Effects of increased pCO₂ on zinc uptake and calcification in the tropical coral Stylophora pistillata

摘要

Zinc (Zn) is an essential element for corals. We investigated the effects of ocean acidification on zinc incorporation, photosynthesis, and gross calcification in the scleractinian coral Stylophora pistillata. Colonies were maintained at normal pH_T (8.1) and at two low-pH conditions (7.8 and 7.5) for 5 weeks. Corals were exposed to 65Zn dissolved in seawater to assess uptake rates. After 5 weeks, corals raised at pH_T (8.1) exhibited higher 65Zn activity in the coral tissue and skeleton, compared with corals raised at a lower pH. Photosynthesis, photosynthetic efficiency, and gross calcification, measured by 45Ca incorporation, were however unchanged even at the lowest pH.