Metals in the environment can be transported through the air, oceans, freshwater, and land. Iron plays a crucial role in marine ecosystems. Trace metals in freshwater can vary in form and availability to living organisms. Plants and cyanobacteria can absorb heavy metals from the soil. Arsenic can be found in groundwater. Human activities can affect the cycling of antimony in nature. Microbes can transform radioactive elements, impacting the environment. Carbonates can provide insights into past oceans and climate changes.