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在气候变暖及人类活动的双重干扰下,疏勒河上游冻土发生了显著退化,具体表现为活动层厚度加大、植被退化等。然而,关于冻土退化对微生物的影响还未见报道。本文以疏勒河上游不同季节(4月、6月、9月)、不同退化程度冻土为对象,研究了可培养细菌数量的季节性变化及其影响因素。结果表明:研究区域可培养细菌数量介于0.4×10~7~5.3×10~7CFU·g~(-1),3个月份土壤可培养细菌数量均随冻土退化程度增加而显著下降,且同种类型冻土6月份样品中可培养细菌数量最多,但不同类型冻土细菌数量的季节变化未表现出一致的规律性。相关性分析表明,可培养细菌数量与土壤含水量、总氮呈极显著正相关,与有机碳呈显著正相关。这些结果表明,伴随着冻土退化而发生的地上植被逆向演替过程中,青藏高原不同类型冻土间已产生较大的环境异质性如土壤碳氮及含水量,进一步可能导致冻土微生物数量分异。研究结果为利用微生物综合评价青藏高原不同类型冻土的生态环境提供了数据基础。
Under the double interference of climate warming and human activities, the permafrost in the upper Shule River degenerated significantly, which was manifested in the increase of active layer thickness and vegetation degeneration. However, the impact of frozen soil degradation on microorganisms has not been reported yet. In this paper, the seasonal variation of culturable bacteria and its influencing factors were studied in different seasons (April, June and September) and different degraded degrees of frozen soil in upper reaches of Shule River. The results showed that the number of culturable bacteria in the study area ranged from 0.4 × 10 ~ 7 ~ 5.3 × 10 ~ 7CFU · g -1, and the number of soil culturable bacteria decreased significantly with the increase of the degree of permafrost degradation in three months The same type of frozen soil samples in June the largest number of cultivable bacteria, but the different types of frozen soil seasonal changes in the number of bacteria did not show a consistent pattern. Correlation analysis showed that there was a significant positive correlation between the amount of culturable bacteria and total soil water content and total nitrogen, and positively correlated with organic carbon. These results show that during the reverse succession of above-ground vegetation accompanied by the degradation of frozen soils, large environmental heterogeneities such as soil carbon, nitrogen and water content have been produced among different types of frozen soil in the Qinghai-Tibet Plateau, which may further lead to the formation of permafrost microorganisms The number of differences. The results provided a data basis for the comprehensive evaluation of the ecological environment of different types of frozen soil in the Qinghai-Tibet Plateau using microorganisms.