200 and 400 m deep), while this character is decreasing eastwards. A total of 23 fish
species or subspecies frequent in the Atlantic correspond to this type of distribution
in the Mediterranean; 3 of which do not exceed the limits of the Alboran Sea.
11.6 Macroecological Patterns and Processes
Other macroecological studies have shown the effect of macroclimatic oscillations,
captured in indices such as the North Atlantic Oscillation (NAO) or the Arctic
Oscillation (AO), on the physical and biological characteristics of the Alboran
Sea. These broad-scale atmospheric oscillations affect several climatic factors
(e.g. water temperature, prevailing wind direction and speed, and precipitation) at
more regional scales. This results in a macroecological teleconnection atmosphere–
ocean–primary producers. The first step in this chain of effects was addressed in
several oceanographic studies that described the effect of the NAO and AO on the
sea surface temperature of the Alboran Sea. Báez et al. (2013), for example
established that positive AO values before the summer imply a colder atmosphere
in the Polar Regions, which could spell occasional cold waves over the Iberian
Peninsula that, when coupled with precipitations favoured by negative NAO values,
usually result in snow precipitation. This snow typically accumulates in the high
peaks, particularly in the Sierra Nevada, and melt down in the next spring-summer
season. As a consequence, summer runoff of freshwater to the Alboran Sea
increases, which in turn triggers a diminution of sea surface salinity and density,
and blocks the local upwelling of colder water, resulting in a higher sea surface
temperature (SST) in the Alboran Sea. Finally, many embryonic and larval phases of
algae and animals are correlated with high sea temperatures (Vargas-Yáñez et al.
2009) which have an impact on whole populations.
This kind of teleconnections has been shown to affect, in particular, the physical
condition of pre-reproductive bluefin tuna (Báez et al. 2013) or the fishery yields of
the blackspot seabream Pagellus bogaraveo (Báez et al. 2014) from the Strait of
Gibraltar, and the presence or absence of the brown seaweed Fucus guiryi in the
Alboran Sea (Melero-Jiménez et al. 2017). It has been also related to the incidence of
jellyfish swarms on the beaches of the province of Málaga, in the northern coast of
the Alboran Sea (Bellido et al. 2020).
In a good example of macroecological study, Melero-Jiménez et al. (2017)
demonstrated, based on a survey extending over 26 years (from 1990 to 2015),
that the survival of the thalli of F. guiryi at Punta Calaburras (North Alboran Sea) in
midsummer correlates with the overall mean NAO value recorded from April to
June. The presence of the species was clearly favoured under positive NAO, whereas
the algae did not survive or did not develop from microscopic stages under negative
overall mean NAO values from April to June. The sequence of events for the
persistence until midsummer of F. guiryi thalli at Punta Calaburras could imply
the growth from microscopic, cryptic stages, as well as the arrival of few-celled
embryos originating from the populations located on the shores of the Strait of
446
R. Real et al.
species or subspecies frequent in the Atlantic correspond to this type of distribution
in the Mediterranean; 3 of which do not exceed the limits of the Alboran Sea.
11.6 Macroecological Patterns and Processes
Other macroecological studies have shown the effect of macroclimatic oscillations,
captured in indices such as the North Atlantic Oscillation (NAO) or the Arctic
Oscillation (AO), on the physical and biological characteristics of the Alboran
Sea. These broad-scale atmospheric oscillations affect several climatic factors
(e.g. water temperature, prevailing wind direction and speed, and precipitation) at
more regional scales. This results in a macroecological teleconnection atmosphere–
ocean–primary producers. The first step in this chain of effects was addressed in
several oceanographic studies that described the effect of the NAO and AO on the
sea surface temperature of the Alboran Sea. Báez et al. (2013), for example
established that positive AO values before the summer imply a colder atmosphere
in the Polar Regions, which could spell occasional cold waves over the Iberian
Peninsula that, when coupled with precipitations favoured by negative NAO values,
usually result in snow precipitation. This snow typically accumulates in the high
peaks, particularly in the Sierra Nevada, and melt down in the next spring-summer
season. As a consequence, summer runoff of freshwater to the Alboran Sea
increases, which in turn triggers a diminution of sea surface salinity and density,
and blocks the local upwelling of colder water, resulting in a higher sea surface
temperature (SST) in the Alboran Sea. Finally, many embryonic and larval phases of
algae and animals are correlated with high sea temperatures (Vargas-Yáñez et al.
2009) which have an impact on whole populations.
This kind of teleconnections has been shown to affect, in particular, the physical
condition of pre-reproductive bluefin tuna (Báez et al. 2013) or the fishery yields of
the blackspot seabream Pagellus bogaraveo (Báez et al. 2014) from the Strait of
Gibraltar, and the presence or absence of the brown seaweed Fucus guiryi in the
Alboran Sea (Melero-Jiménez et al. 2017). It has been also related to the incidence of
jellyfish swarms on the beaches of the province of Málaga, in the northern coast of
the Alboran Sea (Bellido et al. 2020).
In a good example of macroecological study, Melero-Jiménez et al. (2017)
demonstrated, based on a survey extending over 26 years (from 1990 to 2015),
that the survival of the thalli of F. guiryi at Punta Calaburras (North Alboran Sea) in
midsummer correlates with the overall mean NAO value recorded from April to
June. The presence of the species was clearly favoured under positive NAO, whereas
the algae did not survive or did not develop from microscopic stages under negative
overall mean NAO values from April to June. The sequence of events for the
persistence until midsummer of F. guiryi thalli at Punta Calaburras could imply
the growth from microscopic, cryptic stages, as well as the arrival of few-celled
embryos originating from the populations located on the shores of the Strait of
446
R. Real et al.