讲座题目：Methane emission from lakes: hydroacoustic approach to quantify gas flux & its spatial and temporal variability

主讲人：Ilia Ostrovsky 研究员

主持人：陈雪初 副教授

开始时间：2019-08-01（周四）下午2:30-3:30

讲座地址：闵行校区 生科辅楼119室

主办单位：生态与环境科学学院  科技处

报告人简介：

      Ilia Ostrovsky是海洋学家与湖沼学家，曾担任亚美尼亚科学院Sevan水生生物战的首席科学家，现任以色列海洋与湖沼学研究所教授、欧洲科学技术合作管理委员会成员，并且是国际湖沼学学会的以色列代表。作为国际水协会的湖泊水库管理专家组管理委员会的成员，lia Ostrovsky教授在今年5月份于上海组织了国际水协会第四届湖泊与水库管理学术讨论会，并担任会议主席。同时，lia Ostrovsky教授还是是爱思唯尔编辑系统生态信息学编辑委员会成员。

报告内容简介: 

      Over the last century the atmospheric concentration of methane, has risen approximately 1% per year. The reasons for this trend are not completely understood since the global sources and sinks of methane still need quantification. Quantification of gaseous methane in aquatic ecosystems is a complex task due to large spatial and temporal variability of the gas emission events.  As a result, there is a gap in knowledge about the contribution of gas ebullition to the total methane flux from sediments in shallow lakes and reservoirs. This information is necessary to determine what portion of deposited organic carbon is utilized by methanogenic bacteria, to evaluate the fate of bubbles in the water column, and the amount of methane that ultimately reaches the atmosphere. In contrast to conventional gas traps and optical methods, hydroacoustic technology allows rapid scanning over large volumes of the water column synoptically, quantifying bubble gas abundance, calculating bubble rise velocity, and bubble volumes. Data obtained from hydroacoustic surveys on Lake Kinneret (Israel) allowed estimating the gaseous methane fluxes from sediments, computing its dissolution in the water column and transfer to the atmosphere. In aquatic ecosystems with highly variable water levels, gas ebullition is an important mechanism responsible for rapid methane transfer from the bottom to the atmosphere.