Towards improved understanding of the diversity and abundance patterns of the mid-ocean ridge macro- and megafauna

Mid-ocean ridges are vast features of all oceans but their fauna and ecological significance remain poorly understood. Ridge studies in recent decades were understandably biased in favour of the newly discovered chemosynthetic ecosystems. Investigations of photosynthesis-based systems and communities associated with ridges were scattered and few despite their much larger scale and significance for ocean productivity patterns and biogeography and for the management of human activities on the high seas. This knowledge gap was recognised by the Census Of Marine Life (CoML) programme and led to the initiation of a dedicated field project on non-chemosynthetic systems and communities of a mid-ocean ridge.

The present collection of articles highlights results from the project 'Patterns and Processes of the Ecosystems of the northern MidAtlantic' (MAR-ECO), the CoML field project that aims to explore the diversity and distribution patterns of photosynthesis-based communities of mid-ocean ridges by a range of classical and new technologies and methods. In 2003-2005, comprehensive investigations were conducted on pelagic and epibenthic macro- and megafauna of the Mid-Atlantic Ridge between Iceland and the Azores. Several research vessels participated in the first field phase of the project, but the majority of the results were from a 2-month 'international expedition on the Norwegian vessels RN. G. O. Sars and the chartered fishing vessel M.S. Loran in 2004. This introduction explains the background and goals of MAR-ECO, summarizes the strategies and sampling efforts, and briefly introduces future plans as the project enters a second field phase in 2007-2009. (c) 2007 Elsevier Ltd. All rights reserved.