In almost 40 years, the Bay of Palma has lost 38% of its posidonia meadows

The Bay of Palma has lost 37.8% of its Posidonia oceanica meadows since 1984, a habitat that has suffered “profound deterioration” caused by wastewater discharges from outfalls and spillways, reports EFE.

According to the Spanish Institute of Oceanography (IEO), 93% of the loss of this protected marine plant has occurred in the area near the coast between the port of the capital and the Ciudad Jardín beach, where the evacuation points are located. wastewater and treated water, according to a report on the “Impact of untreated urban wastewater discharges in the Bay of Palma” made by the IEO at the request of the Investigating Court number 12 of Palma, within the framework of the criminal investigation into that contamination.

There is more than enough evidence to affirm that the wastewater discharges from the outfalls that discharge into the Bay of Palma are involved in the profound deterioration shown by the habitat in the study area”, affirm the scientific authors of the study.

The researchers state “the urgent need to adopt all kinds of measures to mitigate and eliminate the influence of wastewater discharges in the Bay of Palma”. They demand to improve the wastewater treatment plants (WWTP) of Palma, apply tertiary treatment treatments, eliminate discharges of rainwater mixed with dirty water into the bay and apply alternative discharge systems with proven efficacy to mitigate the effects on the ecosystem. like venturi diffusers.

Scientists have detected, at a structural level, “very significant alterations of the meadow”, with abnormally low values of density of Posidonia bundles and percentage of coverage in the areas closest to the discharge points of the submarine outfalls. In addition, just in these areas they have observed a particularly high abundance of the invasive macroalga Halimeda incrassata, probably related to the worsening of the environmental quality and structural deterioration of the meadow.

According to the IEO, all the Posidonia meadows in the Bay of Palma analyzed seem to be, to a greater or lesser degree, affected by wastewater. In the deteriorated meadow areas close to the outfall discharges, the size of the plants has been reduced by between one half and one third, and these smaller plants show higher values of necrotic leaf area.