Abstract Precipitation events may rapidly alter soil moisture, and potentially result in a large quantity of soil CO2 release in a short term. However, the effect of pulse precipitation on soil CO2 release among different grassland types on the Tibetan Plateau remains unclear. Here, we investigated soil CO2 release following pulse precipitation in the meadows, grasslands, and deserts of the Tibetan Plateau along a precipitation gradient. This was achieved using a new device that measures soil respiration rate (RS) continuously and frequently, thus allowing us to conduct 48-h simulation incubation experiments. We evaluated the pulse effect using the indices of the accumulation of microbial respiration carbon emission per gram of soil (ARs-Soil) and the accumulation of microbial respiration carbon emission per gram of soil organic carbon (SOC) (ARs-SOC). The results showed strong precipitation pulse effects, with ARs-Soil and ARs-SOC differing among the three grassland types owing to the soil properties, climate factors, and microbial biomass. ARs-Soil was higher in alpine meadows than in alpine deserts and alpine grasslands because of the higher SOC. Conversely, ARs-SOC was higher in alpine deserts (8.73 ± 3.37 mg C g−1 SOC) than in alpine meadows (2.66 ± 0.91 mg C g−1 SOC) and alpine grasslands (4.39 ± 0.84 mg C g−1 SOC). ARs-SOC/phospholipid fatty acid (PLFA) showed trends similar to ARs-SOC, thereby indicating that microbes in alpine desert were more sensitive to changes in soil moisture. Overall, the results show that the response of soil CO2 release to pulse precipitation in the Tibetan Plateau grasslands is related to grassland type. Furthermore, owing to the stronger response of soil microbes to pulse precipitation in arid regions, microbial responses to changing precipitation levels may be stronger under conditions of increasing drought in the future.

中文翻译：

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脉冲降水对青藏高原不同草地类型土壤CO2释放的影响

摘要 降水事件可能会迅速改变土壤水分，并可能在短期内导致大量土壤 CO2 释放。然而，脉冲降水对青藏高原不同草地类型土壤CO2释放的影响尚不清楚。在这里，我们调查了青藏高原草甸、草原和沙漠沿降水梯度脉冲降水后土壤 CO2 的释放。这是使用一种新的设备来实现的，该设备可以连续频繁地测量土壤呼吸率 (RS)，从而使我们能够进行 48 小时的模拟孵化实验。我们使用每克土壤微生物呼吸碳排放累积 (ARs-Soil) 和每克土壤有机碳 (SOC) 微生物呼吸碳排放累积 (ARs-SOC) 的指数评估脉冲效应。结果显示强降水脉冲效应，由于土壤性质、气候因素和微生物生物量，三种草地类型的 ARs-Soil 和 ARs-SOC 存在差异。由于 SOC 较高，高山草甸的 ARs-土壤高于高山沙漠和高山草原。相反，高山沙漠 (8.73 ± 3.37 mg C g-1 SOC) 的 ARs-SOC 高于高山草甸 (2.66 ± 0.91 mg C g-1 SOC) 和高山草原 (4.39 ± 0.84 mg C g-1 SOC) . ARs-SOC/磷脂脂肪酸 (PLFA) 显示出与 ARs-SOC 相似的趋势，从而表明高山沙漠中的微生物对土壤水分的变化更为敏感。总体而言，结果表明青藏高原草地土壤CO2释放对脉冲降水的响应与草地类型有关。此外，由于干旱地区土壤微生物对脉冲降水的响应更强，在未来干旱加剧的条件下，微生物对降水水平变化的响应可能更强。