Predicting the global distribution of planktonic foraminifera using a dynamic ecosystem model
Résumé
We present a new planktonic foraminifera model developed for the global ocean mixed-layer. The main purpose of the model is to explore the response of planktonic foraminifera to different boundary conditions in the geological past, and to quantify the seasonal bias in foraminifera-based paleoceanographic proxy records. This model is forced with hydrographic data and with biological information taken from an ecosystem model to predict monthly concentrations of the most common planktonic foraminifera species used in paleoceanography: N. pachyderma (sinistral and dextral varieties), G. bulloides, G. ruber (white variety) and G. sacculifer. The sensitivity of each species with respect to temperature (optimal temperature and range of tolerance) is derived from previous sediment-trap studies.
Overall, the spatial distribution patterns of most of the species are in agreement with core-top data. N. pachyderma (sin.) is limited to polar regions, N. pachyderma (dex.) and G. bulloides are the most common species in high productivity zones, while G. ruber and G. sacculifer are more abundant in tropical and subtropical oligotrophic waters. For N. pachyderma (sin) and N. pachyderma (dex.), the season of maximum production coincides with that observed in sediment-trap records. Model and sediment-trap data for G. ruber and G. sacculifer show, in general, lower concentrations and less seasonal variability at all sites. A sensitivity experiment suggest that, within the temperature-tolerance range of a species, food availability may be the main parameter controlling its abundance.
Overall, the spatial distribution patterns of most of the species are in agreement with core-top data. N. pachyderma (sin.) is limited to polar regions, N. pachyderma (dex.) and G. bulloides are the most common species in high productivity zones, while G. ruber and G. sacculifer are more abundant in tropical and subtropical oligotrophic waters. For N. pachyderma (sin) and N. pachyderma (dex.), the season of maximum production coincides with that observed in sediment-trap records. Model and sediment-trap data for G. ruber and G. sacculifer show, in general, lower concentrations and less seasonal variability at all sites. A sensitivity experiment suggest that, within the temperature-tolerance range of a species, food availability may be the main parameter controlling its abundance.
Origine : Accord explicite pour ce dépôt
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