ARCHIVED - 1.8 million kilos of organic waste removed from the Mar Menor in 2 months

Chlorophyll levels in the lagoon drop but visibility in the water is extremely low

A little over two months since the severe flooding caused by September’s “gota fría” storm in the Region of Murcia the regional government reports that in the intervening period the cleaning teams on the beaches and on board boats in the lagoon have removed as much as 1.8 million kilos of organic waste from the water.

This was one of the statistics reported by Miriam Pérez, the director of the regional government’s Mar Menor department, following a meeting on Tuesday of the committee overseeing the condition of the lagoon, where there has been a drastic deterioration in water quality since the storm as the floodwater acted as a catalyst on the harmful substances which have accumulated over the last 30 years. Most of the nutrients provoking an imbalance in the marine environment are attributed to reckless agricultural practices in the Campo de Cartagena, although there is no doubt that the debris washed into the Mar Menor in September has also been an important contributing factor.

The Murcia government’s cleaning teams consist of between 20 and 50 people on any given day, and obviously they have been unusually busy for the last two months as their manual labour has been supplemented by the incorporation of diggers, tractors and trucks as well as divers in the Mar Menor itself. In the meantime, Sra Pérez reports that work is still on-going to draw up new legislation to regenerate and protect the lagoon in future.

The latest water quality data and scientific analysis provide grounds for both optimism and pessimism regarding the recovery of the Mar Menor. The good news is that over the last week the level of chlorophyll in the water, which had risen to a historic high a week ago at 17.97 micrograms per litre, has dropped significantly to 10.3 micrograms – this is still well above what might be considered the norm (1 or 2 micrograms) but it may indicate that the worst of the episode in terms of this particular parameter is over.

In addition, the salinity of the water is gradually increasing, although it is still around 10 per cent lower than immediately before the storm, and the level of oxygen is close to normal after the episode of anoxia (lack of oxygen) which resulted in tons of dead fish and crustaceans being washed up on the beaches of the lagoon in October, despite a significant fall in recent days which will become a risk if it continues.

On the other hand, though, the visibility in the water is as low as it has been since data were first collected following the episode of eutrophication which turned the water green in 2016, due in part to the windy conditions over the last few days keeping sediment in motion. When calmer weather prevails for a few days the visibility is expected to improve, but at the same time that will mean the sediment settling on the seabed, where it will effectively stifle plant life according to some analyses.

This will also add to the amount of mud already hampering the recovery in water quality, a factor which has already been identified as an obstacle which will need to be overcome. Experts estimate that plant life has been obliterated from 70 per cent of the seabed, but there are hopes that sufficient sea grass survives around the shore of the Mar Menor to make it possible to repopulate the centre, where the water is deeper.

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