Aix-Marseille Université, Université de Toulon, CNRS/INSU, IRD, Mediterranean Institute of Oceanography (MIO), Marseille, France.
PLoS One. 2023 Oct 23;18(10):e0292536. doi: 10.1371/journal.pone.0292536. eCollection 2023.
Sixteen years (2005-2020) of zooplankton monitoring in the Bay of Marseille (N-W Mediterranean Sea) are analyzed in relation to physical, meteorological, climatic and biotic data. Samples were collected every two weeks by a vertical haul (0-55 m) of a 200 μm plankton net. Different indices characterizing the mesozooplankton are compared: biomass dry weight of four size fractions between 200 and 2000 μm; abundances of the whole of the mesozooplankton and of 13 main taxonomic groups defined from plankton imagery; seasonal onset timing of each zooplankton group; and two other types of indices: the first characterized diversity based on abundance data, and the second was derived from zooplankton size spectra shape. The clearest pattern in the environmental compartment was an overall decreasing trend in nutrients, shifts in phytoplankton metrics (i.e. size structure and particulate organic matter), and changes in winter conditions (i.e. increasing temperatures, precipitation and NAO). Interannual patterns in the mesozooplankton community were: (i) a decrease of total abundance (ii) a decrease in biomass for the four size fractions, with an earlier decrease for the 1000-2000 μm size fraction (in 2008); (iii) a reduced dominance of copepods (calanoids and oithonoids) and a concomitant increase in abundance of other taxonomic groups (crustaceans, pteropods, chaetognaths, salps) which induced higher diversity; (iv) a first shift in size spectra towards smaller sizes in 2009, when the 1000-2000 μm size fraction biomass decreased, and a second shift towards larger sizes in 2013 along with increased diversity; and (iv) a later onset in the phenology for some zooplankton variables and earlier onset for salps. Concomitant changes in the phytoplankton compartment, winter environmental conditions, zooplankton community structure (in size and diversity) and zooplankton phenology marked by a shift in 2013 suggest bottom-up control of the pelagic ecosystem.
十六年来（2005-2020 年）对马赛湾（西北地中海）的浮游动物进行了监测，将其与物理、气象、气候和生物数据相关联。每两周通过垂直拖网（0-55 m）采集 200 μm 浮游网的样品。比较了描述中型浮游动物的不同指数：200-2000 μm 四个大小范围内的生物量干重；整个中型浮游动物和 13 个主要分类群的丰度，这些分类群是根据浮游动物图像定义的；每个浮游动物组的季节开始时间；以及另外两种类型的指数：第一种基于丰度数据的特征多样性，第二种是从浮游动物大小谱形状得出的。环境组中最明显的模式是营养物质的整体下降趋势、浮游植物指标的变化（即大小结构和颗粒有机物质）以及冬季条件的变化（即温度、降水和北大西洋涛动增加）。中型浮游动物群落的年际模式为：（i）总丰度下降；（ii）四个大小范围内的生物量下降，1000-2000 μm 大小范围内的生物量下降更早（2008 年）；（iii）桡足类（哲水蚤和真哲水蚤）的优势度降低，其他分类群（甲壳类、翼足类、毛颚动物、樽海鞘）的丰度增加，导致多样性增加；（iv）2009 年，当 1000-2000 μm 大小范围内的生物量减少时，大小谱首次向较小的尺寸转移，2013 年，随着多样性的增加，大小谱再次向较大的尺寸转移；（iv）一些浮游动物变量的物候学出现较晚，樽海鞘的物候学出现较早。浮游植物区系、冬季环境条件、浮游动物群落结构（大小和多样性）以及以 2013 年发生转移为标志的浮游动物物候学的同时变化表明，浮游生态系统受到自上而下的控制。
