Nemo and the
Zombie
Anemone
By: Alison Barrat
omparing a bleached anemone to the undead may be a bit of a stretch, but it is fair
to say a bleached anemone is hovering somewhere between life and death and depending on what happens next, it can go either way.
Scientists at the Khaled bin Sultan Living Oceans Foundation got a close look at the phenomenon of bleaching anemones during a research mission in the British Indian Ocean Territory. When we arrived in this massive Marine Protected Area (MPA) we saw thousands of corals competing for reef space in the shallow water. Sponges dotted the nooks and crannies of the reef and anemones clung to the open reef theirtentacles dancing back and forth with the waves. Thousands upon thousands of glittering fish filled the surrounding blue water. It was the kind of reef we had dreamed of seeing on the Global Reef Expedition.
Warm, sunny days with little wind made the diving easy, but the hot temperatures and calm seas we enjoyed belied their real impact. The ocean began to heat up. For stationary creatures of the reef, like corals and anemones, there is no escape from the rising temperature and excess light. In response, they begin to transform.
Coral bleaching may be more familiar than anemone bleaching, but these two processes are nearly identical. Some anemones host algae inside their bodies which gives them their color, both the anemone and the algae benefit from their partnership. The anemone provides the algae with carbon dioxide and othernutrients that they need to live, and in return the algae provide the anemone with oxygen and food like glycerol that the anemone needs. But this happy co-existence breaks down when the surrounding water gets too hot or when the anemones get exposed to too much light. Then the algae are expelled, or leave on their own, and the anemones become colorless and bleached white.
20 - SEVENSEAS
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