title: Significant discharge of CO2 from hydrothermalism associated with the submarine volcano of El Hierro Island.
abstract: The residual hydrothermalism associated with submarine volcanoes, following an eruption event, plays an important role in the supply of CO2 to the ocean. The emitted CO2 increases the acidity of seawater. The submarine volcano of El Hierro, in its degasification stage, provided an excellent opportunity to study the effect of volcanic CO2 on the seawater carbonate system, the global carbon flux, and local ocean acidification. A detailed survey of the volcanic edifice was carried out using seven CTD-pH-ORP tow-yo studies, localizing the redox and acidic changes, which were used to obtain surface maps of anomalies. In order to investigate the temporal variability of the system, two CTD-pH-ORP yo-yo studies were conducted that included discrete sampling for carbonate system parameters. Meridional tow-yos were used to calculate the amount of volcanic CO2 added to the water column for each surveyed section. The inputs of CO2 along multiple sections combined with measurements of oceanic currents produced an estimated volcanic CO2 flux = 6.0 10(5) ± 1.1 10(5 )kg d(-1) which is ~0.1% of global volcanic CO2 flux. Finally, the CO2 emitted by El Hierro increases the acidity above the volcano by ~20%.
authors.affiliation: Instituto de Oceanografía y Cambio Global (IOCAG). Universidad de Las Palmas de Gran Canarias. Las Palmas de Gran Canaria. Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Santana-Casiano
authors.affiliation: Instituto Español de Oceanografía. Centro Oceanográfico de Canarias. 38180 Santa Cruz de Tenerife. Spain.
authors.forename: E
authors.initials: E
authors.lastname: Fraile-Nuez
authors.affiliation: Instituto de Oceanografía y Cambio Global (IOCAG). Universidad de Las Palmas de Gran Canarias. Las Palmas de Gran Canaria. Spain.
authors.forename: M
authors.initials: M
authors.lastname: González-Dávila
authors.affiliation: Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, and Pacific Marine Environmental Laboratory, NOAA, Seattle WA, USA.
authors.forename: E T
authors.initials: ET
authors.lastname: Baker
authors.affiliation: Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, and Pacific Marine Environmental Laboratory, NOAA, Seattle WA, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Resing
authors.affiliation: Pacific Marine Environmental Laboratory, NOAA, Seattle WA, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Walker