Responses of summer phytoplankton biomass to changes in top-down forcing: Insights from comparative modelling
|Author(s)||Maar Marie1, Butenschon Momme2, 15, Daewel Ute3, Eggert Anja4, Fan Wei5, Hjollo Solfrid S.6, Hufnagl Marc7, Huret Martin8, Ji Rubao9, Lacroix Genevieve10, Peck Myron A., Radtke Hagen4, Sailley Sevrine2, Sinerchia Matteo11, Skogen Morten D.6, Travers-Trolet Morgane12, 13, Troost Tineke A., Van De Wolfshaar Karen14|
|Affiliation(s)||1 : Aarhus Univ, Dept Biosci, DK-4000 Roskilde, Denmark.
2 : Plymouth Marine Lab, Plymouth PL1 3DH, Devon, England.
3 : Helmholtz Zentrum Geesthacht, Inst Coastal Res, D-21502 Geesthacht, Germany.
4 : Leibniz Inst Balt Sea Res Warnemunde IOW, D-18119 Rostock, Germany.
5 : Zhejiang Univ, Ocean Coll, Hangzhou 316021, Zhejiang, Peoples R China.
6 : Inst Marine Res, N-5817 Bergen, Norway.
7 : Univ Hamburg, Inst Hydrobiol & Fisheries Sci, D-22767 Hamburg, Germany.
8 : IFREMER, Ctr Brest, STH LBH, Plouzane, France.
9 : Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA.
10 : Royal Belgian Inst Nat Sci, B-1200 Brussels, Belgium.
11 : CNR, IAMC, Inst Coastal Marine Environm, I-09170 Torregrande, Oristano, Italy.
12 : IFREMER, Ctr Manche Mer Nord, F-62321 Boulogne Sur Mer, France.
13 : Deltares, Boussinesqweg 1, NL-2629 HV Delft, Netherlands.
14 : Wageningen Marine Res, NL-1976 CP Ijmuiden, Netherlands.
15 : Euromediterranean Ctr Climate Change CMCC, I-40127 Bologna, BO, Italy.
|Source||Ecological Modelling (0304-3800) (Elsevier Science Bv), 2018-05 , Vol. 376 , P. 54-67|
|WOS© Times Cited||10|
|Keyword(s)||Plankton functional types, Trophic cascades, Zooplankton mortality, Phytoplankton, Ensemble modelling|
The present study describes the responses of summer phytoplankton biomass to changes in top-down forcing (expressed as zooplankton mortality) in three ecosystems (the North Sea, the Baltic Sea and the Nordic Seas) across different 3D ecosystem models. In each of the model set-ups, we applied the same changes in the magnitude of mortality (±20%) of the highest trophic zooplankton level (Z1). Model results showed overall dampened responses of phytoplankton relative to Z1 biomass. Phytoplankton responses varied depending on the food web structure and trophic coupling represented in the models. Hence, a priori model assumptions were found to influence cascades and pathways in model estimates and, thus, become highly relevant when examining ecosystem pressures such as fishing and climate change. Especially, the different roles and parameterizations of additional zooplankton groups grazed by Z1, and their importance for the outcome, emphasized the need for better calibration data. Spatial variability was high within each model indicating that physics (hydrodynamics and temperature) and nutrient dynamics also play vital roles for ecosystem responses to top-down effects. In conclusion, the model comparison indicated that changes in top-down forcing in combination with the modelled food-web structure affect summer phytoplankton biomass and, thereby, indirectly influence water quality of the systems.