Date Published: 31/05/2022
ARCHIVED - More nitrates have already entered the Mar Menor so far this year than in the whole of 2021
ARCHIVED ARTICLE Nearly 6,000 tonnes of seaweed have been removed from the Mar Menor in the first five months of 2022
So far this year, the Mar Menor has already received more freshwater contaminated with phosphorous and nitrogen through the Rambla del Albujón than in the whole of 2021, while some 5,900 tonnes of algae have been removed, 4,200 of which were in the last month and a half alone.
This was stated on Monday by the head of the Fisheries and Aquaculture Service of the Directorate General of Agriculture, Livestock and Fisheries in Murcia, Emilio María Dolores, who acts as spokesman for the Monitoring Committee on the Environmental Status of the Mar Menor, which meets fortnightly.
At a press conference following the committee meeting, it was revealed that the Mar Menor has already received freshwater inflows through the Albujón Rambla of some 6.22 cubic hectometres (hm3) this year, while in the whole of 2021 it received 4.5 hm3 through this route, an increase of 44%. And we’re not even halfway into the year yet.
This morning, at 7.55am, the rambla was discharging a flow of 308 litres per second, which Mr Dolores said was “very high”. 308 litres per second is 18,480 litres per minute, 1,108,800 litres per hour and a massive 26,611,200 litres per day, although this is actually lower than it was on the reading recorded on May 16, when the flow was 531 litres per second.
The
reactivation of the pump has apparently improved the situation somewhat, but it is still not enough and the inflow of water into the Mar Menor must be reduced further. The water entering through this Rambla waterway deposits phosphorous into the Mar Menor, with 85% of the registered phosphorous in the lagoon having come through the Albujón, and nitrogen, with the Albujón responsible for 57% of all nitrogen in the lagoon.
These two chemicals are largely responsible for the proliferation of algae.
The removal of biomass in the waters of the Mar Menor, carried out by The regional Government in Murcia has already removed more than 5,900 tonnes of biomass and seaweed so far this year alone. Between January and March, 1,600 tonnes were removed and in the months of April and May more than 4,200 tonnes, “as a result of the massive proliferation of algae that we are suffering, coinciding with the massive influx of water through the Albujón Rambla and with the increase in temperatures.”
The algae must be removed, according to Mr Dolores, not only to
make the bathing area accessible for people to swim in, but also to prevent the algae from rotting, which would have two harmful effects on the ecosystem: worsening the conditions of the seabed by increasing sediment and encouraging the massive proliferation of phytoplankton, which would lead to a further reduction in oxygen levels.
Currently, the average oxygen level in the lagoon is 6.84 milligrams per litre, a level that is apparently “perfectly compatible with life”, but the tendency is for this to fall as temperatures rise.
To improve this situation, the
microbubble oxygenation pilot test was launched last week. The installation of oxygen distribution devices is now complete and the system is being regulated so that it can automatically inject the microbubbles of oxygen whenever the values are below 4 micrograms per litre and up to 8 micrograms.
The test will continue for two months in order to assess the level of scalability of the system, which is “unlikely” to be applied to the entire surface of the lagoon, but in any case, it will not be operational by this summer.
Nor will the so-called “green filters”, which will remove nitrogen from the polluted water, but they might be ready by next summer.