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14-01-2024, 09:02 PM
Noticias:
Climate change is already modifying marine ecosystems in the Canary Islands.
Biologist Alejandro de Vera warns of its effect on the seabed, algae, island moss, plankton, corals and other flora
Climate change acts differently in the sea and in the territory, but it acts and will continue to do so in an increasing way, although human beings can slow down its current pace. Its effects on the coasts of the Canary Islands have been appreciated for some time, ecosystems are noticing it, everything points to considerable modifications and scientists such as Alejandro de Vera, PhD in Marine Biology from the ULL and curator in this area of the Museum of Nature and Archaeology of Tenerife, explains it every time he has the opportunity, he explains to Álvaro Morales in DIARIO DE AVISOS.
As it is a liquid medium, and apart from the increase in temperatures, climate change is also affecting the sea due to the increase in atmospheric carbon dioxide (CO2) as it dissolves, which generates a decrease in pH (acidification).
The rise in temperature in recent decades is causing fauna and flora to rise from warmer areas, while other species that used to live here at its limit are moving away from the Canary Islands, but now cannot cope with this increase in degrees. "There is a change in the distribution of species that is noticeable on a large scale (macrobiology) with fish, corals and others, but we also notice it in microbiology, especially with plankton, very small beings," he explains to DIARIO DE AVISOS.
The MUNA has samples of plankton from the Canary Islands dating back to 1987-88 and has a line of research on the effects of climate change. According to De Vera, "at that time some tropical species appeared in the studies from time to time, but now, especially on the islands with warmer waters (El Hierro and La Palma), if trawls are made to achieve sampling, much higher concentrations appear, something that is happening with molluscs" (his specialty).
According to him, the change in the marine ecosystems of the Canary Islands coast has been evident for years. "Tropical species are arriving that, in some cases, are invasive, especially if they don't run into predators and the conditions are more beneficial than for others that were here before, which causes them to proliferate. Their problem is that they displace the ones that were there before and totally change the ecosystem, with all that that implies."
This is more noticeable with species that settle on the seabed, especially cnidarians (corals, anemones...). "Unlike fish, which are constantly moving, corals, for example, can colonize the bottom of an area, displace all the algae that were there before, and modify that ecosystem. In addition, and apart from climate change, this is also influenced by the constant passage of ships or platforms from other parts of the world, which also introduce species accustomed to higher temperatures, displace others, changing the entire food chain and, thus, the ecosystem".
According to him, another problem with invasive species is that, when forming a new ecosystem structure, "it may not have the ecological valence of the previous one, it does not generate an ecosystem as diverse as the previous one, the biodiversity of the area is impoverished and this is another negative effect of climate change."
In the case of fish, which is where the general population can see these changes more clearly, he points out that the most outstanding thing is the growing presence of species that previously stopped in the Gulf of Guinea and Cape Verde and did not reach the Canary Islands, but now do. Among others, he points to the fula sargento (with vertical stripes that make them similar to bream), of which some specimens used to appear, but now their presence is very frequent, first in El Hierro and La Palma and, later, in the rest.
Also the surgeonfish (acanthurus monroviae), "a species that began to be seen little by little in Gran Canaria and La Palma, but now there are whole schools everywhere". However, he assures that, for the time being, these fish "do not seem to be invasive, although their populations are increasing, although there are no studies on whether they affect other species; What is true is that they are already part of the ecosystem."
A positive change is the greater presence of viejas (of the parrotfish family) which, although not exactly endemic to the Canary Islands (just look at those sold by many supermarkets in Mauritania, Senegal...), is rooted in the Islands as a native species and is part of the idiosyncrasy and culture of the Canary Islands. In this case, and given that it is very fond of heat (tropical waters), the increase in temperature is benefiting its populations and they are becoming more and more appreciated, as he confirms. "No matter how much old fish are caught, there are always and the change is coming in handy for the fishing stcok, but it's a very specific case."
