摘要
火作为陆地生态系统中重要的环境因子,与气候、植被和人类活动密切相关,古火演化已成为目前全球变化关注的热点问题之一。炭屑是探索古火活动和人类用火及其驱动机制的重要指标,为研究古环境和古气候的演变提供了一种新的途径。我国东北地区的炭屑研究较为薄弱,仅有的少数研究集中在全新世,缺少更长时间尺度的沉积记录。为此,基于光释光、电子自旋共振、深海氧同位素转折年龄构建了哈尔滨黄土的年代框架。在此基础上,重点对黄土-古土壤中炭屑和总有机碳(TOC)进行分析,以重建中晚更新世以来松嫩平原东部的古火活动与古植被-古气候间的关系,并进一步探讨古火活动的驱动机制。结果表明:哈尔滨黄土-古土壤炭屑中圆叶炭屑总数最多,长叶炭屑数量较少,炭屑形态揭示研究区主要为木本型炭屑;炭屑粒度以<30μm的炭屑为主,>100μm的炭屑最为稀少,炭屑粒度特征记录本地区为区域性古火事件。哈尔滨荒山黄土-古土壤炭屑总浓度、圆叶炭屑浓度、长叶炭屑浓度的变化具有较高的一致性,炭屑浓度曲线与TOC曲线比较吻合,古土壤炭屑浓度高,在弱古土壤层呈现出逐渐增加的趋势,表明温度的上升和生物量增多导致古火活动增强,揭示出古火活动主要受控于生物量。通过与铷/锶比值、全球CO_(2)浓度以及深海氧同位素的对比,发现古火还受温度条件的限制。温度作为触发因素,对植物的生长和古火的发生起到了积极的作用,即温度影响木本植物生长,较高的温度导致更密集的蒸发,较低的温度会导致较高的有效湿度,从而对火灾的发生和植物的生长产生影响,这也揭示了古火-植被-气候之间的复杂性。
Fire,a significant envrionmental factor in the terrestrial ecosystem,is closely related to climate,vegetation and human activity,and the evolution of paleofire has become one of the most striking issues of attention in global changes.Charcoal,an important index for exploring the activity of paleofire and artificial fire and their driving mechanisms,provides a new way to study the evolution of paleoenvironment and paleoclimate.Research on charcoal in northeastern China is relatively weak,with only a few studies focusing on the Holocene,lacking longer-timescale sedimentary records.Therefore,based on the optically stimulated luminescence(OSL),electron spin resonance(ESR)datings and transition ages of the deep-sea oxygen isotope stages,the study constructed the chronological framework of the loess in Harbin Huangshan section.Based on this,we selectively analyzed the charcoal and total organic carbon(TOC)from the loess-paleosol sequence to reconstruct the relationship between paleovegetation and paleoclimate in the eastern Songnen Plain since the middle and late Pleistocene,and to further explore the driving mechanism of paleofire.The results show that the amount of the round leaf charcoal is dominant for the Harbin loess deposits,and however,that of the long leaf charcoal is least,reflecting that the study area is mainly made up of woody charcoal.The grain size composition of the charcoals is characterized by the dominance of<30μm fraction,with the least amount of>100μm fraction,which reveals a regional paleofire event in this area.The variations in the total concentration of the charcoal(TCC),the round leaf charcoal(CRLC)and the long leaf charcoal(CLLC)in the loess-paleosol sequence are highly consistent.Additionally,the variations of the charcoal concentration in the loess-paleosol sequence are well consistent with those of the TOC.The charcoal concentration in the paleosol is high and gradually increases in weak paleosol layer,indicating that the increasing temperature and biomass lead to the enhanced paleofire
作者
张瑞
迟云平
谢远云
康春国
吴鹏
孙磊
魏振宇
ZHANG Rui;CHI Yunping;XIE Yuanyun;KANG Chunguo;WU Peng;SUN Lei;WEI Zhenyu(College of Geographic Science,Harbin Normal University,Harbin 150025,China;Heilongjiang Province Key Laboratory of Geographical Environment Monitoring and Spatial Information Service in Cold Regions,Harbin Normal University,Harbin 150025,China;Geography Department,Harbin Institute,Harbin 150086,China)
出处
《生态学报》
CAS
CSCD
北大核心
2022年第24期10317-10328,共12页
Acta Ecologica Sinica
基金
国家自然科学基金项目(41601200,41871013)
黑龙江省自然科学基金项目(D2017003)
哈尔滨师范大学学术创新项目(HSDSSCX2021-23)
关键词
炭屑
古火
古气候
木本植物
哈尔滨黄土
charcoal
paleofire
paleoclimate
woody plants
Harbin loess
