Abrupt climate change and collapse of deep-sea ecosystems

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doi: 10.1073/pnas.0705486105
Author(s): Yasuhara, Moriaki; Cronin, Thomas M.; deMenocal, Peter B.; Okahashi, Hisayo; Linsley, Braddock K.
Author Affiliation(s): Primary:
U. S. Geological Survey, Reston, VA, United States
Other:
Lamont-Doherty Earth Observatory, United States
State University of New York, University at Albany, United States
Volume Title: Proceedings of the National Academy of Sciences of the United States of America
Source: Proceedings of the National Academy of Sciences of the United States of America, 105(5), p.1556-1560. Publisher: National Academy of Sciences, Washington, DC, United States. ISSN: 0027-8424 CODEN: PNASA6
Note: In English. Supplemental information/data is available in the online version of this article. 72 refs.; illus., incl. charts
Summary: We investigated the deep-sea fossil record of benthic ostracodes during periods of rapid climate and oceanographic change over the past 20,000 years in a core from intermediate depth in the northwestern Atlantic. Results show that deep-sea benthic community "collapses" occur with faunal turnover of up to 50% during major climatically driven oceanographic changes. Species diversity as measured by the Shannon-Wiener index falls from 3 to as low as 1.6 during these events. Major disruptions in the benthic communities commenced with Heinrich Event 1, the Inter-Allerod Cold Period (IACP: 13.1 ka), the Younger Dryas (YD: 12.9-11.5 ka), and several Holocene Bond events when changes in deep-water circulation occurred. The largest collapse is associated with the YD/IACP and is characterized by an abrupt two-step decrease in both the upper North Atlantic Deep Water assemblage and species diversity at 13.1 ka and at 12.2 ka. The ostracode fauna at this site did not fully recover until ≈8 ka, with the establishment of Labrador Sea Water ventilation. Ecologically opportunistic slope species prospered during this community collapse. Other abrupt community collapses during the past 20 ka generally correspond to millennial climate events. These results indicate that deep-sea ecosystems are not immune to the effects of rapid climate changes occurring over centuries or less.
Year of Publication: 2008
Research Program: ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Absolute age; Arctic region; Argilloecia; Arthropoda; Assemblages; Atlantic Ocean; Benthic taxa; Biodiversity; Bond events; C-14; Carbon; Carolina Slope; Cenozoic; Climate change; Cores; Correlation; Crustacea; Dates; Deep-sea environment; Deep-water environment; Deglaciation; Depositional environment; Ecology; Ecosystems; Faunal studies; Foraminifera; GISP2; Glacial North Atlantic Intermediate Water; Globigerinacea; Globigerinidae; Globigerinoides; Greenland; Heinrich events; Holocene; Ice; Ice cores; Inter-Allerod Cold Period; Invertebrata; Isotope ratios; Isotopes; Krithe; Labrador Sea Water; Leg 172; Mandibulata; Marine environment; Microfossils; North Atlantic; North Atlantic Deep Water; Northeast Atlantic; O-18/O-16; ODP Site 1055; Ocean Drilling Program; Ocean circulation; Ostracoda; Oxygen; Paleo-oceanography; Planktonic taxa; Pleistocene; Protista; Quaternary; Radioactive isotopes; Rotaliina; Sea water; Shallow-water environment; Species diversity; Stable isotopes; Summit Greenland; Tests; Upper Pleistocene; Upper Weichselian; Ventilation; Weichselian; Younger Dryas
Coordinates: N723400 N723400 W0373700 W0373700
N324704 N324704 W0761711 W0761711
Record ID: 2010028500
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