文献类型：期刊文献

英文题名：Dynamics of the Nitrogen Cycle and Paleoproductivity across the Guadalupian-Lopingian Boundary

作者：Chen, Qiuping[1,2]; Cao, Hansheng[1,2,3]; Chen, Fajin[1,2,3]; Hu, Sheng[1,2,3]; Li, Shiqi[1,2,3]; Wang, Zaiyun[1,2,3]; Huang, Hanli[1,2,3]; Chen, Chunqing[1,2,3]; Zeng, Yuda[1,2,3]

机构：[1] Laboratory for Coastal Ocean Variation and Disaster Prediction, College of Ocean and Meterology, Guangdong Ocean University, Zhanjiang, 524088, China; [2] Key Laboratory of Climate, Resources and Environment in Continental Shelf Sea and Deep Sea, Department of Education of Guangdong Province, College of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang, 524088, China; [3] Key Laboratory of Space Ocean Remote Sensing and Application, Ministry of Natural Resources, Beijing, 100081, China

年份：2025

外文期刊名：SSRN

收录：EI(收录号：20250537951)

语种：英文

外文关键词：Carbon - Carbon cycle - Ecology - Nitrates - Nitrogen - Nitrogen removal

外文摘要：The Guadalupian-Lopingian Boundary marks a crucial phase of biological and environmental turnover during the Permian. However, the evolutionary patterns and mechanisms controlling paleo-primary productivity during this interval remain inadequately constrained, particularly the co-evolutionary dynamics between perturbations of the nitrogen cycle and primary productivity. To investigate this, we performed a high-resolution analysis of carbon and nitrogen isotopes, along with BSi content, from the Supplementary Auxiliary Standard Section at Fengshan, Guangxi, on the South China Block. Our results show a significant decoupling between δ13Ccarb and δ13Corg during the late Guadalupian, accompanied by a marked decrease in Δ13C (~26.0‰). Considering the widespread development of marine euxinic conditions during this period, it is inferred that primary productivity was primarily sustained by anaerobic photoautotrophic microorganisms. Concurrently, a significant positive shift in δ15N values, reaching up to +7.3‰, indicates enhanced denitrification driven by the expansion of anoxic water masses, resulting in a substantial reduction of the nitrate reservoir and subsequent suppression of primary productivity. By the early Lopingian, Δ13C increased to ~28.5‰, coupled with elevated C/N ratios, suggesting a gradual ecological transition from microbial-dominated to algal-dominated communities. Simultaneously, δ15N values decreased to approximately +2.5‰, accompanied by significant increases in BSi, TOC, and TN contents. These observations collectively indicate weakened denitrification and enhanced nitrate assimilation under increasingly oxic conditions, which may have facilitated the initial recovery of productivity. This study systematically elucidates the critical role of the nitrogen cycle in regulating paleo-primary productivity through nitrate availability across the end-Guadalupian mass extinction, providing new empirical evidence for understanding the coupled biological-environmental co-evolutionary mechanisms during major geological crises. ? 2025, The Authors. All rights reserved.