The burial of permafrost organic carbon in the Chukchi Sea and its response to climate change in the past 200 years
Against the backdrop of global warming,the Arctic has experienced a series of changes,including perma-frost degradation,reduced summer sea ice,increased land runoff,and intensified coastal erosion.With global warm-ing,organic carbon(OC)stored in permafrost is accelerating its migration and release to the sea,which will affect the pattern of carbon cycling in the Arctic Ocean.However,there is currently little evidence to directly confirm this inference.This article analyzes the lignin and carbon isotopes of two hundred year scale sedimentary cores in the Chukchi Sea,and discusses the sources and profile changes of the buried organic matter.The results showed that the organic carbon in the columnar sediments of the Chukchi Sea came from a mixed contribution of herbaceous tis-sue of terrestrial C3 plants and marine source production.The absolute content of lignin Σ8 in sediment shows an overall upward trend,indicating that with global warming,more terrestrial materials are being transported to the Chukchi Sea.This study indicates that global warming caused by human activities has indeed increased the migra-tion of organic carbon from permafrost to the sea,and the increase in lignin content due to enhanced terrestrial in-puts is direct evidence of the enhanced melting of permafrost caused by global warming on a century scale.
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