Remediating Mar Menor Lagoon in Spain with Enzymes
Introduction
The Mar Menor lagoon, located in Murcia on the south-eastern coast of Spain, is the largest saltwater lagoon in Europe. Its shallow, semi-enclosed waters cover an area of nearly 170 square kilometres, once celebrated for their clarity, biodiversity and importance to tourism and fisheries. The lagoon has long been a hub for local livelihoods and recreation, attracting visitors with its unique landscape, sandy beaches, and ecological richness.
Yet in recent decades, the Mar Menor has been at the centre of growing environmental concern. The lagoon has suffered repeated episodes of eutrophication, commonly referred to as the “green soup” phenomenon, where algal blooms turn its waters opaque and deplete oxygen. These events have led to mass fish kills, seagrass die-offs, and widespread loss of ecological balance.
The drivers of this ecological collapse are well documented: high nutrient loads from agricultural runoff, inadequate wastewater management, and legacy nutrient accumulation in sediments. While efforts have been made to reduce external inputs, the lagoon remains under immense stress. Natural recovery processes are slow, and the ecological state of the lagoon is fragile.
In this context, innovative solutions are urgently needed. Bioglobe’s organic enzyme remediation approach, combined with bioextraction strategies, offers a new path forward. This article explores how such methods could help stabilise nutrient levels and accelerate ecological recovery in the Mar Menor.
The Ecological Importance of Mar Menor
Mar Menor is not merely a local lagoon. It is recognised as a wetland of international importance under the Ramsar Convention, and it is part of the Natura 2000 network of protected sites in Europe. The lagoon and its surrounding ecosystems once hosted seagrass meadows, a diverse fish population, and migratory bird habitats.
Its semi-enclosed structure makes it particularly sensitive to nutrient imbalances. Unlike open seas, where dilution and mixing are greater, the Mar Menor’s exchange with the Mediterranean is limited. This means that excess nutrients, organic matter, or pollutants introduced into the system are retained for longer periods, heightening the risk of ecological disruption.
Tourism and fisheries have historically depended on the lagoon’s health. Crystal-clear waters attracted thousands of visitors each year, and artisanal fisheries supported local economies. However, ecological decline has also brought economic hardship, with declining visitor numbers, reduced fishing catches, and reputational damage for the region.
Understanding the Problem: Eutrophication
Eutrophication occurs when water bodies receive excessive nutrients, primarily nitrogen and phosphorus, which stimulate the overgrowth of algae. In the Mar Menor, these nutrients mainly originate from intensive agriculture in the Campo de Cartagena region, where fertiliser use is widespread. Runoff carries nitrates and phosphates into the lagoon through aquifers, drainage channels, and seasonal floods.
Once in the water, these nutrients fuel the rapid proliferation of phytoplankton and macroalgae. The results are visible algal blooms that cloud the water and block sunlight from reaching seagrass meadows. Without sunlight, seagrass dies, releasing even more organic matter into the lagoon.
As algal blooms die off, their decomposition consumes large quantities of dissolved oxygen. This creates hypoxic or anoxic conditions, where oxygen levels drop so low that fish and other aquatic organisms cannot survive. This has led to catastrophic events, including the death of tonnes of fish washing up on Mar Menor’s shores, shocking residents and visitors alike.
Adding to the complexity, the lagoon’s sediments act as a reservoir of nutrients. Even when external inputs are reduced, the stored nitrogen and phosphorus in sediments can be released back into the water column, perpetuating eutrophication. This creates a vicious cycle where the system becomes locked in a degraded state.
The Limitations of Conventional Approaches
Conventional strategies for addressing eutrophication often focus on reducing nutrient inputs. For Mar Menor, measures such as stricter fertiliser controls, improved wastewater treatment, and hydrological interventions have been proposed and partially implemented. While these are essential, they alone may not be sufficient.
First, the legacy of decades of nutrient loading cannot be reversed overnight. Even if external inputs were dramatically reduced, the internal recycling of nutrients from sediments would continue to fuel blooms. Second, enforcement of agricultural regulations has proven difficult, as the region’s economy is heavily dependent on intensive farming. Third, physical or chemical treatments, such as algicides, can carry unintended ecological consequences.
There is therefore a pressing need for complementary approaches that can accelerate recovery without harming the lagoon further. This is where enzyme-based remediation and bioextraction come into play.
Enzymatic Remediation: Harnessing Natural Processes
Enzymes are natural proteins that catalyse biochemical reactions. They are highly specific, biodegradable, and leave no harmful residues. Bioglobe’s research and development focuses on formulating enzyme blends tailored to environmental remediation, targeting pollutants ranging from hydrocarbons to excess nutrients.
In the context of Mar Menor, enzyme remediation offers several key advantages:
- Nutrient Transformation
Specialised enzymes can accelerate the breakdown of organic nitrogen and phosphorus compounds into forms that are less available to algae. By altering nutrient availability, enzymes can suppress the conditions that drive blooms. - Reduction of Organic Loads
Enzymes can catalyse the decomposition of organic matter before it consumes oxygen during natural decay. This helps reduce biochemical oxygen demand (BOD) and prevents hypoxic conditions. - Targeted Algae Management
Certain enzyme formulations can degrade structural components of algal biomass, assisting in controlling bloom density and facilitating natural clearance mechanisms. - Biodegradability and Safety
Unlike chemical treatments, enzymes are naturally biodegradable. Once they complete their function, they break down into amino acids, leaving no toxic residues or harmful by-products. - Customisation
Enzyme blends can be tailored to specific conditions such as temperature, salinity, and pH. For a lagoon like Mar Menor, with its unique characteristics, bespoke formulations can be developed for maximum effectiveness.
