"The observed instability with the proven occurrence of short warming events during the transition from the last interglacial to the last glacial epoch
could be, when viewed carefully, a general, naturally occurring characteristic of such transition phases," said Dr Tatjana Boettger of the UFZ, who analyzed the sediment profiles at the UFZ's isotope laboratory in Halle.
Knoll says that some changes in plankton communities appear to have coincided with the glacial epochs
. On the other hand, some of the most complex life at the time--the red, green, and brown algae--survived just fine.
Global temperatures in the glacial epoch
swung up and down radically from one millennium to the next.
The availability of the extra nitrate during the glacial epoch
may have stimulated the proliferation of this basic marine staple in waters now considered nutrient deprived.
When the rest of the globe turned frosty during the last ice age, some 115,000 to 10,000 years ago, Earth's midsection seemed to weather the glacial epoch
with little or no cooling.
Geologists in the past speculated that the melting of such ice at the end of the glacial epoch
could have stimulated volcanic eruptions by unweighting the crust.
Climate researchers have long thought that the Arctic held only thin sea ice during the last glacial epoch
. But the new results raise the possibility that a floating ice sheet some 400 to 600 m thick could have covered much of the ocean, say the researchers.
During the last glacial epoch
, Earth repeatedly swayed from extremely frigid conditions to warmth and back again with startling speed.
Oceanographers who study deep-sea sediments detect signs that the tropical seas weathered the glacial epoch
with remarkable stability, hardly cooling at all.
First of all this is confirmed by the fact that the last three glacial epochs
, Dnieper (Mindel), Sozh (Riss), and Poozerian (Wurm), which are reflected in the modern surface, are represented here (Matveev et al.
The climate of 11,000 years ago was particularly harsh, with more extreme seasons than animals had experienced during the last ice age or the warm periods between previous glacial epochs
, says Lundelius.