In this study, the first in situ static-chamber measurements were conducted at coastal Antarctica tundra for CHCl3 fluxes, which showed that CHCl3 was naturally emitted from the Antarctic tundra at 35 ± 27 nmol m−2 d−1, comparable to other reported important natural sources. Significantly, enhanced CHCl3 emission rates (66 ± 20 nmol m−2 d−1) were observed from ornithogenic soil on the island populated with penguins, which was rich in organic matter and halides coming from penguin excrements. It is estimated that Antarctic tundra emits up to 0.1 Gg CHCl3 per year, which is an important source for regional atmospheric CHCl3. Laboratory-based incubations suggested that organic carbon and chlorine inputs by penguins may stimulate O2 dependent microbial-mediated CHCl3 emission from the Antarctic tundra, and all tundra soils showed the maximum CHCl3 emission at 4°C. The strength of this CHCl3 source is also expected to change in response to Antarctic warming.
Antarctic work supported by National Natural Science Foundation of China (No. 41776190; 41976220), National Key Research and Development Program of China (No. 2020YFA0608501) and Strategic Priority Research Program of Chinese Academy of Sciences (No. XDB40010200). Note: No funds from China were received by UC Berkeley or our laboratory for this work.