* frontiers | Frontiers in Marine Science
TYPE Original Research
PUBLISHED 15 May 2023
DO! 10.3389/fmars.2023.1129951
D Check for updates ı
Deriving pre-eutrophic
conditions from an ensemble
model approach for the
North-West European seas
OPEN ACCESS
<DITED BY
Alessandro Bergamasco,
1stitute of Marine Science, National
kesearch Council (CNR), Italy
<EVIEWED BY
1ugian Yu,
ong Kong University of Science and
‚echnology (Guangzhou), China
Maximilian Berthold,
Mount Allison University, Canada
Justus Van Beusekom,
lelmholtz Centre for Materials and Coastal
kesearch (HZG), Germany
'CORRESPONDENCE
Sonja M. van Leeuwen
53 sonja.van.leeuwen@nioz.nl
RECEIVED 22 December 2022
ACCEPTED 13 March 2023
DUBLISHED 15 May 2023
Sonja M. van Leeuwen*, Hermann-J. Lenhart“, Theo C. Prins®,
Anouk Blauw*, Xavier Desmit*, Liam Fernand®,
Rene Friedland“, Onur Kerimoglu®, Genevieve Lacroix*,
Annelotte van der Linden, Alain Lefebvre®,
Johan van der Molen*, Martin Plus®, Itzel Ruvalcaba Baroni*®,
Tiago Silva®, Christoph Stegert*““*, Tineke A. Troost*
and Lauriane Vilmin*
Department of Coastal Systems, Netherlands Institute for Sea Research (NIOZ), Texel, Netherlands,
Department of Informatiks, Scientific Computing Group, Hamburg University, Hamburg, Germany,
Department of Marine and Coastal Systems, Deltares, Delft, Netherlands, *Operational Directorate
Natural Environment, Royal Belgian Institute for Natural Sciences (RBINS), Brussels, Belgium, °Centre
or Environment, Fisheries and Aquaculture Science (Cefas), Lowestoft, United Kingdom, Joint
tesearch Centre, Directorate D — Sustainable Resources, Ispra, Italy, 7Physical Oceanography and
nstrumentation, Leibniz Institute for Baltic Sea Research Warnemünde, Rostock, Germany, SInstitute
‘or Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of
Oldenburg, Oldenburg, Germany, °DYNECO-PELAGOS Laboratory, Institut Francais de Recherche
0ur l’Exploitation de la Mer (IFREMER), Plouzane, France, !*Department of Research and
Development, Oceanography, Swedish Meteorological and Hydrological Institute,
Norrköping, Sweden, Institute of Coastal Systems: Analysis and Modelling, Helmholtz-Zentrum
dereon, Geesthacht, Germany, *?Operational Modelling Group, Bundesamt für Seeschifffahrt und
Aydroagraphie. Hamburg, Germany
CITATION
van Leeuwen SM, Lenhart H-J, Prins TC,
3lauw A, Desmit X, Fernand L, Friedland R,
ferimoglu O, Lacroix G, van der Linden A,
„‚efebvre A, van der Molen J, Plus M,
Auvalcaba Baroni |, Silva T, Stegert C,
Troost TA and Vilmin L (2023) Deriving
ore-eutrophic conditions from an
ansemble model approach for the North-
West European seas.
Front. Mar. Sci. 10:1129951.
doi: 10.3389/fmars.2023.1129951
ZOPYRIGHT
© 2023 van Leeuwen, Lenhart, Prins, Blauw,
Desmit, Fernand, Friedland, Kerimoglu,
acroix, van der Linden, Lefebvre,
‚an der Molen, Plus, Ruvalcaba Baroni, Silva,
Stegert, Troost and Vilmin. This is an open-
access article distributed under the terms of
'he Creative Commons Attribution License
CC BY). The use, distribution or
‚eproduction in other forums is permitted,
orovided the original author(s) and the
copyright owner(s) are credited and that
‘he original publication in this journal is
zited, in accordance with accepted
academic practice. No use, distribution or
‚eproduction is permitted which does not
comply with these terms.
The pre-eutrophic state of marine waters is generally not well known,
czomplicating target setting for management measures to combat
autrophication. We present results from an OSPAR ICG-EMO model
assessment to simulate the pre-eutrophic state of North-East Atlantic marine
waters. Using an ecosystem model ensemble combined with an observation-
based weighting method we derive sophisticated estimates for key
autrophication indicators. Eight modelling centres applied the same riverine
nutrient loads, atmospheric nutrient deposition rates and boundary conditions to
heir specific model set-up to ensure comparability. The pre-eutrophic state was
defined as a historic scenario of estimated nutrient inputs (riverine, atmospheric)
at around the year 1900, before the invention and widespread use of industrial
'ertilizers. The period 2009-2014 was used by all participants to simulate both
‘he current state of eutrophication and the pre-eutrophic scenario, to ensure
hat differences are solely due to the changes in nutrient inputs between the
scenarios. Mean values were reported for winter dissolved inorganic nutrients
and total nutrients (nitrogen, phosphorus) and the nitrogen to phosphorus ratio,
and for growing season chlorophyll, chlorophyll 90° percentile, near-bed
oxygen minimum and net phytoplankton production on the level of the
OSPAR assessment areas. Results showed distinctly lower nutrient
concentrations and nitrogen to phosphorus ratio’s in coastal areas under pre-
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