Pollen Characteristics And Environmental Significance Of Five-linked-great-pool Lake In Heilongjiang Province Since The Last200Years

With the end of the little ice age, global temperature increased significantly in2007, the IPCC released comprehensive climate change report:from the1900-2000average global temperature increases year by year, and predict that the future will be a sharply rising trend, but lack in the northeast china of research data. Global warming is leading to ecological system significantly change, the most obviously is the highest latitudes of the northern hemisphere.In July2010, getting112centimeters of sediment column in Five-linked-great-pool2pool middle (48.46°N,126.09°E), The112cm core was obtained, at1-cm intervals for samples. Through to the sample of the210Pb and137Cs for radioactive isotopes dating, age span the is1836-2009AD. Through to the pollen in laboratory processing,112pieces pollen films, statistics to63pollen types, each can number about600grains of terrestrial plants pollens, and the statistics corresponding aquatic plants. Calculating the percentage of each sample and quality concentration. Get the following main results and knows:1, Pollen assemblag I (depths of122-63cm,1836-1914AD), the shrubs and herbs dominated (average of72.5%), and present a gradually reduce tendency and trees opposite; pollen assemblage II (depths of63-28cm,1915-1965AD), the change of the percentage content of shrubs, herbs (65%-74%) and trees (26%-35%) is not be much, but herbs, shrubs dominanted; pollen assemblage III (depths28-0cm1966-2009AD) the tree pollen(average of41%) increase obviousily, the main tree is Betual, but herbs and shrubs (average of58%) are maily composed of Artemisa, Poaceae, Chenopodiaceae.2, From the pollen of percentage content and concentration instruct to half wet area ecological and environmental conditions:1836-1914AD herbs and shrubs occupy absolute superiority, all kinds of species change stable and coverage is lower, and suggests that the end of the little ice age in the area is a relatively cold wet period;1914-1965AD this period of herbs percentage slightly decreased, but the coverage sharp increase, and Pediastrum appeared, and show a significantly higher temperature;1965-2009AD Artemisa reduce obviously, and Chenopodiaceae rises harply; Shrubs like dry of Corylus and trees of Ulmus and Quercus increase and explains the temperature rise. And the increase of Betula is likely to be the cause of human activities.3, Through the total pollen concentration and the main trees, herbs, and nearly50years local meteorological data, we can see that the pollen change and meteorological data have very good consistency.4, Through the high resolution pollen instructions of vegetation succession near200years and contrast the northern hemisphere temperature curve, find the succession of vegetation and climate change have very good consistency too.