北京市夏季空气微生物群落结构和生态分布

Community structure and ecological distribution of airborne microbes in summer in Beijing

着重研究北京市夏季空气微生物的群落结构和生态分布特征。结果表明 :北京市夏季空气中革兰氏阳性菌明显多于革兰氏阴性菌 ,约占 70 %～ 85 % ,其中阳性球菌占总数的占 35 %～ 4 5 %。 3个功能区 (文教区、交通干线和公园绿地 )共发现 30属空气细菌 ,其中革兰氏阳性菌 2 0属 ,革兰氏阴性菌 10属。优势细菌属为微球菌属 (Micrococcus)、芽孢杆菌属 (Bacillus)、葡萄球菌属 (Staphylococcus)和假单胞菌属 (Pseudomonas)。 3个功能区共出现 10属空气真菌 ,优势菌属枝孢属 (Cladosporium)、链格孢属 (Alternaria)、无孢菌 (nonsporing)、青霉属 (Penicillium)和曲霉属 (Aspergillus) ,其中枝孢属是绝对优势菌属 ,占总数的4 8.2 %。空气细菌浓度交通干线和文教区明显高于公园绿地 ,而空气真菌浓度公园绿地和文教区明显高于交通干线。空气细菌浓度一日中 13:0 0时较低 ,0 9:0 0时和 17:0

Airborne microbes are living bodies which include airborne bacteria, fungi, actinomycetes, etc. They are fundamental biological components in an urban ecosystem and have a direct relationship with ecological balance and the function of many other life forms in nature. Initial research on airborne microbes can be traced back to the mid-19th Century, when Schwann found that the axenic materials were the cause of fermentation and contagion by airborne microbes. Now, due to the effects of human activities, the main focus has gradually changed from the investigation on animal and plant-life diseases to urban microbe contamination and the discrepancy of different microbe monitoring system. Admittedly, airborne microbes propagate and diffuse all around the environment, which does lead to human allergies and affect human health. Elevated levels of airborne microbe concentration have been proven to be associated with decreased lung function, increased adverse respiratory symptoms such as cough, shortness of breath, wheezing and asthma attacks, as well as chronic obstructive pulmonary disease, cardiovascular diseases, and lung cancer. Moreover, green space and fancy vegetation in urban locals could succumb to disease because of the pathogens in the atmosphere. In addition, metal materials of urban structures and precise instruments of scientific research could also be eroded by airborne microbes, which could lead to significant economic loss.This study on the community structure and ecological distribution characteristic of airborne microbes was carried out in detail in Beijing. Results showed that Gram positive bacteria contributing 70%～85% were much more than Gram negative bacteria, the Gram positive cocci accounting for 35%～45% were the dominant bacteria. Amongst 30 genera of bacteria, including 20 Gram positive bacteria and 10 Gram negative bacteria, Micrococcus, Bacillus, Staphylococcus and Pseudomonas were most predominant. In different functional regions, the most frequently isolated fungal genus were Cladosporium, Alternaria, non-sporulating mycelia, Penicillium and Aspergillus respectively. Cladosporium, which account for 48.22% of the total fungi concentration, was the most dominant genus. The concentration of airborne bacteria was significantly lower in Garden Greenbelt (GGB) than in Culture and Education Region (CER), and Main Traffic Line (MTL). Whereas the concentration of airborne fungi in GGB was higher than in CER and MTL. In different time in a day, the lower number of airborne bacteria was exhibited at 13 o′clock.