[U-08] Advances in Legacy and Emerging Contaminant Biogeosciences

9:30 〜 9:45

[U08-03] Elevated methylmercury in Antarctic mosslands

*Martin Tsui^1,2、Matthew Cheng¹、Shaoyi Wang¹、Ganxing Liu¹、Yingyu Bao²、Marcellus Leung¹、Luming Yang¹、Zhao Liang Chen¹、Jiying Li³、Jake Chung¹、Sae Yun Kwon⁴、Huan Zhong⁵、Patrick Lee²、Lin Liu¹、Alex Chow¹ (1.Chinese University of Hong Kong、2.City University of Hong Kong、3.Hong Kong University of Science and Technology、4.Pohang University of Science and Technology、5.Nanjing University)

キーワード：

Mercury、Antarctica、Greening、Transformations

Antarctic Peninsula (AP), the northernmost part of Antarctica (62 to 75^oS), is a vast land (~522,000 km²) with a rapid warming rate (+0.22-0.32 ^oC/decade). Recent studies demonstrated rapid greening phenomenon across different parts of AP, especially the coastal region, in which non-vascular, cryptogamic life forms including mosses, lichens, and ice algae dominate. Despite its remoteness, gaseous pollutants such as mercury (Hg) can arrive in Antarctica through long-range atmospheric transport and deposition. At King George Island (~62.2^oS), one of the northernmost islands in AP, we found that the non-vascular moss can sequester more atmospheric Hg (total Hg = 78±44 ng/g; n=32) compared to the non-vegetated soils (22±8 ng/g; n=22), thus greening of AP can elevate atmospheric deposition of inorganic Hg. Further, we found that within the "mosslands" the substrates contained elevated levels of highly toxic methylmercury (MeHg = 8.0±4.7 ng/g, n=28) compared to non-vegetated soils (0.10±0.17 ng/g, n=22). When we compare the MeHg data from mosslands with other wetland ecosystems such as mangroves, peatlands and swamps, their MeHg values are among the highest. In the meantime, our team is conducting remote-sensing-based mapping of moss distribution, analyses of organic matter compositions and metagenomics across the heterogeneous mossland landscapes and with or without the fertilization by penguin guano, etc. Thus, assuming these Hg and MeHg data are representative of other mosslands across AP, it is probable that Antarctic mosslands would represent an emerging biogeochemical hotspot for Hg in the most remote continent on the planet.