Spatial and seasonal variations of phytoplankton populations in the upper region of the Euphrates River, Iraq

AbstractThe phytoplankton composition of five selected stations at the upper region of the Euphrates River, Iraq, was studied monthly during 1993. A total of 135 taxa were identified, and 43 species were common at all stations. Diatoms were the dominant group (65.2%), followed by green (12.5%) and blue-green algae (8.9%). More than 37% of the identified species belong to the three genera Nitzschia, Cymbella and Scenedesmus. Nine species were newly recorded for the Iraqi flora. The total cell numbers ranged between 0.25 × 106 − 45.82 × 106 cells/l. Highest cell numbers were found at the most northerly station. Cell counts were dominated by diatoms (77.1%) with two peaks during spring and autumn seasons. The seasonal variations of the dominant species were discussed