Dispersal and biogeography of marine plankton; long-distance dispersal of the foraminifer Truncorotalia truncatulinoides

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doi: 10.1130/G25232A.1
Author(s): Sexton, Philip F.; Norris, Richard D.
Author Affiliation(s): Primary:
University of Southampton, National Oceanography Centre, Southampton, United Kingdom
Scripps Institution of Oceanography, United States
Volume Title: Geology (Boulder)
Source: Geology (Boulder), 36(11), p.899-902. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613 CODEN: GLGYBA
Note: In English. 34 refs.; illus., incl. sketch map
Summary: Speciation models for marine plankton commonly assume that tectonic barriers and water mass fronts act as potent isolating mechanisms. Here we present evidence indicating that tectonic and water mass barriers to dispersal are, in some cases, very weak. We identify a transient occurrence (19 k.y. duration) of the planktic foraminifer Truncorotalia truncatulinoides in the Atlantic Ocean 500 k.y. before its generally accepted first appearance anywhere outside the southwest Pacific. This finding provides strong evidence for long-distance dispersal of plankton, enabling them to opportunistically colonize normally inhospitable environments as soon as they become favorable. Our newly described appearances of T. truncatulinoides in the Atlantic are restricted to the onset of the first very severe glacial stage (marine isotope stage 100) at 2.54 Ma, approximately 200 k.y. after the global evolution of the species in the southwest Pacific. This ability of plankton to disperse long distances, combined with recent evidence for high gene flow throughout the extra-polar oceans, suggests that it may be very difficult, even impossible, to geographically isolate pelagic populations for extended periods of time, a key component in vicariant and allopatric speciation models. Instead, high dispersal capability favors sympatric or parapatric processes as the prevalent modes of marine speciation.
Year of Publication: 2008
Research Program: ODP Ocean Drilling Program
Key Words: 10 Paleontology, Invertebrate; 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; Biogeography; Biologic evolution; Caribbean Sea; Ceara Rise; Cenozoic; Colombian Basin; Equatorial Atlantic; Foraminifera; Genetics; Invertebrata; Leg 154; Leg 165; MIS 100; Marine environment; Microfossils; Morphology; Neogene; North Atlantic; ODP Site 925; ODP Site 999; Ocean Drilling Program; Paleogeography; Plankton; Planktonic taxa; Pliocene; Protista; Reconstruction; Spatial distribution; Speciation; Temporal distribution; Tertiary; Truncorotalia truncatulinoides; Upper Pliocene
Coordinates: N041215 N041216 W0432920 W0432922
N124437 N124437 W0784422 W0784422
Record ID: 2009001633
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