anthropogenic pressures and combines integrated observation/experimentation/
modeling approaches. Durrieu de Madron et al. (2011) reviewed the state of the
current functioning and responses of Mediterranean marine biogeochemical cycles
and ecosystems and concluded the need for international multi-disciplinary research
coupling experiments, long-term observations, eco-regionalization, and modeling.
Herrmann et al. (2014) study represents one of the first attempts to model and
assess the effects of the oceanic and atmospheric long-term evolution of the pelagic
planktonic ecosystem, using a 3D coupled physical-biogeochemical model focusing
only on the NW Mediterranean Sea. In Macías et al. (2018) a coupled model system
is also used to explore potential changes in future scenarios (~2030) in the deep
convection, in the euphotic layer fertilization, and the impact on phytoplankton and
primary productivity in the NW Mediterranean Sea. Their results show an increase in
the strength and duration of the annual deep convection event (which is the main
trigger of the typical phytoplankton bloom of this area) and changes in the seasonal
plankton cycles. On the other hand, Macías et al. (2015) present the results of a 3D
hydrodynamic-biogeochemical coupled model (for the entire Mediterranean Sea).
Simulations under two emission scenarios showed that the western basin becomes
more oligotrophic due to a surface density decrease (increase stratification) because
of the influence of the Atlantic waters that prevents surface salinity to increase.
Another important stressor is acidification and one of the EU initiatives that have
addressed this issue in the Mediterranean is the MedSea project, which aimed at
forecasting changes in the Mediterranean Sea driven by increases in CO 2 and other
greenhouse gases, while focusing on the combined impacts of acidification and
warming on the marine shell and skeletal building, productivity, and food webs.
The combined effect of Mediterranean seawater acidification with warming on
Mediterranean biogeochemistry, and ecosystems, through direct impacts on its
highly adapted calcareous and non-calcareous organisms, may be larger than in
other regions (http://medsea-project.eu/). The Mediterranean Sea is acidifying
quickly (Goyet et al. 2016). Up to 30% of the anthropogenic CO 2 remains in the
upper 200 m of the water column (Sabine et al. 2004). The acidification of the
euphotic layer (Sabine et al. 2004; Orr et al. 2005) can affect physiological processes
and the composition of the phytoplankton community (Reul et al. 2014). Current
signals point to the reduction in the rate of calcification in phytoplankton (mainly
coccolithophores), which could lead to changes both in marine ecosystems and in the
carbon cycle. Nevertheless, there is no a consensus and different studies conjecture
the widely varying responses under elevated pCO 2 (Beaufort et al. 2011; Álvarez
et al. 2014; Meier et al. 2014; Dutkiewicz et al. 2015).
In general, climate projections tend to agree, with relatively high confidence, that
the Mediterranean region will experience higher temperatures and reduced rainfall in
the coming decades (IPCC 2013). In consequence, as climate model projections
show, there will be increasing rates of evaporation and salinification of the Mediterranean Sea over the twenty-first century under anthropogenic greenhouse gas
emission scenarios (Giorgi and Lionello 2008; Somot et al. 2008; Mariotti et al.
2008, 2015; Adloff et al. 2015). Mediterranean thermohaline circulation may significantly change by weakening in the western basin and a less certain response in
7 The Biogeochemical Context of Marine Planktonic Ecosystems
237
modeling approaches. Durrieu de Madron et al. (2011) reviewed the state of the
current functioning and responses of Mediterranean marine biogeochemical cycles
and ecosystems and concluded the need for international multi-disciplinary research
coupling experiments, long-term observations, eco-regionalization, and modeling.
Herrmann et al. (2014) study represents one of the first attempts to model and
assess the effects of the oceanic and atmospheric long-term evolution of the pelagic
planktonic ecosystem, using a 3D coupled physical-biogeochemical model focusing
only on the NW Mediterranean Sea. In Macías et al. (2018) a coupled model system
is also used to explore potential changes in future scenarios (~2030) in the deep
convection, in the euphotic layer fertilization, and the impact on phytoplankton and
primary productivity in the NW Mediterranean Sea. Their results show an increase in
the strength and duration of the annual deep convection event (which is the main
trigger of the typical phytoplankton bloom of this area) and changes in the seasonal
plankton cycles. On the other hand, Macías et al. (2015) present the results of a 3D
hydrodynamic-biogeochemical coupled model (for the entire Mediterranean Sea).
Simulations under two emission scenarios showed that the western basin becomes
more oligotrophic due to a surface density decrease (increase stratification) because
of the influence of the Atlantic waters that prevents surface salinity to increase.
Another important stressor is acidification and one of the EU initiatives that have
addressed this issue in the Mediterranean is the MedSea project, which aimed at
forecasting changes in the Mediterranean Sea driven by increases in CO 2 and other
greenhouse gases, while focusing on the combined impacts of acidification and
warming on the marine shell and skeletal building, productivity, and food webs.
The combined effect of Mediterranean seawater acidification with warming on
Mediterranean biogeochemistry, and ecosystems, through direct impacts on its
highly adapted calcareous and non-calcareous organisms, may be larger than in
other regions (http://medsea-project.eu/). The Mediterranean Sea is acidifying
quickly (Goyet et al. 2016). Up to 30% of the anthropogenic CO 2 remains in the
upper 200 m of the water column (Sabine et al. 2004). The acidification of the
euphotic layer (Sabine et al. 2004; Orr et al. 2005) can affect physiological processes
and the composition of the phytoplankton community (Reul et al. 2014). Current
signals point to the reduction in the rate of calcification in phytoplankton (mainly
coccolithophores), which could lead to changes both in marine ecosystems and in the
carbon cycle. Nevertheless, there is no a consensus and different studies conjecture
the widely varying responses under elevated pCO 2 (Beaufort et al. 2011; Álvarez
et al. 2014; Meier et al. 2014; Dutkiewicz et al. 2015).
In general, climate projections tend to agree, with relatively high confidence, that
the Mediterranean region will experience higher temperatures and reduced rainfall in
the coming decades (IPCC 2013). In consequence, as climate model projections
show, there will be increasing rates of evaporation and salinification of the Mediterranean Sea over the twenty-first century under anthropogenic greenhouse gas
emission scenarios (Giorgi and Lionello 2008; Somot et al. 2008; Mariotti et al.
2008, 2015; Adloff et al. 2015). Mediterranean thermohaline circulation may significantly change by weakening in the western basin and a less certain response in
7 The Biogeochemical Context of Marine Planktonic Ecosystems
237