Coastal Lagoons in Crisis

Unraveling the Environmental Mystery of the Southern Mediterranean

The quiet struggle where land meets sea, and human activity meets ecosystem survival.

Between Land and Sea: What Makes Coastal Lagoons Unique

Transitional zones where freshwater and saltwater mingle

Dynamic Salinity

Coastal lagoons exhibit dramatic salinity variations—from lower than the sea when freshwater inputs are high, to hypersaline when evaporation outstrips water inflow 1 .

Priority Habitat

The European Union recognizes coastal lagoons as a priority habitat in its Habitats Directive because they are threatened with extinction 1 .

Low Water Renewal

Characterized by low water renewal rates due to limited exchange with the sea and reduced freshwater inputs 5 .

Human-Environment Conflict

The conflict between human exploitation of water resources and the ecological needs of these aquatic ecosystems is starkly evident across the Mediterranean coast 1 .

The MELMARINA Project: A Scientific Deep Dive

Integrated hydro-ecological monitoring and modelling across three primary lagoons

Merja Zerga

Location: Morocco (Atlantic coast)

Size: 13.2 km²

Key Features: Large tidally induced water level variations, extensive inter-tidal environments

Ghar El Melh

Location: Tunisia (Mediterranean coast)

Size: 35.6 km²

Key Features: Small tidal variations, decreased freshwater inflows

Lake Manzala

Location: Egypt (Mediterranean coast)

Size: ~700 km²

Key Features: Strongly influenced by agricultural drains, multiple pollution sources

Research Methodologies

Methodology Application Key Insight
Sediment Core Analysis Environmental reconstruction from lagoon sediment Invaluable for understanding past conditions when monitoring data are lacking 8
Continuous Monitoring & Site Surveys Combined for temporal and spatial coverage Provides detailed hydrological and ecological data 8
Remote Sensing Imagery Space-borne or aerial image analysis Enables wider spatial coverage of lagoon characteristics 8
Historical Map Analysis Examination of historical documents and maps Reveals longer-term trends in site characteristics and land use 8
Coupled Hydro-Ecological Models Computer simulations of lagoon processes Informs understanding of lagoon functioning and tests management scenarios 8

A Landscape Transformed: The Human Hand on Three Lagoons

Significant changes during the twentieth century, driven largely by human activity

Merja Zerga, Morocco

This Atlantic-coast lagoon has faced altered freshwater inflows due to upstream diversions, while also receiving increased nutrient inputs from agricultural runoff and irrigation drainage .

Ghar El Melh, Tunisia

Located on the Mediterranean, this lagoon has suffered from decreased freshwater inflows due to upstream diversions, disrupting its natural hydrological balance .

Lake Manzala, Egypt

The largest of the three sites, Lake Manzala is strongly influenced by freshwater inflows from agricultural drains. It faces the triple threat of agricultural, domestic, and industrial waste discharge .

Human Pressures on MELMARINA Lagoons

Pressure Category Specific Impacts Primary Lagoons Affected
Hydrological Modification Upstream diversions decreasing freshwater inflow; drainage return increasing inflow All three lagoons
Water Quality Degradation Nutrient enrichment from agricultural runoff; domestic wastewater discharge All three lagoons
Industrial Pollution Direct discharge of industrial waste Particularly Lake Manzala
Land Use Change Reclamation for agriculture; urbanization All three lagoons

The Hydrology-Ecology Connection: A Central Finding

Understanding the fundamental role of hydrology in lagoon ecosystem dynamics

One of MELMARINA's crucial revelations was the fundamental role of hydrology as the primary control upon lagoon functioning and ecosystem dynamics 8 .

Modifications to water regimes—whether through dams, diversions, or drainage—have cascading effects throughout the ecosystem.

This hydrological change has direct consequences for lagoon vegetation. The project identified clear linkages between water quality, water availability, human activities, and biological characteristics of the lagoons 8 . As water flows change and nutrients accumulate, plant communities shift, which in turn affects the entire food web, including fish and bird populations that local communities depend on.

Cascading Effects

Hydrological modifications impact the entire ecosystem from vegetation to fish populations

Clear Linkages

Direct connections between water quality, availability, and biological characteristics

The Road to Recovery: Management Insights

Valuable insights for the future management of these vulnerable ecosystems

Integrated Approach

Effective management must extend beyond the lagoon's shoreline to encompass the entire watershed 8 . This means coordinating water resource management, agricultural practices, and urban planning across administrative boundaries.

DAPSI(W)R(M) Framework

This conceptual model helps organize complex social-ecological interactions into a logical hierarchy: Drivers, Activities, Pressures, State Changes, Impacts, and Responses 4 .

Climate Change Preparation

Future management must account for climate change and sea-level rise 8 . Developing adaptation strategies is crucial to minimize further degradation of these sensitive ecosystems.

Research Tools for Lagoon Monitoring

Research Tool Primary Function Application in Lagoon Science
Hydrological Sensors Continuous measurement of water level, temperature, salinity Tracking lagoon-seawater exchange and freshwater inputs 8
Sediment Corers Extraction of layered sediment samples from lagoon beds Reconstructing historical environmental conditions 8
Multiparameter Water Quality Probes In-situ measurement of pH, dissolved oxygen, chlorophyll Assessing ecological status and detecting eutrophication 1
Remote Sensing Imagery Satellite-based observation of land and water surfaces Monitoring changes in lagoon size, vegetation cover, and water quality 8
Coupled Hydro-Ecological Models Computer simulation of physical and biological processes Predicting impacts of management scenarios and climate change 8

An Uncertain Future for Mediterranean Lagoons

The work of the MELMARINA Project reveals a stark reality—the coastal lagoons of the Southern Mediterranean Region stand at a crossroads.

Hydrological modifications, pollution, and overexploitation have already diminished their ecological value and ability to support human communities .

As demands for freshwater intensify and climate change accelerates, the conflicts between human and environmental water needs will only sharpen . Without significant improvements in water use efficiency and wastewater treatment, these unique ecosystems face further degradation.

Yet, the project's integrated approach—combining advanced monitoring, historical analysis, and predictive modeling—offers a path forward. By understanding the intricate connections between human activities and ecological responses, we can develop management strategies that preserve both the biodiversity of these precious lagoons and the livelihoods that depend on them.

The fate of these remarkable where land meets sea ultimately rests in our hands.

References

References will be listed here

References