The summer of 2020 will be remembered for restricted numbers of people on beaches, social distancing, having to wear a mask when walking along the shore and the lack of foreign tourists toasting themselves in the sun. It will probably also be remembered as one of the best in terms of water quality for swimmers on the Costa del Sol.
There has been a combination of different environmental and social factors during this unusual summer season: an increase in the sea temperature to 28 degrees, water that was cleaner than usual and, the icing on the cake, there have been hardly any jellyfish.
"From the point of view of swimmers, this has been a fantastic summer, one to remember," says Jesús Bellido, who is a biologist at the Aula del Mar. There have been reasons for all this, of course. Some of them are positive, but others are not so good for the marine ecosystem.
The increase in the water temperature is particularly significant. The measurements taken early in the morning (before the sun has an effect) by the Spanish Oceanography Institute on the beach at Fuengirola, next to its headquarters, reached 26.6ºC, which is considerably higher than the average 21.3ºC in August and a new record since these daily measurements began to be taken in 1984. Until now, the highest temperature was 25.5ºC in August 2013.
Apart from the global warming that affects the whole of the Mediterranean because of climate change, the reason for this is purely meteorological. More specifically, it is due to the winds.
"The persistent Levante wind in recent weeks, combined with high ambient temperatures, is the reason the water is warmer," says Manuel Vargas, who is a scientist at the Malaga Oceanographic Centre.
The Levante wind
As he explains, this Levante wind pushes the surface water towards the coast, which is warm from the sun. On the other hand, the Poniente winds which bring the dreaded Terral with them have the opposite effect, dragging the surface layer of the sea away from the coast to deep waters, which are colder.
The difference compared with previous summers is that the winds have not alternated so much this year and the Levante has been predominant.
"In a normal summer we would have four or five days of Terral, but so far this year we have only had a couple of episodes, and there have been several consecutive weeks of Levante. That's why the sea temperature is higher," says Vargas.
"Last summer there were more days of Poniente, and so the water was the coldest it had been for ten years," says Francisco Ignacio Franco, director of the University of Malaga's Chair of Coastal Sciences, and he also points out that the waters on the eastern side of Malaga are the warmest. "We can find 24 degrees in Estepona, 26 in Marbella, 27 in Malaga and one or two degrees higher between Torre del Mar and Nerja, where it can easily be 28," he says.
So the water is warmer, but it is also generally cleaner in terms of rubbish and sewage. In this case, there is a simple explanation. "There has been less pressure on the beaches, so people have not left as much rubbish behind as usual, and also as there have been fewer tourists the sewage plants have been able to cope and haven't overflowed," says Bellido.
Manuel Vargas agrees: "Normally the Levante also pushes the dirty stuff towards the coast and the Poniente does the opposite, replacing the surface water with deeper, clearer water. But this year that hasn't been happening so we conclude that it is cleaner because there have not been as many people."
Adrián Westendorp, who owns the Alnasur company, agrees. Alnasur operates two 'scum-skimmer' boats in Rincón de la Victoria and two others off the beaches at Almuñécar, in Granada province.
"We are removing about 25 per cent less material than in other years, and by material I mean rubbish left behind by people on the beach. Also, we are seeing less sewage because the treatment plants are not overloaded," he says.
Francisco Ignacio Franco says people need to be more aware of the problem they are causing. "The rubbish that appears is nothing to do with the lack of treatment, because everything is treated properly here, especially this year as there are fewer people. Studies show that the scum is basically of a mineral nature, specifically clays which are moved by the currents and are therefore innocuous. But we do have waste on the sea bed which is caused by people on the beach. We find plastic, food containers, bags and a huge amount of wet-wipes," he says.
The third factor which Manuel Vargas says has been making this "the perfect summer for swimmers" is that there have been hardly any jellyfish, like last year, and very different to the swarm that made life a misery in 2018.
The Aula del Mar corroborates this. "Our studies indicated that there would not be so many this year. We started with a normal jellyfish population, but then other circumstances came into play and they haven't reached the coast, so we saw very few of them," says Jesús Bellido.
Why are there fewer of them? There are different hypotheses.
"It's something that needs more study," admits Vargas. "Some scientists say it is to do with the amount of rain because the river water, which is fresh, creates a natural barrier when it reaches the sea, but in some areas of Malaga, Granada, Almeria and even further up the coast there are no rivers to have that effect. Other studies say it simply depends on the winds, but in that case they would be brought by the Levante, and that hasn't been happening."
Franco has another suggestion, however. "It seems that what has been happening is that opposite our beaches we have two places with a major change of currents, known as the 'giros de Alborán'. These are cyclical and they keep the jellyfish out at sea. It isn't that there are fewer of them this year, just that not so many are reaching us because they are trapped. In 2018 there were a lot of Atlantic fronts at the end of the spring, and those broke the currents and set the jellyfish free, and then the Levante brought them close to the beaches," he says.
Whatever the reason, it looks as if these invertebrates that everybody hates will not be a problem for what is left of the summer, so those of us who enjoy swimming can continue to do so in peace.