Satellite-Based Detection of Noctiluca Bloom in the Coastal Waters of the South-eastern Arabian Sea: A Case Study Implicating Monitoring Needs

The south-western coast of India recently witnessed an intense bloom of green Noctiluca scintillans (NS) that resulted in water discolouration, scummy surface layer, bioluminescent tides, and mass fish mortality. The Algal Bloom Information Service (ABIS) of the Indian National Centre for Ocean Information Services could efficiently provide information on the spatial extent of the bloom from its occurrence to disintegration. The initiation of the bloom was evidenced on 30 November, attained its peak on 12 December, and waned on 21 December 2021 with chlorophyll- a concentrations of 5.42, 3.01, and 0.33 mg m −3 , respectively, and with NS spread area of 3888, 10,608, and 48 Sq Km, respectively. Based on the information generated from ABIS, this manuscript addresses the ecosystem-disrupting algal bloom event and reiterates the need for autonomous coastal water quality observatories as a suitable alternative to field measurements to trace out the underlying factors responsible for the blooms and resultant harmful impacts on the ecosystem.