Impact of barge movement on phytoplankton diversity in a river: A Bayesian risk estimation framework

The adverse effect of barge movement on the river's aquatic ecosystem is of global concern. The phytoplankton community, a bioindicator, is possibly the foremost victim of the barge movement. This study hypothesized phytoplankton diversity loss induced by barge movement in a large river. This article presents a novel risk assessment framework to evaluate the hypothesis—with a goal to uncoupling phytoplankton diversity loss due to barge movement over a spatiotemporal scale. For this purpose, a study was conducted in the Bhagirathi-Hooghly stretch of Inland National Waterway 1 of India. This study has proposed a new index of diversity loss and its inferential framework based on full Bayesian Generalized Linear Mixed Model. The results have diagnosed significant barge-induced impact on the phytoplankton diversity and identified ten most impacted species. The proposed framework has successfully disentangled barge-induced phytoplankton diversity loss from the biological process and predicted a substantive overall risk of phytoplankton loss of 31.44%. Besides, it has uncoupled spatiotemporal differential estimates, suggesting a risk of diversity loss in order of ‘During vs After’ (38.0%) > ‘Before vs After’ (30.7%) > ‘Before vs During’ (24%) barge movement in temporal scale and increasing diversity loss along downstream. Finally, the instant study has highlighted the utility of these results to facilitate better water framework directive for inland waterways. •Developed a new barge movement-induced risk index of phytoplankton loss.•Proposed Bayesian GLMM uncoupled risk prediction discounting heterogeneity.•Predicted 31.44% risk of phytoplankton species loss due to barge movement.•Diatoms are the most vulnerable planktonic community to barge movement.•Results will facilitate strategic water management planning.