January 25, 2022 5:41 pm

Escape, acidification and burial: how marine biodiversity deals with lava

After several days of eruption, the lava flow that emerges from the Cumbre Vieja volcano finally reached the sea last Tuesday night, which not only caused large clouds of water vapor and the emission of toxic gases, but also a strong impact on the local marine biodiversity.

According to the scientists, most of the fishes that have a high capacity of movement will have fled the area, since the advance of the lava occurs slowly. But the benthic communities, that is, all those organisms that live on the seabed and that cannot move, will have been devastated by it.

“What will be affected is the fauna that cannot get away from that lava, from that thermal shock. The sea ​​stars, the hedgehogs, the began or some crabs, that they cannot move, they have no escape ”, the geochemist tells SINC Pedro Hernandez from INVOLCAN.

That is how you are plants e sessile invertebrates they have been buried under the volcanic material that solidifies as it cools.

The lava flow buries the marine communities that have not been able to flee and, in addition, produces a great thermal shock and the acidification of the ocean

The river of lava that penetrates the sea also produces a great thermal shock and the acidification the environment, as a consequence of the emissions of carbon dioxide, carbonic acid and sulfuric acid.

“This acidification is going to make the calcareous species [esponjas cuyo esqueleto mineral está compuesto por espículas de carbonato cálcico cristalizado], since the calcification process is going to harm them. Smaller species will also begin to appear, that is, there will be a miniaturization of the communities, “he explains to SINC. Jose Carlos Hernandez, professor and researcher at the Biodiversity, Marine Ecology and Conservation Research Group of the University of La Laguna (ULL).

However, experts emphasize that the environmental impact occurs at a very located of the island and, in the first instance, it should not be greater than that which occurred a decade ago after the underwater volcano eruption Tagoro on the island of El Hierro.

The lava flow from the La Palma volcano that reaches the sea continues to advance and forms a delta of lava. / EFE | Angel Medina G.

A faster recovery than on land

In fact, at sea the rate of renewal of marine populations and communities is much faster than in terrestrial ecosystems: “There is a greater Connection among their communities. It will be the surrounding systems that replace those diasporas that will settle in the affected area, ”says the biologist.

The renewal of marine ecosystems is usually rapid compared to that of terrestrial systems, but not all species recover at the same rate

But not all species will recover at the same time. rhythm. “Thanks to the studies carried out after the El Hierro eruption, we know that some species take longer to recover than others,” says the ULL researcher.

For example, the populations of the fish called old red (Sparisoma cretense) were re-established in a relatively short period, but others such as the Mere (Epinephelinae) a slower-growing, late-maturing species – have not yet reached the biomass that existed before the eruption.

In the case of La Palma, once the lava in the ocean cools, there will be a recolonization of the middle, starring mainly bacteria, diatoms and other microscopic organisms. These will once again create an environment in which the sessile invertebrates (bryozoans and mollusks, among others) together with began rojas, brown and verdes. Later, the rest of the fish will progressively return.

Until the algae recover, local fish populations will be affected

Jose Carlos Hernandez

“For the Fishing resources there must be algal communities, which have surely been buried. Until these algae are recovered, local fish populations will be affected ”, indicates the biologist.

Natural laboratories

As has been observed in other volcanoes that caused a serious impact on marine life, such as Tagoro (El Hierro) and El Kilauea (Hawaii), bacterial activity is stimulated after eruptions.

Lava flows into the sea after the eruptions of the Kilauea volcano that yesterday erupted again raise concentrations of minerals and nutrients in the ocean (iron and silicates, among others) that are fundamental for the development of the phytoplankton ─ photosynthesizing microorganisms that live dispersed in water─, sAccording to a study published in the journal Science.

As a consequence, a algal bloom, which acts as a blanket on the surface of the sea, blocking the passage of sunlight and causing a decrease in oxygen in the ocean.

The entry of the lava causes the nutrients from the ocean floor to rise to the surface as a result of the strong thermal shock, which accelerates the growth of algae

In addition, the entry of the lava causes the nutrients from the ocean floor, especially nitrates, to rise to the surface as a result of the strong thermal shock. This further accelerates the growth of these algae.

“This strong biological response not only depends on the lava itself, but also on an exogenous source of nitrate, which is believed to come from lava that enters the deep ocean, creating plumes that carry deep nitrate-rich water to the surface. ”, Conclude its authors.

New species of organisms can also emerge after eruptions. It happened with the Tagoro, in El Hierro: Thiolava Friday was the new species of bacteria extremófila discovered.

Investigation of the University of Barcelona, published in the magazine Nature, revealed, thanks to images from a remotely controlled unmanned underwater vehicle, that the new bacterial community formed a microbial tapestry of highly showy white filaments that covered almost 2,000 m2 near the top of the Tagoro volcano, at a depth of between 129 and 132 meters. This organism was found in the area most affected by the eruption, 32 months after it occurred.

Extremophilic bacteria (Thiolava veneris) covered almost 2,000 square meters near the top of the Tagoro volcano

Experts hope that the impact of lava flows from the volcano of Old Summit have a minor effect on the ecosystem. However, we have to wait and see how the contribution of volcanic material in the ocean continues to evolve. At the moment it continues to slowly enter the sea.

According to scientists, this eruption on La Palma is a new opportunity to better understand how these natural disasters affect ecosystems, both marine and terrestrial, and thus monitor the recovery of the areas.


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