For the first time in history, Chinese scientists discovered that without human interference, climate alone has caused the number of penguins in the South Pole to change drastically over the past 3,000 years.
The number of penguins recorded four major periods of growth and decline and decreases, falling to the lowest during the ice-age about 1,800 to 2,300 years ago, and reaching its climax about 1,400 to 1,800 years ago when the climate turned warmer.
The above results were carried in the recently published "Nature," the first time that a Chinese polar research paper has ever been selected to be printed in this authoritative magazine.
Chinese scientists coincidentally made the discovery when collecting mud samples in lakes, representing different time periods, to study through the changes of chemical elements how the climate in the South Pole has been affected.
However, Professor Sun Guangli, with the Chinese University of Science and Technology, and his group, surprisingly observed in the samples proportional change in the quantity of elements like fluorine and sulfur.
These contaminants are caused by the deposit of penguin excrement, they are believed to reflect the growth and decline of the life of penguins.
Experts say that the results are helpful to the study of changes in species and food chain in the South Pole in different historical periods, and can shed light on the relationship between the environmental evolution in the South Pole and the changes of the global climate.
(Xinhua 11/20/2000)
