The increasing global use of rare earth elements (REEs) in high-technology industries has raised concerns about their release, persistence, and accumulation in marine environments. Although REEs were historically considered to exhibit relatively low toxicity, emerging evidence indicates that REEs act as ecological stressors, particularly for marine invertebrates that play fundamental roles in the structure and functioning of coastal ecosystems. This review synthesizes current knowledge regarding the occurrence, environmental distribution, and biological effects of REEs across major marine invertebrate groups, including mollusks, arthropods, and echinoderms. Reported effects include oxidative stress, altered enzymatic activity, impaired development and calcification, disturbed ion homeostasis, behavioral alterations, and trophic transfer. Mechanistic pathways are further examined, with an emphasis on cellular uptake, reactive oxygen species generation, membrane destabilization, and interference with calcium- and magnesium-dependent physiological processes. Building on this ecological risk perspective, the review also evaluates the mitigation potential of brown macroalgae, whose alginate- and fucoidan-rich cell walls exhibit strong binding affinity for REEs through biosorption. Evidence indicates that dried or processed macroalgal biomass can efficiently remove both light and heavy REEs from seawater, offering a nature-based strategy to reduce REE exposure in vulnerable marine invertebrate communities. A conceptual framework is proposed that integrates macroalgal biosorption with environmental monitoring, risk assessment, and coastal management. Key research gaps include defining chronic toxicity thresholds, identifying synergistic interactions with co-occurring pollutants, understanding long-term ecosystem consequences, and evaluating the scalability of biosorption systems under realistic field conditions. Overall, REEs represent a growing concern to marine biodiversity, while brown macroalgae represent a promising and nature-based approach for mitigation.
Mohammadpour et al. (Sat,) studied this question.