Risks of mercury release from disturbance of blue carbon ecosystems

Unofficial AI-generated summary based on the public title and abstract. Not an official translation.

🔬研究者:Provides a quantitative framework linking BCE disturbance to mercury release, with a first-order global estimate and hotspot mapping.

🏢実務担当者:Coastal managers and conservation planners should consider mercury remobilization risks when designing blue carbon restoration or protection projects.

🏛政策担当者:Highlights the need to integrate legacy mercury governance with climate mitigation under the Minamata Convention and national adaptation strategies.

Blue carbon ecosystems (BCEs) function as dual repositories of organic carbon and legacy contaminants. While BCEs are recognized carbon sinks, their role as mercury (Hg) sinks and the risk of their conversion into sources due to human and climatic disturbances remain unexplored. This review synthesizes current knowledge on the drivers and risks of contaminant remobilization from threatened BCEs, with a primary focus on mercury. We explore how natural and human disturbances influence Hg storage, release, and bioavailability, while evaluating the risks posed to ecosystems and human health. Through a three-level meta-analysis, we show that physical disturbance remobilizes approximately 54% (95% CI: 8% to 77%) of sediment-bound metals from coastal sediments. Applying this fraction to published BCE Hg stock and loss-rate data, we derived a first-order estimate of 26 (95% CI: 3.9 to 40.8) Mg of total mercury (THg) released annually from BCE degradation and loss worldwide, a flux that offsets approximately 60% of annual BCE Hg burial capacity. The proportion of this bulk THg flux subsequently converted to bioavailable methylmercury (MeHg) depends on local redox conditions and microbial activity, and remains an important uncertainty. We organized the biogeochemical cascade linking sediment disturbance to ecological exposure into two temporally overlapping phases, an immediate physical and chemical release and a delayed biogeochemical exchange, and identified compound disturbance amplification as a critical but previously unrecognized mechanism by which sequential stressors produce non-additive Hg release. Additionally, we identified global BCE-derived Hg risk hotspots through a five-dimensional, evidence-weighted framework applied to 17 UN M49 sub-regions, classifying East Asia, Latin America and the Caribbean, Sub-Saharan Africa, and three Pacific Island sub-regions as Tier 1 high-risk priorities where multiple risk dimensions converge. These findings reframe BCE conservation as simultaneously a carbon, contaminant, and food-security imperative, underscoring the need for legacy-Hg governance alongside atmospheric emission controls under the Minamata Convention.

• openalex https://doi.org/10.1016/j.earscirev.2026.105622first seen 2026-07-13 06:05:24