Affiliations: Institute of Geographical Sciences and Natural
Resources Research, Chinese Academy of Sciences, Beijing 100101, China | Northeast Institute of Geography and Agricultural
Ecology, Chinese Academy of Sciences, Changchun 130012, China
Abstract: Horizontal and vertical variations of daily average
CO_2 concentration above the wetland surface were studied in
Xianghai National Nature Reserve of China in August, 2000. The primary purpose
was to study spatial distribution characteristics of CO_2
concentration on the four levels of height (0.1 m, 0.6 m, 1.2 m and 2 m) and
compare the differences of CO_2 concentration under
different land covers. Results showed that daily average
CO_2 concentration above wetland surface in Xianghai
National Natural Reserve was lower than that above other wetlands in northeast
China as well as the worldwide average, suggesting that Xianghai wetland
absorbed CO_2 in August and acted as "sink" of
CO_2. The horizontal variations on the four levels of height
along the latitude were distinct, and had the changing tendency of "decreasing
after increasing" with the increase of height. The areas with obvious
variations were consistent on different levels of height, and those with the
highest variations appeared above surface of shore, sloping field, Typha
wetland and Phragmites wetland; the vertical variations were greatly different,
with the higher variations in Phragmites wetland and Typha wetland, and the
lands near the shore and the sloping field with the lower variations. Spatial
variations of daily average CO_2 concentrations above
wetland surface were affected by surface qualities and land covers.
