The Age Newspaper had an interesting article on the value seagrass performs as a sink for absorbing carbon dioxide. Research has demonstrated that seagrass areas are 40 times faster than a rain forest in fixing carbon.

So these areas are certainly a unique environmental habitat needing protection.   A significant area of seagrass meadows exists in Stingaree Bay where it is under threat from inappropriate development.  Canals with housing will lead to increase pollutants entering the bay particularly phosphorous promoting algae growth at the expense of the important marine seagrass.  

Article from The Age on Seagrass