Wednesday, October 27

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


The lava from the new La Palma volcano that has erupted this Sunday has not yet reached the sea, the speed of the wash has slowed down in the last hours, but the forecast is that it will do so sooner rather than later after traveling the island from the point of explosion, in Cabeza de Vaca (El Paso), destroying everything in its path. As the experts have explained, when coming into contact with the ocean, the lava, which is at about 1,100 degrees Celsius, and the salt water, at about 20, would produce a thermal contraction that would cause a white smoke harmful to health due to the toxic substances it contains. The professor of Geology at the University of Las Palmas de Gran Canaria (ULPGC), José Mangas, explains it like this:

The AEMET sees acid rain as “unlikely” after the eruption of the La Palma volcano

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“What does salt water have? For each liter, there are 35 grams of salts: chloride, sodium, sulfur, bromine, fluorine … When the lava arrives, the water evaporates and large columns of smoke are formed rich in hydrochloric and hydrofluoric acid, which are corrosive to people. Eruptions in Hawaii, for example, cause corrosion in people’s lungs. Everyone there talks about fluorosis and hydrochloric disease, “the expert details.

The phenomenon, according to forecasts, would take place in Playa de los Guirres, in Tazacorte, where emergency teams and the Police have cordoned off the area so that no one approaches a distance that could be considered dangerous. La Palma does not have a good memory the last time the lava and sea water melted. It happened during the eruption of the Teneguía volcano, 50 years ago, when Juan Acosta, a Fuencaliente neighbor, died of poisoning shortly after going to fish in “percheles”, two kilometers from the lava flows that fell into the ocean. Toxic gases, according to the newspaper library The vanguard, made Acosta dizzy, who was left unconscious and could not reach the hospital alive. He left his wife pregnant and five children, the oldest being 11 years old.

More consequences: smell of sulfur and possible impact on marine ecosystems

Magdalena Santana Casiano is Professor of Chemical Oceanography at the ULPGC. Ten years ago he embarked on the island of El Hierro, at the southernmost and western end of the Archipelago, to study the effects that the underwater Tagoro volcano had caused in the Mar de Las Calmas reserve, about 350 meters from La Restinga. Now he has headed to La Palma for the same purpose.

Santana Casiano assures that the white smoke and the bubbling in the sea that is produced by the collision of temperatures between the lava and the ocean is accompanied by an intense smell of sulfur that warns of the risk. “The most volatile gases begin to be eliminated and generate that typical odor that can affect the respiratory system, so it should be far away,” says the professor, who states that in Hawaii this type of event has been observed “at a certain distance “.

According to the scientist, the magnitude of the chemical reaction in the sea depends on the characteristics and nature of the magma that the volcano has expelled, the amount that reaches the ocean and the time it has taken to arrive. “We are talking about a coastal area, a very shallow area. In the case of El Hierro, the volcano appeared in the water, 350 meters from land, and rose to 80. In that area there were a lot of fish. Now we are on the shore. The lava will settle on the substrate “of the area where the river flows.

In any case, the professor is prudent and believes that the condition will not be known “for sure” until the amount of lava that arrives and what type of reactions are produced is calculated and until it is also measured in the depths.

At what point on La Palma will the sea touch the lava?

The area is cordoned off so that no one breathes toxic gases


What is the difference with the El Hierro volcano

In El Hierro, the eruption devastated the marine ecosystem in the initial phases due to the high concentration of harmful gases. The emission of carbon dioxide and other components caused a drop of three units in the PH. That is, the water became much more acidic. In turn, other substances released by the volcano in smaller quantities, such as iron or manganese, caused the dissolved oxygen to decrease, explains Santana Casiano. The environment became “much more corrosive” due to the characteristics of the lava and all the organisms in the area died. However, six months after the eruptive activity ceased, the system began to regenerate, motivated, in part, by all the nutrients that the volcano had also deposited in a marine reserve of great biological richness.

The professor of the ULPGC predicts that the consequences in the sea of ​​La Palma “will not be so radical.” “It’s different. On El Hierro, the lava came out directly into the sea and all the gases were initially released into the water column. On La Palma, it comes from the land to the sea and is already giving off gases directly into the atmosphere. That is why Maybe neither the change in PH nor the conditions will be so extreme, except for the border area, very close (to the area where the lava river has joined the sea), but we cannot say for sure ” , affirms the researcher and professor of Marine Sciences of the ULPGC.

After more than 25 years studying the levels of carbon dioxide and acidification in the open ocean of the Canarian region, Santana Casiano and his team will have the opportunity to analyze for the first time on the coast the reaction produced in the sea by lava flows from of a terrestrial volcano. A behavior that, he says, has already been studied and proven in Hawaii. “Lava contains sulfur, fluorine or chlorine and when it comes into contact with seawater it generates an important reaction, more gases. These gases, if dissolved in water, can contribute to a slight decrease in PH, to which the water becomes more acidic, “he says.

What other hypotheses are being considered

With the acid rain prediction, for the moment, one would have to be very cautious. Geologist José Mangas has said that, indeed, “there will be explosions” when the lava contacts the surface of the sea. “It is as if we mixed boiling oil with water. Acid rain can be generated that causes throat and nose irritations to the population,” he explained. However, Itahiza Domínguez, seismologist of the National Geographic Institute (IGN) in statements Canary TVSee “complicated” for something like this to take shape.

The State Meteorological Agency (AEMET) has also spoken out. But it has not done it on the white smoke generated when the lava has touched the sea, but on the toxic gases that come out of the many mouths of the volcano. According to meteorologist David Suárez, there is a low probability of an acid rain episode taking place because the gases, for the most part, once they enter the atmosphere, enter the general circulation of the same. In addition, “removal phenomena by dry, wet and transport deposition” also occur, the expert explained.

As with the Tagoro volcano, on El Hierro, the lava could act as a fertilizer for the ocean. According to a study published in 2018 in the prestigious magazine ScienceAfter the eruption of the Kilawea volcano, on the island of Hawaii, rivers of magma that fell into the sea raised temperatures and concentrations of metals and nutrients in the ocean, which in turn stimulated the rise to the surface of phytoplankton, which left a greenish blanket on the affected area for weeks.

The research authors concluded that the lava heated the groundwater and caused the influx of nutrients from deep waters to the surface, rather than the direct injection of micronutrients from the lava. “This oceanic fertilization was, therefore, a unique disturbance event that revealed how marine ecosystems respond to exogenous nutrient inputs,” the text adds. It is unknown if something similar could happen on La Palma, since in this case the lava is less liquid than that of Hawaii.



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