Abstract
Abstract. 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.
Highlights
Planktonic foraminifera are widely used for paleoceanographic reconstructions
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, G. bulloides, G. ruber and G. sacculifer
The global distribution of N. pachyderma shows the lowest root mean squared error (RMSE), around 9%, while for the remaining the species the error varies between 22% and 25%
Summary
Planktonic foraminifera are widely used for paleoceanographic reconstructions. The spatial distribution of planktonic foraminifera species is controlled by physiological requirements, feeding preferences and temperature (e.g., Beand Hamilton, 1967; Beand Tolderlund, 1971). Shells of planktonic foraminifera extracted from marine sediments serve as an archive of chemical and physical signals that can be used to quantify past environmental conditions, such as temperature (e.g., Pflaumann et al, 1996; Malmgren et al, 2001), ocean stratification (e.g., Mulitza et al, 1997), atmospheric CO2 concentration (Pearson and Palmer, 2000) and biological productivity (Kiefer, 1998). Past sea-surface temperatures can be estimated by either quantifying differences between modern and fossil species assemblages (e.g., CLIMAP, 1976; Pflaumann et al, 1996; Malmgren et al, 2001), or by analyzing the isotopic or trace-element composition of the calcite in the shell (e.g., Rohling and Cooke, 1999; Lea, 1999). The seasonality of foraminiferal production is an important factor which has to be taken into account in paleoceanographic interpretations
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
