Tuesday, October 26

When the lava reaches the sea there will not be “an environmental catastrophe, quite the opposite”


The precedent of what will occur on the coast of La Palma if the lava from the Cumbre Vieja volcano reaches the sea is what happened in El Hierro. Next month marks the 10th anniversary of the submarine eruption in the Mar de las Calmas, on the coast of El Hierro. Just three years after the volcanic activity ended, there was already “a much richer and more productive marine ecosystem” than there was. “So why isn’t the same going to happen on La Palma?” Asks the physical oceanographer and researcher at the Spanish Institute of Oceanography Eugenio Fraile.

What will happen when the lava from the La Palma volcano reaches the sea?

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It seems like a huge contradiction. After the destruction of the first moment, marine life will emerge with more force thanks to the new nutrients that will have been deposited. At least, that’s how it happened in El Hierro. “Those compounds of silica, aluminum, iron, magnesium or calcium also reach the sea and there they undergo a process of alteration by the water, which releases these compounds and logically also provides many nutrients so that more underwater life develops” , confirms María José Hueras, a petrologist from the Department of Petrology and Geochemistry of the Faculty of Geological Sciences of the Complutense University of Madrid.

At first, as in its passage over the earth’s surface, the lava will destroy all organisms. Some fish will escape, but many others will die. “It must be taken into account that volcanic ash can also have a fertilizing effect in the area,” continues Fraile, who points out that the planned entry point is very close to the La Palma marine reserve.

In the Canary Islands there are three marine reserves: La Graciosa, La Palma and La Restinga-Mar de las Calmas. The marine reserve of La Palma It is located on the south western coast of the island, between Caleta de los Pájaros and Punta Gruesa, indicates the Ministry of Agriculture, Fisheries and Food on its website. The reserve begins about eight kilometers south of the area where the lava is expected to arrive. On the reserve of La Palma there is a great diversity of marine flora and fauna. In these waters you can find tropical anemones, brown algae, the Canary lobster, old (Cretan Sparisoma), salemas or even sea turtles.

VIDEO | Chronology in images of the first week of the eruption of the La Palma volcano

El Hierro as a guide

“We already have a background of what has happened in El Hierro “, he assures.” We know that, of course, in a first stage it will be something negative from an ecosystem point of view because only the action of the lava will bury the organisms that exist in the coastline “.

“Nobody can do anything”, laments the researcher. “But later we know that there may be a positive effect, we have seen it in El Hierro,” he says animatedly. Three years later, there was already “a much richer and more productive marine ecosystem.” “Organisms that are tied to the bottom, that cannot move, are going to die. They are going to be buried by lava that enters at 1,100 degrees Celsius.” This also happened on the neighboring island, but only two years later “the recolonization of this new substrate was impressive.”

Fraile adds that recent studies published in Science or the University of Hawaii confirm that washing when entering the water can produce a upwelling natural physique that can lead to “an enrichment of the marine ecosystem”.

But what is the upwelling exactly? It is a process of physical fertilization through upward movements of water. “The lava enters the sea and produces an effect that brings nutrient-rich bottom water to the surface”, defines Fraile. There is an effect similar to what happens “near the African coast, near the Canary Islands in the outcrop, there it is due to the wind and here it may be due to the intrusion of magma”.

“Nature has regeneration mechanisms”

For the expert, that lava reaches the sea is not dangerous for society, because the area has been delimited, and it will not be an environmental catastrophe. “We cannot stop nature, but nature has regeneration mechanisms, and we have found it, that they are fast and effective. In that sense, it will not be an environmental catastrophe, but quite the opposite. Volcanoes are life. Please Let it be understood that we speak from a scientific point of view “, specifies Fraile. “Yes, it will be destroyed in the first stage, but we already have the certainty that it will be able to recover soon and quite well,” he adds.

On the other hand, the moment the lava enters the sea, explosions will occur, steam columns will be generated and toxic gases will be produced. “But there is no danger,” says Fraile. “The whole area will be perfectly delimited, so no one will be able to breathe these gases emanating from contact with water.”

At the same time, a solidification process will take place that will generate “small marine platforms” that will advance in the sea and that could “collapse and continue to generate magma and small explosions.”

The lava has not yet reached the sea. At first, due to the rate at which the lava flowed down the island’s slopes in the first eruptive hours, it was thought that the magma would reach the coast during the second day of eruption. However, the rate of descent slowed and, after eight days, the lava had not reached the sea. Doubts then arose as to whether the meeting would take place. Throughout the week, the Cumbre Vieja volcano has had peaks and valleys of activity, something normal in strombolian eruptions, so the subsequent advance of the lava has not been constant.

The Institute of Oceanography of the Higher Council for Scientific Research has urgently mobilized its ship Ramón Margalef. The Marine Geology team has traveled to La Palma to carry out “a topometric survey” of the area, that is, a three-dimensional relief or reconstruction of the seabed “to compare with data that we already have prior, from before the eruption. “, concludes Fraile.

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