Metallic nanoparticle enrichment at low temperature, shallow CO seeps in Southern Italy

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Authors

Colleges, School and Institutes

External organisations

  • University of Birmingham, Birmingham, B15 2TT, UK
  • Plymouth University
  • PLYMOUTH MARINE LABORATORY
  • University of Palermo
  • Department of Environmental Sciences / Center of Excellence in Environmental Studies, King Abdulaziz University, PO Box 80203, Jeddah, 21589, Saudi Arabia

Abstract

We report on metal enrichment along a natural pH gradient owing to increased CO degassing at cold, shallow seeps of Vulcano Island in the Mediterranean Sea, off Sicily. We assessed composition of unfiltered and filtered seawater (<100nm) along acidic zones ranging between ambient and pH 5, and showed that most seep derived elements are present as nanoclusters which then aggregate into larger colloids while mixing with ambient seawater along a pH gradient. Size and elemental composition of such naturally occurring nanoparticles assessed by modern characterisation methods were in good agreement with the results from conventional analytical methods.We provide analytical evidence for the presence in the water column of a large fraction of seep derived elements (e.g. approximately 50% of iron, over 80% of Mn, 100% of Cr, S and Zn) in the form of nano sized particles (e.g. <100nm) even at typical open ocean pHs. We launch in situ sampling protocols and sample preparation procedures for multi-method suitable to obtain accurate measurements on nanoparticles from environmental samples. Based on our results a first insight to the formation of natural nanoparticles at cold CO seeps is presented and the persistence of such nano-clusters in the surrounding seawater is stipulated.

Bibliographic note

Copyright 2012 Elsevier B.V., All rights reserved.

Details

Original languageEnglish
Pages (from-to)24-32
Number of pages9
JournalMarine Chemistry
Volume140-141
Publication statusPublished - 20 Aug 2012