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Why can shallow barrier island lagoons be warmer than the open ocean during summer?
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lagoon
Lagoons lie behind the coral reef and barrier islands surrounding Raiatea and Tahaa in the Society Islands, Pacific Ocean.
Barrier island lagoons are often warmer than the open ocean during the summer primarily because of their shallow depth.1
Because these bodies of water are relatively shallow, their water temperatures closely approximate the ambient air temperature. During the summer months, this limited volume of water heats up more rapidly and reaches higher temperatures than the much larger, deeper mass of the open ocean. Conversely, this same characteristic causes them to become colder than the open ocean during the winter.1