The factors that influence the composition of marine epiphytic microalgal assemblages are poorly-understood. To address this short-coming, 93 samples were collected from four distinct regions in the Florida Keys National Marine Sanctuary (FKNMS) during winter and summer months to test the model that epiphytic microalgal communities are influenced by environmental gradients related to different sites, seasons, and host macrophyte species. One hundred and eighty-three morphotypes from 13 classes (7 phyla) were identified, dominated by 106 Bacillariophyta (77 identified to species equivalent or below), 37 Cyanophyta (13 identified to species equivalent or below), and 30 Dinophyta (21 identified to species equivalent or below). The largest proportion of variability in epiphytic communities was related to physico-chemical parameters (37%), followed by site location (ocean- versus bayside; 15%), seasonal differences (11%), and host macrophyte species (10%). Four physico-chemical variables were found to be most influential: wave height, temperature, ammonium concentration, and salinity. Only six out of 616 epiphyte – host comparisons exhibited significant differences in individual epiphyte taxon abundance between different host species (within site and season), further demonstrating that host-specificity was not strongly evident in this study. Overall, the results of this (sub)tropical study indicate that changing environmental characteristics between sites and seasons were the primary drivers influencing epiphyte community composition. Similar findings were found in an accompanying study of phytoplankton and other studies from temperate and (sub)polar regions, suggesting that common, underlying processes exist among these disparate environments.

影响海洋附生微藻组合组成的因素知之甚少。为了解决这个缺点，在冬季和夏季月份从佛罗里达群岛国家海洋保护区 (FKNMS) 的四个不同地区收集了 93 个样本，以测试附生微藻群落受与不同地点、季节、环境梯度相关的环境梯度影响的模型，和宿主大型植物物种。鉴定出来自 13 个纲（7 个门）的 183 种形态类型，以 106种芽孢杆菌门（77 种鉴定为等同或以下）、37 种蓝藻门为主（13 种确定为等同或以下物种）和 30 种甲藻门（21 种确定为等同或以下物种）。附生群落变异的最大比例与物理化学参数有关（37%），其次是地点位置（海洋与海湾；15%）、季节差异（11%）和宿主大型植物物种（10%）。发现四个物理化学变量影响最大：波高、温度、铵浓度和盐度。在 616 个附生植物 - 宿主比较中，只有 6 个在不同宿主物种（地点和季节内）之间的个体附生植物分类群丰度上表现出显着差异，进一步表明宿主特异性在本研究中并不明显。全面的，这项（亚）热带研究的结果表明，地点和季节之间环境特征的变化是影响附生植物群落组成的主要驱动因素。在一项伴随的研究中也发现了类似的发现来自温带和（亚）极地地区的浮游植物和其他研究表明，这些不同的环境中存在共同的潜在过程。