Oysters have an incredible ability to filter and remove pollutants from waterways, pumping water through their shells and taking out algae, sediment, bacteria and excess nitrogen as they feed.
Oyster reefs also provide a habitat for hundreds of species of plants and invertebrates, but despite enhancing the environment, 85 percent of oyster reefs have been lost worldwide.
Juliana Schatz travels to the east coast of the US to see how marine conservationists are trying to get these vital habitats flourishing again.
earthrise can be seen each week at the following times GMT: Tuesday: 2230; Wednesday: 0930; Thursday: 0330; Friday: 1630; Saturday: 2230; Sunday: 0930; Monday: 0330; Tuesday: 1630.
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Source: Al Jazeera