A KEY LOSS
As for the species that are migrating northwards or being lost due to warming, he is especially concerned about the Canarian moss, the yellow moss. "Before, it was very common to see it in spring on the northern slopes of the Islands, when it was torn away by sea storms and appeared on the beaches, but it is being lost. It is a structuring species, key to ecosystems when they are formed. A conch shell is not structuring, but this yellow moss is and it is very important for life, because in that rocky northern strip the fry live, lay eggs a lot of invertebrates and fish, it serves as hunting and refuge for all the marine fauna and, if it disappears, then the entire ecosystem almost disappears, and we have noticed this in all the islands. In fact, there are studies on Gran Canaria that confirm that more than 90% has been lost between 1987-89 and 2016, something that is happening the same in the rest of the islands".
As he emphasizes, in ecology any change does not have to be negative, it simply gives rise to something else, to something different. However, this loss of Canarian moss is very counterproductive and, in general, "climate change is leaving more negative than positive things in the Canary Islands, even with worrying imbalances because we do not know what the invasive species will bring. It's similar to what's happening on land with the cat's tail, that there are no species that eat it or that can handle it."
Of other species that are migrating, he points to the cabrilla and, above all, the rosemary, whose populations are decreasing considerably, although they are still on the islands. "In this case, it's not something of concern for the ecosystem because they are not structuring species, but it is influenced because it is a bottom fish of algae and, as these are disappearing, that explains why there are fewer and fewer."
As he explains, the problem with climate change or the effect on the sea by plastics is that, as it is a long-term effect, "reversing this is very complicated. We have been producing an excess of CO2 into the atmosphere for more than 100 years and that is not easy to reverse. No matter how much renewable energy is installed, oil is still being burned and CO2 is being emitted, we are not investing it and we are slowing down its progress somewhat, but not stopping it or turning it around."
However, he is neither pessimistic nor optimistic, although he is clear that "we are going towards a change, towards something different, we do not know very well what it will be like. The important thing is to stop the most tremendous consequences with environmental education and taking the reins, because the real engine of the brakes is in society. Whether this change is more positive or negative, we don't know either because nature tends to regulate itself and species self-regulate, like diseases (bacteria, viruses...), which fit together. That is why I am neither pessimistic nor optimistic, but we are living in uncertainty, although it is a fact that marine biology in the Canary Islands is changing and will continue to do so and someone who knew about it before the 60s and analysed it now or in 20 years may think that it is on another continent".
On whether or not fishermen are aware of these changes, he assures that, due to their relationship with the work of dissemination, "there is everything, although we have noticed a greater sensitivity and ecological awareness".
OVERPOPULATION
As he points out, climate change is not affecting species such as shrimp so much, not even due to the effect of fishing, or limpets, crabs and others, but there is a problem with overpopulation in the Canary Islands. "There are a lot of us. The population has grown by more than 100% in 50 years and that translates into double the pressure on the coast compared to before. Although it is regulated with minimum sizes and with seasons in which it cannot be harvested, there are many people catching limpets, shellfish and others on the coast and that affects."
On the contrary, climate change "does not harm cetaceans or the squid they feed on as they pass through the Canary Islands, nor sharks, which are affected by overfishing, plastics and pollution. I wish there were more sharks on our coasts because that's a reflection of rich ecosystems, being at the top of the food chain."
The harms of microplastics
The study focused on plankton and plastics that affect the Islands that De Vera is developing from the MUNA already has sampling in Fuerteventura and Tenerife. Although it is still too early to draw conclusions, he does welcome the international effort to try to change the trend.
"The world is still producing about 300 billion tons a year, and that's too much, of course. About 14 to 15 million tonnes of that amount end up in the oceans. It is true that we have begun a small transition towards biodegradable plastics that, unlike those that previously remained between 200 and 300 years without degrading in the sea (a chronic problem), last about six months, as is the case with supermarket bags made now, as a rule, with potato starch. It's happening a bit like CO2: we've slowed down the rate of pollution, we're not reversing it, but it's slower.
In the Canary Islands, where we also export plastics that reach the coasts of Cape Verde, for example, we have noticed that we receive them from all over the world, some from very remote countries. Those that come from the north-west currents are more important, and the eddies affect places such as the beach of Porís de Abona (Arico), but they come from everywhere. What we have found in Fuerteventura, north of Lobos, near Corralejo, its port and other population centres, is that in these areas there are no more plastics floating around than outside; on the contrary, there may be fewer. It is already a global problem, although we must continue to contribute with as little pollution as possible and, for that, the best thing is to have as much environmental awareness as possible," he explains.
