Time-transgressive North Atlantic productivity changes upon Northern Hemisphere glaciation

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doi: 10.1002/2013PA002546
Author(s): Lawrence, K. T.; Sigman, D. M.; Herbert, T. D.; Riihimaki, C. A.; Bolton, C. T.; Martinez-Garcia, A.; Rosell-Melé, Antoni; Haug, G. H.
Author Affiliation(s): Primary:
Lafayette College, Department of Geology and Environmental Geosciences, Easton, PA, United States
Other:
Princeton University, United States
Brown University, United States
Universidad de Oviedo, Spain
Eidgenössische Technische Hochschule Zürich, Switzerland
Universitat Autonoma de Barcelona, Spain
Volume Title: Paleoceanography
Source: Paleoceanography, 28(4), p.740-751. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0883-8305 CODEN: POCGEP
Note: In English. NSF grants OCE-0623310, OCE-0447570, and OCE-0623487. 63 refs.; illus., incl. 1 table, sketch maps
Summary: 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. Abstract Copyright (2013), . American Geophysical Union. All Rights Reserved.
Year of Publication: 2013
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Arctic Ocean; Atlantic Ocean; Cenozoic; Climate forcing; DSDP Site 607; Deep Sea Drilling Project; Detroit Seamount; East Pacific; Emperor Seamounts; Equatorial Atlantic; Equatorial Pacific; Glaciation; IPOD; Leg 108; Leg 138; Leg 145; Leg 162; Leg 167; Leg 177; Leg 178; Leg 94; Marine environment; Mid-Atlantic Ridge; Neogene; North Atlantic; North Pacific; Northeast Atlantic; Northeast Pacific; Northwest Pacific; Norwegian Sea; ODP Site 1012; ODP Site 1090; ODP Site 1091; ODP Site 1096; ODP Site 662; ODP Site 846; ODP Site 882; ODP Site 907; ODP Site 982; Ocean Drilling Program; Orbital forcing; Pacific Ocean; Paleo-oceanography; Paleoclimatology; Paleoecology; Paleoenvironment; Pleistocene; Pliocene; Productivity; Quaternary; Rockall Bank; South Atlantic; South Pacific; Southeast Pacific; Southern Ocean; Tertiary; Theoretical models; Upper Pliocene; West Pacific; Winds
Coordinates: N691459 N691459 W0124154 W0124154
N410004 N410005 W0325726 W0325727
S012325 S012324 W0114421 W0114421
S425449 S425449 E0085359 E0085359
Record ID: 2014034896
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from John Wiley & Sons, Chichester, United Kingdom