Particulate geochemistry of sediment core AL561_15-1

The AL561 cruise was conducted in the framework of the project APOC ("Anthropogenic impacts on Particulate Organic Carbon cycling in the North Sea"). This collaborative project between GEOMAR, AWI, HEREON, UHH, and BUND is to understand how particulate organic carbon (POC) cycling contributes to carbon sequestration in the North Sea and how this ecosystem service is compromised and interlinked with global change and a range of human pressures include fisheries (pelagic fisheries, bottom trawling), resource extraction (sand mining), sediment management (dredging and disposal of dredged sediments) and eutrophication. The main aim of the sampling activity during AL561 cruise was to recover undisturbed sediment from high accumulation sites in the Skagerrak/Kattegat and to subsample sediment/porewater at high resolution in order to investigate sedimentation transport processes, origin of sediment/POC and mineralization processes over the last 100- 200 years. Moreover, the actual processes of sedimentation and POC degradation in the water column and benthic layer will be addressed by sampling with CTD and Lander devices. In total 9 hydroacoustic surveys (59 profiles), 4 Gravity Corer, 7 Multicorer, 3 BIGO Lander and 3 CTD stations were successfully conducted during the AL561 cruise.

AL561航次是在APOC项目（“北海人为活动对颗粒有机碳循环的影响”）框架下开展的。该合作项目由GEOMAR、AWI、HEREON、UHH与BUND共同实施，旨在阐明颗粒有机碳（Particulate Organic Carbon，POC）循环对北海碳封存的贡献机制，以及该生态系统服务如何受到损害，并与全球变化及一系列人类活动压力密切关联，这些压力包括渔业（中上层渔业、底拖网作业）、资源开采（采砂作业）、沉积物管理（疏浚及疏浚物处置）与富营养化。AL561航次的采样活动核心目标为：在斯卡格拉克海峡/卡特加特海峡的高堆积速率站位获取未受扰动的沉积物，并以高分辨率对沉积物/孔隙水进行分样，以此研究过去100至200年间的沉积搬运过程、沉积物/POC的来源与矿化过程。此外，本航次还将借助温盐深仪（Conductivity, Temperature, Depth，CTD）与着陆器设备开展采样，以解析水柱及底栖层内的实际沉积过程与POC降解机制。AL561航次共顺利完成9条水声调查（总计59条测线）、4个重力柱状采样站位、7个多管采样站位、3个BIGO着陆器站位以及3个CTD站位。