The eruption of the submarine volcano Tagoro at the island of El Hierro, Canary Islands, Spain: 5 years registering physical-chemical anomalies

Monday, 30 January 2017
Marina/Gretel (Hobart Function and Conference Centre)
Eugenio Fraile-Nuez1, J. Magdalena Santana-Casiano2, Melchor González-Dávila2, Carmen Presas-Navarro1, Juan-Tomas Vazquez1, Luis Miguel Fernández Salas3, Nieves López-González4, Maria Gómez-Ballesteros5, Olga Sánchez-Guillamón4, Desirée Palomino4, Olvido Tello5 and Vulcano Team, (1)Spanish Institute of Oceanography, Santa Cruz de Tenerife, Spain, (2)Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain, (3)Instituto Español de Oceanografía, Cádiz, Spain, (4)Instituto Español Oceanografia, Fuengirola - Malaga, Spain, (5)Instituto Español de Oceanografía, Madrid, Spain
Abstract:
On October 10 2011 an underwater eruption gave rise to a novel shallow submarine volcano south of the island of El Hierro, Canary Islands, Spain. During the eruption large quantities of mantle-derived gases, solutes and heat were released into the surrounding waters.

During the magmatic phase, from October 2011 to March 2012, extreme physical-chemical perturbations comprising thermal changes, water acidification, deoxygenation and metal-enrichment, resulted in significant alterations to the activity and composition of local plankton communities. The release of CO2 produced total inorganic carbon concentrations ranging from 4,000 to 7,500 μmol kg-1 causing water acidification of up to 2.8 units. These high CO2 levels generated high pCO2 waters with values ranging from 12,000 to 150,000 μatm at the surface. The area exhibit maximum concentrations of reduced sulfur and total Fe (II) species (200 and 50 μmol kg-1, respectively) and higher concentrations of dissolved Cu, Cd, Pb and Al with maximum values of 6.1, 6.7, 5.8 and 2,122 nM, respectively. These physical-chemical anomalies had a major impact on local pelagic communities. In that way, the volcano-affected area has exhibited responses that are occurring globally, making El Hierro into a unique natural laboratory where the principal climate change stressors are acting simultaneously. The results emerging from this volcanic eruption will help to improve our understanding of how future climate change may impact marine biota [1].

After March 2012, the area evolved to a hydrothermal system offering the opportunity to study both the dynamic associated to the degassing process and changes at the physical-chemical properties of the system. In order to keep monitoring the impact of the eruption, periodic multidisciplinary cruises were carried out during the last 5 years (Bimbache, Raprocan, Cetobapth, Vulcano-I-II and Vulcana).

This study and monitoring have been supported by funds from Spanish Institute of Oceanography (IEO) through BIMBACHE and VULCANA projects and FEDER and MINECO funds through VULCANO I-II projects (CTM2012-36317; CTM2014-51837-R).

[1] Fraile-Nuez et al., 2012. The submarine volcano eruption at the island of El Hierro: physical-chemical perturbation and biological response. Scientific Reports 2:486.

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