These scenarios are used to force models of different complexity and resolution
(Lazzari et al. 2014). There are different types of models: General circulation models
(GCM), higher resolution regional ocean models, or coupled atmosphere-ocean
regional climate models (RCSM), but global models with low spatial resolution
cannot sufficiently resolve the local and mesoscale processes that characterize the
Mediterranean region (Jordá et al. 2011; Gomis et al. 2016; Akhtar et al. 2018), even
less the Alboran Sea. The use of RCSM for future projections started recently with
Somot et al. (2008) and Carillo et al. (2012) studies, followed by the European
project CIRCE (Dubois et al. 2012; Gualdi et al. 2013) and actually in the
Med-CORDEX initiative (Ruti et al. 2016). In this section, we present a detailed
summary of different studies that have analyzed the projections obtained from
models on the evolution of physical, chemical, and biological properties during
the twenty-first century in the Mediterranean Sea.
The first attempt to predict the effect of ocean warming on the Mediterranean Sea
circulation was the one by Thorpe and Bigg (2000). These authors used ocean and
air-sea fluxes models with the low resolution which predicted a weakening of the
MTHC in a scenario of 2Â CO 2 . In the same way, Somot et al. (2006) using A2
scenario (IPCC SRES) obtained projections with higher resolution models that show
an increase of sea surface temperature (SST) and salinity (SSS), and also a strong
weakening of the MTHC and changes in the characteristics of the Mediterranean
outflow. Somot et al. (2008) improved simulations by developing a global atmospheric model coupled with a high-resolution oceanic model of the Mediterranean
Sea. Simulations for the period 1960–2099 performed in a SRES-A2 scenario
showed once again an increase of the surface temperature in the Mediterranean
basin.
Under the umbrella of the EU project SESAME (Lazzari et al. 2014), ecosystem
models were developed to connect low and high trophic levels and basin scale
models to execute scenario simulations (the IPCC SRES, A1B scenario) for the
future (2070–2100). The results obtained for the twenty-first century simulations
showed: (1) an upper layer warming that enhances photosynthesis and increase
Gross Primary Productivity (higher in the Eastern Mediterranean Sea) and (2) an
increase in the vertical stability of the water column which limits the nutrient vertical
supply into the euphotic zone and therefore improves the microbial loop of the
marine trophic web. The maximum increase of temperature is achieved in the
Alboran Sea during wintertime and the primary productivity maps show a strong
positive signal in the Alboran Sea.
The projections of models developed under the framework of the EU project
CIRCE (Gualdi et al. 2013) show a decrease of the surface net heat loss during the
twenty-first century. Dubois et al. (2012) study presented projections under A1B
scenario for the period 1950–2050 and found a decrease in the heat loss and an
increase in water loss, which may affect the Mediterranean water masses and the
associated MTHC. Numerous studies have been carried out within the framework of
the Med-CORDEX initiative, such as the study conducted by Harzallah et al. (2018),
which evaluates the Mediterranean Sea heat budget components. Results for the
period 1990–2010 show positive and significant trends in the temperature of the
7 The Biogeochemical Context of Marine Planktonic Ecosystems
235
(Lazzari et al. 2014). There are different types of models: General circulation models
(GCM), higher resolution regional ocean models, or coupled atmosphere-ocean
regional climate models (RCSM), but global models with low spatial resolution
cannot sufficiently resolve the local and mesoscale processes that characterize the
Mediterranean region (Jordá et al. 2011; Gomis et al. 2016; Akhtar et al. 2018), even
less the Alboran Sea. The use of RCSM for future projections started recently with
Somot et al. (2008) and Carillo et al. (2012) studies, followed by the European
project CIRCE (Dubois et al. 2012; Gualdi et al. 2013) and actually in the
Med-CORDEX initiative (Ruti et al. 2016). In this section, we present a detailed
summary of different studies that have analyzed the projections obtained from
models on the evolution of physical, chemical, and biological properties during
the twenty-first century in the Mediterranean Sea.
The first attempt to predict the effect of ocean warming on the Mediterranean Sea
circulation was the one by Thorpe and Bigg (2000). These authors used ocean and
air-sea fluxes models with the low resolution which predicted a weakening of the
MTHC in a scenario of 2Â CO 2 . In the same way, Somot et al. (2006) using A2
scenario (IPCC SRES) obtained projections with higher resolution models that show
an increase of sea surface temperature (SST) and salinity (SSS), and also a strong
weakening of the MTHC and changes in the characteristics of the Mediterranean
outflow. Somot et al. (2008) improved simulations by developing a global atmospheric model coupled with a high-resolution oceanic model of the Mediterranean
Sea. Simulations for the period 1960–2099 performed in a SRES-A2 scenario
showed once again an increase of the surface temperature in the Mediterranean
basin.
Under the umbrella of the EU project SESAME (Lazzari et al. 2014), ecosystem
models were developed to connect low and high trophic levels and basin scale
models to execute scenario simulations (the IPCC SRES, A1B scenario) for the
future (2070–2100). The results obtained for the twenty-first century simulations
showed: (1) an upper layer warming that enhances photosynthesis and increase
Gross Primary Productivity (higher in the Eastern Mediterranean Sea) and (2) an
increase in the vertical stability of the water column which limits the nutrient vertical
supply into the euphotic zone and therefore improves the microbial loop of the
marine trophic web. The maximum increase of temperature is achieved in the
Alboran Sea during wintertime and the primary productivity maps show a strong
positive signal in the Alboran Sea.
The projections of models developed under the framework of the EU project
CIRCE (Gualdi et al. 2013) show a decrease of the surface net heat loss during the
twenty-first century. Dubois et al. (2012) study presented projections under A1B
scenario for the period 1950–2050 and found a decrease in the heat loss and an
increase in water loss, which may affect the Mediterranean water masses and the
associated MTHC. Numerous studies have been carried out within the framework of
the Med-CORDEX initiative, such as the study conducted by Harzallah et al. (2018),
which evaluates the Mediterranean Sea heat budget components. Results for the
period 1990–2010 show positive and significant trends in the temperature of the
7 The Biogeochemical Context of Marine Planktonic Ecosystems
235