- Quote: ‘The ecosystem is in a critical state, with a serious risk of dystrophic crises and eutrophication’
By Andrew Atkinson
The accumulation of decomposing organic matter on the shores of the Mar Menor has increased considerably, reveals a report issued by the Environmental Planning department of the Urban Planning area of the Cartagena City Council.
“It is considered urgent and a priority, to proceed immediately to the removal of the decomposing plant biomass accumulated on the coastline of the Mar Menor,” said a spokesperson.
An urgency is mooted, due to the consequences decomposing organic matter can increase during the remainder of autumn and into the winter on the shores of the salt lagoon.
“The ecosystem is in a critical state, with a serious risk of dystrophic crises and eutrophication,” the report states.
The Environmental Planning Department added: “Due to the continuous entry of water with nutrients from the watershed, both superficially and subsurface through many beach areas of the lagoon perimeter, the water of the Mar Menor has low salinity.
“To prevent its condition from worsening, it is necessary that the cleaning crews begin to remove biomass – as soon as possible.
“The accumulation of decomposing algae, not only affects the quality of the water and the health of the area, the decomposing sludge generates anoxia and produces hydrogen sulfide.
“Also a loss of sandy habitats, that are scarce, and that they maintain a unique biodiversity differentiated from the muddy ones.”
A large accumulation of algae on the shores of the beaches of the Mar Menor increases the chances of a new episode of massive fish kills – such as the one that took place last August, due to the lack of oxygen in the water.
“The sludge accumulated in the shallow areas, when re-suspended by the waves and currents, contributes to the formation of accumulations of decomposing organic matter in the deep layers of the water column and which give rise to crises and bags of hypoxia in the spring, summer and fall,” states the Environmental Planning report.
This increase in decomposing organic matter is not specific, but will extend over the next few months.
The municipal report has been carried out to justify the urgent processing of the new biomass withdrawal contract that the Cartagena City Council, which has already been contracted and is pending award since the deadline ended on November 2.
The new contract, which will be in force from December 1, 2021 to June 30, 2022, has an estimated budget of €200,000.
The scope of action will focus on the coastal edge of the bathing areas and urban beaches of the coastal lagoon of the Mar Menor, in the municipality of Cartagena.
The works will be carried out on demand, depending on the amount of biomass accumulated, consisting of removing it from the shoreline, floating vegetation (OVA) and other debris, susceptible to decomposition and contribute organic matter to the lagoon, contributing to eutrophication of waters.
All kinds of waste that could be a source of contamination, affect public use or the state of conservation of habitats or species present in the Mar Menor, will also be removed.
