expelled, or leave on their own, and the anemones become colorless and bleached white.
But some anemones have more than one symbiotic relationship. As well as sharing their body tissues with algae, these anemones share their tentacles with clownfish. Sea anemones thrive in warm tropical waters on shallow reefs, home to hundreds of species of fish, some of which would quite like to eat a tasty chunk of anemone.Studies have shown that the clownfish may protect the anemone against predatory bites from butterflyfish. And, they can help the anemone in other ways like keeping it clean by removing debris or their waste may even supply some nutrients to theanemone. Studies also suggest that hosting a clownfish allowed certain anemones to evolve a larger diameter, which in turn created a large surface area for the algae to receive more light. The anemone, the algae, and the clown fish all benefit from the partnership.
The advantages to the anemone fish are fairly obvious; the anemone provides the fish with a home where it lives under the protection of the anemones many stinging
tentacles. When anemones and clownfish live together they depend on each other for survival. Without a host anemone most clown fish very quickly die on the reef,picked off by larger predatory fish.
As the water of the British Indian Ocean Territory kept warming, we watched as some corals went through a rainbow transformation becoming multicolored, some continued to look healthy and others turned a bleached white. The anemones faded into a colorless existence, their ghostly tentacles waving in the current while thebrilliantly colored anemonefish stuck with their ailing partner. Our research mission ended before the water temperature cooled and we were left with this faded image of BIOT’s reefs.
Because anemones get most of their nutrition from plankton and small fish, rather than symbiotic algae, many of them can survive bleaching if the water temperature goes back down, but studies show that their body size may shrink by over a quarter after they have bleached. Anemonefish living with them will similarly endure the bleaching, but produce fewer eggs the following year. As we face widespread bleaching this year, and the promise of more in the future if our ocean temperatures keep rising, we know that it is not only the corals that suffer during rising ocean temperatures. Bleaching diminishes the reef in ways that we are just beginning to understand reducing the overall health and sustainability of the entire ecosystem.
24- SEVENSEAS