Monday, January 30, 2023

Will we go back to the Pliocene? Study predicts ‘dead zones’ in the ocean this century

5.3 million years ago, large parts of the North Atlantic Ocean were salt water pools, areas where life could not develop. The lack of oxygen and nutrients prevented anything close to fish from developing there. A recent study published in Nature Communications revealed Global warming sends us back to that scenario.

The document shows that in a scenario in which the planet continues on its current warming path and exceeds a 3 °C increase in temperature by the end of the century, many regions of the world, but especially the North Atlantic,’ become ‘dead zones’.something that already happened in the geological epoch of the Pliocene (which occurred between 5.3 and 2.6 million years ago), when nature flooded the planet with CO2 to levels similar to those currently seen by human action.

“The importance of identifying these dead zones in the Pliocene is that it gives us a prediction of what will happen if warming continues like we have been going.”, explains Diana Diaz, professor and researcher at Jorge Tadeo Lozano University. For him, what has been achieved in the study not only provides clues to what may be happening in the upper reaches of the world’s second-largest ocean, but also provides warnings about what it may pose to the rest of the world.

Research manages to define these dead zones thanks to foraminifera, a type of unicellular marine organism the size of a grain of sand. The researchers used one particular foraminifera species, Glaborotaloides hexagonalus, because they were primarily present in low-oxygen areas. Thus, they were able to find, through a mathematical model with data from foraminifera fossils, the regions with the greatest presence of hexagonal globorotaloids in the Pliocene and therefore most likely to harbor life, given the low concentrations of oxygen present there. were unsuitable.

Given that today we are getting closer and closer to a similar scenario in terms of CO2 concentrations and temperatures than we saw in the Pliocene, what the paper predicts is that CO2 concentrations in these regions with depths of 100 to 1,000 meters Will be the future Less oxygen than at present and therefore less chance for the appearance of life forms.

“In warmer waters, there will be less oxygen available, and less oxygen will translate into less availability of suitable habitats for various marine species, either for consumption or healthy ecosystems. And how are we going to be affected? Well, there are species The lower the number, the less food is available, especially when it comes to the sea”, emphasizes Diaz.

“What we see is that the Earth has already gone through this, the only difference is that we were not there at that time, and now we are going to be affected by these changes”

According to the scientist, who is a doctor in geology and has investigated issues of physical oceanography and climate variability, what we may see in the future with ocean warming will be a sharp reduction in the availability of suitable environments for species And so there will be change in them. Getaway. Additionally, changes in global climate variability and the relocation or disappearance of large marine populations that are in cooler waters today but will begin to migrate to other locations due to warming and lack of habitable ecosystems, the research noted. has gone.

According to the expert, it is important to understand that most marine species prefer cooler waters with higher concentrations of oxygen and other nutrients, so a rise in temperature already means migratory pressure, fish that will have the ability to migrate, But the death of coral areas, for example, would be inevitable.

The increase in temperature will result in the disappearance of corals, among other things.

In this sense, one thing that the study highlights as a sign that this is happening or will happen is that on some occasions fishermen may see an increase in the amount of catch of specific species in areas where they normally are not present. that, Most of the time, this does not mean that the number of individuals in a species has increased, but rather that it is concentrating in smaller areas in search of more optimal conditions for survival.

“Why is Peru so rich in the amount of marine species? Because there are upwelling areas of cold water off the coast of Peru that the Humboldt Current carries from the South Pole, which attracts these species. When we get to the Colombian Pacific, the same thing doesn’t happen because our water is warmer. So if the warming process continues and it starts to become normal: fish will move to where the temperature is more suitable, they will believe that there is an increase but in fact there is a decrease in the area where the animals feel comfortable to live and Subsistence ”, highlighted the expert.

For that, it is important, as the study also noted, to start reconsidering the current level of fishing for consumption, taking into account that not doing so also worsens the availability of these species. Can “It’s going to affect the whole geochemical cycle, and let’s not get into the discussion of who is to blame, because that’s another topic. What we see is that the Earth has already gone through it, only With the difference that we weren’t there then, and now we’re going to be affected by these changes”, Diaz concluded.

Nation World News Desk
Nation World News Desk
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