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Provedor de dados:  5
País:  France
Título:  Phytoplankton growth formulation in marine ecosystem models: Should we take into account photo-acclimation and variable stoichiometry in oligotrophic areas?
Autores:  Ayata, S. -d.
Levy, Marina
Aumont, Olivier
Sciandra, Antoine
Sainte-marie, J.
Tagliabue, A.
Bernard, Olivier
Data:  2013-09
Ano:  2013
Palavras-chave:  Biogeochemical modeling
Redfield ratio
Internal quota
Micro-genetic algorithm
Resumo:  The aim of this study is to evaluate the consequences of accounting for variable Chl:C (chlorophyll:carbon) and C:N (carbon:nitrogen) ratios in the formulation of phytoplankton growth in biogeochemical models. We compare the qualitative behavior of a suite of phytoplankton growth formulations with increasing complexity: 1) a Redfield formulation (constant C:N ratio) without photo-acclimation (constant Chl:C ratio), 2) a Redfield formulation with diagnostic chlorophyll (variable and empirical Chl:C ratio), 3) a quota formulation (variable C:N ratio) with diagnostic chlorophyll, and 4) a quota formulation with prognostic chlorophyll (dynamic variable). These phytoplankton growth formulations are embedded in a simple marine ecosystem model in a 1D framework at the Bermuda Atlantic Time-series (BATS) station. The model parameters are tuned using a stochastic assimilation method (micro-genetic algorithm) and skill assessment techniques are used to compare results. The lowest misfits with observations are obtained when photo-acclimation is taken into account (variable Chl:C ratio) and with non-Redfield stoichiometry (variable C:N ratio), both under spring and summer conditions. This indicates that the most flexible models (i.e., with variable ratios) are necessary to reproduce observations. As seen previously, photo-acclimation is essential in reproducing the observed deep chlorophyll maximum and subsurface production present during summer. Although Redfield and quota formulations of C:N ratios can equally reproduce chlorophyll data the higher primary production that arises from the quota model is in better agreement with observations. Under the oligotrophic conditions that typify the BATS site no clear difference was detected between quota formulations with diagnostic or prognostic chlorophyll.
Tipo:  Text
Idioma:  Inglês

Editor:  Elsevier Science Bv
Formato:  application/pdf
Fonte:  Journal Of Marine Systems (0924-7963) (Elsevier Science Bv), 2013-09 , Vol. 125 , P. 29-40
Direitos:  2013 Elsevier B.V. All rights reserved.

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