What causes jellyfish blooms? – The Hindu

Mention jellyfish and the first thought that comes to mind is “Watch out! Jellyfish can sting!” Actually, not all species of jellyfish sting humans. But all jellyfish are capable of showing a peculiar behaviour. They may congregate in thousands in certain parts of the ocean. Imagine the sight: miles and miles of the ocean’s surface covered by these colourful translucent creatures. At night, some even sparkle with bioluminescence to scare off their enemies. This strange phenomenon is described as a jellyfish bloom.

What causes a jellyfish bloom? A change in ocean currents, warmer waters caused by global warming, and a sudden surge in nutrients (eutrophication) can offer ideal conditions for these very simple balloon-like marine animals to multiply. But where do the excess nutrients come from? Mainly from human activities that result in agricultural run-off, untreated sewage discharge, or industrial waste.