According to a study led by Helga do Rosario Gomes, a biogeochemist at Columbia University’s Lamont-Doherty Earth Observatory, the growing spread of N octiluca scintillans , a species known as sea spark, a bioluminescent dinoflagellate that feeds on other species of plankton and extracts energy from the Sun through microscopic algae that live inside its cells, it is due to increased sewage flows in the Arabian Sea.
This abundance of plankton can have disastrous consequences for the predatory fish on which millions of people who live on the shores of this sea depend.
According to scientists, the tide of nutrient-rich sewage flowing from the increasingly populated cities that border the Arabian Sea is driving the spread of the Noctiluca , which turns water emerald green in winter, from the shores of Oman in the west, to India and Pakistan in the east.
The blooms are huge and will be devastating to the marine ecosystem in the long term. Very few animals are capable of feeding on Noctiluca, as it is too large a species for crustaceans that feed on diatoms, which can significantly modify the marine food chain.
Many fisheries in the Arabian Sea are already in slow decline . Fishermen from the Indian states of Tamil Nadu and Maharashtra say their catches have fallen in the last two decades.
The increased abundance of pufferfish off the coast of the southern Indian state of Kerala is also believed to be due to a sharp decline in cobia populations , while in Oman, the catch of large fish fell by 18 % in 2013 compared to the previous year.
The researchers who participated in the study, published in the journal Nature Communications , highlight that the millions of algae that live inside the green cells of Noctiluca scintillans allow this species to exploit dead zones without oxygen.
