Alex Mustard - Jelly Swarm
An aggregation of golden jellyfish (Mastigias sp.) above a fallen tree in a marine lake in Palau, the golden colour of this species comes from symbiotic algae in its tissues. This is in a marine lake that has been isolated from the sea for around 20,000 years. Water can seep in through the limestone rocks, but the jellies are trapped.Over this time they have evolved a new way of life. Loosing their stings and instead farming algae in their tissues. Each day the jellyfish migrate around the lake by day to stay in the sunny spots for the benefit of their algae (and therefore their own food supply). They jellyfish also avoid the edges of the lake for that is where white jellyfish eating anemones are attached to the bottom, visible here on the branches of a fallen tree.
Location: Jellyfish Lake, Eil Malk island, Rock Islands, Palau. Tropical north Pacific Ocean.