Éditeur(s) : The Oceanography Society
Résumé : Submarine hydrocarbon seeps are geologically driven "hotspots" of increased biological activity on the seabed. As part of the HERMES project, several sites of natural hydrocarbon seepage in the European seas were investigated in detail, including mud volcanoes and pockmarks, in study areas extending from the Nordic margin, to the Gulf of Cadiz, to the Mediterranean and Black seas. High-resolution seabed maps and the main properties of key seep sites are presented here. Individual seeps show ecosystem zonation related to the strength of the methane flux and distinct biogeochemical processes in surface sediments. A feature common to many seeps is the formation of authigenic carbonate constructions. These constructions exhibit various morphologies ranging from large pavements and fragmented slabs to chimneys and mushroom-shaped mounds, and they form hard substrates colonized by fixed fauna. Gas hydrate dissociation could contribute to sustain seep chemosynthetic communities over several thousand years following large gas-release events.
Oceanography (1042-8275) (The Oceanography Society), 2009-03 , Vol. 22 , N. 1 , P. 92-109

Droits : 2009 by The Oceanography Society. All rights reserved. Permission is granted to copy this article for use in teaching and research. Republication, systemmatic reproduction, or collective redistirbution of any portion of this article by photocopy machine, reposting, or other means is permitted only with the approval of The Oceanography Society. Send all correspondence to: info@tos.org or The Oceanography Society, PO Box 1931, Rockville, MD 20849-1931, USA.
http://archimer.ifremer.fr/doc/2009/publication-6387.pdf
DOI:10.5670/oceanog.2009.11
http://archimer.ifremer.fr/doc/00000/6387/

Éditeur(s) : Nature Publishing Group
Résumé : Submarine mud volcanoes are important sources of methane to the water column. However, the temporal variability of their mud and methane emissions is unknown. Methane emissions were previously proposed to result from a dynamic equilibrium between upward migration and consumption at the seabed by methane-consuming microbes. Here we show non-steady-state situations of vigorous mud movement that are revealed through variations in fluid flow, seabed temperature and seafloor bathymetry. Time series data for pressure, temperature, pH and seafloor photography were collected over 431 days using a benthic observatory at the active Hakon Mosby Mud Volcano. We documented 25 pulses of hot subsurface fluids, accompanied by eruptions that changed the landscape of the mud volcano. Four major events triggered rapid sediment uplift of more than a metre in height, substantial lateral flow of muds at average velocities of 0.4m per day, and significant emissions of methane and CO2 from the seafloor.
Nature Communications (2041-1723) (Nature Publishing Group), 2014-11-11 , Vol. 5 , P. 1-8

Droits : 2014 Macmillan Publishers Limited. All rights reserved.
http://archimer.ifremer.fr/doc/00245/35601/34137.pdf
http://archimer.ifremer.fr/doc/00245/35601/34138.pdf
DOI:10.1038/ncomms6385
http://archimer.ifremer.fr/doc/00245/35601/

HERMES Newsletter, 2007 , N. 7 , P. 4

Droits : HERMES 2008
http://archimer.ifremer.fr/doc/00185/29669/28041.pdf
http://archimer.ifremer.fr/doc/00185/29669/28071.pdf
http://archimer.ifremer.fr/doc/00185/29669/