The inland waters surrounding Charleston SC hosts a variety of wildlife, from tiny microbes to modern day megafauna. A wealth of microscopic organisms help break down contaminants that are harmful to other parts of the ecosystem. In addition a large, healthy Eastern Oyster population is essential, as during the course of their feeding, they filter through 30-50 gallons of water helping to purify it even more. This process of filtration that the marsh is so involved in is important for the sake of itself and its inhabitants but also for the survival and maintenance of those adjoining ecosystems.
The salt marsh serves as a buffer between the mainland and the islands of the outer coast, swelling as fresh water from rain fall makes its way toward the ocean, bringing along with it all kinds of pollution from pesticides and fertilizers as well as sources of contamination naturally found in the sediment in the surrounding areas. This swelling helps absorb excess water and mitigate flooding but the time that the runoff spends in the marsh also allows for those dangerous chemicals to be broken down my microbes and oysters so that the waters on the outer coast are fairly protected from inland pollutants. Similarly, if contaminants come from the outer coast they will be filtered by the marsh and a degree of safety will be shed upon those creatures that take refuge within it and along its coasts.
The buffer that is the tidal salt marsh has the amazing effect of bringing so many different strange creatures together. At high tide ocean faring creatures are able to take advantage of deeper inland waters to prey on unsuspecting foe and thus all kinds of predators move into these more narrow water ways as they are over taken by a generous high tide that can average six feet. Then, as the water recedes, in succession all such beasts of all sizes must make their way back into bigger seas.
However some of its inhabitants are more careful and stick to what they know. For example, there are two ecotypes of bottlenose dolphins in the charleston area. Transient dolphins live mostly offshore and are more difficult to track because they move over a larger area of more open ocean. Resident dolphins however have developed unique behaviors that they have adapted for life within the salt marsh estuaries. These local dolphins live in pods of about 20-30 individuals and are identified by photographs of their dorsal fins. Resident pods have seemingly overlapping territories with an average range of only about 40 miles but they are rarely, if ever, spotted offshore. It has been postulated that the marsh has protected them from contaminants that killed and beached many offshore, transient dolphins. It is for this reason that some speculate that they physically isolate themselves by not taking the risk of going offshore. This allows for the development of notably different behavioral sets and sets the dolphins along the coast of SC apart. There is no better way to get a good look at one of our local resident dolphins than to hop in a kayak or a small power boat and float around in the inland waters.