Settling marine aggregates, such as zooplankton fecal pellets and marine snow, transport organic matter from the surface ocean to the deep sea and are largely responsible for the ocean’s sequestration of carbon. However, our understanding of the functioning of the biological pump and the distribution of particulate organic matter in the water column often hinge on limited bulk data from sediment traps, large volume filtration or instantaneous snap-shots from in situ optical systems that only see a small part of the particle and aggregate spectra. We evaluated the added value of combining different optical systems to detect a range of organic and inorganic particle types during a case-study in the Cape Blanc upwelling region. Laboratory calibrations showed that one camera system detected large organic aggregates well and in situ data showed that it correlated positively with fluorescence. The other camera was better at detecting small, mainly inorganic particles which were not seen by the first camera and correlated positively with turbidity. The combined deployments of the two optical systems together with fluorescence and turbidity sensors showed potentials for added insights into spatial (depth) and temporal (diurnal) particle dynamics. The case study exemplified the different efficiencies of two camera systems to detect particles of different types in marine waters. From this, the results highlighted the importance of discriminating between qualitative and quantitative ranges of imaging systems, in order to understand the quantitative range of sizes as well as types of particles detected by a given system. This is especially important when optical systems are used to estimate carbon fluxes and particulate organic matter distribution in the water column from vertical profiles of particle size-distribution and abundance.

中文翻译：

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雪中​​的轨迹——结合光学方法来表征海洋粒子和聚集体的优势

沉降海洋聚集体，如浮游动物粪便颗粒和海洋雪，将有机物质从表层海洋运输到深海，并在很大程度上负责海洋的碳封存。然而，我们对生物泵的功能和水体中颗粒有机物分布的理解通常取决于来自沉积物捕集器、大容量过滤或原位光学系统的瞬时快照的有限批量数据，这些数据只能看到一小部分粒子和聚集体光谱的一部分。我们在 Cape Blanc 上升流区域的案例研究中评估了组合不同光学系统以检测一系列有机和无机颗粒类型的附加价值。实验室校准表明，一个相机系统可以很好地检测到大型有机聚集体，原位数据表明它与荧光呈正相关。另一台相机更擅长检测小颗粒，主要是无机颗粒，第一台相机看不到这些颗粒，并且与浊度呈正相关。两个光学系统与荧光和浊度传感器的组合部署显示出增加对空间（深度）和时间（昼夜）粒子动力学的洞察力的潜力。该案例研究举例说明了两种相机系统在检测海水中不同类型颗粒方面的不同效率。由此，结果突出了区分成像系统的定性和定量范围的重要性，以了解给定系统检测到的颗粒大小的定量范围和类型。当使用光学系统从粒度分布和丰度的垂直剖面估计水柱中的碳通量和颗粒有机物分布时，这一点尤其重要。