Figueiredo Gabriela Guerra Araújo Abrantes de, Lira Simone Maria de Albuquerque, Bertrand Arnaud, Neumann-Leitão Sigrid, Schwamborn Ralf
Departamento de Oceanografia, Universidade Federal de Pernambuco, Recife, Brazil.
Departamento de Oceanografia, Universidade Federal de Pernambuco, Recife, Brazil.
Mar Environ Res. 2025 Feb;204:106906. doi: 10.1016/j.marenvres.2024.106906. Epub 2024 Dec 10.
Mesozooplankton plays a pivotal role within marine food webs. However, there is a paucity of studies examining the size-spectra and trophic efficiency of these communities in tropical neritic and oceanic waters. Here, normalised biovolume (NBSS) and normalised numbers size-spectra (NNSS) were fitted on zooplankton data from the southwestern tropical Atlantic. The spectra were compared to assess the trophic efficiency slope (NBSS) across different regions, the Shelf, the western boundary current system (WBCS), and the South equatorial current system (SECS) off oceanic islands. Zooplankton was collected from September to October 2015, at 34 stations using oblique hauls with a 300 μm mesh bongo net from 200 m depth to the surface during either day or night. Samples were analysed using a ZooScan. A total of 30 zooplankton taxa were recorded. Mean abundance and biovolume were 62.6 ind m and 36.2 mm³ m, respectively. Zooplankton community structure differed significantly between areas, in abundance and biovolume. Copepoda was the most abundant group, representing 66% and 57% of the abundance in coastal areas and oceanic islands, respectively. Fish larvae, gelatinous plankton (mostly Chaetognatha, Thaliacea, and Siphonophora), and Decapoda were the main contributors in terms of biovolume. Overall, smaller organisms were found at the shelf, while larger organisms were found in the SECS. Total abundance was significantly higher on the shelf and in the WBCS than in the SECS, while individual biovolume was higher in the SECS. The NNSS and NBSS slopes were significantly steeper on the shelf than in the other areas. This can be attributed to the higher contribution of small copepods on the shelf and the higher contribution of large-sized copepods and other large organisms in oceanic waters. Flatter NBSS and NNSS slopes offshore reveal a higher trophic efficiency, illustrating the importance of large zooplankton, particularly chaetognaths and decapods, in contributing to the ecosystem secondary productivity in oligotrophic tropical pelagic marine ecosystems. The combination of both NNSS and NBSS provided a more comprehensive view of ecosystem structure and fluxes.
中型浮游动物在海洋食物网中起着关键作用。然而，关于热带近岸和大洋水域中这些群落的大小谱和营养效率的研究却很少。在此，对来自热带西南大西洋的浮游动物数据拟合了标准化生物量（NBSS）和标准化数量大小谱（NNSS）。对这些谱进行比较，以评估不同区域（陆架、西部边界流系统（WBCS）和大洋岛屿附近的南赤道流系统（SECS））的营养效率斜率（NBSS）。2015年9月至10月期间，在34个站点使用300μm网目的邦戈网从200米深度到海面进行斜拖网采集浮游动物，白天或夜间均可。样本使用ZooScan进行分析。共记录了30种浮游动物分类单元。平均丰度和生物量分别为62.6个/立方米和36.2立方毫米/立方米。浮游动物群落结构在不同区域的丰度和生物量方面存在显著差异。桡足类是最丰富的类群，分别占沿海地区和大洋岛屿丰度的66%和57%。就生物量而言，鱼卵、胶质浮游动物（主要是毛颚类、海樽类和管水母类）和十足目是主要贡献者。总体而言，在陆架发现的生物个体较小，而在SECS发现的生物个体较大。陆架上的总丰度显著高于SECS，而WBCS中的总丰度也显著高于SECS，而个体生物量在SECS中更高。陆架上的NNSS和NBSS斜率比其他区域显著更陡。这可归因于陆架上小型桡足类的贡献更高，以及大洋水域中大型桡足类和其他大型生物的贡献更高。近海较平缓的NBSS和NNSS斜率表明营养效率更高，说明了大型浮游动物，特别是毛颚类和十足目，对贫营养热带远洋海洋生态系统中生态系统次级生产力的贡献的重要性。NNSS和NBSS的结合提供了对生态系统结构和通量更全面的认识。
