Natural Global Warming Period Illuminated by New Data
Filed under: Discovery,News & Resources,Scientific Ocean Drilling
(Click to enlarge) The succession of exposed sediment representing the PETM event was found on the hill behind the glacier seen in the middle ground. The photograph was taken during fieldwork on Spitsbergen. (Credit: Dr Ian Harding (SOES))
Documentable knowledge of the effects of the Paleocene–Eocene Thermal Maximum (PETM) on plant and ocean life has been reported from a new Arctic drill site on Spitsbergen was reported by scientists on February 25, 2011, at the EurekaAlert site.
(From Examiner.com / by Paul Hamaker) – The Paleocene–Eocene Thermal Maximum (PETM) occurred about 56 million years ago. The global sea surface temperature rose about 5 degrees Celsius during that time.
All previous knowledge of the effect or the PETM on plant and ocean life in the Arctic came from ice and sediment cores extracted from Lomonosov Ridge (~ 88°N) by the Integrated Ocean Drilling Program (IODP Site 302-4A). These samples do not represent the entirety of the affect of the PETM global warming worldwide.
A new set of sediment core samples taken from the Spitsbergen area of the high Arctic (~78°N) shows a much different set of effects. The two sites are about 670 miles distance from each other.
The PETM samples from Spitsbergen suggest an earlier onset of the rise in global ocean levels that peaked about 13,000 years into the 170,000 years PETM period.
The existence of the remains of cyst-forming dinoflagellate plankton Apectodinium augustum and a change in the isotope content that is characteristic of the PETM suggest that the PETM affected lower ocean life predominately in the Spitsbergen by depleting the oxygen from lower levels of the ocean while the IODP Site 302-4A indicates oxygen depletion from the upper levels of the ocean.
There was also a lack of flowering plants at the Spitsbergen site but flowering plants were abundant at IODP Site 302-4A.
The authors of the paper suggest a larger variety of samples from other sites would provide sufficient evidence to enable computer mapping of the effects of the PETM and aid in the prediction of the effects of global warming on today’s plant life and ocean life.
Authors
Ian Harding, Adam Charles , John Marshall, Heiko Pälike, Paul Wilson, Edward Jarvis, Robert Thorne, Emily Morris, Rebecca Moremon, Richard Pearce and Shir Akbari of the University of Southampton’s School of Ocean and Earth Science (SOES) based at the National Oceanography Centre, Southampton, England, and Andrew Roberts of the Australian National University, Canberra.
Paper
Harding, I. C., Charles, A. J., Marshall, J. E. A., Pälike, H., Roberts, A. P., Wilson, P. A., Jarvis, E., Thorne, T., Morris, E., Moremon, R., Pearce, R. B. & Akbari, S. Sea-level and salinity fluctuations during the Paleocene–Eocene thermal maximum in Arctic Spitsbergen. Earth Planet. Sci. Lett. (2011). doi:10.1016/j.epsl.2010.12.043
