The Taperaçu Estuary is distinct from other Amazonian estuaries due to the absence of significant fluvial discharge and consequent dominance of marine influence. The present study investigated the influence of physical-chemical variables on the composition and dynamics of the local phytoplankton and their spatiotemporal variation, with emphasis on the taxonomic analysis of the diatoms of the order Eupodiscales. During the rainy and dry seasons of 2013 and 2014, three sectors of this estuary were monitored over cycles of 24 hours. The samples were analyzed by light and scanning electron microscopy. Significant temporal and spatial differences were found in salinity, which was high (>32) in all the sectors. Turbidity and Chl-a concentrations were higher during the rainy period due to the increased input of water from the relatively small drainage basin of the estuary, as well as the material washed out of the soil of the adjacent mangroves. The local phytoplankton community was dominated by diatoms, which reached high abundances during the dry season. The local hydrodynamics determined the occurrence of benthic and/or tychoplanktonic species in the water column, including the Eupodiscales Hobaniella longicruris, Odontella aurita, and Zygoceros rhombus, while the high salinity recorded during the dry season favored the presence of Trieres species. The presence of high abundances of the benthic diatom Cymatosira belgica contributed to the observed high Chl-a concentrations and endorse the ecological importance of sediment resuspension processes and the consequent accumulation of phytobenthos cells in the water column in shallow estuarine Amazonian ecosystems.

Taperaçu 河口与其他亚马逊河口不同，因为没有明显的河流排放，因此海洋影响占主导地位。本研究调查了物理化学变量对当地浮游植物组成和动态及其时空变化的影响，重点是对真鳞目硅藻的分类学分析。在 2013 年和 2014 年的雨季和旱季，该河口的三个部分在 24 小时的周期内进行了监测。通过光学和扫描电子显微镜分析样品。在盐度方面发现了显着的时空差异，所有部门的盐度都很高（> 32）。浊度和 Chl- a由于河口相对较小的流域的水输入增加，以及从邻近红树林土壤中冲走的物质，雨季浓度较高。当地浮游植物群落以硅藻为主，在旱季达到高丰度。当地的流体动力学决定了水体中底栖和/或浮游物种的出现，包括 Eupodiscales Hobaniella longicruris、Odontella aurita和Zygoceros rhombus，而在旱季记录的高盐度有利于Trieres物种的存在。高丰度的底栖硅藻Cymatosira belgica的存在促成了观察到的高Chl-a浓度并认可沉积物再悬浮过程的生态重要性以及随之而来的底栖植物细胞在浅河口亚马逊生态系统水柱中的积累。