observe all of. those particles are plankton which drift like snowflakes through the oceans the supply at those depths is meager so cold water corals grow slowly not more than fifteen metres in a thousand years. still the team have discovered astonishing coral formations. harm sions aphelion found very many reefs especially in the atlantic with coral mounds some more than three hundred meters tall. that s as tall as the eiffel tower the t.v. tower and berlin if that s really dig. absolute was a year. to find out more about how the reef may mauritania developed cloudy i ve been back and her colleagues collected samples of fossil coral from different layers they determined that it had been growing for a million years but then it stopped. side to begin.