various isopods, insects and the oligochaete Pontodrilus litoralis among others
(García Raso et al. 1992).
9.3 Coastal Lagoons
The coastline of the Alboran Sea currently has extensive sandy beaches, cliff areas
and some large bays (Algeciras, Almería), leaving only very few inlets that can be
considered coastal lagoons (Ojeda Zújar 2004). The evolution of the coast in the
Quaternary, with the Flandrian transgression (about 6000 years ago), allowed some
valleys of Andalusia (Guadiaro, Guadalhorce and Andarax) to be flooded, forming
inlets and making navigable the final sections where the Phoenicians and Romans
constructed their ports. Those are now filled with sediment, and very limited areas
with a favourable topography allowed the formation of sand bars that delimited
coastal lagoons.
The most extensive coastal lagoon of the Alboran Sea is undoubtedly the Mar
Chica or Sebkha Bou Areg, located in Morocco east of Melilla (Zine 2003; Ruiz
et al. 2006). It is a large lagoon of 11,500 ha with a semi-circular shape and a
maximum depth of 8 m. The Mar Chica is separated from the Alboran Sea by two
sandy strips, Boukana (10 km long) to the north west and Aljazeera (12.5 km) to the
south east, separated by a mouth 120 m wide, where it connects with the Mediterranean. Several cities are settled on its banks, being the most important Nador,
located on the inner shore and representing a source of urban and agricultural spills.
The Mar Chica mostly comprises soft bottoms, sandy or mud, historically with
dense meadows of seagrasses and of the alga Caulerpa prolifera. The seagrasses
Zostera marina, Cymodocea nodosa and Zostera noltei were reported by González
García and Conde Poyales (1994), but only the latter two are mentioned in recent
reports (Ruiz et al. 2006).
A less extensive area of coastal lagoons is located in Rio Martil near the city of
Tetuan, on the Moroccan coast, in which Pallary (1920) mentioned several species of
hydrobiids found also on the Atlantic coasts.
On the north coast of the Alboran Sea, the most important coastal lagoons are
those of Adra (Albufera Honda of 13 ha and Albufera Nueva of 29 ha). Some coastal
lagoons have been transformed into saline ponds by man. There were several of
these “salinas” on the north coast of the Alboran Sea in the provinces of Granada
(Motril) and Almería (Guardias Viejas, Cerrillos, Roquetas and Cabo de Gata).
Among them, only those of Cabo de Gata Natural Park (400 ha) are still yielding
annual harvests of salt. The salt process involves the entry of marine water through a
long channel in which there is marine fauna (Ojeda Zújar 2004).
Due to the scarcity of coastal lagoons, the Alboran Sea acts as a major biogeographic barrier between the numerous lagoons of the European and Moroccan
Atlantic coasts and those of the Western Mediterranean starting from Cabo de
Gata eastwards.
298
J. L. Rueda et al.
(García Raso et al. 1992).
9.3 Coastal Lagoons
The coastline of the Alboran Sea currently has extensive sandy beaches, cliff areas
and some large bays (Algeciras, Almería), leaving only very few inlets that can be
considered coastal lagoons (Ojeda Zújar 2004). The evolution of the coast in the
Quaternary, with the Flandrian transgression (about 6000 years ago), allowed some
valleys of Andalusia (Guadiaro, Guadalhorce and Andarax) to be flooded, forming
inlets and making navigable the final sections where the Phoenicians and Romans
constructed their ports. Those are now filled with sediment, and very limited areas
with a favourable topography allowed the formation of sand bars that delimited
coastal lagoons.
The most extensive coastal lagoon of the Alboran Sea is undoubtedly the Mar
Chica or Sebkha Bou Areg, located in Morocco east of Melilla (Zine 2003; Ruiz
et al. 2006). It is a large lagoon of 11,500 ha with a semi-circular shape and a
maximum depth of 8 m. The Mar Chica is separated from the Alboran Sea by two
sandy strips, Boukana (10 km long) to the north west and Aljazeera (12.5 km) to the
south east, separated by a mouth 120 m wide, where it connects with the Mediterranean. Several cities are settled on its banks, being the most important Nador,
located on the inner shore and representing a source of urban and agricultural spills.
The Mar Chica mostly comprises soft bottoms, sandy or mud, historically with
dense meadows of seagrasses and of the alga Caulerpa prolifera. The seagrasses
Zostera marina, Cymodocea nodosa and Zostera noltei were reported by González
García and Conde Poyales (1994), but only the latter two are mentioned in recent
reports (Ruiz et al. 2006).
A less extensive area of coastal lagoons is located in Rio Martil near the city of
Tetuan, on the Moroccan coast, in which Pallary (1920) mentioned several species of
hydrobiids found also on the Atlantic coasts.
On the north coast of the Alboran Sea, the most important coastal lagoons are
those of Adra (Albufera Honda of 13 ha and Albufera Nueva of 29 ha). Some coastal
lagoons have been transformed into saline ponds by man. There were several of
these “salinas” on the north coast of the Alboran Sea in the provinces of Granada
(Motril) and Almería (Guardias Viejas, Cerrillos, Roquetas and Cabo de Gata).
Among them, only those of Cabo de Gata Natural Park (400 ha) are still yielding
annual harvests of salt. The salt process involves the entry of marine water through a
long channel in which there is marine fauna (Ojeda Zújar 2004).
Due to the scarcity of coastal lagoons, the Alboran Sea acts as a major biogeographic barrier between the numerous lagoons of the European and Moroccan
Atlantic coasts and those of the Western Mediterranean starting from Cabo de
Gata eastwards.
298
J. L. Rueda et al.