卫星海洋环境监测预警全国重点实验室为增进学术交流，促进实验室对外开放，组织系列“海星系列学术讲座”，邀请国内外知名专家与青年科研人员分享前沿科学动态，讨论最新学术成果，欢迎大家踊跃参加。

召集人：孟启承 副研究员

会议时间：3月28日（周五）上午10：00-11:30

会议地点：2号楼801会议室

报告人：张文彦 研究员（德国赫姆霍兹协会海岸带研究所）

报告题目：Fluxes of sediment and organic carbon mediated by human activities in shelf seas

报告人简介：Dr. Wenyan Zhang is head of the department Sediment Transport and Morphodyamics in the Institute of Coastal Systems - Analysis and Modeling, Helmholtz-Zentrum Hereon. His expertise mainly lies on sediment dynamics, coastal morphodynamics and benthic-pelagic coupling. In particular, the role of benthic fauna and flora in morphodynamics and carbon cycling is the focus of interest. Dr. Zhang has published more than 90 peer-reviewed research papers since 2010 with h-index=29 (Google Scholar), Scopus & WoS h-index= 23. He is member of the expert group Climate change in the Baltic Sea of HELCOM (lead author of coastal sediment transportation), and member of ICES working groups Fisheries Benthic Impact and Trade-offs (WGFBIT) and Impact of Fishing on Oceanic Carbon (WKFISHCARBON).

报告摘要：The disturbance of coastal sediments by human activities constitutes a potentially large disruption to natural sediment and carbon fluxes, but large-scale estimates of these impacts are lacking thus far. Using data analysis and process-based numerical modelling, we estimate the amounts of sediment and organic carbon disturbed, as well as potential CO2 released from North Sea sediments resulting from (1) dredging in the form of mineral aggregate extraction, (2) dumping of material dredged during waterway maintenance, (3) bottom trawling, and (4) offshore wind farms. Despite disturbing less sediment than aggregate extraction, dumping has a greater potential for carbon remineralization due to a higher organic carbon content in estuarine muds compared to subtidal sands and gravels. Overall, we estimate carbon disturbance by both activities of dredging and dumping to be 1-2 magnitudes higher than by marine construction, but 1-2 magnitudes lower than by bottom-contacting fisheries. On the other hand, offshore wind farms may alter the residual transport pathways of fine-grained sediment and lead to considerable accumulative change in mud deposition on a long-term, thereby changing the benthic ecosystem and carbon burial. Simulations show that most material dumped within the German Bight and Wadden Sea deposits within the coastal basins and intertidal areas after one year, the amount being similar in magnitude to natural sedimentation in that area. These results highlight the potential of human activities to shape long-term coastal morphology and sedimentary carbon storage, and we argue that they should be considered in regional to global sediment and carbon budgets.