Organic ligands in soil
Soil organic carbon is one of the largest carbon pools on the earth's surface and plays an important role in the global carbon cycle and response to climate change. Association with minerals is one of the most important processes stabilizing organic carbon. However, the chemical nature of organic carbon strongly binding with minerals is still largely unknown. We have developed and applied methods to identify the chemical nature of unknown ligands in soil environment, by integrating high-resolution mass spectrometry, iron isotopologue analysis, and metabolomic tools.
Arctic soils store two to three times carbon as in the atmosphere, and their fate under climate change is a threat to global societies. Greenhouse gas emissions generated during the melting of permafrost soils can be one of the strongest feedback of terrestrial ecosystems to temperature increase. Identifying the reactive organic carbon in tundra soil responsible for greenhouse gas emissions and feedback on climate change can be very crucial for the sustainable management of the tundra ecosystem.
Organic carbon in tundra soils
Legacy and emerging contaminants in climate change-sensitive regions
In parallel to accelerating carbon cycles in certain ecosystems, climate change can also potentially result in the release of legacy and emerging contaminants to the environment, such as in the Arctic region. The mobilized pollutants can potentially be taken up by human beings through the food chains. PI Yang has led a large interdisciplinary team to investigate human exposure to organic pollutants at formerly used defense sites through collaboration with Qawalangin Tribe of Unalaska.
Quinones in complex environment
Quinones have been claimed as the critical organic compounds in natural organic matter reactive for redox reactions, important for the biogeochemical cycles of carbon and other associated elements, such as iron. However, the chemical nature of natural quinones remains a mystery. We have been tackling this challenging question, by developing chemical tagging method, and integrating it with mass spectrometry analysis and metabolomic screening.
Wildfire and watershed functions
Wildfire surges under climate change and exerts significant influences on watershed functions, including the carbon cycle, mobilization of nutritional elements, and others. Reactive organic carbon in soil and ashes at wildfire-impacted sites is key to understanding the impact of wildfire on ecosystem functions. We have been applying the methods developed in our group to identify the reactive organic carbon, including organic ligands, quinones, and other compounds, in wildfire-derived materials and link them to the impact of wildfire on watershed functions.
