Marine particle dynamics and carbon export, involving extracellular polymeric substances (EPS) like transparent exopolymer particles (TEP) and Coomassie Brilliant Blue‐stained particles (CSP), are poorly understood. Although TEP adhesive properties may enhance carbon export by facilitating aggregate formation, their low density can also enhance particle suspension. Factors influencing TEP regulation of particle dynamics remain unclear. To investigate EPS contributions to particle dynamics, we investigated ratios of TEP to particulate organic carbon (POC) and of CSP to POC in suspended and sinking particles collected with marine snow catchers. Samples were collected in a subarctic region near Hokkaido during a spring phytoplankton bloom and in the oligotrophic, subtropical Kuroshio region. At Hokkaido, the mean TEP : POC ratio of sinking particles (0.075 μg Xeq. : μg C) was > 30× lower than in suspended particles (2.3), consistent with a model prediction of selective retention of buoyant TEP‐rich particles in the upper water column. In the Kuroshio region, sinking particles also contained fewer TEP than suspended particles; however, the TEP : POC ratio of sinking particles (1.0) was > 10× higher than at Hokkaido, suggesting that TEP constitute a significant carbon component of sinking particles. These findings indicate that TEP facilitate aggregation of high‐density particles and particle sinking in the Kuroshio region. Distributions of CSP : POC ratios between suspended and sinking particles resembled TEP : POC ratios in both regions, implying a significant contribution of CSP to particle dynamics. We propose that EPS have divergent effects on suspension and sinking of marine particles, which vary with particle composition and biogeochemical conditions.

中文翻译：

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细胞外聚合物在两个开放海洋系统上层海洋中分隔悬浮和下沉颗粒的功能

海洋颗粒动力学和碳输出，涉及细胞外聚合物（EPS），如透明外聚合物颗粒（TEP）和考马斯亮蓝染色颗粒（CSP），人们知之甚少。尽管 TEP 粘合特性可以通过促进聚集体形成来增强碳输出，但它们的低密度也可以增强颗粒悬浮。影响粒子动力学 TEP 调节的因素仍不清楚。为了研究 EPS 对颗粒动力学的贡献，我们研究了海洋集雪机收集的悬浮和下沉颗粒中 TEP 与颗粒有机碳 (POC) 的比率以及 CSP 与 POC 的比率。样本是在北海道附近的亚北极地区春季浮游植物大量繁殖期间以及贫营养的亚热带黑潮地区采集的。在北海道，下沉颗粒的平均 TEP : POC 比率 (0.075μg Xeq。 :μg C) 比悬浮颗粒 (2.3) 低 > 30 倍，与上层水柱中富含 TEP 的浮力颗粒选择性保留的模型预测一致。在黑潮地区，下沉颗粒中的 TEP 含量也低于悬浮颗粒；然而，下沉颗粒的 TEP : POC 比率 (1.0) 比北海道高 10 倍以上，表明 TEP 构成了下沉颗粒的重要碳成分。这些发现表明，TEP 促进了黑潮地区高密度颗粒的聚集和颗粒下沉。悬浮颗粒和下沉颗粒之间的 CSP : POC 比率分布与两个区域中的 TEP : POC 比率相似，这意味着 CSP 对颗粒动力学有显着贡献。我们认为 EPS 对海洋颗粒的悬浮和下沉具有不同的影响，其随颗粒组成和生物地球化学条件的不同而变化。