Bioaccumulation and release of heavy metals during growth and decomposition of cultivated Gracilaria lemaneiformis

Seaweeds are important primary producers and bioremediation materials, but its litter produced during growth and harvest is one of the restrictions to the sustainable development of seaweed cultivation. In this study, we conducted field investigation and indoor experiments to analyze the bioaccumulation and release of metals in Gracilaria lemaneiformis during the growth and decaying. The investigation revealed the 3.5 × 105 t (wet weight) G. lemaneiformis from a 1500 ha cultivation area bioaccumulated 1925–2353 kg Zn, 233.5–251 kg Cu, 70.5–80.5 kg Pb and 25.5–47 kg Cd, indicating that G. lemaneiformis is a good metals remover. The growth and decaying period of G. lemaneiformis releases, absorbs or adsorbs metals. It has the function of a “heavy metal pool”, simultaneously accumulate and release metals. G. lemaneiformis has a strong influence on heavy metals cycling in the seaweed cultivation ecosystem and provides a very good sample for biogeochemistry study for the globally seaweed sustainable development.