La biomass removal in the Mar Menor The year has started with unusually high figures for the first few months, in a context marked by the continuous influx of fresh water and nutrients from the Campo de Cartagena basin, including agricultural chemicals washed away by rainThe regional government maintains a permanent cleaning operation deployed around the entire perimeter of the lagoon to contain the impact of this sustained pressure on the ecosystem.
So far in the first quarter, the following have already been extracted 3.514 tons of coastal biomass from the lagoon, and forecasts indicate that the volume will exceed 4.000 tons by the end of the month. This is a cleaning effort far exceeding the usual levels for this time of year, which authorities directly attribute to the increased influx of freshwater and nutrients through the Albujón ravine and the high level of the Campo de Cartagena aquifer.
Why is biomass skyrocketing in the Mar Menor?
The intense and prolonged rains of the current hydrological year These changes have clearly altered the flow of water into the Mar Menor. Since the start of the hydrological period on October 1st, the volume of water reaching the lagoon via the Albujón ravine has more than doubled compared to the same stretch last year.
Specifically, the following have been counted 7,31 cubic hectometers of fresh water that have flowed into the lagoon through this channel, compared to 3,11 cubic hectometers in the equivalent period of the previous year. Translated to a more everyday scale, the volume represents approximately 2.925 Olympic-sized swimming pools discharged in just a few months into an ecosystem that is, by nature, hypersaline.
This increase is not only due to episodes of heavy rain, but also to a virtually constant flow of water from the Campo de Cartagena aquiferwhose level remains high. This aquifer continuously flows into the ravine even during periods without significant storms, maintaining a steady supply of fresh water and nutrients that eventually reach the lagoon.
Regional authorities emphasize that these are no longer isolated spikes, but rather... constant pressure on the Mar Menor This fuels biomass growth and the accumulation of wrack on the shores. This situation necessitates continued monitoring and the planning of measures in advance, especially in anticipation of spring and summer, when rising temperatures can exacerbate the effects of nutrient accumulation.
Meanwhile, environmental indicators show a scenario of relative stability, but with nuances. salinity is around 40,44 PSUThis value is considered low for this time of year and between one and three points below typical levels in previous years. Dissolved oxygen is around 6,11 milligrams per liter, while water transparency reaches 4,31 meters and chlorophyll is close to 0,90 milligrams per cubic meter, a level that represents a decrease of approximately 48% compared to previous values.
A reinforced cleaning operation all year round
To address this scenario, the Community maintains an active permanent biomass removal device The operation, which covers the entire coastline of the Mar Menor, involves approximately 70 people per day, with the capacity to increase staffing levels depending on how the lagoon's situation evolves and the storms that may wash more debris ashore.
During a recent visit to the facility in Santiago de la Ribera, the Minister of the Environment, Universities, Research and Mar Menor, Juan MarÃa Vázquez, accompanied by the mayor of San JavierHe personally observed the intensity of the work and the increase in debris following the recent episodes of bad weather. He explained that the crews are working along the entire perimeter and are being redeployed to the areas with the greatest accumulation.
The data handled by the regional administration illustrates the magnitude of the effort: in the first quarter, [number] have been withdrawn 1.158 tons of biomass in January, 1.540 in February and 816 so far in MarchThe official forecast is to close the month with around 4.000 tons extracted, which would be approximately 40% of all that was collected during the previous year.
This figure is particularly striking when compared to previous years. In the last full season, the following was achieved: 8.821 tons of biomass removedThis volume already represents an increase of nearly 25% compared to the previous year. The fact that almost half of that amount has been reached in just the first few months of the new hydrological year gives an idea of ​​the current pressure on the ecosystem.
The councilor insists that the removal of biomass is a action necessary to reduce organic load and extract nutrients of the lagoon system, but warns that it cannot be considered a definitive solution. In his opinion, until the continuous influx of freshwater and nutrients is stopped, it will be necessary to maintain and even reinforce these types of direct interventions on the shoreline.
The areas most affected by the accumulation of biomass
The distribution of biomass in the Mar Menor is not uniformThe highest concentrations are located in the southern basin and in the area of ​​La Manga, where the dynamics of winds and currents, together with storms, favor the accumulation of material in certain points of the coast.
Among the most affected areas are Los Urrutias, El CarmolÃ, Los Nietos and Mar de Cristalas well as the smaller islands and the stretch between kilometers 1 and 6 of La Manga. These are areas where, after each episode of bad weather, significant seaweed influxes occur, forcing the cleaning crews to be redeployed to prevent the biomass from degrading on the shore and releasing more nutrients into the water.
The regional government emphasizes that these removal efforts not only aim to improve the image and public use of the beaches, but above all, reduce the organic matter load that can fuel future eutrophication episodesThe physical removal of biomass from the system helps to extract from the ecosystem some of the nutrients that have arrived from the watershed.
Even so, the authorities insist that the work on the ground must be accompanied by continuous monitoring of environmental parameters and close monitoring for any sudden changes. The goal is to anticipate risky situations, especially during the warmer months, when the system's balance is more delicate and any disruption can trigger oxygenation problems.
Claims against the State and pending measures
Beyond the daily work on the shore, the Autonomous Community reiterates that the The key is to act on the source of freshwater and nutrient inputsand in measures such as aid for the ecological transition of livestock farmingIn this regard, the regional government is once again focusing on state powers regarding the management of surface and groundwater in the Mar Menor area.
The advisor recalls that the pumping of the Albujón ravine It was declared a project of public utility and urgency in 2021, but it has not yet been effectively implemented. This infrastructure is considered strategic for reducing the flow of nutrient-laden water reaching the lagoon through this channel, especially during periods like the current one, with the Campo de Cartagena aquifer at high levels.
Furthermore, the aquifer was declared to be in poor condition in 2020, which entails a legal obligation to develop and implement a recovery planAccording to the regional administration, this plan has not yet been fully implemented, even though the situation of the Mar Menor continues to be heavily influenced by seepage and underground runoff from the agricultural basin.
While these fundamental issues are being resolved, the Community continues its work on continuous monitoring and tracking of the ecosystemSpecialized technicians continuously analyze parameters such as salinity, oxygen, transparency, temperature and nutrient levels, in order to have up-to-date information that allows adjusting management measures.
The set of actions on the ground, environmental monitoring, and demands for the execution of the promised works and plans currently constitute the regional strategy to try to stabilize the Mar Menor. In a context of abundant rainfall and sustained inflows of freshwater, the Biomass removal has become a central issue of the institutional response to contain the most immediate effects of the pressure on the lagoon.
