As the water flows over the reef flat, its velocity decreases. Previous investigations had shown a negative correlation between distance from the reef crest and water velocity that is, the water slows down as it flows over the reef flat. The researchers used their results to formulate a new hypothesis : The rate of uptake of nitrate ions from the water by the organisms on the reef is determined by the rate of flow of water across them. Explain why the velocity of the water decreases as it flows over the reef flat