International Journal of Biology Reports

fa Diversity and abundance of epiphytic diatoms and cyanobacteria as bioindicators in Chabahar Bay, Oman Sea تخصصي Special پژوهشي Research This study investigates the diversity and abundance of epiphytic diatoms and cyanobacteria in Chabahar Bay, emphasizing their role as bioindicators of ecological health. Biodiversity assessments were conducted at six sampling sites during four seasons in 2020-2021. Macroalgal samples were collected, and water samples were analyzed for nutrients, including nitrite, nitrate, phosphate and silicate. Biodiversity in Chabahar Bay varied seasonally. Winter showed the highest diversity (87.22 species, Shannon-Wiener index 4.45, Margalef index 19), followed by summer in abundance (96.22 cells/cm2). Spring peaked at station 3 (82 species, Shannon index 4.38); autumn showed the lowest values (station 2: 47.33 species, 50 cells/cm2). The Simpson index remained stable (~0.98), with a winter peak (0.988). The highest biodiversity was observed in winter. Correlations between biodiversity indices and environmental parameters indicated that lower oxygen levels negatively impacted species diversity, while higher nitrate concentrations were associated with increased taxonomic richness. Gyrosigma consistently scored the highest Indicator Value index values throughout all seasons (averaging >0.20), confirming its role as Chabahar Bay’s primary bioindicator due to its frequent presence and higher abundance compared to other genera. Navicula was the second most important indicator, particularly in spring and autumn (scores 0.16–0.19), while the genera Mastogloia, Nitzschia and Pleurosigma showed weaker associations (scores <0.15), making them less reliable bioindicators. The findings highlight the need for continuous monitoring and conservation efforts to protect diatom taxocoenoses, particularly in the face of environmental stressors, such as declining dissolved oxygen levels and increasing nutrient concentrations. Gyrosigma and Navicula provide valuable tools for assessing water quality and ecosystem health, ensuring the sustainable management of the studied marine ecosystem.   Diatoms, Cyanobacteria, Biodiversity, Bioindicators, Chabahar Bay 167 185 http://injbir.com/browse.php?a_code=A-10-1-35&slc_lang=fa&sid=1 M. Nazari No Department of Animal Sciences and Marine Biology, Faculty of Biological Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran G. Attaran Fariman Yes Department of Marine Biology, Faculty of Marine Sciences, Chabahar Maritime University, Chabahar, Iran Y.B. Okolodkov No Instituto de Ciencias Marinas y Pesquerías (ICIMAP-UV), Universidad Veracruzana, Calle Mar Mediterráneo 314, Fracc. Costa Verde, Boca del Río, 94290, Mexico