Mangrove ecosystems and microbial dynamics driving coastal heavy metal detoxification through phytoremediation

• Mangrove ecosystems function as natural biofilters for coastal heavy metals through coordinated phytoremediation and microbe-assisted detoxification mechanisms. • Taxon-dependent tolerance and accumulation strategies, particularly in Avicennia marina, enhance metal sequestration, antioxidant defense, and overall remediation efficiency. • Rhizosphere microorganisms transform, chelate, and immobilize toxic metals, synergistically reducing metal bioavailability and phytotoxicity. • Environmental drivers such as salinity, redox potential, sediment texture, and tidal dynamics critically regulate metal mobility and phytoremediation outcomes. Heavy metal (HM) contamination, including cadmium (Cd), lead (Pb), mercury (Hg), arsenic (As), and chromium (Cr), poses a critical threat to coastal ecosystems due to industrial effluents, mining, agricultural runoff, and urban wastewater, leading to bioaccumulation, microbial disruption, and impaired nutrient cycling. This review synthesizes current knowledge on the role of mangrove ecosystems in mitigating HM pollution through phytoremediation, integrating plant physiological adaptations, molecular detoxification pathways, and microbial-assisted metal transformations. Mangroves exhibit species-level metal tolerance mechanisms, including vacuolar sequestration, leaf shedding, antioxidant enzyme activation (SOD, CAT, APX), and expression of metal-binding proteins, phytochelatins (PC) and metallothioneins (MT), which collectively reduce metal bioavailability and protect essential tissues. Rhizosphere microorganisms further enhance detoxification by transforming toxic metal species, producing chelators and siderophores, and stabilizing sediments. Our study demonstrates that Avicennia marina exhibits superior accumulation, antioxidant response, and microbe-assisted detoxification compared with Rhizophora mucronata and Sonneratia alba , highlighting the importance of species selection for effective coastal remediation. Environmental factors such as salinity, redox potential, sediment texture, and tidal dynamics critically influence metal mobility and phytoremediation efficiency. The study underscores that integrating plant-microbe interactions with ecological considerations enhances HM detoxification, maintains coastal ecosystem resilience, and reduces risks to human health. These findings provide mechanistic insights and actionable knowledge for developing targeted, sustainable, and microbe-assisted mangrove-based remediation strategies, advancing the scientific understanding and practical implementation of nature-based solutions for coastal pollution management.