What is an example of mutualism in estuary?

One example of mutualism in an estuary is the relationship between fiddler crabs and mangrove trees. Fiddler crabs live in burrows in the mudflats of estuaries, and they feed on the organic matter that is found in the mud. Mangrove trees grow in the intertidal zone of estuaries, and they have a complex root system that helps to stabilize the sediment. The roots of the mangrove trees also provide a habitat for the fiddler crabs, and the crabs help to aerate the soil around the roots of the trees. This relationship is beneficial to both the fiddler crabs and the mangrove trees, and it is an example of mutualism.