This study investigates the presence and characteristics of acid sulfate soils in the temperate coastal ecosystems of Australian mangroves, salt marshes, and paperbark forests, identifying their potential acidification risks. It further explores the impact of flooding and organic matter on the formation of acid sulfate soils in paperbark forests under rising sea levels and extreme sea level events. This thesis contributes to the broader understanding of ASS formation and management in temperate coastal wetlands. This research contributes to the practices aimed at preserving the ecological integrity of temperate coastal wetlands in Australia and potentially in similar ecosystems globally.