Climate change is already modifying marine ecosystems in the Canary Islands.
Biologist Alejandro de Vera warns of its effect on the seabed, algae, island moss, plankton, corals and other flora
Climate change acts differently in the sea and in the territory, but it acts and will continue to do so in an increasing way, although human beings can slow down its current pace. Its effects on the coasts of the Canary Islands have been appreciated for some time, ecosystems are noticing it, everything points to considerable modifications and scientists such as Alejandro de Vera, PhD in Marine Biology from the ULL and curator in this area of the Museum of Nature and Archaeology of Tenerife, explains it every time he has the opportunity, he explains to Álvaro Morales in DIARIO DE AVISOS.
As it is a liquid medium, and apart from the increase in temperatures, climate change is also affecting the sea due to the increase in atmospheric carbon dioxide (CO2) as it dissolves, which generates a decrease in pH (acidification).
The rise in temperature in recent decades is causing fauna and flora to rise from warmer areas, while other species that used to live here at its limit are moving away from the Canary Islands, but now cannot cope with this increase in degrees. "There is a change in the distribution of species that is noticeable on a large scale (macrobiology) with fish, corals and others, but we also notice it in microbiology, especially with plankton, very small beings," he explains to DIARIO DE AVISOS.
The MUNA has samples of plankton from the Canary Islands dating back to 1987-88 and has a line of research on the effects of climate change. According to De Vera, "at that time some tropical species appeared in the studies from time to time, but now, especially on the islands with warmer waters (El Hierro and La Palma), if trawls are made to achieve sampling, much higher concentrations appear, something that is happening with molluscs" (his specialty).
According to him, the change in the marine ecosystems of the Canary Islands coast has been evident for years. "Tropical species are arriving that, in some cases, are invasive, especially if they don't run into predators and the conditions are more beneficial than for others that were here before, which causes them to proliferate. Their problem is that they displace the ones that were there before and totally change the ecosystem, with all that that implies."
This is more noticeable with species that settle on the seabed, especially cnidarians (corals, anemones...). "Unlike fish, which are constantly moving, corals, for example, can colonize the bottom of an area, displace all the algae that were there before, and modify that ecosystem. In addition, and apart from climate change, this is also influenced by the constant passage of ships or platforms from other parts of the world, which also introduce species accustomed to higher temperatures, displace others, changing the entire food chain and, thus, the ecosystem".
According to him, another problem with invasive species is that, when forming a new ecosystem structure, "it may not have the ecological valence of the previous one, it does not generate an ecosystem as diverse as the previous one, the biodiversity of the area is impoverished and this is another negative effect of climate change."
In the case of fish, which is where the general population can see these changes more clearly, he points out that the most outstanding thing is the growing presence of species that previously stopped in the Gulf of Guinea and Cape Verde and did not reach the Canary Islands, but now do. Among others, he points to the fula sargento (with vertical stripes that make them similar to bream), of which some specimens used to appear, but now their presence is very frequent, first in El Hierro and La Palma and, later, in the rest.
Also the surgeonfish (acanthurus monroviae), "a species that began to be seen little by little in Gran Canaria and La Palma, but now there are whole schools everywhere". However, he assures that, for the time being, these fish "do not seem to be invasive, although their populations are increasing, although there are no studies on whether they affect other species; What is true is that they are already part of the ecosystem."
A positive change is the greater presence of viejas (of the parrotfish family) which, although not exactly endemic to the Canary Islands (just look at those sold by many supermarkets in Mauritania, Senegal...), is rooted in the Islands as a native species and is part of the idiosyncrasy and culture of the Canary Islands. In this case, and given that it is very fond of heat (tropical waters), the increase in temperature is benefiting its populations and they are becoming more and more appreciated, as he confirms. "No matter how much old fish are caught, there are always and the change is coming in handy for the fishing stcok, but it's a very specific case."
