2nd of Three Parts
The Mar Menor provides crucial ecosystems services, including supporting unique biodiversity and offering significant cultural and economic benefits like tourism, recreation and fishing. But it has been pushed to the brink.
Green soup
Experts had long warned that unsustainable development in the surrounding region of Murcia was overloading the lagoon with nutrients, a process known as eutrophication.
Murcia, fed by water transfers from the north, has become a mass producer of fruit and vegetables, much of it for export. But fertilizer spread on the intensively farmed crops has leached into streams and groundwater, and from there into the lagoon.
Heavy metals from disused mines in the nearby Sierra Minera hills added to the problem, as did pollutants from the houses, hotels and marinas that crowd around the lagoon.
In 2016, the Mar Menor could absorb no more. A proliferation of nutrient-fed phytoplankton turned the water into “green soup,” according to media reports. Scientists found that more than 80 percent of the seagrass meadows on the bed of 135-square-kilometre lagoon died for lack of light, replaced by thick mud. Three years later, floodwaters following heavy rain dumped an estimated 100–150 tons of dissolved phosphates into the water, triggering the mass death of fish, seahorses and other marine creatures, found a government report. In 2021, there was another die-off of fish, crabs and mollusks.
(To be continued) UNEP News
