Trophic cascades of bottom-up and top-down forcing on nutrients and plankton in the Kattegat, evaluated by modelling
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Trophic cascades of bottom-up and top-down forcing on nutrients and plankton in the Kattegat, evaluated by modelling. / Petersen, Marcell Elo; Maar, Marie; Larsen, Janus; Møller, Eva Friis; Hansen, Per Juel.
In: Journal of Marine Systems, Vol. 169, 05.2017, p. 25-39.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Trophic cascades of bottom-up and top-down forcing on nutrients and plankton in the Kattegat, evaluated by modelling
AU - Petersen, Marcell Elo
AU - Maar, Marie
AU - Larsen, Janus
AU - Møller, Eva Friis
AU - Hansen, Per Juel
PY - 2017/5
Y1 - 2017/5
N2 - The aim of the study was to investigate the relative importance of bottom-up and top-down forcing on trophic cascades in the pelagic food-web and the implications for water quality indicators (summer phytoplankton biomass and winter nutrients) in relation to management. The 3D ecological modelERGOM was validated and applied in a local set-up of the Kattegat, Denmark, using the off-line Flexsem framework. The model scenarios were conducted by changing the forcing by ±20% of nutrient inputs (bottom-up) and mesozooplankton mortality (top-down), and both types of forcing combined. The model results showed that cascading effects operated differently depending on the forcing type. In the single-forcing bottom-up scenarios, the cascade directions were in the same direction as the forcing. For scenarios involving top-down, there was a skipped-level-transmission in the trophic responses that was either attenuated or amplified at different trophic levels. On a seasonal scale, bottom-up forcing showed strongest response during winter-spring for DIN and Chl a concentrations, whereas top-down forcing had the highest cascade strength during summer for Chl a concentrations and microzooplankton biomass. On annual basis, the system was more bottom-up than top-down controlled. Microzooplankton was found to play an important role in the pelagic food web as mediator of nutrient and energy fluxes. This study demonstrated that the best scenario for improved water quality was a combined reduction in nutrient input and mesozooplankton mortality calling for the need of anintegrated management of marine areas exploited by human activities.
AB - The aim of the study was to investigate the relative importance of bottom-up and top-down forcing on trophic cascades in the pelagic food-web and the implications for water quality indicators (summer phytoplankton biomass and winter nutrients) in relation to management. The 3D ecological modelERGOM was validated and applied in a local set-up of the Kattegat, Denmark, using the off-line Flexsem framework. The model scenarios were conducted by changing the forcing by ±20% of nutrient inputs (bottom-up) and mesozooplankton mortality (top-down), and both types of forcing combined. The model results showed that cascading effects operated differently depending on the forcing type. In the single-forcing bottom-up scenarios, the cascade directions were in the same direction as the forcing. For scenarios involving top-down, there was a skipped-level-transmission in the trophic responses that was either attenuated or amplified at different trophic levels. On a seasonal scale, bottom-up forcing showed strongest response during winter-spring for DIN and Chl a concentrations, whereas top-down forcing had the highest cascade strength during summer for Chl a concentrations and microzooplankton biomass. On annual basis, the system was more bottom-up than top-down controlled. Microzooplankton was found to play an important role in the pelagic food web as mediator of nutrient and energy fluxes. This study demonstrated that the best scenario for improved water quality was a combined reduction in nutrient input and mesozooplankton mortality calling for the need of anintegrated management of marine areas exploited by human activities.
U2 - 10.1016/j.jmarsys.2017.01.006
DO - 10.1016/j.jmarsys.2017.01.006
M3 - Journal article
VL - 169
SP - 25
EP - 39
JO - Journal of Marine Systems
JF - Journal of Marine Systems
SN - 0924-7963
ER -
ID: 172060775