Hey there, time traveller!
This article was published 12/7/2013 (1244 days ago), so information in it may no longer be current.
Floating through water, jellyfish look ethereal and delicate. But research is showing jellyfish are much hardier than many realize.
According to Stung!, by biologist Lisa-ann Gershwin, jellyfish have few predators and thrive in warm water. Jellyfish are an indicator of the oceans' overall health, or lack thereof, the book says. Water environments that are more favourable to jellies -- warm and acidic, due in large part to pollution, overfishing, coastal construction and other man-made influences -- are toxic to other sea life.
-- Washington Post