Changes in upwelling mechanisms drove the evolution of marine organisms

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doi: 10.1016/j.palaeo.2012.04.014
Author(s): Suto, Itsuki; Kawamura, Keita; Hagimoto, Shinta; Teraishi, Akihito; Tanaka, Yuichiro
Author Affiliation(s): Primary:
Nagoya University, Department of Earth and Planetary Sciences, Nagoya, Japan
Other:
Nissei Gakuen, Japan
ADMATECHS Company, Japan
NTT COMWARE Company, Japan
National Institute of Advanced Industrial Science and Technology, Japan
Volume Title: Palaeogeography, Palaeoclimatology, Palaeoecology
Source: Palaeogeography, Palaeoclimatology, Palaeoecology, Vol.339-341, p.39-51. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0031-0182 CODEN: PPPYAB
Note: In English. 116 refs.; illus., incl. sects., sketch map
Summary: Long-term evolution is thought to take opportunities that arise as a consequence of mass extinction (as argued, for example, by Gould, 2002) and the following biotic recovery, but there is absolutely no evidence for this being the case. However, our study shows that eutrophication by oceanic mixing also played a part in the enhancement of several evolutionary events amongst marine organisms, and these results could indicate that the rates of oceanic biodiversification may be slowed if upwelling becomes weakened by future global warming. This paper defines three distinct evolutionary events of resting spores of the marine diatom genus Chaetoceros, to reconstruct past upwelling through the analysis of several DSDP, ODP and land-based successions from the North, South and equatorial Pacific as well as the Atlantic Ocean during the past 40 million years. The Atlantic Chaetoceros Explosion (ACE) event occurred across the E/O boundary in the North Atlantic, and is characterized by resting spore diversification that occurred as a consequence of the onset of upwelling following changes in thermohaline circulation through global cooling in the early Oligocene. Pacific Chaetoceros Explosion events-1 and -2 (PACE-1 and PACE-2) are characterized by relatively higher occurrences of iron input following the Himalayan uplift and aridification at 8.5 Ma and ca. 2.5 Ma in the North Pacific region. These events not only enhanced the diversification and increased abundance of primary producers, including that of Chaetoceros, other diatoms and seaweeds, but also stimulated the evolution of zooplankton and larger predators, such as copepods and marine mammals, which ate these phytoplankton and plants. Current thinking suggests new evolutionary niches open up after a mass extinction, but our study finds that eutrophication can also stimulate evolutionary diversification. Moreover, in the opposite fashion, our results show that as thermohaline circulation abates, global warming progresses and the ocean surface becomes warmer, many marine organisms will be affected by the environmental degradation. Abstract Copyright (2012) Elsevier, B.V.
Year of Publication: 2012
Research Program: DSDP Deep Sea Drilling Project
IODP Integrated Ocean Drilling Program
ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Algae; Assemblages; Atlantic Ocean; Biodiversity; Biologic evolution; Biostratigraphy; Cenozoic; Cetacea; Chaetoceros; Chordata; Climate change; Cores; Deep Sea Drilling Project; Diatoms; Eocene; Eocene-Oligocene boundary; Eutheria; Eutrophication; Integrated Ocean Drilling Program; Mammalia; Marine environment; Marine sediments; Microfossils; Miocene; Neogene; Ocean Drilling Program; Ocean circulation; Oligocene; Pacific Ocean; Paleo-oceanography; Paleocirculation; Paleoclimatology; Paleoecology; Paleogene; Plantae; Sediments; Spores; Tertiary; Tetrapoda; Theria; Upwelling; Vertebrata
Record ID: 2012083605
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands

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