Observed evidence for the impact of coastal currents on the recurrent Noctiluca scintillans blooms in the northwest Indian Ocean coast

Recently, South Eastern Arabian Sea (SEAS) experiences recurrent winter blooms of green Noctiluca scintillans with serious ecological consequences. Here, the analysis of green N. scintillans blooms in SEAS for the past three consecutive years (2018-2021) is presented. The daily monitoring showed intense winter blooms during November with stable sea surface temperatures, high nitrate-phosphate concentrations and relatively lower pH levels. Dissolved oxygen concentration decreased to near hypoxia in the later stages of the bloom. Our analysis finds that the increased occurrence of N. scintillans blooms along SEAS is driven by the coastal currents (EICC), which transport the bloom species from the east coast (south west Bay of Bengal) to west coast of India. Therefore, the N. scintillans seeding from the South west Bay of Bengal intensifies winter blooms in SEAS, thus unveils the influence of oceanic currents in deciding the phytoplankton blooms across the coastal regions of north Indian Ocean.