Bioextraction: Closing the Loop
While enzymes help to reduce nutrient availability and suppress blooms, bioextraction strategies are necessary to remove nutrients physically from the system. Bioextraction refers to the use of biological processes to capture and extract excess nutrients from water bodies.
Examples include:
- Algal Harvesting
Macroalgae that proliferate under nutrient enrichment can be harvested and removed. This not only reduces nutrient concentrations but also provides biomass that can be repurposed for fertiliser, bioenergy, or compost. - Filter Feeders
Bivalves such as mussels and clams naturally filter water, removing phytoplankton and suspended particles. Establishing or supporting populations of such organisms in controlled ways could contribute to nutrient control. - Constructed Wetlands
Wetland plants absorb nutrients as they grow. Creating or restoring wetlands in inflow areas can act as natural nutrient sinks, reducing the load before water enters the lagoon. - Integrated Systems
Combining enzyme treatments with bioextraction provides a synergistic effect. Enzymes destabilise nutrient availability and accelerate breakdown processes, while bioextraction ensures nutrients are physically removed rather than recycled within the system.
Applying Enzymes and Bioextraction to Mar Menor
An effective remediation strategy for Mar Menor would likely proceed in phases:
Phase 1: Baseline Assessment
A comprehensive baseline study would map nutrient inputs, identify hotspots of pollution, measure sediment nutrient loads, and monitor ecological indicators. Seasonal patterns in water quality would be recorded to determine the most effective timing for interventions.
Phase 2: Targeted Enzyme Treatments
Enzyme formulations would be applied to tributaries, drainage channels, and shallow zones of the lagoon where nutrient concentrations are highest. This would help intercept nutrients before they disperse across the entire system.
Phase 3: Bioextraction and Biomass Removal
During bloom events, macroalgal biomass could be harvested systematically to prevent decomposition and nutrient recycling. Controlled aquaculture of filter feeders could complement this by maintaining clearer water.
Phase 4: Sediment Remediation
If sediments are found to release significant amounts of nutrients, enzyme treatments could be applied to reduce mobilisation. In some areas, selective dredging or capping may be considered, but enzymes offer a less invasive option.
Phase 5: Monitoring and Adaptive Management
Continuous monitoring would be essential to evaluate the success of interventions. Data on water clarity, nutrient concentrations, dissolved oxygen, and biodiversity recovery would guide adjustments in treatment protocols.
Anticipated Benefits
Implementing enzyme-based remediation and bioextraction in Mar Menor could bring multiple benefits:
- Ecological Recovery: Reduced frequency and intensity of algal blooms, improved water clarity, and the return of seagrass beds.
- Biodiversity Enhancement: Recovery of habitats for fish, birds, and invertebrates.
- Socio-Economic Gains: Revival of tourism, improved fisheries, and restoration of the lagoon’s reputation as a natural jewel.
- Sustainability: A long-term solution that avoids chemical pollutants and works with natural processes.
- Community Confidence: Demonstrating action and results can rebuild trust among local residents who have been disillusioned by years of ecological decline.
Challenges to Overcome
While promising, the approach is not without challenges.
- Scale of the Lagoon: At nearly 170 square kilometres, interventions must be carefully scaled and prioritised.
- Upstream Pressures: Agricultural practices in the Campo de Cartagena must be addressed in tandem to prevent continuous nutrient influx.
- Regulatory Approval: New methods require approval from environmental authorities, which can be a lengthy process.
- Public Perception: Stakeholders must be reassured of the safety and ecological compatibility of enzyme treatments.
- Cost and Logistics: Large-scale deployment of enzyme treatments and bioextraction systems requires investment and coordinated management.
Why Bioglobe is Uniquely Positioned
Bioglobe has developed organic enzyme remediation solutions through years of research and testing. Our laboratory in Cyprus has created bespoke enzyme blends capable of addressing diverse forms of pollution, from hydrocarbons in soil to algal blooms in water.
The advantages of Bioglobe’s approach include:
- Scientific Expertise: Advanced understanding of enzyme biochemistry and its application to environmental remediation.
- Customisation: Ability to tailor formulations to the specific conditions of Mar Menor.
- Environmental Responsibility: Commitment to sustainable methods that do not harm ecosystems.
- Innovation: Combining enzymatic remediation with bioextraction in an integrated strategy.
Our work is guided by the belief that remediation must be both effective and ecologically responsible. The Mar Menor, with its unique challenges, is ideally suited for such an approach.
A Vision for Recovery
The vision is simple: a Mar Menor where waters are once again clear, seagrass meadows flourish, fish populations thrive, and residents and visitors alike can enjoy its beauty. Achieving this requires moving beyond stopgap measures and embracing systemic, biological solutions.
If successfully implemented, enzyme remediation combined with bioextraction could transform Mar Menor from a symbol of ecological crisis into a global model for lagoon restoration. It could demonstrate how science, innovation, and environmental stewardship can work hand in hand to address some of the most pressing ecological challenges of our time.
Conclusion
Mar Menor’s decline has been decades in the making, driven by nutrient overload and mismanagement. Reversing this trajectory will require bold, innovative interventions. Enzymatic remediation and bioextraction represent such an intervention—one that works with natural processes, not against them, and one that offers a sustainable path to recovery.
Bioglobe stands ready to contribute our expertise, technology, and commitment to help restore Mar Menor. The lagoon’s future is not yet lost, but action must be taken without delay. With the right collaboration between scientists, policymakers, and communities, the Mar Menor can once again be a thriving ecosystem and a source of pride for Murcia and Spain as a whole.
Bioglobe offer Enzyme pollution remediation for major oil-spills, oceans and coastal waters, marinas and inland water, sewage and nitrate remediation and also agriculture and brown-field sites, globally.
For further information:
BioGlobe LTD (UK),
Phone: +44(0) 116 4736303| Email: info@bioglobe.co.uk