The apple snail is a keystone species in Pantanal's ecosystem. When the wetlands are flooded once a year, the grass and other plants will eventually die and start to decay. During this process, decomposing microbes deplete the shallow water of all oxygen, suffocating larger decomposers. Unlike other decomposing animals, the apple snails have both gills and lungs, making it possible for them to thrive in anoxic waters where they recycle the nutrients. To get oxygen, they extend a long snorkel to the water surface, pumping air into their lungs. This ability allows them to consume all the dead plant matter and turn it into nutritious fertilizer available for the plants in the area. The snails themselves are also food for a variety of animals.