Selenium volatilization from tundra soils in maritime Antarctica

Area of Science:

• Environmental Science
• Geochemistry
• Antarctic Research

Background:

• Maritime Antarctica receives substantial selenium (Se) input into terrestrial ecosystems from penguin and seal guano.
• Se emissions via biomethylation and volatilization from these sources have not been previously studied.
• Understanding Se biogeochemical cycling is crucial for polar ecosystems.

Purpose of the Study:

• To investigate selenium volatilization and speciation in Antarctic soils influenced by seabird and seal colonies.
• To determine the impact of soil temperature and freeze-thaw cycles on Se volatilization rates.
• To assess the role of Se volatilization in the regional biogeochemical cycling of selenium.

Main Methods:

• Collection of soils from penguin colony soils (PCS), seal colony soils (SCS), and adjacent tundra soils.
• Incubation experiments using a chemo-trapping method to measure Se volatilization rates (VR_Se).
• Analysis of Se speciation, including methylated Se compounds (DMSe, DMDSe).

Main Results:

• PCS and SCS showed significantly higher Se content than normal tundra soils, primarily bound to organic matter.
• Greatest Se volatilization rates were observed in PCS and SCS at low temperatures (4°C).
• Soil frozen-thawing and increasing soil temperature significantly enhanced Se volatilization rates, showing a strong positive correlation.

Conclusions:

• Climate warming, freeze-thaw cycles, and high Se inputs from marine animals will increase tundra soil Se volatilization in maritime Antarctica.
• Volatilization of Se from penguin colony soils is a significant factor in Se mobilization and regional biogeochemical cycling.
• Elevated Se levels in mosses near penguin colonies support the importance of Se volatilization in this polar environment.