Phytoplankton, which conduct a bulk of primary production and can rapidly respond to a wide range of environmental perturbations, represent a sensitive and important indicator for detecting ecological changes in coastal systems, like Mar Piccolo in Taranto. In this ecosystem, in the last fifty years, urban expansion and intensive agricultures have caused an increase in nutrients and organic matter levels, which are higher than the self-depurating capacities of the basin. Since 2000, to improve the water quality, a depuration plan has been implemented in Mar Piccolo. In the framework of the Integrated Project, SPICOSA (Science and Policy Integration for COastal Systems Assessment), system-based models are being developed to provide higher-level information and decision-support tools for solving problematic issues in coastal zones. Particularly, the preliminary results on phytoplankton community dynamics and productivity obtained by constructing a system based simulation model are here presented. The phytoplankton submodel provided us with a better quantitative understanding of primary production and has raised some questions concerning the controls on its production. The phytoplankton biomass variability is out of phase with the mussel biomass in a manner that resembles a predator-prey relationship, i.e. plankton bloom when the mussel population (grazing) is at a minimum and vice versa. During winter, plankton growth is favored because grazing is low and new nitrogen is added from fall-winter runoff. During summer, the phytoplankton biomass minimum appears to be primarily caused by grazing, due a minimum of diatoms, and limiting N/P ratios (phosphate is below detection levels in summer). During July-August period the phytoplankton community composition changes, with an increase in phytoflagellates and a decrease in diatoms. Our interpretation is that mussels have less good food to sustain their weight during the summer harvest period. In sum, this complicated sequence suggests a strong control on the phytoplankton by the mussel grazing. The simulation of the phytoplankton groups succession provides a useful indicator of system response to human perturbations, a calibration parameter for the species-specific growth, an indicator of trophic changes, and a control on the growth of mussels reared in Mar Piccolo.
Phytoplankton and mussel culture modelling in the framework of the sustainable management of the coastal zones: the case of the Mar Piccolo in Taranto
Caroppo C;Giordano L;
2012
Abstract
Phytoplankton, which conduct a bulk of primary production and can rapidly respond to a wide range of environmental perturbations, represent a sensitive and important indicator for detecting ecological changes in coastal systems, like Mar Piccolo in Taranto. In this ecosystem, in the last fifty years, urban expansion and intensive agricultures have caused an increase in nutrients and organic matter levels, which are higher than the self-depurating capacities of the basin. Since 2000, to improve the water quality, a depuration plan has been implemented in Mar Piccolo. In the framework of the Integrated Project, SPICOSA (Science and Policy Integration for COastal Systems Assessment), system-based models are being developed to provide higher-level information and decision-support tools for solving problematic issues in coastal zones. Particularly, the preliminary results on phytoplankton community dynamics and productivity obtained by constructing a system based simulation model are here presented. The phytoplankton submodel provided us with a better quantitative understanding of primary production and has raised some questions concerning the controls on its production. The phytoplankton biomass variability is out of phase with the mussel biomass in a manner that resembles a predator-prey relationship, i.e. plankton bloom when the mussel population (grazing) is at a minimum and vice versa. During winter, plankton growth is favored because grazing is low and new nitrogen is added from fall-winter runoff. During summer, the phytoplankton biomass minimum appears to be primarily caused by grazing, due a minimum of diatoms, and limiting N/P ratios (phosphate is below detection levels in summer). During July-August period the phytoplankton community composition changes, with an increase in phytoflagellates and a decrease in diatoms. Our interpretation is that mussels have less good food to sustain their weight during the summer harvest period. In sum, this complicated sequence suggests a strong control on the phytoplankton by the mussel grazing. The simulation of the phytoplankton groups succession provides a useful indicator of system response to human perturbations, a calibration parameter for the species-specific growth, an indicator of trophic changes, and a control on the growth of mussels reared in Mar Piccolo.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
