Impact of recent volcanic eruptions in the Canary Islands on the physical-chemical and biological properties of the local marine environment

Abstract

Oceanic volcanism is a key process with the potential to alter all properties of the marine environment at different scales, along with a great impact on global biogeochemical budgets. The interaction between volcanoes and the ocean can occur in different forms: submarine volcanic eruptions, hydrothermal emissions, or the arrival of lava and ashes from a subaerial eruption to the ocean. However, the direct observation and instrumental monitoring of these processes is not a common occurrence, as they usually present important logistical challenges. In the Canary Islands, an archipelago with active intraplate volcanism, two eruptions have taken place this century so far, at the two youngest and most active islands: a submarine eruption at the southern coast of El Hierro island in 2011, and a subaerial eruption at the area of Cumbre Vieja in La Palma in 2021. In the first case, the submarine volcano named Tagoro erupted during 6 months, with dramatic consequences for the surrounding marine environment. However, after the eruption ended, the volcano evolved towards a hydrothermal system with diffuse flow which remains active, and the ecosystem was completely recovered in a few years. In the case of La Palma, the lava flows emitted from the subaerial volcano during 85 days of eruption made their way downslope until they reached the ocean, forming two lava deltas; these are new emerged platforms formed by the deposition of new volcanic materials over previous oceanic seafloor [...]