Absorption measurements of Nodularia spumigena bloom from Lake Bante In Wilhelmshaven, Germany

We derived the absorption coefficients (m-1) from 400 to 700 nm at 2 nm resolution of surface water samples from the German Lake Bante in Wilhemshaven. The water samples were analyzed for the total absorption coefficients of the unfiltered water (a_tot) and colored dissolved organic material (a_cdom) after filtration using a membrane filter of 0.2 µm pore size. Absorption coefficient of algal material (a_ph) was computed as the difference between a_tot and a_cdom under the assumption that no contribution was expected from suspended particulate solids. Absorption coefficient measurements were conducted in a point-source integrating-cavity absorption meter (PSICAM) with a sample chamber volume of ~400 mL. Information about the PSICAM measurements, calibration of the instrument and data correction are explained more in literature (Leathers et al., 2000; Röttgers et al.,2007). Raw data is available upon reasonable request from the authors.

本研究针对采自威廉港（Wilhemshaven）境内德国班特湖（German Lake Bante）的地表水样本，以2 nm的光谱分辨率，推导得到了400~700 nm波段的吸收系数（单位：m⁻¹）。研究人员对未过滤水样的总吸收系数（a_tot）以及经0.2 µm孔径滤膜过滤后的有色溶解有机物（colored dissolved organic material）的吸收系数（a_cdom）开展了分析测定。在假设悬浮颗粒物无吸收贡献的前提下，藻类物质吸收系数（a_ph）通过总吸收系数a_tot与有色溶解有机物吸收系数a_cdom的差值计算得到。吸收系数的测定采用点源积分腔吸收光度计（point-source integrating-cavity absorption meter, PSICAM）完成，其样品舱体积约为400 mL。有关PSICAM的测定方法、仪器校准及数据校正流程的详细说明可参见相关文献（Leathers等人，2000；Röttgers等人，2007）。原始数据可在提出合理申请后向作者获取。