Journal Article

The influence of high pCO2 on otolith shape, chemical and carbon isotope composition of six coastal fish species in a Mediterranean shallow CO2 vent

Mirasole, Alice, Vizzini, Salvatrice, Capasso, Giorgio, Reis-Santos, Patrick, Gillanders, Bronwyn May, Scopelliti, Giovanna, Grassa, Fausto, Mazzola, Antonio

2017

Overview

Naturally acidified environments, such as CO 2 vents, are important sites to evaluate the potential effects of increased ocean acidification on marine ecosystems and biota. Here we assessed the effect of high CO 2 /low pH on otolith shape and chemical composition of six coastal fish species ( Chromis chromis , Coris julis , Diplodus vulgaris , Gobius bucchichi , Sarpa salpa , Symphodus ocellatus ) in a Mediterranean shallow CO 2 vent. Taking into consideration the major and trace elements found near the vent and the gradient of dissolved inorganic carbon, we compared the otolith chemical signatures of fish exposed long-term to elevated CO 2 emissions and reduced pH (mean pH 7.8) against fish living in two control sites (mean pH 8.2). A number of element:Ca ratios (Na:Ca, Mg:Ca, Mn:Ca, Cu:Ca, Zn:Ca, Sr:Ca, Ba:Ca and Pb:Ca), along with isotope ratios, were measured in otoliths (δ 13 C and δ 18 O) and water (δ 13 C DIC ) samples. Additionally, we performed otolith outline shape and morphometric analysis to evaluate the effect of high CO 2 /low pH. We observed species-specific responses with regards to both shape and chemical signatures. Significant differences among sites were found in otolith shape (elliptical Fourier descriptors) of G. bucchichi and D. vulgaris . Elemental and isotopic signatures were also significantly different in these site attached species, though not for the other four. Overall, the carbon isotopic composition seems a good proxy to follow pH gradient in naturally acidified area. Ultimately, besides improving our knowledge of the effects of high CO 2 /low pH on otoliths, the present results contribute to our understanding on their use as natural tags.

• Publisher: Springer,Springer Berlin Heidelberg,Springer Nature B.V
• Subject: Acidification / Animal populations / Barium / Biomedical and Life Sciences / Biota / Carbon / Carbon dioxide / Carbon dioxide emissions / Carbon isotopes / Chemical composition / Chromis / Coasts / Composition effects / Copper / Coris julis / Diplodus vulgaris / Dissolved inorganic carbon / Ecosystems / Fish / Freshwater & Marine Ecology / greenhouse gas emissions / Habitats / Inorganic carbon / Isotope composition / Isotope ratios / Isotopes / Life Sciences / Magnesium / Manganese / Marine & Freshwater Sciences / Marine biology / Marine ecosystems / Marine invertebrates / Microbiology / Morphometry / Ocean acidification / Oceanography / Original Paper / Otoliths / oxygen / pH effects / Ratios / Sarpa salpa / Shape / Species / stable isotopes / Strontium / Symphodus / Tags / Trace elements / Vents / Zinc / Zoology