Climate-related variations in atmospheric selenium as recorded in Greenland ice core during the past 30,000 years

Abstract

Selenium (Se) is an essential element for human and animal heath and plant growth. Atmospheric Se is well known to play an important role in global biogeochemical cycle of Se. Recently, it was reported that Se in Greenland snow samples originated mainly from coal combustion in Asian countries. However, the natural biogeochemical cycle of atmospheric Se is required to understand to what extent human activities have perturbed the atmospheric Se cycle. In this research, we present the first record of past natural change in the occurrence of Se in Greenland ice core covering the past 30,000 years. Se was directly measured by ICP-SF-MS. Out data show a strong variability in concentrations with lower values during the Last Glacial Maximum (LGM) and much higher values during warm Holocene period. This pattern is opposite to any known climatic variations in dust-derived trace elements in polar regions, indicating that there exists different natural sources other than crustal dust for atmospheric Se. The variations in Se concentrations during the last 100 years is shown to be similar to those in chlorophyll concentrations in the North Atlantic. This indicates that an important natural source of atmospheric Se could be marine biogenic activities.