Anhui Province Key Laboratory of Polar Environment and Global Change, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China.
Department of Geography, University of California Berkeley, Berkeley, California 94720, United States.
Environ Sci Technol. 2020 Oct 20;54(20):13354-13363. doi: 10.1021/acs.est.0c04257. Epub 2020 Oct 8.
Methyl chloride (CHCl) and methyl bromide (CHBr) are the predominant carriers of natural chlorine and bromine from the troposphere to the stratosphere, which can catalyze the destruction of stratospheric ozone. Here, penguin colony soils (PCS) and the adjacent tundra soils (i.e., penguin-lacking colony soils, PLS), seal colony soils (SCS), tundra marsh soils (TMS), and normal upland tundra soils (UTS) in coastal Antarctica were collected and incubated for the first time to confirm that these soils were CHCl and CHBr sources or sinks. Overall, tundra soil acted as a net sink for CHCl and CHBr with potential flux ranges from -18.1 to -2.8 pmol g d and -1.32 to -0.24 pmol g d, respectively. The deposition of penguin guano or seal excrement into tundra soils facilitated the simultaneous production of CHCl and CHBr and resulted in a smaller sink in PCS, SCS, and PLS. Laboratory-based thermal treatments and anaerobic incubation experiments suggested that the consumption of CHCl and CHBr was predominantly mediated by microbes while the production was abiotic and O independent. Temperature gradient incubations revealed that increasing soil temperature promoted the consumption of CHCl and CHBr in UTS, suggesting that the regional sink may increase with Antarctic warming, depending on changes in soil moisture and abiotic production rates.
甲基氯（CHCl）和甲基溴（CHBr）是从对流层向平流层输送天然氯和溴的主要载体，可催化平流层臭氧的破坏。在这里，首次采集了南极沿海地区的企鹅聚居地土壤（PCS）和相邻的冻原土壤（即无企鹅聚居地土壤，PLS）、海豹聚居地土壤（SCS）、冻原沼泽土壤（TMS）和正常高地冻原土壤（UTS），并进行了培养，以确认这些土壤是 CHCl 和 CHBr 的源或汇。总体而言，冻原土壤对 CHCl 和 CHBr 表现出净汇，潜在通量范围分别为-18.1 至-2.8 pmol g d 和-1.32 至-0.24 pmol g d。企鹅粪便或海豹排泄物的沉积促进了 CHCl 和 CHBr 的同时产生，从而导致 PCS、SCS 和 PLS 的汇较小。基于实验室的热处理和厌氧培养实验表明，CHCl 和 CHBr 的消耗主要由微生物介导，而产生则是无生命的，与 O 无关。温度梯度培养揭示了土壤温度的升高促进了 UTS 中 CHCl 和 CHBr 的消耗，这表明随着南极变暖，区域汇可能会增加，这取决于土壤湿度和非生物产生速率的变化。
