Time-transgressive North Atlantic productivity changes upon Northern Hemisphere glaciation
Lawrence, K. T. (Lafayette College, Pennsylvania. Department of Geology and Environmental Geosciences)
Sigman, D. M. (Princeton University. Department of Geosciences)
Herbert, T. D. (Brown University. Department of Geological Sciences)
Riihimaki, C. A. (Princeton University. Council on Science and Technology)
Bolton, C. T. (Universidad de Oviedo. Departamento de Geología)
Rosell Melé, Antoni (Universitat Autònoma de Barcelona. Institut de Ciència i Tecnologia Ambientals)
Martínez García, Alfredo (Universitat Autònoma de Barcelona. Institut de Ciència i Tecnologia Ambientals)
Haug, Gerald H (ETH Zürich. Geologisches Institut)

Fecha:	2013
Resumen:	Marine biological export productivity declined in high-latitude regions in the North Pacific and Southern Ocean 2. 7 million years ago, in parallel with the intensification of Northern Hemisphere glaciation. Here we present data from the North Atlantic, which show a similar but time-transgressive pattern of high-latitude productivity decline from 3. 3 to 2. 5 Ma, with productivity decreasing first at 69°N, hundreds of thousands of years before it declined at 58°N. We propose that the cumulative data are best explained by an equatorward migration of the westerly winds, which caused a southward shift in the zone of Ekman divergence and upwelling-associated major nutrient supply over this time interval. We suggest that a similar equatorward migration of the westerly winds may also help explain the productivity changes observed in other high-latitude regions, particularly the Southern Ocean. At 2. 7 Ma, equatorial and temperate Atlantic sites began to show orbitally paced productivity pulses, consistent with a shoaling and meridional contraction of the nutrient-poor "warm sphere" that characterizes the low latitude upper ocean. This timing coincides with observed productivity changes in Southern Ocean, consistent with previous findings that the Southern Ocean exerts a strong influence on the fertility of the low-latitude Atlantic. Finally, we propose that the unique basin geometry of the North Atlantic caused deep water formation in this region to remain relatively stable despite equatorward migration of winds and ocean fronts.
Ayudas:	Ministerio de Economía y Competitividad AP2004/7151
Derechos:	Tots els drets reservats.
Lengua:	Anglès
Documento:	Article ; recerca ; Versió publicada
Publicado en:	Paleoceanography, Vol. 28 Issue 4 (December 2013) , p. 740-751, ISSN 1944-9186

DOI: 10.1002/2013PA002546

12 p, 4.7 MB

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Documentos de investigación > Documentos de los grupos de investigación de la UAB > Centros y grupos de investigación (producción científica) > Ciencias > Institut de Ciència i Tecnologia Ambientals (ICTA)
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