“The fish are migrating. They can’t get enough air here.” — Saleh al-Mashari, captain of a researcher vessel in the Gulf of Oman
They are an ancient, primordial race of tiny organisms called noctiluca scintillans. And for millenia they have lived undisturbed in the deep waters between Oman and India. But as human fossil fuel burning forced the world to warm, this 1.2 billion year old species was dredged up from the deep.
Growing atmospheric and ocean heat fed the great storms that make up India’s southern monsoon. And as these storms intensified, they churned the waters of the Gulf of Oman, drawing the ancient noctiluca scintillans up from below. As these dinoflaggelates reached the surface they encountered more food in the form of plankton even as they gained access to more sunlight. Meanwhile, the strengthening monsoons seeded surface waters with nutrients flushed down rivers and streams and into the ocean.
(Noctiluca blooms have become a common feature of the Gulf of Oman and the Arabian Sea. They have also recently appeared off New Zealand, Tasmania, and Hong Kong. Such blooms are a result of warmer waters, more intense storms, related increasing rates of soil nutrients flushing into the oceans due to more intense rainfall events, and other conditions consistent with human-caused climate change. Image source: FaHaD.)
In this newly favorable environment, noctiluca subsequently bloomed. Covering the ocean in a green mat by day and an oddly iridescent blue when disturbed by the waves at night.
Phytoplankton are the base of the marine food chain and noctiluca has been voraciously devouring this key nutrient source over a Mexico-sized stretch of ocean water during recent years. As the noctiluca blooms expanded, they emitted toxins and an ammonia smell that some in the region are calling sea stench. And as the great mats died and decayed, they have robbed the surrounding waters of oxygen.
As a result, mass fish kills have been reported and much of the local sea life has fled the region.
Earth’s environment usually changes slowly, over the course of thousands or tens of thousands of years. In the past, this has given life a chance to adjust. But the human-caused climate change that is spurring the massive noctiluca blooms in the Arabian Sea is bringing on these new conditions over the mere course of a few decades. Thirty years ago, there was no visible trace of noctiluca in the waters of the Gulf of Oman and Arabian Sea. Now, they have come to dominate.
The oceans beneath the noctiluca mats are now increasingly robbed of life. Oxygen levels are plummeting. The fish can’t breathe there. And one wonders if or when a dangerous and deadly follow-on of hydrogen sulfide producing microbes will begin to spread up from the bottom regions of these oxygen starved waters.
Hat tip to Andy in San Diego
Hat tip to Mulga