An experimental study of the gorgonian coral Subergorgia suberosa response to polluted sea water from a former coastal mining site in Taiwan.

Abstract

The response of the gorgonian coral Subergorgia suberosa to heavy metal-contaminated seawater in the Yin-Yang Sea of Liang-Dong Bay, a former mining site in northeastern Taiwan, was investigated. Subergorgia suberosa bioaccumulation and tissue injury were recorded and examined throughout the study period. Heavy-metal concentrations in tissues of the corals showed a significantly increasing trend with incubation time. Cu, Zn, and Cd each showed characteristic bioaccumulation in this soft coral. Metallic Zn accumulated, but rapidly dissipated. In contrast, Cu easily accumulated, but was slow to dissipate, and Cd was only slowly absorbed and dissipated. Our results indicate that significant bioaccumulation of heavy metals occurred in S. suberosa coral. Histopathological and scanning electron microscopic results identified polyp necrosis, mucus secretion, tissue expansion, and increased mortality in S. suberosa corals exposed to water polluted with heavy metals.