Neumann-Leitão Sigrid, Melo Pedro A M C, Schwamborn Ralf, Diaz Xiomara F G, Figueiredo Lucas G P, Silva Andrea P, Campelo Renata P S, de Melo Júnior Mauro, Melo Nuno F A C, Costa Alejandro E S F, Araújo Moacyr, Veleda Dóris R A, Moura Rodrigo L, Thompson Fabiano
Departamento de Oceanografia, Universidade Federal de Pernambuco, Recife, Brazil.
Departamento de Biologia, Universidade Federal Rural de Pernambuco, Recife, Brazil.
Front Microbiol. 2018 Mar 1;9:355. doi: 10.3389/fmicb.2018.00355. eCollection 2018.
At the mouth of the Amazon River, a widespread carbonate ecosystem exists below the river plume, generating a hard-bottom reef (∼9500 km) that includes mainly large sponges but also rhodolith beds. The mesozooplankton associated with the pelagic realm over the reef formation was characterized, considering the estuarine plume and oceanic influence. Vertical hauls were carried out using a standard plankton net with 200 μm mesh size during September 2014. An indicator index was applied to express species importance as ecological indicators in community. Information on functional traits was gathered for the most abundant copepod species. Overall, 179 zooplankton taxa were recorded. Copepods were the richest (92 species), most diverse and most abundant group, whereas meroplankton were rare and less abundant. Species diversity (>3.0 bits.ind) and evenness (>0.6) were high, indicating a complex community. Small holoplanktonic species dominated the zooplankton, and the total density varied from 107.98 ind. m over the reef area to 2,609.24 ind. m in the estuarine plume, with a significant difference between coastal and oceanic areas. The most abundant copepods were the coastal species and and early stages copepodites of Paracalanidae. The holoplanktonic , an important producer of mucous houses, was very abundant on the reefs. The indicator species index revealed three groups: (1) indicative of coastal waters under the influence of the estuarine plume [ and Hydromedusae]; (2) characterized coastal and oceanic conditions (); (3) characterized the reef system (). Two major copepods functional groups were identified and sorted according to their trophic strategy and coastal-oceanic distribution. The species that dominated the coastal area and the area over the rhodolith beds are indicators of the estuarine plume and are mixed with species of the North Brazil Current. These species practically disappear offshore, where occur oceanic species commonly found in other oligotrophic tropical areas. This ecosystem shows a mixture of estuarine, coastal and oceanic communities coexisting in the waters over the Amazon reefs, with no significant differences among these areas. However, the MDS clearly separated the communities along the salinity gradient in the plume.
在亚马孙河河口，河羽流下方存在着一个广泛的碳酸盐生态系统，形成了一个硬底礁（约9500千米），其中主要包括大型海绵动物，也有红藻床。考虑到河口羽流和海洋的影响，对礁体形成上方与远洋区域相关的中型浮游动物进行了特征描述。2014年9月，使用网孔尺寸为200微米的标准浮游生物网进行垂直拖网采样。应用一个指示指数来表达物种作为群落生态指标的重要性。收集了最丰富的桡足类物种的功能性状信息。总体而言，记录了179种浮游动物分类单元。桡足类是种类最丰富（92种）、最多样化且数量最多的类群，而小型浮游生物则稀少且数量较少。物种多样性（>3.0比特/个体）和均匀度（>0.6）较高，表明群落复杂。小型全浮游生物物种在浮游动物中占主导地位，总密度在礁区从107.98个/立方米到河口羽流中的2609.24个/立方米不等，沿海和海洋区域之间存在显著差异。最丰富的桡足类是沿海物种 和 以及伪哲水蚤科的桡足幼体早期阶段。全浮游生物 是黏液房的重要生产者，在礁体上非常丰富。指示物种指数揭示了三组：（1）指示受河口羽流影响的沿海水域[ 和水螅水母纲]；（2）表征沿海和海洋状况（ ）；（3）表征礁体系统（ ）。根据它们的营养策略和沿海 - 海洋分布，确定并分类了两个主要的桡足类功能群。在沿海地区和红藻床上方区域占主导的物种是河口羽流的指示物种，并与巴西北海流的物种混合。这些物种在近海几乎消失，在那里出现的是在其他贫营养热带地区常见的海洋物种。这个生态系统显示出河口、沿海和海洋群落混合共存于亚马孙礁体上方的水域中，这些区域之间没有显著差异。然而，多维尺度分析（MDS）清楚地沿着羽流中的盐度梯度将群落分开。
