Reconstructing tropical Atlantic hydrography using planktonic foraminifera and an ocean model
Abstract. In the tropical Atlantic, planktonic fomminfera species are vertically distributed with highest abundances occunfng in the photic zone (approximately 0-100 m). The tropical Atlantic thermocline dips from east to west and varies seasonally due to changes in the southeast and northeast trade...
| Main Authors: | , , |
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| Other Authors: | |
| Format: | Text |
| Language: | English |
| Published: |
1990
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| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.353.9450 http://www.gfdl.noaa.gov/bibliography/related_files/acr9001.pdf?PHPSESSID=731ffe23b1cb09be698f7efaf0495a7e |
| Summary: | Abstract. In the tropical Atlantic, planktonic fomminfera species are vertically distributed with highest abundances occunfng in the photic zone (approximately 0-100 m). The tropical Atlantic thermocline dips from east to west and varies seasonally due to changes in the southeast and northeast trade winds. In the east, the thermocline is in the photic zone, and in the west, the well-mixed surface layer extends below the photic zone most of the year. As expected from species vertical distributions in plankton tows, the species assemblages on the seafloor are correlated to the hydrographiconditions of the overlying surface ocean layer. A new technique to reconstruct past tropical Atlantic (20øN to 20øS) photic zone hydrography and surface wind field uses faunal assemblage data from deep-sea cores. Planktonic foraminiferabundances in core tops correlate with observations of modern photic zone hydrography defined here as seasonal temperature variation and mixed layer depth. The hydrography is mathematically described using empirical orthogonal function (EOF) analysis of annual temperature range as a function of depth. Factor analysis of 29 species of planktonic foraminifera from 118 core tops produces three factors. The factors correlate to mixed layer depth and the two EOF modes. The ocean model of the Atlantic ocean producesimilar map patterns of the EOF modes. Therefore the |
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