Ocean acidification modulates the incorporation of radio-labeled heavy metals in the larvae of the Mediterranean sea urchin Paracentrotus lividus

© 2018 Elsevier Ltd The marine organisms which inhabit the coastline are exposed to a number of anthropogenic pressures that may interact. For instance, the accumulation of toxic metals present in coastal waters is expected to be modified by ocean acidification through e.g. changes in physiological performance and/or elements availability. Changes in bioaccumulation due to lowering pH are likely to be differently affected depending on the nature (essential vs. non-essential) and speciation of each element. The Mediterranean is of high concern for possible cumulative effects due to strong human influences on the coastline. The aim of this study was to determine the effect of ocean acidification (from pH 8.1 down to −1.0 pH units) on the incorporation kinetics of six trace metals (Mn, Co, Zn, Se, Ag, Cd, Cs) and one radionuclide (241Am) in the larvae of an economically- and ecologically-relevant sea urchin of the Mediterranean coastline: Paracentrotus lividus. The radiolabelled metals and radionuclides added in trace concentrations allowed precise tracing of their incorporation in larvae during the first 74 h of their development. Independently of the expected indirect effect of pH on larval size/developmental rates, Paracentrotus lividus larvae exposed to decreasing pHs incorporated significantly more Mn and Ag and slightly less Cd. The incorporation of Co, Cs and 241Am was unchanged, and Zn and Se exhibited complex incorporation behaviors. Studies such as this are necessary prerequisites to the implementation of metal toxicity mitigation policies for the future ocean. We discuss possible reasons and mechanisms for the specific effect of pH on each metals

New insight into marine alkaloid metabolic pathways: Revisiting oroidin biosynthesis

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Effects of increased pCO <inf>2</inf> on zinc uptake and calcification in the tropical coral Stylophora pistillata

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. © 2011 Springer-Verlag