Abstract Seasonal distribution and diversity of surface phytoplankton have been studied in relation to anthropogenic activities at seven locations along the coastal waters of Jeddah, Saudi Arabia in 2017. The concentration of nitrite, nitrate, ammonia, phosphate and silicate varied over wide ranges: 0.04–20.27, 0.05–29.3, 0.22–78.16, 0.02–25.90 and 43–24.50 μmol l−1, respectively. Inorganic nutrients, phytoplankton biomass and density were at eutrophic levels at two lagoon locations (4 and 5), while other coastal locations showed oligotrophic characteristics of the Red Sea. Phytoplankton biomass was positively correlated with all measured inorganic nutrients. The total phytoplankton density varied between 52.4 × 103 and 40800 × 103 cells m−3 (average 6249.9×103 ± 10797×103 cells m−3). A total of 174 species of phytoplankton (95 diatoms, 75 dinoflagellates, 3 cyanophytes and 1 silicoflagellates) were recorded in this study, with the dominance of diatoms (95.1%). Higher densities observed at lagoon locations were mainly due to the proliferation of the diatom species Skeletonema costatum and Chaetoceros decipiens. In terms of diversity, dinoflagellates were more numerous than diatoms in July, otherwise mostly diatoms dominated. On the other hand, cyanophytes were more abundant in November. Based on the present study, anthropogenic activities (especially sewage effluent) in Jeddah coastal waters had a significant impact on the phytoplankton densities and diversity.

中文翻译：

---

微浮游植物的分布和群落结构与红海中部吉达沿海水域不断增加的人为影响有关

摘要 2017 年在沙特阿拉伯吉达沿海七个地点研究了与人为活动相关的地表浮游植物的季节性分布和多样性。亚硝酸盐、硝酸盐、氨、磷酸盐和硅酸盐的浓度变化范围很广：0.04–分别为 20.27、0.05-29.3、0.22-78.16、0.02-25.90 和 43-24.50 μmol l-1。无机养分、浮游植物生物量和密度在两个泻湖位置（4 和 5）处于富营养水平，而其他沿海位置则显示出红海的贫营养特征。浮游植物生物量与所有测量的无机养分呈正相关。总浮游植物密度在 52.4 × 103 和 40800 × 103 个细胞 m-3 之间变化（平均 6249.9×103 ± 10797×103 个细胞 m-3）。浮游植物共174种（硅藻95种，本研究共记录到 75 种鞭毛藻、3 种蓝藻和 1 种硅鞭毛虫，其中硅藻占优势（95.1%）。在泻湖位置观察到的较高密度主要是由于硅藻种类 Skeletonema costatum 和 Chaetoceros decipiens 的增殖。在多样性方面，7月份甲藻比硅藻多，否则以硅藻为主。另一方面，11 月的蓝藻更为丰富。根据目前的研究，吉达沿海水域的人为活动（尤其是污水）对浮游植物密度和多样性有显着影响。在泻湖位置观察到的较高密度主要是由于硅藻种类 Skeletonema costatum 和 Chaetoceros decipiens 的增殖。在多样性方面，7月份甲藻比硅藻多，否则以硅藻为主。另一方面，11 月的蓝藻更为丰富。根据目前的研究，吉达沿海水域的人为活动（尤其是污水）对浮游植物密度和多样性有显着影响。在泻湖位置观察到的较高密度主要是由于硅藻种类 Skeletonema costatum 和 Chaetoceros decipiens 的增殖。在多样性方面，7月份甲藻比硅藻多，否则以硅藻为主。另一方面，11 月的蓝藻更为丰富。根据目前的研究，吉达沿海水域的人为活动（尤其是污水）对浮游植物密度和多样性有显着影响。