Tundra Plants Act as Important Sinks for Carbonyl Sulfide and Carbon Disulfide in Maritime Antarctica.

Carbonyl sulfide (OCS) and carbon disulfide (CS2) are important sulfur carrier gases in the atmosphere. Higher plants have been identified as both their consumers and emitters, but relatively few studies focus on plants in high-latitude ecosystems. In this study, dominant plants (moss, lichen, and hair grass) and soils were collected across tundra ecotopes in maritime Antarctica and incubated under controlled conditions to explore the uptake and emission of OCS and CS2. Tundra vegetation (e.g., Sanionia georgicouncinata, Sanionia uncinata, Usnea antarctica) consistently consumed OCS (-2.66 to -11.36 pmol m-2 s-1) and CS2 (-0.08 to -0.48 pmol m-2 s-1) with a significant positive correlation between their uptake rates (r = 0.99, p < 0.001), likely driven by the activities of RuBisCO, an enzyme involved in photosynthesis. In comparison, tundra soils fluctuated between sources and sinks of OCS (-1.65 to 4.29 pmol m-2 s-1) but showed consistent CS2 emissions (4.70 to 7.65 pmol m-2 s-1). Particularly, penguin colony soils were uniform sources of OCS and CS2. Plants dominated the overall uptake of OCS and CS2 by Antarctic tundra (≥66%), and these biogenic sinks are expected to be conserved under climate warming, accompanying the enhancement in OCS uptake with light intensity. This study improved our understanding of sulfur biogeochemical interactions and their environmental implications in Antarctic tundra.