The Submarine Volcano Eruption off El Hierro Island: Effects on the Scattering Migrant Biota and the Evolution of the Pelagic Communities |
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| Authors: | Alejandro Ariza Stein Kaartvedt Anders R?stad Juan Carlos Garijo Javier Arístegui Eugenio Fraile-Nuez Santiago Hernández-León |
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| Institution: | 1. Instituto de Oceanografía y Cambio global, Universidad de Las Palmas de Gran Canaria, Las Palmas, Canary Islands, Spain.; 2. Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Makkah, Saudi Arabia.; 3. Instituto Español de Oceanografía, Centro Oceanográfico de Canarias, Santa Cruz de Tenerife, Canary Islands, Spain.; University of Connecticut, United States of America, |
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| Abstract: | The submarine volcano eruption off El Hierro Island (Canary Islands) on 10 October 2011 promoted dramatic perturbation of the water column leading to changes in the distribution of pelagic fauna. To study the response of the scattering biota, we combined acoustic data with hydrographic profiles and concurrent sea surface turbidity indexes from satellite imagery. We also monitored changes in the plankton and nekton communities through the eruptive and post-eruptive phases. Decrease of oxygen, acidification, rising temperature and deposition of chemicals in shallow waters resulted in a reduction of epipelagic stocks and a disruption of diel vertical migration (nocturnal ascent) of mesopelagic organisms. Furthermore, decreased light levels at depth caused by extinction in the volcanic plume resulted in a significant shallowing of the deep acoustic scattering layer. Once the eruption ceased, the distribution and abundances of the pelagic biota returned to baseline levels. There was no evidence of a volcano-induced bloom in the plankton community. |
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