Science and Tech

Studying the vulnerability of life to acidification brought about by global warming

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Global climate change is one of the great problems facing society and, to combat it, scientific teams develop new techniques and research that help us understand, mitigate and reduce the impact it is causing on our planet. Both in the oceans and in the soils there is evidence of how environmental conditions are changing and, thanks to this, the impact of climate change on the environment and biodiversity can be measured.

A radiotracer is a substance that contains molecules in which one or more atoms have been replaced by a radioisotope. That is, a radioactive isotope that disintegrates emitting particles and electromagnetic radiation called gamma. Thanks to the development of nuclear instrumentation, this gamma radiation can be detected and, in this way, it is possible to use them to visualize the flow of certain substances along different paths. This makes it possible to diagnose diseases, evaluate the functioning of complex hydraulic systems, or even measure the uptake of certain substances by living beings in certain endangered ecosystems. It is, therefore, a kind of GPS, which makes it possible to identify spatial movements of different substances.

In recent months, within the framework of a collaboration between the Higher Council for Scientific Research (CSIC) in Spain and the University of Costa Rica (UCR), Enrique Nácher, a CSIC researcher at the Institute of Corpuscular Physics (IFIC) and Mario Cubero, professor and researcher at the University of Costa Rica, have started a collaboration to carry out a series of studies on the environment and climate change using radiotracers. The objective is to identify concrete problems and be able to subsequently develop solutions and applied research. To this end, important field work has begun, highlighting the study of marine ecosystems and the collection of samples of different types of soils and sediments in the crater of a volcano.

From the depths of seas and oceans…

The REMO project plans to carry out studies on the sensitivity of molluscs and corals to the acidification of the sea caused by global climate change. To carry out these studies, calcium-45 is used as a radiotracer, that is, a radioactive isotope of calcium that allows us to know where it accumulates and, therefore, makes it easier to investigate the synthesis of calcium carbonate in mollusk shells or coral skeletons. in different aquariums and with different levels of acidity.

The Institute of Corpuscular Physics (IFIC) is studying, together with researchers from the Oceanogràfic de Valencia in Spain, the increase in the acidity of the seas and oceans as one of the direct effects of climate change due to the increase in carbon dioxide (CO2 ) in the atmosphere. The measurement of calcification in aquariums with radiotracers, working with corals and molluscs from the Oceanogràfic, is a pioneering analysis technique in Spain, it is not invasive and it does not cause damage to the species under study. In addition, it allows comparing the results with those obtained in open spaces, serving as a point of support in the investigations.

The most innovative part of the project is found in the analysis of the calcium that these invertebrates capture, using a detector that the IFIC is developing with nuclear instrumentation technology. The researchers use a radiotracer dissolved in the water (radioactive calcium-45 that does not disturb the study) and the amount that the animal captures in a way that is not harmful or destructive to its body is measured. The technique also makes it possible to monitor the calcium uptake of the same individual throughout their growth and development.

In this sense, the collaboration with the UCR will be very enriching since its Marine Research Center (CIMAR) is planning similar experiments on acidification and calcium uptake in molluscs, using other indirect techniques, such as the incremental average weight, which will allow the intercomparison of results with the REMO project and the exchange of research strategies.

In addition to these first studies, the IFIC group has the long-term objective of implementing its use in other fields of scientific research with marine ecosystems, such as nutrition, parasitology, microbiology and ecology, in other organisms. that incorporate calcium in other molecular forms such as jellyfish and calcium sulfate.

… to the crater of an active volcano

On the other hand, Nácher and Cubero carried out an expedition last October that visited different locations in Costa Rica. One of them consisted of going up, or rather, going down, to the crater of the Poás volcano, located 2,708 meters high, recognized as one of the main peaks in the country, considered one of the most important eruptive centers in Costa Rica and one of the natural wonders of the country. As it is an active volcano, there are different substances in the environment that make breathing difficult, and for this reason you must go well protected with respiratory masks, and also the handling of electronic devices, due to the environmental conditions.

Gases continuously emanate from the crater, mainly sulfur and chlorine, however, unlike in other volcanoes, most of the sulfur reacts with the lake water that covers the crater and precipitates, remaining in a solid form on the surface of the lake. Chlorine does not precipitate and is expelled as a gas that is very uncomfortable to breathe, causing severe itching in the throat and eyes, which makes it essential to use appropriate masks.

The ascent to Poás is done by car, but the difficult thing is going down into the crater, since it is a descent of about two hours between areas of solid lava from the 2017 eruption, others of eroded earth and above all many cut. Afterwards, the journey through the entire crater takes another hour and a half taking samples of earth, ashes, lava, lake water with temperatures of about 50 degrees Celsius and water from the emanations, in which the temperature reaches 70 degrees Celsius. The presence of the volcanologist and guide Geoffroy Avard was decisive in being able to carry out this field activity.

In addition, the team also toured different locations in the Monteverde Cloud Forest, a natural reserve of more than 10,500 hectares of tropical forest with a high amount of biodiversity, which has six ecological zones, 90% of which are virgin forest. On this occasion, the researchers toured different areas of the forest looking for possible locations close to the existing meteorological stations, eventually locating four, to leave buckets with different types of soil such as clay and grass, among others, and subsequently study the presence of beryllium-7. using gamma radiation detectors.

Enrique Nácher and Mario Cubero in the crater of the Poás volcano. Gas fumes, mainly chlorine, cause irritation to the respiratory tract and eyes. (Photo: IFIC)

The analysis of the samples

The main objective of this expedition has been the analysis of the samples collected during the trip, in parallel in the environmental radioactivity laboratories of the University of Valencia, LARAM, and of the University of Costa Rica, CICANUM. This study looks for the presence of beryllium-7 in the collected samples, since it is a natural radioisotope that originates from the interaction of cosmic rays with the Earth’s atmosphere, and is introduced mainly due to rain. It is therefore ideal for measuring land redistribution, especially through erosion and sedimentation processes, caused by rainfall in short periods of time.

Obtaining the results of both investigations will allow a better understanding of the processes produced in volcanic areas and in the oceans, thus allowing the identification of specific environmental problems and the development of strategies to combat climate change and the environmental crisis.

In the short and medium term, IFIC and UCR researchers will continue this collaboration to make intercomparative measurements within the framework of these environmental study projects with radiotracers, of special relevance for the achievement of sustainable development objectives, particularly those related to preserve the soils, the seas and the species that inhabit them. Both groups will seek synergies and applications through exchange projects in which interdisciplinarity and cooperation prevail. (Source: Ángela Molina / IFIC / CSIC)

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