Elena Ceballos placeholder image, physicist and researcher at the University of Seville (US), born 32 years ago in Guadalcanal, a small town in the northern Sierra de Sevilla (2,646 inhabitants), landed a few days ago from an unprecedented oceanographic expedition, in which, literally against Through thick and thin, three research vessels and 150 international scientists have participated for the first time simultaneously to explore the North Atlantic Abyssal Plain as part of the EXPORTS program, funded by the US space agency (NASA), and the OTZ project (Ocean Twiglight Zone). Ceballos settled in the US last week to continue the work.
The strip of sea where sunlight does not reach, located between 200 and 1,000 meters deep and known as the twilight zone or twilight zone, represents 60% of the planet’s surface. It is the largest lung on Earth and the habitat of billions of beings that multiply by up to 20 the number of specimens that swim in shallower waters. Its activity creates a biological pump for the capture of CO₂ and exchange of organic compounds that reduces to hours processes that, without its existence, would take months to take place. It is crucial to understand future oxygen levels, how organic carbon will be stored in the long term, and the effects of climate change. However, despite its key importance in the survival of the planet as we know it, it is the last unexplored frontier of the Earth, of which little is known and on which the risk of exploitation by humanity already looms. .
Question. What is NASA doing at the bottom of the sea?
Answer. The ultimate objective of the oceanographic expedition is to develop predictive capacity of the processes that occur within the ocean through the satellites that NASA already has operational. You want to be able to develop models to predict all the oceanic carbon flux, to know all the processes well enough to, by measuring parameters accessible via satellite, to know what happens in the depths of the oceans.
P. What has been your role in this scientific deployment?
R. Quantifying carbon fluxes is quite complex. We need to accurately assess the amount of carbon sinking and the speed at which it sinks. Different techniques have been in the works for a long time, but the numbers don’t quite add up. There is a branch of oceanography focused on reducing the uncertainty associated with these numbers. That’s my job. We have used an instrument that is still in the development phase, the TZEX, which we still use as a prototype, but we have found that it has been very useful and we have a lot of ideas to improve the lines of research and the precision of oceanic carbon fluxes. . It is an autonomous platform that can go down to depths of 2,000 meters and allows for the first time to collect the particles that sink carrying carbon to the ocean floor and take photos of them simultaneously at different depths.
P. How was she recruited for this project?
R. The project has been in the works for a long time in the minds of the researchers who have led it. It is financed by NASA and the most important oceanographic institutions in the US have participated. One of them is the Woods Hole Oceanographic Institution (WHOI), where I participated in a stay in 2018 in Ken Buesseler’s laboratory [radioquímico marino estadounidense al frente de la WHOI]. We developed a very good personal and professional relationship and decided to seek funding through different means to continue working together in a post-doctorate. Three oceanographic vessels have participated in the project and they suggested that I participate in the campaign to collect the particle samples that I will analyze during my post-doctorate.
Three ships at the same time in the same area with an immense amount of instruments of different kinds deployed simultaneously. The campaign has been intense and pioneering: it is the first time that it has been carried out and it will set the course for future expeditions.
P. How has the campaign been?
R. On the high seas it has lasted three weeks and it has been very intense. We have been to an area of the Atlantic in the south of Ireland that has a reputation for having very bad weather. And it has been fulfilled: we have had winds of 70 knots and waves of 10 meters. Under these conditions you cannot do anything, neither deploy the instruments nor investigate. But when time has allowed, it has been wonderful. Three ships at the same time in the same area with an immense amount of instruments of different kinds deployed simultaneously. It has been intense and pioneering: it is the first time it has been done and it will set the course for future expeditions.
P. What is measured?
R. What we are studying is how, when spring arrives, the same thing happens in the ocean as on land, when vegetation flourishes. Ocean plants, which is phytoplankton [el conjunto de organismos fotosintéticos que viven dispersos en el agua], flourish and take the carbon dioxide that is left in the atmosphere and carry out photosynthesis, producing oxygen and carbon. This carbon is the food supply that is eaten by zooplankton, or microscopic animals, and then by fish and other animals in the food chain. As they eat, they expel fecal matter that sticks to other particles in the water and forms what scientists call “sea snow.” Usually only a small fraction of marine snow descends through the twilight zone to the depths of the sea. The reason we need to pay close attention to marine snow is that it plays an important role in regulating the climate. As marine snow sinks below depths of 1,000 meters, it is sequestered and does not return to the atmosphere for a long time. A part of the oceanographic community tries to quantify the carbon we have on the ocean surface and how much is removed from the atmosphere. NASA wants, by measuring chlorophyll levels with its satellites, to know how much phytoplankton exists in an area, how much carbon is produced and how much is sequestered.
Fecal matter that sticks to other particles in the water and forms what scientists call “sea snow,” which plays an important role in regulating the climate.
P. Based on this biological bomb, can the oceans be considered the lungs of the world?
R. Yes. The oceans are the lungs of the Earth, especially the twilight zone because it is the vastest zone. And the biological carbon pump is a fundamental component of the oceanic and terrestrial carbon cycle, since it is removing large amounts of CO₂ from the atmosphere. Without blue there is no green.
P. Is that area in danger?
R. From the point of view of global warming, everything is in danger. For example, the stratification of the oceanic layers, the distribution of nutrients and the marine currents are altered. Another future danger is overfishing. The shallower part of the ocean is already well exploited and the industry is thinking of making the leap to greater depths, below 200 meters. It is a danger for an area that we still do not know well. Up to 200 meters deep, it is moderately well known. Also the bottom, better than the intermediate zone.
The consequences of the exploitation of the twilight zone are not very well known, what would happen if there were fewer fish. Protection and investigation are the only avenues
P. And what should be done?
R. Protect and investigate what we know and what we know we do not know. The consequences of the exploitation of the twilight zone are not very well known, what would happen if there were fewer fish. Protection and investigation are the only avenues.
P. Have you had difficulties developing your scientific career?
R. Mentally, many, because it is a tremendously unstable world and with that pressure of financing problems and linking scholarships and temporary contracts, it is very difficult to work at the highest level. As a woman, I noticed some condescension from both classmates and teachers during my degree, although it didn’t make things easier for me. But at no time have I felt neglected and, so far, fortunately, the scientific career has gone very well.