<span>An estuary is an
enclosed body of coastal water that is a mixture of saltwater and freshwater.
This type of body of water provides a transition zone between river
environments and maritime environments. This body of water is subject to both
marine influences (e.g. tides, waves, salt water) and river influences (e.g. flow
of fresh water and sediment) which provide high levels of nutrients in the
water and in the soil. Estuaries are known to be one of the most productive
natural habitats of different organisms on Earth.</span>