A KEY LOSS
As for the species that are migrating northwards or being lost due to warming, he is especially concerned about the Canarian moss, the yellow moss. "Before, it was very common to see it in spring on the northern slopes of the Islands, when it was torn away by sea storms and appeared on the beaches, but it is being lost. It is a structuring species, key to ecosystems when they are formed. A conch shell is not structuring, but this yellow moss is and it is very important for life, because in that rocky northern strip the fry live, lay eggs a lot of invertebrates and fish, it serves as hunting and refuge for all the marine fauna and, if it disappears, then the entire ecosystem almost disappears, and we have noticed this in all the islands. In fact, there are studies on Gran Canaria that confirm that more than 90% has been lost between 1987-89 and 2016, something that is happening the same in the rest of the islands".
As he emphasizes, in ecology any change does not have to be negative, it simply gives rise to something else, to something different. However, this loss of Canarian moss is very counterproductive and, in general, "climate change is leaving more negative than positive things in the Canary Islands, even with worrying imbalances because we do not know what the invasive species will bring. It's similar to what's happening on land with the cat's tail, that there are no species that eat it or that can handle it."
Of other species that are migrating, he points to the cabrilla and, above all, the rosemary, whose populations are decreasing considerably, although they are still on the islands. "In this case, it's not something of concern for the ecosystem because they are not structuring species, but it is influenced because it is a bottom fish of algae and, as these are disappearing, that explains why there are fewer and fewer."
As he explains, the problem with climate change or the effect on the sea by plastics is that, as it is a long-term effect, "reversing this is very complicated. We have been producing an excess of CO2 into the atmosphere for more than 100 years and that is not easy to reverse. No matter how much renewable energy is installed, oil is still being burned and CO2 is being emitted, we are not investing it and we are slowing down its progress somewhat, but not stopping it or turning it around."
However, he is neither pessimistic nor optimistic, although he is clear that "we are going towards a change, towards something different, we do not know very well what it will be like. The important thing is to stop the most tremendous consequences with environmental education and taking the reins, because the real engine of the brakes is in society. Whether this change is more positive or negative, we don't know either because nature tends to regulate itself and species self-regulate, like diseases (bacteria, viruses...), which fit together. That is why I am neither pessimistic nor optimistic, but we are living in uncertainty, although it is a fact that marine biology in the Canary Islands is changing and will continue to do so and someone who knew about it before the 60s and analysed it now or in 20 years may think that it is on another continent".
On whether or not fishermen are aware of these changes, he assures that, due to their relationship with the work of dissemination, "there is everything, although we have noticed a greater sensitivity and ecological awareness".
OVERPOPULATION
As he points out, climate change is not affecting species such as shrimp so much, not even due to the effect of fishing, or limpets, crabs and others, but there is a problem with overpopulation in the Canary Islands. "There are a lot of us. The population has grown by more than 100% in 50 years and that translates into double the pressure on the coast compared to before. Although it is regulated with minimum sizes and with seasons in which it cannot be harvested, there are many people catching limpets, shellfish and others on the coast and that affects."
On the contrary, climate change "does not harm cetaceans or the squid they feed on as they pass through the Canary Islands, nor sharks, which are affected by overfishing, plastics and pollution. I wish there were more sharks on our coasts because that's a reflection of rich ecosystems, being at the top of the food chain."
The harms of microplastics
The study focused on plankton and plastics that affect the Islands that De Vera is developing from the MUNA already has sampling in Fuerteventura and Tenerife. Although it is still too early to draw conclusions, he does welcome the international effort to try to change the trend.
"The world is still producing about 300 billion tons a year, and that's too much, of course. About 14 to 15 million tonnes of that amount end up in the oceans. It is true that we have begun a small transition towards biodegradable plastics that, unlike those that previously remained between 200 and 300 years without degrading in the sea (a chronic problem), last about six months, as is the case with supermarket bags made now, as a rule, with potato starch. It's happening a bit like CO2: we've slowed down the rate of pollution, we're not reversing it, but it's slower.
In the Canary Islands, where we also export plastics that reach the coasts of Cape Verde, for example, we have noticed that we receive them from all over the world, some from very remote countries. Those that come from the north-west currents are more important, and the eddies affect places such as the beach of Porís de Abona (Arico), but they come from everywhere. What we have found in Fuerteventura, north of Lobos, near Corralejo, its port and other population centres, is that in these areas there are no more plastics floating around than outside; on the contrary, there may be fewer. It is already a global problem, although we must continue to contribute with as little pollution as possible and, for that, the best thing is to have as much environmental awareness as possible," he explains.