Paleoenvironmental significance of 5α-stigmastanol in surface soil and lake sediment from the Nianbaoyeze Mountains, eastern Qinghai-Tibet Plateau

Autor: Philip A. Meyers, Yang Pu
Rok vydání: 2021
Předmět:
Zdroj: Journal of Paleolimnology. 68:103-118
ISSN: 1573-0417
0921-2728
Popis: We identified a suite of steroid biomarkers in sediments and surface soils around Lake Ximencuo, a typical glacial lake in the Nianbaoyeze region, eastern Qinghai-Tibet Plateau (QTP). Various sterols, stanols, sterones, and sterenes appear in the sediments and surface soil samples. Among these steroids, plant-derived β-sitosterol and the 5α-stigmastanol that is derived from it exhibit high relative abundances. Notably, we found that the relative abundance of 5α-stigmastanol and the 5α-stigmastanol/n-alkanol ratio in a core of Lake Ximencuo sediment increased significantly in the last 200–300 year. These biomarker changes are broadly consistent with the growth of human settlement and the rapid development of animal husbandry in this region, which resulted in the former nomadic pastoral lifestyles gradually being transformed into permanent settlements since the early eighteenth century. The environmental and cultural changes led to greater delivery to soils around the lake of β-sitosterol that was transformed into 5α-stigmastanol by microbial communities in soil horizons, which include aerobic and anaerobic bacteria, and eventually surface runoff transport of the increased abundance of 5α-stigmastanol into Lake Ximencuo. We further postulate that the progressively greater human impacts in the Nianbaoyeze region over the past 200–300 year have modified the kinds of microbes that participate in the biogeochemical cycles of local soils.
Databáze: OpenAIRE
Externí odkaz: