considered paleoendemics, species that do not have a close relationship with other
species from neighboring regions, such as the seagrass Posidonia oceanica or the red
alga Rissoella verruculosa.
It was in the Pliocene that the waters of the ancient Tethys Sea were once again
connected with the Atlantic Ocean, thanks to a series of orographic movements that
created a huge waterfall 2000 m high and 30 km long, which for hundreds of years
poured Atlantic waters into the newly originated Mediterranean Sea (Roveri et al.
2014). It is this moment, when the enrichment by species of Atlantic macrophytes
begins, that distinguishes the Alboran Sea from the rest of the Mediterranean.
Subsequent successive glaciations that characterized the Quaternary period produced significant changes of sea level and seawater temperature to as much as 6
C
less in summer than at present (Thunell 1979). These thermal fluctuations produced
successive migrations of boreal and subtropical species of Atlantic origin through
the Strait of Gibraltar, which extended into much of the Mediterranean and which
conferred the marked Atlantic character of much of the Alboran Sea today. During
the glaciations, species from the North Atlantic were established in Alboran waters
and the rest of the Mediterranean, such as Halopithys incurva, Sphaerococcus
coronopifolius, Porphyra umbilicalis, Gymnogongrus griffthsiae, Nemalion
elminthoides, Chondracanthus acicularis, Pterocladiella capillacea, Cutleria
multifida, and Ralfsia verrucosa, the last with its southern distribution limit in
these waters. To these it is necessary to add the marine seagrass Zostera noltei,
presently extending to Atlantic Scandinavian coasts. Some of these species, originating in colder waters, are nowadays considered glacial relicts in the Mediterranean,
and they remain in very localized locales of colder, often deep, waters, such as
Alboran Island, where Laminariales and Tilopteridales (i.e., kelps and kelp-like
species) can be found (Flores 2004; Flores-Moya 2012).
During the interglacial periods, species from the coasts of the tropical Atlantic
could enter the Mediterranean through the Strait of Gibraltar. Some of them are still
present in the Alboran Sea, such as Dasycladus vermicularis in Almeria and Karia
Arkeman (open sea at the southeast end of the Sebkha Bou Areg of Nador, Morocco)
and Caulerpa prolifera, abundant in the Bay of Algeciras and very abundant inside
the Sebkha Bou Areg of Nador, forming mixed meadows with the seagrass
Cymodocea nodosa. In the Alboran Sea, however, there are few Atlantic elements
of tropical origin compared to other areas of the Mediterranean.
The Alboran Sea algae species from the quaternary are considered as
neoendemics, boreal and subtropical species native to the Atlantic which evolved
anatomical modifications that resulted in new species or varieties over time. Example of this is species of the genus Cystoseira, a genus that has intensive speciation,
such as C. tamariscifolia and C. usneoides (Rodríguez-Prieto et al. 2013).
In the last 20 years, the flora has experienced important changes due to the
unnatural migrations of species of Indo-Pacific origin. These changes are mediated
by anthropogenic activities, perhaps in some cases linked in turn to changes in the
surface temperature of the seawater. Asparagopsis armata, A. taxiformis, Caulerpa
cylindracea, and very recently the brown alga Rugulopteryx okamurae (Fig. 8.2)
have spread alarmingly on both shores of the Alboran Sea, probably favored at many
250
A. Flores-Moya et al.
species from neighboring regions, such as the seagrass Posidonia oceanica or the red
alga Rissoella verruculosa.
It was in the Pliocene that the waters of the ancient Tethys Sea were once again
connected with the Atlantic Ocean, thanks to a series of orographic movements that
created a huge waterfall 2000 m high and 30 km long, which for hundreds of years
poured Atlantic waters into the newly originated Mediterranean Sea (Roveri et al.
2014). It is this moment, when the enrichment by species of Atlantic macrophytes
begins, that distinguishes the Alboran Sea from the rest of the Mediterranean.
Subsequent successive glaciations that characterized the Quaternary period produced significant changes of sea level and seawater temperature to as much as 6
C
less in summer than at present (Thunell 1979). These thermal fluctuations produced
successive migrations of boreal and subtropical species of Atlantic origin through
the Strait of Gibraltar, which extended into much of the Mediterranean and which
conferred the marked Atlantic character of much of the Alboran Sea today. During
the glaciations, species from the North Atlantic were established in Alboran waters
and the rest of the Mediterranean, such as Halopithys incurva, Sphaerococcus
coronopifolius, Porphyra umbilicalis, Gymnogongrus griffthsiae, Nemalion
elminthoides, Chondracanthus acicularis, Pterocladiella capillacea, Cutleria
multifida, and Ralfsia verrucosa, the last with its southern distribution limit in
these waters. To these it is necessary to add the marine seagrass Zostera noltei,
presently extending to Atlantic Scandinavian coasts. Some of these species, originating in colder waters, are nowadays considered glacial relicts in the Mediterranean,
and they remain in very localized locales of colder, often deep, waters, such as
Alboran Island, where Laminariales and Tilopteridales (i.e., kelps and kelp-like
species) can be found (Flores 2004; Flores-Moya 2012).
During the interglacial periods, species from the coasts of the tropical Atlantic
could enter the Mediterranean through the Strait of Gibraltar. Some of them are still
present in the Alboran Sea, such as Dasycladus vermicularis in Almeria and Karia
Arkeman (open sea at the southeast end of the Sebkha Bou Areg of Nador, Morocco)
and Caulerpa prolifera, abundant in the Bay of Algeciras and very abundant inside
the Sebkha Bou Areg of Nador, forming mixed meadows with the seagrass
Cymodocea nodosa. In the Alboran Sea, however, there are few Atlantic elements
of tropical origin compared to other areas of the Mediterranean.
The Alboran Sea algae species from the quaternary are considered as
neoendemics, boreal and subtropical species native to the Atlantic which evolved
anatomical modifications that resulted in new species or varieties over time. Example of this is species of the genus Cystoseira, a genus that has intensive speciation,
such as C. tamariscifolia and C. usneoides (Rodríguez-Prieto et al. 2013).
In the last 20 years, the flora has experienced important changes due to the
unnatural migrations of species of Indo-Pacific origin. These changes are mediated
by anthropogenic activities, perhaps in some cases linked in turn to changes in the
surface temperature of the seawater. Asparagopsis armata, A. taxiformis, Caulerpa
cylindracea, and very recently the brown alga Rugulopteryx okamurae (Fig. 8.2)
have spread alarmingly on both shores of the Alboran Sea, probably favored at many
250
A. Flores-Moya et al.