Sonnet Virginie, Guidi Lionel, Mouw Colleen B, Puggioni Gavino, Ayata Sakina-Dorothée
CNRS, Laboratoire d'Océanographie de Villefranche Sorbonne Université Villefranche-sur-Mer France.
Graduate School of Oceanography University of Rhode Island Narragansett Rhode Island.
Limnol Oceanogr. 2022 Aug;67(8):1850-1864. doi: 10.1002/lno.12171. Epub 2022 Jun 15.
Functional traits are increasingly used to assess changes in phytoplankton community structure and to link individual characteristics to ecosystem functioning. However, they are usually inferred from taxonomic identification or manually measured for each organism, both time consuming approaches. Instead, we focus on high throughput imaging to describe the main temporal variations of morphological changes of phytoplankton in Narragansett Bay, a coastal time-series station. We analyzed a 2-yr dataset of morphological features automatically extracted from continuous imaging of individual phytoplankton images (~ 105 million images collected by an Imaging FlowCytobot). We identified synthetic morphological traits using multivariate analysis and revealed that morphological variations were mainly due to changes in length, width, shape regularity, and chain structure. Morphological changes were especially important in winter with successive peaks of larger cells with increasing complexity and chains more clearly connected. Small nanophytoplankton were present year-round and constituted the base of the community, especially apparent during the transitions between diatom blooms. High inter-annual variability was also observed. On a weekly timescale, increases in light were associated with more clearly connected chains while more complex shapes occurred at lower nitrogen concentrations. On an hourly timescale, temperature was the determinant variable constraining cell morphology, with a general negative influence on length and a positive one on width, shape regularity, and chain structure. These first insights into the phytoplankton morphology of Narragansett Bay highlight the possible morphological traits driving the phytoplankton succession in response to light, temperature, and nutrient changes.
功能性状越来越多地用于评估浮游植物群落结构的变化，并将个体特征与生态系统功能联系起来。然而，它们通常是从分类鉴定中推断出来的，或者是对每个生物体进行手动测量，这两种方法都很耗时。相反，我们专注于高通量成像，以描述纳拉甘西特湾（一个沿海时间序列站点）浮游植物形态变化的主要时间变化。我们分析了一个为期两年的数据集，该数据集包含从单个浮游植物图像的连续成像中自动提取的形态特征（成像流式细胞仪收集了约1.05亿张图像）。我们使用多变量分析确定了综合形态性状，并揭示形态变化主要是由于长度、宽度、形状规则性和链结构的变化。形态变化在冬季尤为重要，较大细胞的连续峰值出现，复杂性增加，链连接更清晰。小型纳米浮游植物全年都有，构成了群落的基础，在硅藻大量繁殖的过渡期间尤为明显。还观察到较高的年际变异性。在每周的时间尺度上，光照增加与链连接更清晰有关，而在较低氮浓度下出现更复杂的形状。在每小时的时间尺度上，温度是限制细胞形态的决定性变量，对长度有普遍的负面影响，对宽度、形状规则性和链结构有正面影响。这些对纳拉甘西特湾浮游植物形态的初步见解突出了可能驱动浮游植物演替以响应光照、温度和养分变化的形态性状。
