"Soil organisms, as recorded by trace fossils in paleosols of the Willwood Formation, Wyoming, show significant body-size reductions and increased abundances during the Paleocene-Eocene Thermal Maximum (PETM). Paleobotanical, paleopedologic, and oxygen isotope studies indicate high temperatures during the PETM and sharp declines in precipitation compared with late Paleocene estimates," researchers in the United States report (see also Science).
"Insect and oligochaete burrows increase in abundance during the PETM, suggesting longer periods of soil development and improved drainage conditions. Crayfish burrows and molluscan body fossils, abundant below and above the PETM interval, are significantly less abundant during the PETM, likely because of drier floodplain conditions and lower water tables. Burrow diameters of the most abundant ichnofossils are 30-46% smaller within the PETM interval. As burrow size is a proxy for body size, significant reductions in burrow diameter suggest that their tracemakers were smaller bodied. Smaller body sizes may have resulted from higher subsurface temperatures, lower soil moisture conditions, or nutritionally deficient vegetation in the high-CO2 atmosphere inferred for the PETM. Smaller soil fauna co-occur with dwarf mammal taxa during the PETM; thus, a common forcing mechanism may have selected for small size in both above-and below-ground terrestrial communities. We predict that soil fauna have already shown reductions in size over the last 150 years of increased atmospheric CO2 and surface temperatures or that they will exhibit this pattern over the next century," wrote J.J. Smith and colleagues, University of Kansas.
The researchers concluded: "We retrodict also that soil fauna across the Permian-Triassic and Triassic-Jurassic boundary events show significant size decreases because of similar forcing mechanisms driven by rapid global warming."
Smith and colleagues published their study in Proceedings of the National Academy of Sciences of the United States of America (Transient dwarfism of soil fauna during the Paleocene-Eocene Thermal Maximum. Proceedings of the National Academy of Sciences of the United States of America, 2009;106(42):17655-17660).
For additional information, contact J.J. Smith, University of Kansas, Kansas Geol Survey, 1930 Constant Avenue, Lawrence, KS 66047, USA.
Publisher contact information for the journal Proceedings of the National Academy of Sciences of the United States of America is: National Acad Sciences, 2101 Constitution Avenue NW, Washington, DC 20418, USA.
Keywords: United States, Lawrence, Life Sciences, Dwarfism, University of Kansas.
This article was prepared by Science Letter editors from staff and other reports. Copyright 2009, Science Letter via NewsRx.com.
"Research results from University of Kansas update knowledge of science." Science Letter 17 Nov. 2009: 2058. Academic OneFile. Web. 28 Nov. 2009.
Gale Document Number:A211905837
Disclaimer:This information is not a tool for self-diagnosis or a substitute for professional care.
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