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Biogeochemical control of marine productivity in the Mediterranean Sea during the last 50 years.

Macias D, Garcia-Gorriz E, Piroddi C, Stips A - Global Biogeochem Cycles (2014)

Bottom Line: Almost identical low-frequency signals are found in the nutrient loads of the rivers and in the integrated nutrient levels in the surface marine ecosystem.That result seems to indicate that the control of marine productivity (plankton to fish) in the Mediterranean is principally mediated through bottom-up processes that could be traced back to the characteristics of riverine discharges.Biogeochemical evolution of the Mediterranean over the past 50 yearsRiver nutrient loads drive primary and secondary productionsStrong link between low trophic levels and fisheries.

View Article: PubMed Central - PubMed

Affiliation: European Commission, Joint Research Centre, Institute for Environment and Sustainability, Water Research Unit Ispra, Italy.

ABSTRACT

: The temporal dynamics of biogeochemical variables derived from a coupled 3-D model of the Mediterranean Sea are evaluated for the last 50 years (1960-2010) against independent data on fisheries catch per unit effort (CPUE) for the same time period. Concordant patterns are found in the time series of all of the biological variables (from the model and from fisheries statistics), with low values at the beginning of the series, a later increase, with maximum levels reached at the end of the 1990s, and a posterior stabilization. Spectral analysis of the annual biological time series reveals coincident low-frequency signals in all of them. The first, more energetic signal peaks around the year 2000, while the second, less energetic signal peaks near 1982. Almost identical low-frequency signals are found in the nutrient loads of the rivers and in the integrated nutrient levels in the surface marine ecosystem. Nitrate concentration shows a maximum level in 1998, with a later stabilization to present-day values, coincident with the first low-frequency signal found in the biological series. Phosphate shows maximum concentrations around 1982 and a posterior sharp decline, in concordance with the second low-frequency signal observed in the biological series. That result seems to indicate that the control of marine productivity (plankton to fish) in the Mediterranean is principally mediated through bottom-up processes that could be traced back to the characteristics of riverine discharges. The high sensitivity of CPUE time series to environmental conditions might be another indicator of the overexploitation of this marine ecosystem.

Key points: Biogeochemical evolution of the Mediterranean over the past 50 yearsRiver nutrient loads drive primary and secondary productionsStrong link between low trophic levels and fisheries.

No MeSH data available.


Related in: MedlinePlus

Model domain. Background color indicates bottom depth as included in the model configuration (isobaths of 100, 1000, and 3000 m are also indicated). Blue stars along the coast indicate the position of the 37 rivers included in the model setup. The three main rivers of the Mediterranean basin are indicated by larger red dots.
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fig01: Model domain. Background color indicates bottom depth as included in the model configuration (isobaths of 100, 1000, and 3000 m are also indicated). Blue stars along the coast indicate the position of the 37 rivers included in the model setup. The three main rivers of the Mediterranean basin are indicated by larger red dots.

Mentions: A fully coupled 3-D hydrodynamic-biogeochemical model of the entire Mediterranean basin (Figure 1) was run, covering the period from 1957 to 2012. The first 3 years (1957–1959) was not used in the analysis to avoid any influence of the initial conditions (spin-off period). The coupling of hydrodynamic and biogeochemical models was performed using the Framework for Aquatic Biogeochemical Model (FABM) [Bruggeman and Bolding, 2014]. The FABM is a two-way coupled model system in which hydrodynamics modify biogeochemistry by water movement, substance transport, light availability, and temperature-dependent process rates and in which biogeochemistry influences water column properties through light attenuation modifications by phytoplankton shelf-shading [Burchard et al., 2006].


Biogeochemical control of marine productivity in the Mediterranean Sea during the last 50 years.

Macias D, Garcia-Gorriz E, Piroddi C, Stips A - Global Biogeochem Cycles (2014)

Model domain. Background color indicates bottom depth as included in the model configuration (isobaths of 100, 1000, and 3000 m are also indicated). Blue stars along the coast indicate the position of the 37 rivers included in the model setup. The three main rivers of the Mediterranean basin are indicated by larger red dots.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493898&req=5

fig01: Model domain. Background color indicates bottom depth as included in the model configuration (isobaths of 100, 1000, and 3000 m are also indicated). Blue stars along the coast indicate the position of the 37 rivers included in the model setup. The three main rivers of the Mediterranean basin are indicated by larger red dots.
Mentions: A fully coupled 3-D hydrodynamic-biogeochemical model of the entire Mediterranean basin (Figure 1) was run, covering the period from 1957 to 2012. The first 3 years (1957–1959) was not used in the analysis to avoid any influence of the initial conditions (spin-off period). The coupling of hydrodynamic and biogeochemical models was performed using the Framework for Aquatic Biogeochemical Model (FABM) [Bruggeman and Bolding, 2014]. The FABM is a two-way coupled model system in which hydrodynamics modify biogeochemistry by water movement, substance transport, light availability, and temperature-dependent process rates and in which biogeochemistry influences water column properties through light attenuation modifications by phytoplankton shelf-shading [Burchard et al., 2006].

Bottom Line: Almost identical low-frequency signals are found in the nutrient loads of the rivers and in the integrated nutrient levels in the surface marine ecosystem.That result seems to indicate that the control of marine productivity (plankton to fish) in the Mediterranean is principally mediated through bottom-up processes that could be traced back to the characteristics of riverine discharges.Biogeochemical evolution of the Mediterranean over the past 50 yearsRiver nutrient loads drive primary and secondary productionsStrong link between low trophic levels and fisheries.

View Article: PubMed Central - PubMed

Affiliation: European Commission, Joint Research Centre, Institute for Environment and Sustainability, Water Research Unit Ispra, Italy.

ABSTRACT

: The temporal dynamics of biogeochemical variables derived from a coupled 3-D model of the Mediterranean Sea are evaluated for the last 50 years (1960-2010) against independent data on fisheries catch per unit effort (CPUE) for the same time period. Concordant patterns are found in the time series of all of the biological variables (from the model and from fisheries statistics), with low values at the beginning of the series, a later increase, with maximum levels reached at the end of the 1990s, and a posterior stabilization. Spectral analysis of the annual biological time series reveals coincident low-frequency signals in all of them. The first, more energetic signal peaks around the year 2000, while the second, less energetic signal peaks near 1982. Almost identical low-frequency signals are found in the nutrient loads of the rivers and in the integrated nutrient levels in the surface marine ecosystem. Nitrate concentration shows a maximum level in 1998, with a later stabilization to present-day values, coincident with the first low-frequency signal found in the biological series. Phosphate shows maximum concentrations around 1982 and a posterior sharp decline, in concordance with the second low-frequency signal observed in the biological series. That result seems to indicate that the control of marine productivity (plankton to fish) in the Mediterranean is principally mediated through bottom-up processes that could be traced back to the characteristics of riverine discharges. The high sensitivity of CPUE time series to environmental conditions might be another indicator of the overexploitation of this marine ecosystem.

Key points: Biogeochemical evolution of the Mediterranean over the past 50 yearsRiver nutrient loads drive primary and secondary productionsStrong link between low trophic levels and fisheries.

No MeSH data available.


Related in: MedlinePlus