泰国湾百年来有机碳埋藏记录及环境响应

受热带季风气候和周边陆源输入的影响,低纬泰国湾海—陆相互作用强烈,是研究海洋沉积有机碳与陆源输入、海洋初级生产力等气候环境变化响应关系的理想区域.通过对泰国湾泥质区T43柱样中总有机碳(TOC)、总氮(TN)、稳定碳同位素(δ13C)以及粒度等指标的分析,基于210Pb建立的高分辨年代地层框架,重建了该区百年来有机碳的...

Geochemistry Features and Environmental Responses of Organic Carbon Burial in the Gulf of Thailand over the Past Century

Affected by the tropical monsoon climate and the land inputs， the Gulf of Thailand （GOT） is characterized by extensive land-ocean interaction， making it an ideal region for studying the relationship between organic carbon burial in sediments and the land-based input， marine primary productivity， and variation of the marine environment. Based on the highly resolution chronology constrained by the excess of lead isotopes （210Pb， 210Pb_ex）， the geochemical characteristics of organic carbon and its burial records during the past century were reconstructed by analyzing the total organic carbon （TOC）， total nitrogen （TN）， stable carbon isotope （δ13C）， and sediment grain size of core sediments （T43） in the GOT. The results showed that the sedimentary organic matter originated from mixed terrestrial and marine origins and mainly from marine organic matter （OM） contributions. TOC showed a coupled variation with that of TN and δ13C， indicating a consistency of provenance towards organic carbon and nitrogen. Both C/N and δ13C showed that the OM at the lower sections was mainly derived from marine primary productivity， followed by a gradual increase in terrestrial OM. The mass accumulation rate and the burial flux of TOC in the core showed a general decrease after the 1960s， which may be related to the decline of sediment transport caused by the dam construction in the drainage basin. However， since the 1980s， δ13C has shown an obvious depletion with increased terrestrial OM， which may be related to the enhanced heavy rainfall and coastal erosion associated with tropical cyclones over the last 30 years.