Botany Department, Faculty of Science, Tanta University, Tanta, Egypt.
National Institute of Oceanography and Fisheries (NIOF), Cairo, Egypt.
Environ Monit Assess. 2023 Aug 17;195(9):1060. doi: 10.1007/s10661-023-11688-7.
This study was conducted to evaluate the seasonal variability of phytoplankton in the northern part of the Gulf of Suez (Suez Bay), considering the contribution of physicochemical parameters of bay water in shaping the dynamics, and eutrophication assessment. Water and phytoplankton samples were collected seasonally at nine stations in the Suez Bay during the period from the winter to autumn of 2012. A total of 423 phytoplankton species were identified, comprised mainly of 224 diatoms, 127 dinoflagellates, 33 cyanophytes, 20 chlorophytes, and 9 euglenophytes; the rest of the species (10 species) belong to other six groups. Of these, 28 species were potentially harmful. The total phytoplankton abundance exhibits a significant seasonal variation, with the autumn being the most fertile season, followed by the winter due to the proliferation of diatom species Thalassionema nitzschioides and Proboscia alata f. gracillima, respectively. While the seasonal species richness indicates that the winter attained the highest number of species, followed by summer. Generally, the major diatom genera were Chaetoceros (16 species), Navicula (15 species), Nitzschia (15 species), and Amphora (14 species), while dinoflagellates were principally composed of the genera Protoperidinium (34 species), and Tripos (26 species). Water temperature, pH, salinity, nitrate, and nitrite were the most important explanatory parameters in regard to phytoplankton abundance and chlorophyll a concentration. In addition, the phytoplankton stability exhibited a significant positive relationship with the mean values of dissolved oxygen and biological oxygen demand and the variability of salinity and phosphate, while a negative relationship was observed with ammonia and nitrite and the variability of nitrate. Based on the trophic index (TRIX), the bay water was classified as mesotrophic (moderately polluted) for almost the entire year except in the autumn as it turned eutrophic. The results explored the potential importance of the environmental heterogeneity in the bay as a key structuring mechanism of phytoplankton abundance and biomass, influenced by anthropogenic activities.
本研究旨在评估苏伊士湾（苏伊士湾）北部浮游植物的季节性变化，同时考虑到海湾水理化参数对浮游植物动态和富营养化评估的贡献。在 2012 年冬季至秋季期间，在苏伊士湾的 9 个站点季节性采集水和浮游植物样本。共鉴定出 423 种浮游植物，主要由 224 种硅藻、127 种甲藻、33 种蓝藻、20 种绿藻和 9 种眼虫组成；其余的物种（10 种）属于其他六个组。其中，有 28 种具有潜在危害性。浮游植物总丰度表现出显著的季节性变化，秋季是最肥沃的季节，其次是冬季，分别是由于硅藻物种 Thalassionema nitzschioides 和 Proboscia alata f. gracillima 的增殖。而季节物种丰富度表明冬季达到了最高的物种数量，其次是夏季。总的来说，主要的硅藻属是 Chaetoceros（16 种）、Navicula（15 种）、Nitzschia（15 种）和 Amphora（14 种），而甲藻主要由 Protoperidinium（34 种）和 Tripos（26 种）组成。水温、pH 值、盐度、硝酸盐和亚硝酸盐是浮游植物丰度和叶绿素 a 浓度最重要的解释性参数。此外，浮游植物稳定性与溶解氧和生物需氧量的平均值以及盐度和磷酸盐的可变性呈显著正相关，而与氨和亚硝酸盐以及硝酸盐的可变性呈负相关。根据营养指数（TRIX），除秋季外，湾水几乎全年都被归类为中营养型（中度污染），因为秋季变为富营养型。研究结果表明，环境异质性在海湾中作为浮游植物丰度和生物量的关键结构机制具有重要意义，受到人为活动的影响。
