Search

Soil erosion in East and Southeast Asia is believed to have increased significantly since the regional economic boom of the 1970s–1980s. However, limited records of soil erosion make it difficult to understand and indeed verify such changes. Here we present two new monthly resolved Ba/Ca records from Porites coral skeletons from southern Taiwan and central Vietnam, supplemented with some sporadic monthly and annually resolved coral δ138/134Ba data. Our records span the 1980s to the 2000s and suggest that there were intervals of elevated seawater Ba concentrations (Basw) during the intervals 1987–1995 in southern Taiwan and 1992–2001 in central Vietnam. In combination with evidence for insignificant changes in regional seawater δ138/134Ba values, model simulations, and other published coral Ba/Ca records from Lanyu (offshore southeast Taiwan) and Hainan, we infer that the intervals of high Basw values are linked to soil erosion associated with land use changes and socioeconomic developments. The increased sediment loads are also likely responsible for the recent degradation of regional coral reefs. Our study provides new insights into regional soil erosion histories, which may prove useful for guiding soil conservation and sustainable land management. Plain Language Summary: Soil erosion in East and Southeast Asia is considered a serious environmental problem. However, this issue has not been properly addressed, largely because of limited instrumental observations that would highlight the nature of the problem. Here we use new coral Ba/Ca and Ba isotope records from southern Taiwan and central Vietnam in conjunction with published records from Lanyu (offshore southeast Taiwan) and Hainan (northern South China Sea) to study the extent of soil erosion in East and Southeast Asia over recent decades. We conclude that soil erosion has been exacerbated by economic developments in the region and that this is recorded in the Ba/Ca ratios of coral skeletons. This study sheds light on how the concentration and isotopic composition of Ba in coral skeletons can provide a land use history for reference in environmental policies and mitigation strategies. Key Points: Exacerbated soil erosion by economic development registered in coral Ba/Ca records from southern Taiwan and central Vietnam since 1980 ADInsignificant difference of regional coral δ138/134Ba suggests dominant Ba sources attributed to enhanced land use by economic takeoffOur results highlight the vulnerability of coral reefs to increased terrestrial sediment input [ABSTRACT FROM AUTHOR]