were also discussed in the present study. The investigation could provide a fillip to policymakers who are undertaking coastal water quality improvement initiatives.