AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Distribution of Biological Ice Nuclei in the Precipitation of Eastern China
RUI DU, Zongmin Liang, Yaling Wang, Pengrui Du, Ziming Li, University of Chinese Academy of Science
Abstract Number: 24 Working Group: Bioaerosols: Characterization and Environmental Impact
Abstract It was well known that the formation of ice in the atmosphere has significant local, regional and global influence, ranging from precipitation to cloud nucleation and thus climate. Ice nucleation is one of the most basic processes that lead to precipitation. Biological ice nucleators function as catalysts for freezing at relatively warm temperatures (warmer than-10°C). The aim of this paper is to investigate the distribution state of the most active ice nuclei of bacteria Pseudomonas syringae-like which can impact water freezing temperature and were suggested that they have important potential roles in the natural upper atmospheric cloud ice nucleation. We have investigated the freezing temperatures of rainwater collected from the different ecosystems of the eastern China, such as urban, clear grassland and forest regions. Our results show that droplets of rainwater samples can freeze mostly between -14 ℃ and -16 ℃ except those from Hailar and UCAS sites. The further studies demonstrate that although there are pseudomonas bacteria present in the rainwater of these sites through species identification by means of 16srDNA sequencing of filter membranes they do not show as expected ice nucleation activity as reported phenomena. We believe that there may be some effective ice nucleis of biological particles in atmospheric rainwater but they can not be belonged to micro-organisms. Our results suggest that in atmospheric ice nucleation processes, the famous bacterial ice nucleation maybe not play the important role especially in precipitation processes.