Concentrations of Fe, Mn, Cu, Zn, Co, Ni, Pb, Cd, B, and SiO2 in interstitial waters from bottom sediments of the Atlantis II and Discovery Deeps, Red Sea rift zone

Chemical analyzes show that interstitial waters from ore-bearing bottom sediments of the Atlantis II and Discovery Deeps are enriched in Fe, Mn, Cu, Ni, Co, Zn, Pb, and Cd compared to sea water. Enrichment factors of these trace elements in the interstitial waters of the Atlantis II Deep relative to the sea water vary within the following ranges: for Fe from 100 to 7000, for Mn from 19047 to 32738, for Zn from 500 to 1600, for Pb from 78333 to 190000, for Cu from 107 to 654. Comparison of average weighted concentrations of Fe, Mn, Zn, Pb, Cu, Ni in the bottom sediments and the interstitial waters of the Atlantis II Deep indicates common regularities and good relationship in distribution of these elements along sediment cores. Differences in concentrations and distribution of the studied trace elements in the interstitial waters of the Atlantis II and Discovery Deeps result from different chemical compositions of hydrothermal fluids entering these deeps.

Seawater carbonate chemistry, calcification and Zn uptake during experiments with coral Stylophora pistillata, 2011

Many studies have investigated the effect of an increase in pCO2 on coral calcification and photosynthesis but the physiological consequences are still relatively speculative. We investigated the effects of ocean acidification on zinc incorporation and gross calcification in the scleractinian coral Stylophora pistillata. Zn is an essential element for health and growth of corals. Colonies were maintained at normal pHT (8.1) and at two low-pH conditions (7.8 and 7.5) during 5 weeks. Corals were exposed to 65Zn dissolved in seawater to assess uptake rates of this element. After 5 weeks, 65Zn activity measured in the whole coral and in the two compartments: tissue and skeleton, differed significantly between pH conditions with concentration factors higher at pHT 8.1, compared to lower pH. Zn is therefore taken less efficiently by corals at reduced pH. Their gross calcification, as measured by 45Ca incorporation, photosynthesis and photosynthetic efficiency did not change with pH even at the lowest level.