Eco-resilience of China’s mangrove wetlands: The impact of heavy metal pollution and dynamics

Mangrove forests in China have significantly degraded over the past several decades primarily due to rapid economic growth and land reclamation for aquaculture and infrastructure development. Among various threats, heavy metal pollution, primarily from urbanization, agricultural runoff, and industrial runoff, poses a substantial risk to mangroves in China. It impairs their ecological functions, limiting biodiversity and reducing their natural ability to sequester carbon and detoxify coastal areas. Despite these challenges, the mangrove ecosystem's resilience in China has not been completely compromised. Natural adaptations and phytoremediation mechanisms, such as limiting metal uptake, excreting metal binding proteins, upregulating antioxidants, forming Fe plague, excreting metals through salt glands, and tolerance to specific metal concentrations, help mitigate heavy metal toxicity. However, these adaptive strategies are limited by the extent of pollutants and the speed at which these pollution factors arise. This review highlights a need to shift restoration efforts from expanding mangrove areas to enhancing ecosystem integrity, with a specific focus on reducing heavy metal pollution through phytoremediation. It also examines how heavy metal interactions at the sediment-water interface impact microbial communities and local fauna, contributing to climate change. Addressing these challenges is critical to improving mangrove conservation in China and ensuring the long-term health and resilience of these critical ecosystems for future generations.