Mar Menor at risk of suffocating
Council offers help to stop the lagoon turning into a ‘green soup’
TORRENTIAL rain last month increased the risk of another episode of anoxia – lack of oxygen – in the Mar Menor, which could result in a mass dieoff of organisms in its waters.
This was the conclusion of a report by the national oceanography institute (IEO), a public organisation. It was requested by the ministry for the ecological transition following the wettest March in Murcia region for 62 years.
The wet weather coincided with two particularly intense intrusions of dust particulates from the Sahara Desert.
These climatic anomalies combined with the already high concentration of nutrients in the salt lagoon to form a perfect cocktail for the rapid growth of species such as macroalgae, and are the clearest illustration of the process of eutrophication the area has been experiencing for decades.
Previous IEO reports have already fingered the decisive role of nutrients and organic matter in driving eutrophication (nutrient-induced increase in phytoplankton productivity). These nutrients, principally nitrogen and phosphorous mainly from intensive agriculture and mass tourism, enter the lagoon in surface runoff through watercourses, groundwater or with water and other materials during torrential
rain. The report also recorded a brusque drop in the salinity of the lagoon, which it depends on for the functioning of its basic ecosystems and its unique biodiversity.
The IEO noted in September last year that although salinity levels had been recovering since summer 2020, they were only on course to restore their normal levels this summer as long as there was no more torrential rain.
Since the rain elevated the phreatic level, freshwater with high levels of nutrients have continued to enter the lagoon, interfering with the seasonal dynamic of its salinity.
IEO experts also detected a notable increase in the turbidity
of the water since February, primarily due to materials washed in by the rain but which could continue over coming weeks or even months as a result of phytoplankton colonies developing.
The latest data showed a fast increase in chlorophyll which, although lower than when there have been explosive developments of phytoplankton, will probably continue as temperatures and hours of sunlight increase. The danger of the Mar Menor turning into a ‘green soup’ and killing off species again has been raised by Los Alcázares environment councillor Antonio Campoy.
He called for immediate action from the regional and national governments to prevent another ‘environmental catastrophe’, offering the council’s help to collect algae in suspension ‘before it rots and causes a bigger problem’.
This week Los Alcázares mayor Mario Pérez was at the UN in New York presenting the people’s legislation initiative (ILP) to make the Mar Menor the first ecosystem in Europe to have recognised legal rights.
The ILP garnered the required 600,000 signatures for it to be debated in parliament earlier this month, when it received overwhelming approval and will now be analysed to make potential amendments before a definitive vote is held.