the Mediterranean, is due to different periodic and recurrent fertilization mechanisms
operating in the Strait of Gibraltar and also within the Alboran Sea, which are
addressed and discussed in this chapter. These fertilization processes lead to the
injection of new nutrients from subsurface waters into the euphotic layer supporting
enhanced phytoplankton biomass and primary production, particularly in the Northwestern (NW) Alboran Sea (Minas et al. 1991; Garcia-Gorriz and Carr 2001; Bosc
et al. 2004; Reul et al. 2005; Macías et al. 2007). However, the biogeochemical
signatures of the upwelled waters at the Strait of Gibraltar and its proximities, and
also those of Atlantic waters masses incursions, are progressively lost during the
progress of these waters through the Alboran Sea. As the distance to the Strait
increases the upper waters of the Alboran Sea become more oligotrophic (Bosc et al.
2004) due to the uptake of nutrients by phytoplankton and also to a lower number of
fertilization mechanisms and to a higher variability in the eastern sector (Ramírez
2007; Renault et al. 2012; Oguz et al. 2014).
This chapter reviews the biogeochemical features of the different water masses
found in the Alboran Sea, the different fertilization mechanisms (from upwelling
events to incursions of nutrient-rich North Atlantic Deep Water NACW) which
promote the injection of nutrient into the photic layer. The chapter also examines
the nutrient dynamics in this basin and the potential limitation of phytoplankton by
nutrients, as evidenced from the molar nitrate:phosphate (N:P) and nitrate:silicate
(N:Si) ratios, and discusses the role of phytoplankton uptake in regulating nutrient
concentrations and molar ratios in this basin. In addition, it also addresses the
distribution patterns of chlorophyll-a (Chl-a) and primary production (PP) in relation
to the hydrology and biogeochemical fields. The last section of this chapter analyses
the effects of climate change and ocean acidification on the biogeochemistry and
primary production in the Mediterranean and the Alboran Sea.
The average vertical profiles (annual climatologies) of nutrients and dissolved
oxygen, as well as the average seasonal vertical profiles (seasonal climatologies) of
Chl-a in the Alboran Sea (Manca et al. 2004) were plotted using data provided by
OGS Istituto Nazionale di Oceanografia e Geofisica Sperimentale. Source: Data and
metadata are provided by the Italian National Oceanographic Data Center of the
OGS Istituto Nazionale di Oceanografia e Geofisica Sperimentale (NODC/OGS),
acting within the International Oceanographic Data Exchange System of the
UNESCO Intergovernmental Oceanographic Commission (IOC) since 27/6/2002.
In order to illustrate the singularities of the Alboran Sea, in comparison with the
rest of the Mediterranean Sea, as well as to show the high spatial variability of nitrate
concentration, N:P molar ratio, Chl-a and PP in this basin, average integrated values
for these variables have been obtained. The data were “Generated using
E.U. Copernicus Marine Service Information.” Monthly mean data of Mediterranean
Sea Biogeochemistry Reanalysis (Teruzzi et al. 2016) (Product:
MEDSEA_REANALYSIS_BIO_006_008) (https://doi.org/10.25423/MEDSEA_
REANALYSIS_BIO_006_008) were downloaded from the E.U. Copernicus Marine
Environment Monitoring Service website (http://marine.copernicus.eu/servicesportfolio/access-to-products) and processed to get the average integrated values
(0–100 m) over the period 1999–2016 for those variables in the Mediterranean
208
T. Ramírez et al.
operating in the Strait of Gibraltar and also within the Alboran Sea, which are
addressed and discussed in this chapter. These fertilization processes lead to the
injection of new nutrients from subsurface waters into the euphotic layer supporting
enhanced phytoplankton biomass and primary production, particularly in the Northwestern (NW) Alboran Sea (Minas et al. 1991; Garcia-Gorriz and Carr 2001; Bosc
et al. 2004; Reul et al. 2005; Macías et al. 2007). However, the biogeochemical
signatures of the upwelled waters at the Strait of Gibraltar and its proximities, and
also those of Atlantic waters masses incursions, are progressively lost during the
progress of these waters through the Alboran Sea. As the distance to the Strait
increases the upper waters of the Alboran Sea become more oligotrophic (Bosc et al.
2004) due to the uptake of nutrients by phytoplankton and also to a lower number of
fertilization mechanisms and to a higher variability in the eastern sector (Ramírez
2007; Renault et al. 2012; Oguz et al. 2014).
This chapter reviews the biogeochemical features of the different water masses
found in the Alboran Sea, the different fertilization mechanisms (from upwelling
events to incursions of nutrient-rich North Atlantic Deep Water NACW) which
promote the injection of nutrient into the photic layer. The chapter also examines
the nutrient dynamics in this basin and the potential limitation of phytoplankton by
nutrients, as evidenced from the molar nitrate:phosphate (N:P) and nitrate:silicate
(N:Si) ratios, and discusses the role of phytoplankton uptake in regulating nutrient
concentrations and molar ratios in this basin. In addition, it also addresses the
distribution patterns of chlorophyll-a (Chl-a) and primary production (PP) in relation
to the hydrology and biogeochemical fields. The last section of this chapter analyses
the effects of climate change and ocean acidification on the biogeochemistry and
primary production in the Mediterranean and the Alboran Sea.
The average vertical profiles (annual climatologies) of nutrients and dissolved
oxygen, as well as the average seasonal vertical profiles (seasonal climatologies) of
Chl-a in the Alboran Sea (Manca et al. 2004) were plotted using data provided by
OGS Istituto Nazionale di Oceanografia e Geofisica Sperimentale. Source: Data and
metadata are provided by the Italian National Oceanographic Data Center of the
OGS Istituto Nazionale di Oceanografia e Geofisica Sperimentale (NODC/OGS),
acting within the International Oceanographic Data Exchange System of the
UNESCO Intergovernmental Oceanographic Commission (IOC) since 27/6/2002.
In order to illustrate the singularities of the Alboran Sea, in comparison with the
rest of the Mediterranean Sea, as well as to show the high spatial variability of nitrate
concentration, N:P molar ratio, Chl-a and PP in this basin, average integrated values
for these variables have been obtained. The data were “Generated using
E.U. Copernicus Marine Service Information.” Monthly mean data of Mediterranean
Sea Biogeochemistry Reanalysis (Teruzzi et al. 2016) (Product:
MEDSEA_REANALYSIS_BIO_006_008) (https://doi.org/10.25423/MEDSEA_
REANALYSIS_BIO_006_008) were downloaded from the E.U. Copernicus Marine
Environment Monitoring Service website (http://marine.copernicus.eu/servicesportfolio/access-to-products) and processed to get the average integrated values
(0–100 m) over the period 1999–2016 for those variables in the Mediterranean
208
T. Ramírez et al.