Nepheloid layers with elevated concentrations of suspended particulate matter (SPM) are found throughout the world's oceans. They are generated by both natural processes, involving resuspension of seabed sediment by bottom currents, and anthropogenic sediment resuspension due to bottom trawling, dredging and in the future potentially due to deep-sea mining. These nepheloid layers represent pathways of lateral SPM transport, including lithogenic and biogenic sediment, organic matter, (trace) metals, organic pollutants and plastics. For assessment of the dispersion of these materials, it is essential that SPM mass concentrations can be accurately quantified. However, this is not straightforward as the detected turbidity signal, which is used as a proxy for SPM mass concentration, not only depends on the concentration of particles, but also on physical characteristics of these particles, such as particle size, substance and shape. Here we present a comparative study of turbidity data to assess the potential implications different sensors have on the estimates of SPM mass concentration. Optical backscatter sensors (OBSs), transmissometers and both low- and high-frequency ADCPs were deployed simultaneously in the Whittard Canyon (North Atlantic Ocean), and water samples were collected for quantification of SPM mass concentration and ex-situ particle size analysis. We found that SPM mass concentrations inferred from the transmissometer are easily overestimated in the biologically productive surface layer due to higher light absorption by chlorophyll-bearing phytoplankton, compared to suspended detritic particles. Furthermore, we observed that depending on sensor type some particles are not, or less well, detected. This is due to differences in particle size sensitivities of these sensors towards the diverse range of particle sizes found in the Whittard Canyon, whereby the low-frequency ADCP was most sensitive for coarse-grained material and the high-frequency ADCP and OBSs most sensitive for fine-grained material. In future studies, we suggest to use a combination of different sensors as the use of only one type of sensor could potentially lead to misinterpretation and mis-quantification of particle transport processes and fluxes.

在世界各地的海洋中都发现有浓度较高的悬浮颗粒物（SPM）的肾小球层。它们是由自然过程产生的，包括通过海底流将海底沉积物重新悬浮，以及由于拖网，挖泥以及将来可能由于深海采矿而导致的人为沉积物重新悬浮。这些星状胶体层代表了横向SPM传输的途径，包括成岩和生物成因的沉积物，有机质，（痕量）金属，有机污染物和塑料。为了评估这些材料的分散性，必须精确定量SPM质量浓度。但是，这并不简单，因为检测到的浊度信号（可作为SPM质量浓度的代表）不仅取决于颗粒物的浓度，而且还取决于这些粒子的物理特性，例如粒度，物质和形状。在这里，我们对浊度数据进行了比较研究，以评估不同传感器对SPM质量浓度估计值的潜在影响。在惠特德峡谷（北大西洋）同时部署了光学背向散射传感器（OBS），透射仪以及低频和高频ADCP，并收集了水样本用于SPM质量浓度的定量和异位粒度分析。我们发现，与悬浮的有害颗粒相比，由于含叶绿素的浮游植物具有更高的光吸收率，因此从透射计推断出的SPM质量浓度很容易被高估了生物生产性表层。此外，我们观察到，根据传感器类型的不同，某些粒子不会被或不太好地被检测到。这是由于这些传感器对惠特德峡谷中不同粒径范围的粒径敏感性的差异，其中低频ADCP对粗粒物料最敏感，而高频ADCP和OBS对粗粒物料最敏感细颗粒的材料。在未来的研究中，我们建议使用不同传感器的组合，因为仅使用一种类型的传感器可能会导致对粒子传输过程和通量的误解和量化。低频ADCP对粗颗粒材料最敏感，而高频ADCP和OBS对细颗粒材料最敏感。在未来的研究中，我们建议使用不同传感器的组合，因为仅使用一种类型的传感器可能会导致对粒子传输过程和通量的误解和量化。低频ADCP对粗颗粒材料最敏感，而高频ADCP和OBS对细颗粒材料最敏感。在未来的研究中，我们建议使用不同传感器的组合，因为仅使用一种类型的传感器可能会导致对粒子传输过程和通量的误解和量化。