Constraining the Particle Size Distribution of Large Marine Particles in the Global Ocean With In Situ Optical Observations and Supervised Learning
Constraining the Particle Size Distribution of Large Marine Particles in the Global Ocean With In Situ Optical Observations and Supervised Learning
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DOI：
10.1029/2021gb007276
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发表时间：
2022-05-01
影响因子：
5.2
通讯作者：
Bianchi, D.
中科院分区：
文献类型：
--
作者：
Clements, D. J.;Yang, S.;Bianchi, D.
海洋颗粒的丰度和大小分布控制着海洋中的一系列生物地球化学和生态过程，包括碳固存。这些数量是复杂的物理-生物相互作用的结果，很难观察到，它们的空间和时间模式仍然不确定。在这里，我们提出了一个新的分析粒径分布（psd）从全球汇编水下视觉剖面仪5 （UVP5）光学测量。使用机器学习算法，我们从采样良好的海洋变量中推断出全球海洋的稀疏UVP5观测结果。我们重建了粒子在光区底部的PSD参数（生物体积[BV]和斜率）的全局图。这些重建结果显示了一致的全球格局，高叶绿素区通常具有高颗粒BV和较平坦的PSD斜率，即大颗粒相对于小颗粒的相对丰度较高。由此产生的颗粒BV与坡度之间的负相关进一步表明，颗粒通量下沉等依赖于粒径的过程具有协同效应。我们的方法和估计为更好地理解海洋中的粒子周期提供了一个基线，并为从不断增长的UVP5观测数据中重建PSD和下沉粒子通量的全球三维重建铺平了道路。
The abundance and size distribution of marine particles control a range of biogeochemical and ecological processes in the ocean, including carbon sequestration. These quantities are the result of complex physical-biological interactions that are difficult to observe, and their spatial and temporal patterns remain uncertain. Here, we present a novel analysis of particle size distributions (PSDs) from a global compilation of in situ Underwater Vision Profiler 5 (UVP5) optical measurements. Using a machine learning algorithm, we extrapolate sparse UVP5 observations to the global ocean from well-sampled oceanographic variables. We reconstruct global maps of PSD parameters (biovolume [BV] and slope) for particles at the base of the euphotic zone. These reconstructions reveal consistent global patterns, with high chlorophyll regions generally characterized by high particle BV and flatter PSD slope, that is, a high relative abundance of large versus small particles. The resulting negative correlations between particle BV and slope further suggests synergistic effects on size-dependent processes such as sinking particle fluxes. Our approach and estimates provide a baseline for an improved understanding of particle cycles in the ocean, and pave the way to global, three-dimensional reconstructions of PSD and sinking particle fluxes from the growing body of UVP5 observations.